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The CpG island methylator phenotype (CIMP), important for carcinogenesis, is a predictor of prognosis and chemotherapy sensitivity in colorectal cancer (CRC). However, there is a lack of consensus on CIMP markers, and thus, more comprehensive methylation markers are required to reliably predict the clinical outcomes. This study aimed to clarify the effects of genome-wide DNA methylation status on clinical outcomes in patients with metastatic CRC (mCRC) treated with epidermal growth factor receptor (EGFR) inhibitors.We enrolled 241 patients with mCRC, who received chemotherapy plus EGFR inhibitors as a first-line treatment. We analyzed the incidence and clinicopathological characteristics of highly methylated CRC (HMCC) and associations between genome-wide DNA methylation status and response rate (RR), progression-free survival (PFS), and overall survival (OS).In total, 169 patients were included in the final analyses. The frequency of HMCC was 8.9% (15/169). The characteristics of patients with HMCC included right-sided primary tumor location (P = 0.042), undifferentiated histology (P = 0.047), and BRAF V600E mutation (P 0.0001). Patients with HMCC showed worse clinical outcomes than those with low-methylated CRC in terms of RR (P = 0.017), PFS (P = 0.004), and OS (P = 0.019). In the multivariate analysis, peritoneal metastasis (P = 0.017), methylation status (P = 0.037), and BRAF V600E mutations (P = 0.0001) were independent factors for shorter PFS.Genome-wide DNA methylation status is an independent factor associated with PFS in patients with mCRC treated with first-line EGFR inhibitors.

Purpose The current study aimed to determine the efficacy of trifluridine/tipiracil for elderly patients with advanced colorectal cancer. Methods This single-arm, open-label, multicenter, phase II study included elderly patients aged 65 years or more who had fluoropyrimidine-refractory advanced colorectal cancer and received trifluridine/tipiracil (70 mg/m2, days 1–5 and 8–12, every 4 weeks). The primary endpoint was progression-free survival (PFS), while secondary endpoints included overall survival (OS), overall response rate (ORR), toxicities, association between efficacy and geriatric assessment scores, and association between toxicity and plasma drug concentrations. Results A total of 30 patients with a mean age of 73 years were enrolled. Median PFS was 2.3 months (95% confidence interval, 1.9–4.3 months), while median OS was 5.7 months (95% confidence interval, 3.7–8.9 months). Patients had an ORR of 0%, with 57% having stable disease. Grade 4 neutropenia was observed in 13% of the patients. Patients with a higher G8 score (15 or more) showed longer PFS than those with a lower G8 score (median 4.6 vs. 2.0 months; p = 0.047). Moreover, patients with grade 3 or 4 neutropenia showed higher maximum trifluridine concentrations than those with grade 1 or 2 neutropenia (mean 2945 vs. 2107 ng/mL; p = 0.036). Discussion The current phase II trial demonstrated that trifluridine/tipiracil was an effective and well-tolerated option for elderly patients with advanced colorectal cancer. Moreover, geriatric assessment tools and/or plasma drug concentration monitoring might be helpful in predicting the efficacy and toxicities in elderly patients receiving this drug. Trial registration number UMIN000017589, 15/May/2015 (The University Hospital Medical Information Network)

Whether trastuzumab use beyond disease progression is beneficial in second-line treatment for patients with unresectable human epidermal growth factor receptor 2 (HER2)-positive gastric cancer remains to be elucidated. We conducted this phase II study to assess whether trastuzumab plus docetaxel was effective for patients with previously treated advanced HER2-positive gastric cancer. This trial was a single-arm, open-label, multicenter, phase II study, conducted by Tohoku Clinical Oncology Research and Education Society (T-CORE). Patients aged 20 years or older who had advanced HER2-positive gastric cancer and were refractory to trastuzumab, fluoropyrimidine, and cisplatin were enrolled. Patients were treated with 6 mg/kg trastuzumab and 60 mg/m2 docetaxel every 3 weeks. The primary endpoint was the overall response rate. The threshold overall response rate was estimated to be at 15%. Secondary endpoints were progression-free survival, 6-month survival rate, overall survival, and toxicities. A total of 27 patients were enrolled from 7 hospitals. The median age was 67 years. Partial response was seen in 3 patients among the 26 evaluated patients. The overall response rate was at 11.5% (90% confidence interval 1.2%-21.8%). The median progression-free survival was 3.2 months, the 6-month survival rate was 85%, and the median overall survival was 11.6 months. Febrile neutropenia was observed in 14.8%. The most frequently observed grade 3 non-hematologic toxicity was anorexia (14.8%). The primary endpoint was not achieved. The results support a current consensus that the continuation of trastuzumab in second-line therapy for gastric cancer is not a recommended option.

