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Purpose: Clinical trials are expensive and lengthy, where success of a given trial depends on observing a prospectively defined number of patient events required to answer the clinical question. The point at which this analysis time occurs depends on both patient accrual and primary event rates, which typically vary throughout the trial's duration. We demonstrate real-time analysis date projections using data from a collection of six clinical trials that are part of the IDEA collaboration, an international preplanned pooling of data from six trials testing the duration of adjuvant chemotherapy in stage III colon cancer, and we additionally consider the hypothetical impact of one trial's early termination of follow-up.

Background: Disease-free survival (DFS) with a 3-year median follow-up (3-year DFS) was validated as a surrogate for overall survival (OS) with a 5-year median follow-up (5-year OS) in adjuvant chemotherapy colon cancer (CC) trials. Recent data show further improvements in OS and survival after recurrence in patients who received adjuvant FOLFOX. Hence, reevaluation of the association between DFS and OS and determination of the optimal follow-up duration of OS to aid its utility in future adjuvant trials are needed.Methods: Individual patient data from 9 randomized studies conducted between 1998 and 2009 were included; 3 trials tested biologics. Trial-level surrogacy examining the correlation of treatment effect estimates of 3-year DFS with 5 to 6.5-year OS was evaluated using both linear regression (RWLS2) and Copula bivariate (RCopula2) models and reported with 95% confidence intervals (CIs). For R2, a value closer to 1 indicates a stronger correlation.Results: Data from a total of 18 396 patients were analyzed (median age = 59 years; 54.0% male), with 54.1% having low-risk tumors (T1-3 and N1), 31.6% KRAS mutated, 12.3% BRAF mutated, and 12.4% microsatellite instability high or deficient mismatch repair tumors. Trial-level correlation between 3-year DFS and 5-year OS remained strong (RWLS2 = 0.82, 95% CI = 0.67 to 0.98; RCopula2 = 0.92, 95% CI = 0.83 to 1.00) and increased as the median follow-up of OS extended. Analyses limited to trials that tested biologics showed consistent results.Conclusions: Three-year DFS remains a validated surrogate endpoint for 5-year OS in adjuvant CC trials. The correlation was likely strengthened with 6 years of follow-up for OS. [ABSTRACT FROM AUTHOR]

Background: Adjuvant chemotherapy is a standard treatment option for patients with stage III and high-risk stage II colon cancer. Sex is one of several factors responsible for the wide inter-patient variability in drug responses. Amalgamated data on the effect of sex on the toxicity of current standard adjuvant treatment for colorectal cancer are missing.Methods: The objective of our study was to compare incidence and severity of major toxicities of fluoropyrimidine- (5FU or capecitabine) based adjuvant chemotherapy, with or without oxaliplatin, between male and female patients after curative surgery for colon cancer. Adult patients enrolled in 27 relevant randomized trials included in the ACCENT (Adjuvant Colon Cancer End Points) database, a large, multi-group, international data repository containing individual patient data, were included. Comparisons were conducted using logistic regression models (stratified by study and treatment arm) within each type of adjuvant chemotherapy (5FU, FOLFOX, capecitabine, CAPOX, and FOLFIRI). The following major toxicities were compared (grade III or IV and grade I-IV, according to National Cancer Institute Common Terminology Criteria [NCI-CTC] criteria, regardless of attribution): nausea, vomiting, nausea or vomiting, stomatitis, diarrhea, leukopenia, neutropenia, thrombocytopenia, anemia, and neuropathy (in patients treated with oxaliplatin).Results: Data from 34 640 patients were analyzed. Statistically significant and clinically relevant differences in the occurrence of grade III or IV nonhematological {especially nausea (5FU: odds ratio [OR] = 2.33, 95% confidence interval [CI] = 1.90 to 2.87, P < .001; FOLFOX: OR = 2.34, 95% CI = 1.76 to 3.11, P < .001), vomiting (5FU: OR = 2.38, 95% CI = 1.86 to 3.04, P < .001; FOLFOX: OR = 2.00, 95% CI = 1.50 to 2.66, P < .001; CAPOX: OR = 2.32, 95% CI = 1.55 to 3.46, P < .001), and diarrhea (5FU: OR = 1.35, 95% CI = 1.21 to 1.51, P < .001; FOLFOX: OR = 1.60, 95% CI = 1.35 to 1.90, P < .001; FOLFIRI: OR = 1.57, 95% CI = 1.25 to 1.97, P < .001)} as well as hematological toxicities (neutropenia [5FU: OR = 1.55, 95% CI = 1.37 to 1.76, P < .001; FOLFOX: OR = 1.96, 95% CI = 1.71 to 2.25, P < .001; FOLFIRI: OR = 2.01, 95% CI = 1.66 to 2.43, P < .001; capecitabine: OR = 4.07, 95% CI = 1.84 to 8.99, P < .001] and leukopenia [5FU: OR = 1.74, 95% CI = 1.40 to 2.17, P < .001; FOLFIRI: OR = 1.75, 95% CI = 1.28 to 2.40, P < .001]) were observed, with women being consistently at increased risk.Conclusions: Our analysis confirms that women with colon cancer receiving adjuvant fluoropyrimidine-based chemotherapy are at increased risk of toxicity. Given the known sex differences in fluoropyrimidine pharmacokinetics, sex-specific dosing of fluoropyrimidines warrants further investigation. [ABSTRACT FROM AUTHOR]

