Search

Colorectal cancer is caused by a sequence of somatic genomic alterations affecting driver genes in core cancer pathways 1 . Here, to understand the functional and prognostic impact of cancer-causing somatic mutations, we analysed the whole genomes and transcriptomes of 1,063 primary colorectal cancers in a population-based cohort with long-term follow-up. From the 96 mutated driver genes, 9 were not previously implicated in colorectal cancer and 24 had not been linked to any cancer. Two distinct patterns of pathway co-mutations were observed, timing analyses identified nine early and three late driver gene mutations, and several signatures of colorectal-cancer-specific mutational processes were identified. Mutations in WNT, EGFR and TGFβ pathway genes, the mitochondrial CYB gene and 3 regulatory elements along with 21 copy-number variations and the COSMIC SBS44 signature correlated with survival. Gene expression classification yielded five prognostic subtypes with distinct molecular features, in part explained by underlying genomic alterations. Microsatellite-instable tumours divided into two classes with different levels of hypoxia and infiltration of immune and stromal cells. To our knowledge, this study constitutes the largest integrated genome and transcriptome analysis of colorectal cancer, and interlinks mutations, gene expression and patient outcomes. The identification of prognostic mutations and expression subtypes can guide future efforts to individualize colorectal cancer therapy., (© 2024. The Author(s).)

Background: Careful macroscopic assessment of surgical scars is needed to avoid routine scar resection during cytoreductive surgery (CRS) for peritoneal metastases (PM). This study aimed to analyze the correlation between macroscopically suspected and microscopically confirmed scar metastases (SMs), and to analyze the prognostic impact of not undergoing routine scar resection., Method: All patients with previous surgery, treated with CRS and hyperthermic intraperitoneal chemotherapy, for colorectal PM or pseudomyxoma peritonei (PMP), at Uppsala University Hospital in 2013-2021, were included. Macroscopic SMs in surgical reports were compared with histopathological analyses., Results: In total, 227 patients were included. Among colorectal PM patients (n = 156), SM was macroscopically suspected in 41 (26%) patients, and 63 (40%) underwent scar resection. SM was confirmed in 19 (30%). Among patients with macroscopic suspicion, 45% had confirmed SM (positive predictive value, PPV). A total of 1 of 23 (4%) patients with no macroscopic suspicion had SM (negative predictive value, NPV = 96%). Among the PMP patients (n = 71), SM was macroscopically suspected in 13 (18%), and 28 (39%) underwent scar resection, of whom 12 (43%) had SM. The PPV was 77%. Occult SM was found in 1 of 14 (NPV = 93%). Not undergoing routine scar resection did not affect recurrence-free survival (RFS, p = 0.2) or overall survival (OS, p = 0.1) in colorectal PM patients or PMP patients (RFS p = 0.7, OS p = 0.7)., Conclusion: Occult SM is uncommon and scar resection does not affect RFS or OS. Therefore, macroscopically benign-appearing scars can be left without resection, though resection should be performed upon suspicion or uncertainty.

Background: The greater omentum is routinely resected during cytoreductive surgery (CRS), but few studies have analyzed the rationale behind this. This study aimed to assess the prevalence of omental metastases (OM) and the correlation between macroscopically suspected and microscopically confirmed OM, in patients with pseudomyxoma peritonei (PMP) or colorectal peritoneal metastases (PM)., Method: All patients without previous omentectomy, treated with initial CRS and hyperthermic intraperitoneal chemotherapy for PMP or colorectal PM, at Uppsala University Hospital in 2013-2021, were included. Macroscopic OM in surgical reports was compared with histopathological analyses., Results: In all, 276 patients were included. In those with PMP, 112 (98%) underwent omentectomy and 67 (59%) had macroscopic suspicion of OM. In 5 (4%) patients, the surgeon was uncertain. Histopathology confirmed OM in 81 (72%). In patients with macroscopic suspicion, 96% had confirmed OM (positive predictive value, PPV). In patients with no suspicion, 24% had occult OM (negative predictive value, NPV = 76%). In patients with colorectal PM, 156 (96%) underwent omentectomy and 97 (60%) had macroscopic suspicion. For 5 (3%) patients, the surgeon was uncertain. OM was microscopically confirmed in 90 (58%). PPV was 85% and NPV was 89%. The presence of OM was a univariate risk factor for death in PMP (HR 3.62, 95%CI 1.08-12.1) and colorectal PM (HR 1.67, 95%CI 1.07-2.60), but not in multivariate analyses., Conclusion: OM was common and there was a high risk of missing occult OM in both PMP and colorectal PM. These results support the practice of routine omentectomy during CRS.