The cetuximab gene expression signature and DNA methylation status of colorectal cancer (CRC) are predictive of the therapeutic effects of anti-epidermal growth factor receptor (EGFR) antibody therapy. As DNA methylation is a means of regulating gene expression, it may play an important role in the expression of cetuximab signature genes. This study aims to determine the effects of aberrant DNA methylation on the regulation of cetuximab signature gene expression. Comprehensive DNA methylation and gene expression data were retrieved from CRC patients in three tumor tissue (TT) cohorts and three normal colorectal mucosa/tumor tissue paired (NCM-TT) cohorts. Of the 231 cetuximab signature genes, 57 exhibited an inverse correlation between the methylation of promoter CpG sites and gene expression level in multiple cohorts. About two-thirds of the promoter CpG sites associated with the 57 genes exhibited this correlation. In all 57 gene promoter regions, the methylation levels in NCMs did not differ according to comparisons based on cetuximab signature or DNA methylation status classification of matched TTs. Thus, the altered expression of 57 genes was caused by aberrant DNA methylation during carcinogenesis. Analysis of the association between cetuximab signature or DNA methylation status and progression-free survival (PFS) of anti-EGFR antibody agents in the same cohort showed that DNA methylation status was most associated with PFS. In conclusion, we found that aberrant DNA methylation regulates specific gene expression in cetuximab signature during carcinogenesis, suggesting that it is one of the important determinants of sensitivity to anti-EGFR antibody agents.

206 Background: The ’’Neo RAS’’ phenomenon, in which tissue rat sarcoma viral oncogene homolog ( RAS) status converts from mutant (MT) to wild-type (WT) after treatment in metastatic colorectal cancer (mCRC), is gaining attention because epidermal growth factor receptor (EGFR) inhibitors, which were originally considered to be ineffective, may converted to be effective. This multi-center study investigated its incidence and clinicopathological characteristics that are still unclear. Methods: 107 mCRC patients with tissue RAS MT, confirmed using MEBGEN RASKET-B, who were refractory or intolerant to previous chemotherapies, including fluoropyrimidines, oxaliplatin, or irinotecan were enrolled in 4 institutions from June 2021 to August 2022. The RAS status in ctDNA was investigated after prior chemotherapy using ONCOBEAMTM RAC CRC. Clinicopathological characteristics were compared between patients with RAS MT and RAS WT (Neo RAS) in ctDNA. Results: The incidence of Neo RAS WT mCRC was 21.5% (23/107). The frequency of Neo RAS in KRAS exon 2 was significantly lower than that in other alleles such as exon 3 and 4 or NRAS (18.2% [18/99] vs 62.5% [5/8], P = 0.011). There were significant differences in frequency of Neo RAS between male vs female (30.6% [19/62] vs 8.9% [4/45], P = 0.008), absence vs presence of liver metastasis (38.6% [17/44] vs 9.5% [6/63], P < 0.001), and between two groups divided at the median: tumor diameter (> 60.9 mm vs ≤, 3.8% [2/53] vs 38.9% [21/54], P < 0.001), carcinoembryonic antigen level (> 38.2 ng/ml vs ≤, 11.3% [6/53] vs 31.5% [17/54], P = 0.018), carbohydrate antigen 19-9 level (> 158.0 U/ml vs ≤, 9.4% [5/53] vs 33.3% [18/54], P = 0.004). Logistic regression multivariate analysis, absence of liver metastasis (Odds ratio [OR], 4.62; P = 0.019), smaller tumor diameter (OR, 7.92; P = 0.012) and tissue RAS MT in other than KRAS exon 2 (OR, 9.04; P = 0.026) were significantly related to the appearance of Neo RAS WT mCRC. Conclusions: Original RAS status in tissue, tumor diameter and liver metastasis are related to conversion to Neo RAS WT mCRC.