PURPOSE: Gene fusions are established oncogenic drivers and emerging therapeutic targets in advanced colorectal cancer. This study aimed to detail the frequencies and clinicopathological features of gene fusions in colorectal cancer using a circulating tumor DNA assay. METHODS: Circulating tumor DNA samples in patients with advanced colorectal cancer were analyzed at 4,581 unique time points using a validated plasma-based multigene assay that includes assessment of fusions in FGFR2 , FGFR3 , RET , ALK , NTRK1 , and ROS1. Associations between fusions and clinicopathological features were measured using Fisher's exact test. Relative frequencies of genomic alterations were compared between fusion-present and fusion-absent cases using an unpaired t test. RESULTS: Forty-four unique fusions were identified in 40 (1.1%) of the 3,808 patients with circulating tumor DNA detected: RET (n = 6; 36% of all fusions detected), FGFR3 (n = 2; 27%), ALK (n = 10, 23%), NTRK1 (n = 3; 7%), ROS1 (n = 2; 5%), and FGFR2 (n = 1; 2%). Relative to nonfusion variants detected, fusions were more likely to be subclonal (odds ratio, 8.2; 95% CI, 2.94 to 23.00; P <.001). Mutations associated with a previously reported anti–epidermal growth factor receptor (anti-EGFR) therapy resistance signature (subclonal RAS and EGFR mutations) were found with fusions in FGFR3 (10 of 12 patients), RET (nine of 16 patients), and ALK (seven of 10 patients). For the 27 patients with available clinical histories, 21 (78%) had EGFR monoclonal antibody treatment before fusion detection. CONCLUSION: Diverse and potentially actionable fusions can be detected using a circulating tumor DNA assay in patients with advanced colorectal cancer. Distribution of coexisting subclonal mutations in EGFR , KRAS , and NRAS in a subset of the patients with fusion-present colorectal cancer suggests that these fusions may arise as a novel mechanism of resistance to anti-EGFR therapies in patients with metastatic colorectal cancer. [ABSTRACT FROM AUTHOR]

Background: Our study investigated the demographic characteristics of Mayo Clinic Colon and Rectal Cancer Registry patients and sought to associate tumor location with overall survival. Methods: Using the cohort of patients seen at Mayo Clinic (Minnesota, Arizona, Florida) from 1972 to 2017, we obtained 26,908 colorectal adenocarcinoma patient records. Overall survival of patients with colorectal cancer was analyzed by sidedness (right vs. left) and location (right vs. left vs. rectum). Kaplan–Meier method was used to analyze all demographic and cancer variables available within the dataset to trace survival over a 35-year period. Subgroups within variables were compared to each other using log-rank test and considered significantly different at P < 0.05. Cox proportional hazards regression model was used to assess impact of tumor location while controlling for age, year of diagnosis, sex, tumor stage, and tumor grade. Cox regression models were used to evaluate the independent effect of cancer location on overall survival after adjusting for age, gender, year of diagnosis, and cancer stage. To further explore the potential interaction effect of cancer location with cancer stage and year of diagnosis, similar multivariable Cox model was fit stratified by cancer stage (1–3 vs. 4) and by year of diagnosis (<1980, 1980–2000, >2000). Results: Overall survival differed significantly within all variables studied after Kaplan–Meier method analysis (P < 0.0001). Survival was higher in the left-side group when evaluated by tumor sidedness, and rectal cancer patients had the highest median survival (101.3 months). Right-sided cancer patients had the worst prognosis in both tumor location and sidedness analyses, with a median survival of 76.6 months. However, the stratified analysis showed that, the difference in survival between left- and right-sided cancer only existed in late cancer stage (stage 4) patients but not in early cancer stage; therefore, screening for CRC to pick cancer at an early stage can influence overall survival significantly. Conclusion: These observations confirm some of the previous and recent studies on sidedness of colorectal cancer patients. Our analysis is novel in that it included patients of all stages rather than just stage IV metastatic patients. This initial study provides a platform to investigate more biologic and clinical factors associated with tumor location. Merging this dataset with other available datasets and previously conducted studies within the institution will provide a robust platform for multiple future studies and collaborations. Finally, appropriate screening can result in a decrease in incidence and mortality of CRC. [ABSTRACT FROM AUTHOR]