A comprehensive characterization of blood proteome profiles in cancer patients can contribute to a better understanding of the disease etiology, resulting in earlier diagnosis, risk stratification and better monitoring of the different cancer subtypes. Here, we describe the use of next generation protein profiling to explore the proteome signature in blood across patients representing many of the major cancer types. Plasma profiles of 1463 proteins from more than 1400 cancer patients are measured in minute amounts of blood collected at the time of diagnosis and before treatment. An open access Disease Blood Atlas resource allows the exploration of the individual protein profiles in blood collected from the individual cancer patients. We also present studies in which classification models based on machine learning have been used for the identification of a set of proteins associated with each of the analyzed cancers. The implication for cancer precision medicine of next generation plasma profiling is discussed., (© 2023. The Author(s).)

Background: Colorectal signet ring cell (SRC) carcinoma with ≥50% SRCs (SRC ≥ 50) has a poor prognosis, but the prognostic role of SRCs < 50% (SRC < 50) is unclear. The aim of this study was to provide a clinicopathological characterization of SRC colorectal and appendiceal tumours and analyse the importance of the SRC component size., Methods: All patients in the Swedish Colorectal Cancer Registry diagnosed with colorectal or appendiceal cancer in 2009-2020 at Uppsala University Hospital, Sweden, were included. The SRCs were verified, and the components estimated by a gastrointestinal pathologist., Results: Of the 2229 colorectal cancers, 51 (2.3%) had SRCs, with a median component size of 30% (interquartile range of 12.5-40) and 10 (0.45%) had SRC ≥ 50. The SRC tumours were primarily localized in the right colon (59%) and appendix (16%). No patients with SRCs had stage I disease, and 26 (51%) had stage IV, of whom, 18 (69%) had peritoneal metastases. The SRC tumours were often high grade with perineural and vascular invasion. The 5-year overall survival (OS) rate for patients with SRC ≥ 50 were 20% (95% confidence interval (CI) 6-70), for SRC < 50, 39% (95% CI 24-61); and for non-SRCs, 55% (95% CI 55-60). Among the patients with SRC < 50 and <50% extracellular mucin, the 5-year OS was 34% (95% CI 19-61), while those with ≥50% extracellular mucin had an OS of 50% (95% CI 25-99). The 5-year recurrence-free survival rates were 51% (95% CI 13-83) for patients with SRC tumours, as compared to 83% (95% CI 77-89) and 81% (95% CI 79-84) for mucinous and non-mucinous adenocarcinoma, respectively., Conclusions: The presence of SRCs was strongly associated with aggressive clinicopathological features, peritoneal metastases, and poor prognosis, also when they make up <50% of a tumour.

Purpose: Mucinous rectal cancers are generally associated with poor prognosis. This study aimed to clinically characterize mucinous rectal cancers in a defined region of Sweden., Methods: All patients with rectal cancer in Uppsala and Dalarna, Sweden, between 2010 and 2018, were identified using the Swedish Colorectal Cancer Registry. Data were verified and updated by way of medical, radiology, and histopathology reports. Patients were selected if magnetic resonance imaging, biopsy, and/or surgical specimen were mucinous. Primary outcomes were overall survival (OS), time to recurrence (TTR), pattern of metastatization, and downstaging. Risk factors for recurrence were analysed with univariable and multivariable analyses., Results: Of 1220 patients with rectal cancer, 263 (22 per cent) had a mucinous specimen, median (interquartile range; i.q.r.) age was 71 (63-77) years, and 152 (58 per cent) were men. Most were localized in the low-middle rectum (76 per cent) and were stage III (53 per cent), or stage IV (28 per cent). The 5-year OS was 55 per cent (95 per cent c.i. 49 to 62); after total mesorectal excision (n = 164), 5-year OS was 75 per cent (95 per cent c.i. 68 to 83), and 5-year TTR was 68 per cent (95 per cent c.i. 60 to 77). In those with complete response (pCR), pStage I, pStage II, and pStage III, 5-year TTR was 93 per cent, 85 per cent, 74 per cent, and 44 per cent respectively. Synchronous metastasis was most common in the liver (64 per cent) and metachronous in the lungs (58 per cent). pCR was achieved in 14 patients, (13 per cent); whereas T and N category downstaging was achieved in 31 (28 per cent) and 67 patients (61 per cent) respectively. Perineural invasion had the strongest association with recurrence (hazard ratio 6.34, 95 per cent c.i. 2.50 to 16.10)., Conclusion: Mucinous rectal cancers have high recurrence rates, but pCR rate is more than 10 per cent. Perineural invasion is the main feature associated with recurrence., (© The Author(s) 2022. Published by Oxford University Press on behalf of BJS Society Ltd.)