533 Background: Patients with advanced biliary tract cancer (BTC) have a poor prognosis, and high unmet medical needs still exist for the treatment of this disease. Nivolumab has shown its effectiveness against multiple cancer types, especially those with PD-L1 expression. This study assessed the efficacy and safety of nivolumab in BTC patients with a combined positive score (CPS) ≥ 1 who were refractory or intolerant to the standard of care (SOC): gemcitabine, cisplatin and tegafur/gimeracil/oteracil (S-1). Methods: This was a single-arm, multicenter, open-label, prospective phase II study. Key eligibility criteria were as follows: having unresectable or recurrent BTC (intrahepatic bile duct cancer, extrahepatic bile duct cancer, gallbladder cancer, or ampullary cancer); being refractory or intolerant to SOC; having adequate hepatic, renal and hematological function; and having a CPS ≥ 1 in central assessment. Patients received nivolumab (480 mg, every 4 weeks) until disease progression, clinical deterioration, or unacceptable toxicity. The primary endpoint was objective response rate (ORR) assessed by the central review according to RECIST 1.1. The secondary endpoints included overall survival (OS), progression-free survival (PFS), and safety. Results: A total of 84 patients were enrolled between Mar 11, 2020 and Mar 15, 2021, of them 12 received one regimen and 72 received two or more regimens. The median follow-up period was 6.90 months. ORR per central assessment was 10.7% (CR: 3.6%, PR: 7.1%), and ORR per investigator assessment was 15.5% (CR: 2.4%, PR: 13.1%). The median PFS per central and investigator assessment was 1.02 (95% CI 0.95–1.77) months and 2.48 (95% CI 1.87–2.83) months, respectively. The median OS was 6.90 (95% CI 5.26–9.20) months. The median duration of response per central and investigator assessment was not reached (range 2.8–13.0+) and 10.15 (range 2.0–12.8+) months, respectively. The 1-year survival rate was 25.3% (95% CI 15.4–36.4). The most frequent treatment-related adverse events were pyrexia (19.0%), pruritus (16.7%), and decreased appetite (13.1%). Conclusions: Nivolumab may have some activity with a durable response and a manageable safety profile in heavily treated BTC patients with CPS ≥ 1. Clinical trial information: JapicCTI-205097 .

DNA methylation status correlates with clinical outcomes of anti-epidermal growth factor receptor (EGFR) treatment. There is a strong need to develop a simple assay for measuring DNA methylation status for the clinical application of drug selection based on it. In this study, we collected data from 186 patients with metastatic colorectal cancer (mCRC) who had previously received anti-EGFR treatment. We modified MethyLite to develop a novel assay to classify patients as having highly methylated colorectal cancer (HMCC) or low-methylated colorectal cancer (LMCC) based on the methylation status of 16 CpG sites of tumor-derived genomic DNA in the development cohort (n = 30). Clinical outcomes were then compared between the HMCC and LMCC groups in the validation cohort (n = 156). The results showed that HMCC had a significantly worse response rate (4.2% vs 33.3%; P = .004), progression-free survival (median: 2.5 vs 6.6 mo, P .001, hazard ratio [HR] = 0.22), and overall survival (median: 5.6 vs 15.5 mo, P .001, HR = 0.23) than did LMCC in patients with RAS wild-type mCRC who were refractory or intolerable to oxaliplatin- and irinotecan-based chemotherapy (n = 101). The DNA methylation status was an independent predictive factor and a more accurate biomarker than was the primary site of anti-EGFR treatment. In conclusion, our novel DNA methylation measurement assay based on MethyLight was simple and useful, suggesting its implementation as a complementary diagnostic tool in a clinical setting.

Background Pseudomyxoma peritonei (PMP) is a rare malignancy, and there is insufficient evidence about systemic chemotherapy for this disease. Methods We retrospectively evaluated the efficacy and safety of a chemotherapeutic regimen with 5-fluorouracil and oxaliplatin (modified FOLFOX6, mFOLFOX6) for patients with unresectable pseudomyxoma peritonei. Patients who received the therapy between April 2000 and February 2019 at the Department of Medical Oncology, Tohoku University Hospital, were enrolled in this study. Results Eight patients were treated with mFOLFOX6. The sites of primary tumor were appendix in six patients, ovary in a patient, and urachus in a patient. Six patients received surgery. Seven patients had histologically high-grade PMP, and one patient had low-grade PMP. The median follow-up duration was 27.2 months. All the patients had non-measurable regions as the targets of tumor response. Non-complete response or non-progressive disease was observed in seven patients, with a disease control rate of 87.5%. The median progression-free survival and overall survival were 13.0 months and 27.9 months, respectively. An obvious reduction in the symptoms was observed in two patients. Five patients experienced decline in the serum tumor markers, CEA or CA19-9. The grade 3/4 toxicity that was observed was grade 4 neutropenia in one patient and grade 3 neutropenia in two patients. Conclusions mFOLFOX6 might be an effective and tolerable treatment option for patients with unresectable PMP. To our knowledge, this is the first case series of mFOLFOX6 in patients with unresectable PMP and the first case series of systemic chemotherapy for Asian patients with unresectable PMP.