Purpose: Trifluridine/tipiracil (FTD/TPI; TAS-102, Lonsurf®), a novel form of chemotherapy for metastatic colorectal cancer (mCRC), has shown clinical benefit in the global, phase III RECOURSE trial, regardless of patient age. Here, we report the safety and tolerability profile of FTD/TPI from an expanded-access program (EAP) in the US patients with mCRC whose disease has progressed on the standard therapies.Methods: A total of 549 patients (≥ 18 years) with histologically confirmed mCRC following two or more regimens of standard therapy and an Eastern Cooperative Oncology Group performance status of 0 or 1 participated in this open-label EAP. During the 28-day treatment cycle, patients took FTD/TPI 35 mg/m2 twice daily for 5 days followed by 2 days of rest for 2 weeks, with a 14-day rest period. Data were collected for therapy duration, treatment discontinuation, and adverse events. Age-based post hoc analysis was performed to determine the safety of FTD/TPI in elderly (≥ 65 years) versus younger (< 65 years) patients.Results: FTD/TPI-treated patients in this EAP had a similar therapy duration and time to treatment discontinuation to those in the RECOURSE trial. The safety profile in elderly patients was consistent with that in younger patients, with no unexpected safety concerns.Conclusions: This USA-based, open-label EAP has confirmed a similar safety and tolerability profile for FTD/TPI to that observed in the RECOURSE trial. Furthermore, FTD/TPI is well tolerated and can be considered as a treatment option in elderly patients with mCRC.Trial Registration: NCT02286492. [ABSTRACT FROM AUTHOR]

Background. Preclinical and epidemiological data suggest that metformin might have antineoplastic properties against colon cancer (CC). However, the effect of metformin use on patient survival in stage III CC after curative resection is unknown. The survival outcomes were comparable regardless of the duration of metformin use. Patients and Methods. Before randomization to FOLFOX (folinic acid, 5-fluorouracil, oxaliplatin) with or without cetuximab, 1,958 patients with stage III CC enrolled in the N0147 study completed a questionnaire with information on diabetes mellitus (DM) and metformin use. Cox models were used to assess the association between metformin use and disease-free survival (DFS), overall survival (OS), and the time to recurrence (TTR), adjusting for clinical and/or pathological factors. Results. Of the 1,958 patients, 1,691 (86%) reported no history of DM, 115 reported DM with metformin use (6%), and 152 reported DM without metformin use (8%). The adjuvant treatment arms were pooled, because metformin use showed homogeneous effects on outcomes across the two arms. Among the patients with DM (n = 267), DFS (adjusted hazard ratio [aHR], 0.90; 95% confidence interval [CI], 0.59-1.35; p = .60), OS (aHR, 0.99; 95% CI, 0.65-1.49; p = .95), and TTR (aHR, 0.87; 95% CI, 0.56-1.35; p = .53) were not different for the metformin users compared with the nonusers after adjusting for tumor and patient factors. The survival outcomes were comparable regardless of the duration of metformin use (>1,1-5,6-10, ≥11 years) before randomization (ptrend = .64 for DFS, ptrend = .84 for OS, and ptrend = .87 for TTR). No interaction effects were observed between metformin use and KRAS, BRAF mutation status, tumor site,T/N stage, gender, or age. Conclusions. Patients with stage III CC undergoing adjuvant chemotherapy who used metformin before the diagnosis of CC experienced DFS, OS, and TTR similar to those for non-DM patients and DM patients without metformin use. [ABSTRACT FROM AUTHOR]