Oxaliplatin (OX) and irinotecan (IRI) are used as key drugs for the first‐line treatment of metastatic colorectal cancer (mCRC). However, no biomarkers have been identified to decide which of the drugs is initially used. In this translational research (TR) of the TRICOLORE trial, the advanced colorectal cancer subtype (aCRCS) was analyzed as a potential biomarker for the selection of OX or IRI. We collected 335 (68.8%) formalin‐fixed, paraffin‐embedded (FFPE) primary tumor specimens from 487 patients registered in the TRICOLORE trial and performed direct sequencing and immunohistochemical staining of CRC‐related genes, comprehensive gene‐expression analysis, and genome‐wide methylation analysis. The progression‐free survival (PFS) of the IRI group was significantly better compared with the OX group in BRAF wild‐type (WT), PTEN‐positive, and aCRCS A1 patients. Among the molecular factors, aCRCS were only associated with the PFS of OX and IRI groups. The PFS of the IRI group was significantly better compared with the OX group in aCRCS A1 + B1 (hazard ratio [HR] = 0.58; 95% confidence interval [CI] = 0.41‐0.82; P = .0023). In contrast, the OX group had better PFS compared with the IRI group in aCRCS B2, although this was not statistically significant (HR = 1.66; 95% CI = 0.94‐2.96; P = .083). Nearly half of patients with mCRC (46.8%, aCRCS A1 + B1) respond well to IRI, while only about 18.5% (aCRCS B2) of patients with mCRC responded well to OX. In conclusion, the aCRCS might be a predictive factor for the clinical outcomes of OX‐based and IRI‐based therapies., From translational research of TRICOLORE trail, the advanced colorectal cancer subtypes (aCRCS) can help to select oxaliplatin‐based or irinotecan‐based therapy for first‐line metastatic colorectal cancer treatment.

3528 Background: The CpG island methylator phenotype (CIMP), important for carcinogenesis, is a predictor of prognosis and chemotherapy sensitivity in colorectal cancer. However, there is a lack of consensus of CIMP markers, and thus, more comprehensive methylation markers are required to reliably predict the clinical outcomes. Previously, we reported that genome-wide DNAmethylation statuscould predict the effect of epidermal growth factor receptor (EGFR) inhibitors more accurately than previously reported methylation classifications (Ouchi et al. Cancer Sci 2015). Moreover, we had developed a DNA methylation assay based on MethyLight to reflect genome-wide DNA methylation status and reported its usefulness in predicting prognosis in patients with metastatic colorectal cancer (mCRC) treated with EGFR inhibitors as a third-line chemotherapy (Ouchi et al. Cancer Sci 2022). This study aimed to clarify the effects of genome-wide DNA methylation status on clinical outcomes in patients with mCRC treated with first-line EGFR inhibitors. Methods: We enrolled 241 patients with mCRC, who received chemotherapy plus EGFR inhibitors as a first-line treatment, and analyzed the associations between genome-wide DNA methylation status using a novel comprehensive methylation marker panel and clinical outcomes and evaluated the predictive power and value of the methylation status. Results: Total 169 patients were included in the final analyses. The frequency of highly methylated CRC (HMCC) was 8.9% (15/169). The characteristics of patients with HMCC included right-sided primary tumor location (P = 0.042), undifferentiated histology (P = 0.047), and BRAFV600E mutation (P < 0.001). Patients with HMCC showed worse clinical outcomes than those with low methylated CRC in terms of response rate (P = 0.017), progression-free survival (PFS; P = 0.004), and overall survival (P = 0.019). In the multivariate analysis, peritoneal metastasis (Hazard ratio (HR): 2.24, P = 0.017), methylation status (HR: 3.04, P = 0.037), and BRAFV600E mutations (HR: 5.83, P = 0.0001) were independent factors for shorter PFS. Conclusions: Genome-wide DNA methylation status may be an independent predictor of first-line EGFR inhibitors in patients with mCRC.

The consensus molecular subtypes (CMS) classification is one of the most robust colorectal cancer (CRC) classifications based on comprehensive gene expression profiles. This study aimed to clarify whether the CMS is a predictive factor for therapeutic effects of standard chemotherapies for metastatic CRC (mCRC). We retrospectively enrolled 193 patients with mCRCs, and using comprehensive gene expression data, classified them into 4 subtypes: CMS1-CMS4. The associations between the subtypes and treatment outcomes were analyzed. Regarding first-line chemotherapy, irinotecan (IRI)-based chemotherapy was significantly superior to oxaliplatin (OX)-based chemotherapy for progression-free survival (PFS; hazard ratio [HR] = 0.31, 95% confidence interval [CI] 0.13-0.64) and overall survival (OS; HR = 0.45, 95% CI 0.19-0.99) in CMS4. Regarding the anti-epidermal growth factor receptor (anti-EGFR) therapy, CMS1 showed particularly worse PFS (HR = 2.50, 95% CI 1.31-4.39) and OS (HR = 4.23, 95% CI 1.83-9.04), and CMS2 showed particularly good PFS (HR = 0.67, 95% CI 0.44-1.01) and OS (HR = 0.49, 95% CI 0.27-0.87) compared with the other subtypes. The biological characteristics of CMS may influence the efficacy of chemotherapy. CMS might be a new predictive factor for the efficacy of chemotherapy against mCRCs.

Background Recombinant human soluble thrombomodulin (rTM) has been established and introduced in the clinic as a standard treatment for disseminated intravascular coagulation (DIC). However, the efficacy and safety of rTM for DIC associated with solid tumors (DIC-STs) have not been fully established. Here, we performed a retrospective analysis of the clinical outcomes of rTM for DIC-STs and considered a treatment strategy with rTM for DIC-STs. Methods Patients with DIC-STs between November 2009 and March 2016 in 2 cancer core hospitals were retrospectively analyzed. Data, including patient background, treatment course, and clinical outcomes of rTM for DIC-STs, were extracted. The clinical outcomes were evaluated by comparing the DIC score, resolution rate, and overall survival (OS) duration. Results The study included 123 patients with DIC-STs. The median OS in all patients was 41 days. The DIC resolution rate was 35.2%. DIC scores and DIC-related blood test data (fibrin degradation product and prothrombin time-international normalized ratio) significantly improved at the end of rTM administration (P

The combinations of oral fluoropyrimidines and cisplatin such as capecitabine and cisplatin (XP) or S-1 and cisplatin (SP) are regarded as a standard therapy against unresectable, recurrent, or advanced gastric cancer (AGC). Especially, SP is the most common regimen against AGC in Japan. For patients with human epidermal growth factor receptor type 2 (HER2)-positive AGC, trastuzumab, a monoclonal antibody targeting HER2 antibody, is additionally used in combination. Although trastuzumab in combination with XP (trastuzumab-XP) have been widely accepted, the efficacy of trastuzumab in combination with SP (trastuzumab-SP) lacks sufficient verification. The aim of the present study is to validate the comparability of trastuzumab-SP to trastuzumab-XP. Patients with HER2-positive AGC were assigned to the trastuzumab-XP or trastuzumab-SP group. We then retrospectively compared the efficacy and safety between both groups. As a first-line chemotherapy, trastuzumab in combination with XP or SP was administered to 58 patients: 28 with trastuzumab-XP and 30 with trastuzumab-SP. In the trastuzumab-XP group, response rate (RR), disease control rate (DCR), median progression-free survival (mPFS), and median overall survival (mOS) were 39.3%, 89.3%, 7.9 months, and 20.0 months, respectively. In the trastuzumab-SP group, RR, DCR, mPFS and mOS were 50.0%, 86.7%, 6.9 months, and 16.7 months, respectively. No significant difference in efficacy was observed between both groups. Severe hand-foot syndrome was observed more frequently in the trastuzumab-XP group than in the trastuzumab-SP group (14.3% vs. 0%, p = 0.05). Trastuzumab in combination with SP is a potential first-line therapeutic option for patients with HER2-positive AGC.

Background. Oxaliplatin and irinotecan are generally used to treat advanced colorectal cancer (CRC) patients. Antibiotics improve the cytotoxicity of oxaliplatin but not irinotecan in a colon cancer cell line in vitro. This study retrospectively assessed whether antibiotics improve the treatment efficacy of oxaliplatin- but not irinotecan-based therapy in advanced CRC patients. Patients and Methods. The medical records of 220 advanced CRC patients who underwent oxaliplatin- or irinotecan-based therapy were retrospectively reviewed. The oxaliplatin and irinotecan groups were further divided into antibiotic-treated (group 1) and antibiotic-untreated (group 2) subgroups. Results. In oxaliplatin groups 1 and 2, the response rate (RR) was 58.2% and 30.2%, while the disease control rate (DCR) was 92.5% and 64.2%, respectively; the median progression-free survival (PFS) was 10.5 months (95% confidence interval (CI) = 7.5–12.2) and 7.0 months (95% CI = 17.0–26.0), respectively, and the median overall survival (OS) was 23.8 months (95% CI = 5.1–9.1) and 17.4 months (95% CI = 13.1–24.9), respectively. In irinotecan groups 1 and 2, the RR was 17.8% and 20.0%, while the DCR was 75.6% and 69.1%, respectively; the median PFS was 8.2 months (95% CI = 6.2–12.7) and 7.9 months (95% CI = 12.0–23.0), respectively, and the median OS was 16.8 months (95% CI = 5.9–10.6) and 13.1 months (95% CI = 10.4–23.7), respectively. Conclusion. To improve the treatment efficacy of oxaliplatin-based therapy in advanced CRC patients, adding antibiotics is a potential therapeutic option.