Introduction. A KRAS mutation represented the first genomic biomarker to predict lack of benefit from anti-epidermal growth factor receptor (EGFR) antibody therapy in advanced colorectal cancer (CRC). Expanded RAS testing has further refined the treatment approach, but understanding of genomic alterations underlying primary and acquired resistance is limited and further study is needed. Materials and Methods. We prospectively analyzed 4,422 clinical samples from patients with advanced CRC, using hybrid- capture based comprehensive genomic profiling (CGP) at the request of the individual treating physicians. Comparison with prior molecular testing results, when available, was performed to assess concordance. Results. We identified a RAS/RAF pathway mutation or amplification in 62% of cases, including samples harboring KRAS mutations outside of the codon 12/13 hotspot region in 6.4% of cases. Among cases with KRAS non-codon 12/13 alterations for which prior test results were available, 79 of 90 (88%) were not identified by focused testing. Of 1,644 RAS/RAF wild-type cases analyzed by CGP, 31% harbored a genomic alteration (GA) associated with resistance to anti- EGFRtherapy in advanced CRC including mutations in PIK3CA, PTEN, EGFR, and ERBB2. We also identified other targetable GA, including novel kinase fusions, receptor tyrosine kinase amplification, activating point mutations, as well as micro-satellite instability. Conclusion. Extended genomic profiling reliably detects alterations associated with lack of benefit to anti-EGFR therapy in advanced CRC, while simultaneously identifying alterations potentially important in guiding treatment. The use of CGP during the course of clinical care allows for the refined selection of appropriate targeted therapies and clinical trials, increasing the chance of clinical benefit and avoiding therapeutic futility. [ABSTRACT FROM AUTHOR]

Background: We sought to develop and validate clinically relevant, early assessment continuous tumor measurement-based metrics for predicting overall survival (OS) using the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 data warehouse.Methods: Data from 13 trials representing 2096 patients with breast cancer, non-small cell lung cancer (NSCLC), or colorectal cancer were used in a complete case analysis. Tumor measurements from weeks 0-6-12 assessments were used to evaluate the ability of slope (absolute change in tumor size from 0-6 and 6-12 weeks) and percent change (relative change in tumor size from 0-6 and 6-12 weeks) metrics to predict OS using Cox models, adjusted for average baseline tumor size. Metrics were evaluated by discrimination (via concordance or c-index), calibration (goodness-of-fit type statistics), association (hazard ratios), and likelihood (Bayesian Information Criteria), with primary focus on the c-index. All statistical tests were two-sided.Results: Comparison of c-indices suggests slight improvement in predictive ability for the continuous tumor measurement-based metrics vs categorical RECIST response metrics, with slope metrics performing better than percent change metrics for breast cancer and NSCLC. However, these differences were not statistically significant. The goodness-of-fit statistics for the RECIST metrics were as good as or better than those for the continuous metrics. In general, all the metrics performed poorly in breast cancer, compared with NSCLC and colorectal cancer.Conclusion: Absolute and relative change in tumor measurements do not demonstrate convincingly improved overall survival predictive ability over the RECIST model. Continued work is necessary to address issues of missing tumor measurements and model selection in identifying improved tumor measurement-based metrics. [ABSTRACT FROM AUTHOR]

Metastatic colorectal cancer (mCRC) is a highly heterogeneous disease. Its treatment outcome has been significantly improved over the last decade with the incorporation of biological targeted therapies, including anti-EGFR antibodies, cetuximab and panitumumab, and VEGF inhibitors, bevacizumab, ramucirumab, and aflibercept. The identification of predictive biomarkers has further improved the survival by accurately selecting patients who are most likely to benefit from these treatments, such as RAS mutation profiling for EGFR antibodies. Regorafenib is a multikinase inhibitor currently used as late line therapy for mCRC. The molecular and genetic markers associated with regorafenib treatment response are yet to be characterized. Here, we review currently available clinical evidence of mCRC molecular profiling, such as RAS, BRAF, and MMR testing, and its role in targeted therapies with special focus on regorafenib treatment. [ABSTRACT FROM AUTHOR]