The antibodies targeting programmed death 1 (PD-1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) have provided survival benefits in patients with advanced malignant melanoma. The anti-PD-1 antibodies nivolumab and pembrolizumab are considered superior to the anti-CTLA-4 antibody ipilimumab as first-line therapy, suggesting that ipilimumab should be administered to patients with anti-PD-1 antibody-refractory melanoma in the second-line setting. However, there is limited evidence regarding the efficacy and safety of ipilimumab after disease progression on anti-PD-1 antibody therapy. Moreover, in patients with mucosal melanoma, a rare and aggressive subtype, evidence is extremely poor. This study aimed to clarify the efficacy and safety of ipilimumab among Japanese patients with nivolumab-refractory advanced mucosal melanoma. We retrospectively analyzed the seven patients with advanced mucosal melanoma who were treated with ipilimumab after disease progression on nivolumab at our hospital between September 2015 and December 2017. No patient achieved complete response or partial response to ipilimumab therapy. However, six patients achieved stable disease, and of these patients, three achieved a decline in the tumor size. All the three patients with a decline in tumor size developed grade 3 toxicity: two patients developed colitis and one patient experienced alanine aminotransferase elevation. The median progression-free survival (PFS) for prior nivolumab therapy was 148 days. The median PFS for ipilimumab therapy after disease progression with nivolumab was 193 days. The median overall survival was 661 days. In conclusion, although even partial response was undetectable with ipilimumab therapy, ipilimumab could produce additional PFS among nivolumab-refractory advanced mucosal melanoma patients.

The CpG island methylator phenotype (CIMP) with multiple promoter methylated loci has been observed in a subset of human colorectal cancer (CRC) cases. CIMP status, which is closely associated with specific clinicopathological and molecular characteristics, is considered a potential predictive biomarker for efficacy of cancer treatment. However, the relationship between the effect of standard chemotherapy, including cytotoxic drugs and anti-epidermal growth factor receptor (EGFR) antibodies, and CIMP status has not been elucidated.In 125 metastatic colorectal cancer (mCRC) patients, we investigated how clinical outcome of chemotherapy was related to CIMP status as detected by methylation-specific PCR (MSP) and to genetic status in five EGFR-related genes (KRAS, BRAF, PIK3CA, NRAS, and AKT1) as detected by direct sequencing.CIMP-positive status was significantly associated with proximal tumor location and peritoneum metastasis (all P values0.05). The progression-free survival of patients with CIMP-positive tumors receiving sequential therapy with FOLFOX as the first-line treatment followed by irinotecan-based therapy as the second-line treatment (median = 6.6 months) was inferior to that of such patients receiving the reverse sequence (median = 15.2 months; P = 0.043). Furthermore, CIMP-positive tumors showed higher mutation frequencies for the five EGFR-related genes (74.1 %) than the CIMP-negative tumors did (50.0 %). Among the KRAS wild-type tumors, CIMP-positive tumors were associated with a worse clinical outcome than CIMP-negative tumors following anti-EGFR antibody therapy.Sequential FOLFOX followed by an irinotecan-based regimen is unfavorable in patients with CIMP-positive tumors. High frequencies of mutation in EGFR-related genes in CIMP-positive tumors may cause the lower response to anti-EGFR antibody therapy seen in patients with wild-type KRAS and CIMP-positive tumors.

169 Background: The TRICOLORE trial previously demonstrated that S-1+IRI+Bmab (Arm B) was non-inferior to mFOLFOX6/CapeOX+Bmab (Arm A) in terms of progression-free survival (PFS) as first-line treatment for mCRC, irrespective of RAS status. CMS was reported to be a prognostic factor for mCRC. Previously, it was reported that the CMS could be a predictive factor for the efficacy of oxaliplatin (OX) and IRI (Okita A, et al. Oncotarget. 2018). In this exploratory study of TRICOLORE trial, we examined if the CMS could be a predictive factor of OX and IRI regimen. Methods: We collected formalin-fixed paraffin-embedded (FFPE) primary tumor tissues and performed gene expression analysis by microarray. The subtype of CMS was determined by the CMS classifier (Guinney et al. Nature Med. 2015). PFS and overall survival (OS) were compared between arm A and B in each subtypes of CMS. Results: Total of 308 FFPE samples from 487 cases who were enrolled in the TRICOLORE study were collected. Number of patients classified into CMS1 to CMS4 were 47, 72, 99 and 90, respectively. Similar to the previous reports, the proportion of RAS mutant cases was highest in CMS3 and the most of BRAF mutant cases were classified into CMS1. The median PFS (mPFS) of arm A and B were almost same in CMS2 (16.1m vs. 17.6m, HR = 1.10, p = 0.79) and CMS3 (10.6 vs. 11.4, HR = 0.95, p = 0.81). In CMS1, mPFS of arm A was worse than that of arm B, although not statistically significant (7.4m vs. 13.2m, HR = 0.73, p = 0.35). In CMS4, mPFS of arm B was better than that of arm A, although not statistically significant again (9.7m vs. 14.1m, HR = 0.72, p = 0.15). The median OS (mOS) of both arm in CMS2-CMS4 and arm B in CMS1 were good and were 29.0m or more. On the other hand, mOS of arm A in CMS1 (18.1m) was worse than the others. Conclusions: From these results, it was not concluded that CMS was a predictor of mFOLFOX6/CapeOX+Bmab and S-1+IRI+Bmab. However, mPFS and mOS of mFOLFOX6/CapeOX+Bmab in CMS1 were poor unlike other CMS subtypes, and these were consistent with a previous report. Whereas S-1+IRI+Bmab was effective in all subtypes of CMS. Clinical trial information: UMIN000007834.

Anti‐epidermal growth factor receptor (EGFR) treatment is an effective option for metastatic colorectal cancer (CRC) treatment. However, there are few reliable biomarkers to predict the clinical response to anti‐EGFR treatment. We investigated the genome‐wide DNA methylation status in metastatic colorectal cancer to identify associations between the methylation status and clinical response to anti‐EGFR antibody. We retrospectively reviewed the medical records of 97 patients (45 patients for the first cohort and 52 patients for the second cohort) who received anti‐EGFR treatment for KRAS wild‐type metastatic CRC. Then we analyzed the associations between genome‐wide DNA methylation status and clinical response to anti‐EGFR treatment, and evaluated the predictive power and value of the methylation status statistically. As a result, each cohort was classified into highly methylated CRC and low methylated CRC subgroups by unsupervised clustering analyses. In the first cohort, clinical outcomes were significantly better in the low methylated CRC subgroup than in the highly methylated CRC subgroup (response rate, 35.7% vs 6.3%, P = 0.03; disease control rate, 75% vs 31.3%, P = 0.005; hazard ratio for progression‐free survival, 0.27; 95% confidence interval, 0.13–0.57, P

Background Some elderly cancer patients, even with good Eastern Cooperative Oncology Group performance status (ECOG-PS), have poor survival outcomes and cannot tolerate standard therapy. Few studies have detailed the associations between the G8 screening tool, ECOG-PS, and overall survival (OS) in such patients. Methods Cancer patients, aged 70 years or older, were assessed for G8 and classified into three groups according to their G8 score: 14 as the high score group. We retrospectively analyzed the association between G8 score and OS in all patients and for each ECOG-PS-categorized group. Results Out of 264 enrolled patients, most patients (87%) with solid tumor were categorized as TNM stage IV. ECOG-PS was 0 or 1 in 215 patients and ≥2 in 48; there was missing data for one patient. Among all patients, the low score group with a median OS of 7.7 months survived significantly less than both the high score group with a median OS of 25.6 months [Hazard ratio (HR) 3.48; 95% confidence interval (CI), 1.96–6.63; p < 0.0001] and the intermediate score group with a median of 15.6 months (HR 1.83; 95% CI, 1.28–2.65; p < 0.001). In the multivariate analysis, TNM stage and G8 score were independent prognostic factors for OS. When patients with an ECOG-PS of 0 or 1 were analyzed, patients with a lower G8 score showed significantly shorter OS than patients with a higher score when any two groups were compared. Conclusion This novel classification of the G8 score contributes to prompt identification of patients with poor prognosis and improved the prognostic value of ECOG-PS. Using G8 with ECOG-PS may be helpful in deciding treatment for elderly patients with advanced cancer.

Background Anti-EGFR antibody is one of the options for treatment of RAS wild-type metastatic colorectal cancer (mCRC), especially when the primary tumor site locates in the left sided large intestine. We have shown that methylation status evaluated by genome-wide DNA methylation test correlates with clinical outcomes of anti-EGFR treatment in RAS wild-type mCRC. Here, we report about the development of novel in vitro diagnostics (IVD) based on DNA methylation status of selected CpG sites. Method We retrospectively collected KRAS wild-type mCRC cases who received anti-EGFR treatment in salvage line. DNA methylation status was measured for 16 CpG sites by our novel IVD using real-time PCR method for each case. Based on DNA methylation status, they were classified into 2 groups. Highly-methylated colorectal cancer (HMCC) was defined when 8 or more sites among 16 sites were methylated and low-methylated colorectal cancer (LMCC) was classified when it was less than 8 sites. We compared the clinical outcomes between the 2 groups, and the predictive accuracy of the DNA methylation status by the new diagnostic method was examined. Results A total of 83 cases were collected, with 20 cases classified as HMCC and 63 cases classified as LMCC. The response rate of the anti-EGFR treatment was 5.0% (1/20 cases) in HMCC and 30.2% (19/63 cases) in LMCC, respectively (p = 0.032). The median progression-free survival were 2.8 months and 5.3 months, respectively (p Conclusion DNA methylation status of the 16 CpG sites measured by our novel IVD was significantly correlated with the therapeutic effect of anti-EGFR treatment for KRAS wild-type mCRC. Currently, extended analysis is in progress using the data of more than 200 cases. We will report the results including the analysis of RAS status and primary tumor site.