The liver is the dominant site of metastases for patients with metastatic colorectal cancer (mCRC). Depending on the timing of diagnosis and the biology of the disease, it is not uncommon for these patients to present with visceral crisis in the form of severe liver dysfunction. Treatment of these individuals is, however, difficult and challenging. The decision to consider chemotherapy in these dire circumstances entails consideration of numerous factors. If we were to focus on just the metabolism of the different drugs and biologic agents available to treat mCRC, both 5-fluorouracil and oxaliplatin alone or in combination with a monoclonal antibody are reasonable choices. Specifically, FOLFOX is a feasible and safe option in patients with mCRC with severe liver dysfunction. Choice of the biologic agent to add to the doublet chemotherapy could be individualized based on the RAS status and the clinical scenario. Based on the divergent experience of treating 2 cases and other prior reports, a summary of recommendations with a model in the form of a “therapeutic triad” is presented. The paper highlights the therapeutic challenges in patients with mCRC and severe liver dysfunction. The choice of chemotherapeutic agents and reports of other cases/series is also presented. [ABSTRACT FROM AUTHOR]

With the advent of biologics, the survival and quality of life of patients diagnosed with metastatic colorectal cancer (mCRC) has improved. These agents include anti-VEGF agents (bevacizumab/aflibercept), anti-EGFR antibodies (panitumumab/cetuximab) and regorafenib (an oral multi-kinase inhibitor). With the use of the novel therapeutics, there was a notable increase in the median survival of patients with mCRC; however, there are still several unmet needs with the use of novel therapeutics in mCRC. The focus of this editorial is to highlight some of these issues alongside results of some of the important clinical trials and other studies presented at the American Society of Clinical Oncology meeting last year. [ABSTRACT FROM AUTHOR]

Background Current prognostic tools in colon cancer use relatively few patient characteristics. We constructed and validated clinical calculators for overall survival (OS) and time to recurrence (TTR) for stage III colon cancer and compared their performance against an existing tool (Numeracy) and American Joint Committee on Cancer (AJCC) version 7 staging. Methods Data from 15936 stage III patients accrued to phase III clinical trials since 1989 were used to construct Cox models for TTR and OS. Variables included age, sex, race, body mass index, performance status, tumor grade, tumor stage, ratio of positive lymph nodes to nodes examined, number and location of primary tumors, and adjuvant treatment (fluoropyrimidine single agent or in combination). Missing data were imputed, and final models internally validated for optimism-corrected calibration and discrimination and compared with AJCC. External validation and comparisons against Numeracy were performed using stage III patients from NSABP trial C-08. All statistical tests were two-sided. Results All variables were statistically and clinically significant for OS prediction, while age and race did not predict TTR. No meaningful interactions existed. Models for OS and TTR were well calibrated and associated with C-indices of 0.66 and 0.65, respectively, compared with C-indices of 0.58 and 0.59 for AJCC. These tools, available online, better predicted patient outcomes than Numeracy, both overall and within patient subgroups, in external validation. Conclusions The proposed ACCENT calculators are internally and externally valid, better discriminate patient risk than AJCC version 7 staging, and better predict patient outcomes than Numeracy. These tools have replaced Numeracy for online clinical use and will aid prognostication and patient/physician communication. [ABSTRACT FROM AUTHOR]

BACKGROUND: African Americans are more likely to be diagnosed with metastatic colorectal cancer than whites and have shorter survival once they are diagnosed. In this analysis, the authors examined racial differences in clinical outcomes among patients with metastatic colorectal cancer (mCRC) who received bevacizumab. METHODS: The study cohort consisted of 1589 white patients (81.4%) and 227 African American patients (11.6%) with mCRC who received front-line bevacizumab therapy and who were enrolled in a large, predominantly community-based, prospective, observational cohort study. Differences in time-to-event endpoints and response rates were examined by race. Differences in the incidence of baseline and treatment-related toxicities associated with bevacizumab also were examined. Finally, differences in patterns of care by race were explored. RESULTS: The median overall survival was 22.6 months for African Americans and 22.9 months for whites, and the median progression-free survival was 9.5 months for African Americans and 9.8 months for whites. Response rates (complete responses plus partial responses) were 37.5% for African Americans and 46.3% for whites (adjusted odds ratio, 0.67; 95% confidence interval, 0.50-0.90). African Americans had higher rates of baseline diabetes (18.9% vs 11%; P = .002), higher rates of hypertension (52.9% vs 41.4%; P = .001), and worsening hypertension while on therapy (13.7% vs 8.9%; P = .02), but no differences in on-treatment arterial thromboembolic events were observed. CONCLUSIONS: This large observational cohort study of patients with mCRC demonstrated that, when treated in a similar fashion with modern chemotherapy, African Americans and whites had equivalent cancer outcomes. No significant differences in bevacizumab-related toxicity or patterns of care were observed between African Americans and whites. The lower response rate among African Americans deserves further study. Cancer 2012;. © 2011 American Cancer Society. [ABSTRACT FROM AUTHOR]