We present the case of a 68-year-old woman who presented with a swelling on the left side of her lower jaw. Biopsy revealed neuroendocrine carcinoma of the mandible. Chemoradiotherapy with carboplatin and etoposide with local irradiation induced very rapid remission of the tumor. The massive tumor remission caused severe exacerbation of symptoms, including fatigue and muscle weakness. Her condition was diagnosed as paraneoplastic neurological syndrome with generalized peripheral nerve paralysis and respiratory failure. The syndrome was thought to be triggered by an accelerated immune reaction against the tumor, which attacked neurons with similar antigens to the tumor. The immune attack resulted in overt neurological disturbance that was not well recognized at the time of tumor diagnosis.

736 Background: Since treatment options of chemotherapy for metastatic colorectal cancer (mCRC) have been diversified, biomarkers which could predict efficacy of chemotherapies are needed for optimal treatment. In this study, we analyzed the association of the treatment outcomes by several chemotherapies and the consensus molecular subtypes (CMS), which was developed from large-scale comprehensive gene expression analysis of colorectal cancer (Guinney J et al. Nat Med 21:1350-6, 2015). Methods: A total of 193 patients with previously treated mCRC were classified in 4 subtypes, CMS1 to CMS4 by using the microarrays data of primary tumors and the “CMS classifier” package for the R software. Then the association between the subtypes and the treatment outcomes was analyzed retrospectively. Results: The193 cases were classified into 21 CMS1, 53 CMS2, 69 CMS3 and 50 CMS4. The molecular characteristics of each subtype such as mutation status of KRAS and BRAF genes, and DNA methylation status were consistent with those of the previous study. First-line chemotherapies of the 193 patients were oxaliplatin (OX)-based treatment (121 patients), irinotecan (IRI)-based treatment (59 patients) and others (13 patients). In CMS4, the median progression-free survival (PFS) of the IRI-based group was significantly longer than that of the OX-based group (21.8 months vs. 10.5 months, p < 0.01). The median overall survival (OS) and objective response rate of the IRI-based group were also better than that of the OX-based group in CMS4. Among 193 patients, 103 were RAS wild-type and treated with anti-EGFR antibody. The effect of the anti-EGFR treatment was low in CMS1 (median PFS: 2.4 months, p < 0.01, median OS: 5.7 months, p < 0.01) and whereas was high in CMS2 (median PFS: 8.0 months, p = 0.05, median OS: 26.6 months, p = 0.02). CMS significantly correlated with PFS and OS after anti-EGFR treatment by univariate analysis. However the most useful predictive biomarker was a DNA methylation status by multivariable analysis. Conclusions: The biological characteristics of CMS may affect the therapeutic effect of anti-cancer agents in mCRC and, therefore, might be a new predictive factor of anti-cancer treatment.

OUCHI, K., TAKEDA, K. and MATSUNO, S. Efficacy of Patient-Controlled Analgesia for Management of Pain after Abdominal Operations. Tohoku J. Exp. Med., 1991, 165 (3), 193-199-In order to control pain during the early postoperative period, patient-controlled analgesia (PCA) with buprenorphine as an analgesic drug was applied in 23 patients undergoing abdominal operations. With this “on demand” system, the patient was allowed to self-administer narcotic analgesic medication using a programmable infusion pump. Overdose could be minimized with a mandatory lock-out interval between allowable injections. Average total requirement of buprenorphine was 0.355mg at 48hr after operation. Nineteen of the 23 (82.6%) patients characterized their pain control as “excellent” or “good”. In these patients there existed high correlation between the total number of patient attempts and the number of successful injections. The PCA system was thought to provide improved pain relief at smaller total drug dosages. In addition, earlier and greater spontaneous physical activity was maintained with PCA therapy. The potential for overdose could be minimized, and thereby PCA appears to be an efficacious and safe method of providing for postoperative pain relief.

e14574 Background: For metastatic colorectal cancer (mCRC) treatment, anti-epidermal growth factor receptor (EGFR) treatment is one of the major options. However, there are few reliable biomarkers ...