BACKGROUND: Numeracy and Adjuvant! are 2 web-based calculators that are used widely to estimate the prognosis and potential benefit of adjuvant 5-fluorouracil (5-FU)-based therapy for patients with stage II and III colon cancer. In this study, the authors compared the predicted survival estimates from these models with the actual observed estimates in independent datasets that were derived from a population cohort and from clinical trials. METHODS: The population cohort was derived from the British Columbia Colorectal Cancer Outcomes Unit database, which identified referred patients with stage II and III colon cancer from 1995 to 1996 and from 1999 to 2003. Patients who were enrolled in North Central Cancer Trials Group (NCCTG) trials NCCTG 94651 and NCCTG 914653 were included in the trials dataset. Patient and disease data were used to predict 5-year relapse-free and overall survival using both tools. RESULTS: In the population-based dataset (N = 2033), Adjuvant! offered more reliable predictions of prognosis for patients who underwent surgery alone, but it had reliability similar to that of Numeracy for predicting the prognosis for patients who received adjuvant 5-FU. Both models tended to overestimate survival for patients with stage II disease who received 5-FU. In the trials dataset of patients who underwent and received 5-FU (N = 1729), Numeracy and Adjuvant! demonstrated similar performance and improved correctness. CONCLUSIONS: This independent validation analysis demonstrated that both Numeracy and Adjuvant! had similar predictive performance and acceptable reliability for patients with stage III disease. Survival outcomes of patients with stage II colon cancer who received adjuvant 5-FU were slightly lower than estimated by either model. Cancer 2011;. © 2011 American Cancer Society. [ABSTRACT FROM AUTHOR]

Oxaliplatin-based chemotherapy is an effective first-line treatment option for patients with metastatic colorectal cancer (mCRC), which, in combination with targeted therapies and a sequential treatment approach using all active agents, has extended median overall survival to 2 years and beyond. Prolonged survival brings into focus the burden of treatment, in terms of associated toxicities and quality of life, and attention is now being paid to lowering the toxicity burden for patients receiving chemotherapy for mCRC without compromising efficacy. The use of oxaliplatin can lead to the development of sensory neuropathy, which commonly limits the dose and/or duration of treatment that can be administered. Temporary withdrawal of oxaliplatin (treatment holidays) has been shown to be an effective strategy for the management of this adverse effect. Data from randomized controlled trials indicate that a formalized stop-and-go approach to the delivery of oxaliplatin does not compromise efficacy, and indeed for some patients may prove beneficial by allowing them to continue treatment for longer periods. This paper presents a critical review of the evidence to support the utility of treatment interruption and reintroduction of oxaliplatin for the long-term management of mCRC. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The administration of adjuvant chemotherapy after resection of stage III colon cancer to prolong disease-free survival (DFS) and increase overall survival (OS) has been clinical standard since the early 1990s. Recently, 3-year DFS was recognized as surrogate endpoint for OS based on a meta-analysis of trials utilizing 5- fluorouracil as only active chemotherapy component. The standard of care in adjuvant therapy, however, has moved on to modern combination regimens including oxaliplatin, and novel targeted agents such as angiogenesis inhibitors and antibodies against epidermal growth factor receptor are currently undergoing rigorous testing in phase III adjuvant trials. For the practicing clinician, the use of surrogate endpoints to appreciate the efficacy of a specific adjuvant therapy contains various challenges, in particular, in discussions with patients. It is questionable whether 3-year DFS can still be considered an appropriate predictor of OS in complex clinical scenarios with continuous change in treatment standards in the adjuvant and palliative situation. Thus, the practicing oncologist needs to be aware of the limitations in the definition of surrogate endpoints in the adjuvant setting. [ABSTRACT FROM AUTHOR]

New agents for the treatment of metastatic colorectal cancer have extended median overall survival to more than 20 months, an increase that has changed the view of advanced colorectal cancer from an acute to a chronic condition. This article proposes a shift in treatment strategy from the concept of successive "lines" of therapy, in which chemotherapy is continued until disease progression, to that of a continuum of care, in which the use of chemotherapy is tailored to the clinical setting and includes switching chemotherapy prior to disease progression, maintenance therapy, drug "holidays," and surgical resection of metastases in selected patients. In this approach, the distinction between lines of therapy is no longer absolute. This represents a paradigm shift in the management of metastatic colorectal cancer to that of a continuum of care approach that includes individualized planning, in which patients are given the opportunity to benefit from exposure to all active agents and modalities while minimizing unnecessary treatment and toxicity, with the ultimate goal of improving survival as well as quality of life. [ABSTRACT FROM AUTHOR]

Survival of patients with stage III colon cancer varies widely according to T-N sub-stages. Estimating the benefit of each therapeutic option in each T-N subgroup may provide more accurate information helping doctors and patients in the complex shared decision-making process surrounding adjuvant therapy. The outcomes data of 12,834 patients with stage III colon cancer enrolled in the IDEA trial served as our database. Patients were categorised in 16 sub-stages, based on T-N categories. We created a meta-regression model to predict the expected 5-year DFS within each T-N sub-stage. We then evaluated the efficacy of each therapeutic option in every sub-stage, working backward by subtraction, using an average of the HRs reported in pertinent trial publications as a conversion factor. Large differences in 5-year DFS rate were observed among the subgroups, ranging from 89% (T1N1a) to 31% (T4N2b) in the overall population. The contribution to the outcome of each therapeutic option in this setting varied widely across sub-stages. According to our model, patients with T1N1a cancers have a projected 5-year DFS of 79.6% with surgery alone. Adjuvant fluoropyrimidine alone results in 5.6% absolute DFS gain; an additional 2.3% and 0.8% gain is seen with oxaliplatin for 3 and 6 months, respectively. Patients with T4N2b cancers show a 13.9% 5-year DFS with surgery alone, and an 11.2%, 6.4%, 2.5% increase with the aforementioned adjuvant options, respectively. The resulting overlay bar graph gives patients and doctors the projected relative benefit of each treatment option and may substantially help the shared decision-making process, although caution must be exercised in using this model due to the significant variance of the estimates. • Survival of patients with stage III colon cancer varies according to T-N sub-stages. • Average risk and benefit of adjuvant therapy is not applicable to individual patients • We showed that T1N1a has 89% 5-year DFS and that T4N2b has 31% 5-year DFS. • The contribution of each therapeutic option varied widely across sub-stages. • The resulting overlay bar graph shows the absolute benefit of each treatment option. [ABSTRACT FROM AUTHOR]

The variability of definitions for time-to-event (TTE) end-points impacts the conclusions of randomised clinical trials (RCTs). The Definition for the Assessment of Time-to-event Endpoints in CANcer (DATECAN) initiative aims to provide consensus definitions for TTE end-points used in RCTs. Here, we formulate guidelines for adjuvant colon cancer RCTs. We performed a literature review to identify TTE end-points and events included in their definition in RCT publications. Then, a consensus was reached among a panel of international experts, using a formal modified Delphi method, with 2 rounds of questionnaires and an in-person meeting. Twenty-four experts scored 72 events involved in 6 TTE end-points. Consensus was reached for 24%, 57% and 100% events after the first round, second round and in-person meeting. For RCTs not using overall survival as their primary end-point, the experts recommend using disease-free survival (DFS) rather than recurrence-free survival (RFS) or time to recurrence (TTR) as the primary end-point. The consensus definition of DFS includes all causes of death, second primary colorectal cancers (CRCs), anastomotic relapse and metastatic relapse as an event, but not second primary non-CRCs. Events included in the RFS definition are the same as for DFS with the exception of second primary CRCs. The consensus definition of TTR includes anastomotic or metastatic relapse, death with evidence of recurrence and death from CC cause. Standardised definitions of TTE end-points ensure the reproducibility of the end-points between RCTs and facilitate cross-trial comparisons. These definitions should be integrated in standard practice for the design, reporting and interpretation of adjuvant CC RCTs. • Randomised trials for adjuvant therapy in colon cancer (CC) use multiple time-to-event (TTE) end-points that lack standardised definitions. • Recommendations for the definition of TTE end-point in adjuvant CC randomised trials were established. • These guidelines should become standard practice because they would facilitate data interpretation and across-trial comparisons. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to an article on the use of regorafenib for metastatic colorectal cancer, written by Axel Grothey and colleagues, and published in the January 26, 2013 issue.