Omental metastases in patients with pseudomyxoma peritonei or colorectal peritoneal metastases - is routine omentectomy justified?

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.

No Indication for Routine Resection of Surgical Scars during Cytoreductive Surgery and HIPEC.

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.

Next generation pan-cancer blood proteome profiling using proximity extension assay.

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.

Signet Ring Cell Colorectal and Appendiceal Cancer: A Small Signet Ring Cell Component Is Also Associated with Poor Outcome.

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.

Mucinous rectal cancers: clinical features and prognosis in a population-based cohort.

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.

Oxaliplatin-based hyperthermic intraperitoneal chemotherapy with single drug versus multiple drug treatment for colorectal cancer with peritoneal metastases: an observational cohort study.

BACKGROUND: Long-term survival for selected patients with peritoneal metastases (PM) from colorectal cancer (CRC) is possible when treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The objective of this study was to compare three different oxaliplatin-based (OX)-HIPEC regimens. Primary end-point was disease-free survival (DFS), and secondary endpoints, morbidity and overall survival (OS). METHODS: This is a retrospective study of all patients with colorectal PM treated with CRS and HIPEC between 2004 and 2015 from the prospectively maintained Uppsala HIPEC database. One hundred and thirty-three patients were identified. Three HIPEC regimens were included: OX-HIPEC, OX-HIPEC + post-operative intraperitoneal chemotherapy (EPIC) with 5-fluorouracil (5-FU), and oxaliplatin-irinotecan-based (OXIRI)-HIPEC. Multivariable Cox regression for DFS was performed. RESULTS: Sixty-one patients received OX-HIPEC, 24 patients received OX-HIPEC + 5-FU EPIC, and 48 patients received OXIRI-HIPEC. The DFS for the OX-HIPEC group was 10.5 months, OX-HIPEC + EPIC 11.9 months, and OXIRI-HIPEC 13.4 months (OX-HIPEC vs. OXIRI HIPEC, P=0.049). The morbidity and OS did not differ between the groups. In the multivariable analysis, low peritoneal cancer index (PCI), absence of liver metastases, low completeness of cytoreduction (CC) score, and multiple drug (EPIC or OXIRI) HIPEC regimen were independent prognostic factors for DFS. CONCLUSIONS: This study showed improved DFS with an intensification of HIPEC by adding irinotecan or EPIC compared to oxaliplatin alone without an increase in morbidity or mortality.

Patients with colorectal peritoneal metastases and high peritoneal cancer index may benefit from cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

BACKGROUND: Peritoneal cancer index (PCI) >20 is often seen as a contraindication for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with peritoneal metastases (PM) from colorectal cancer. The aim of this study was to compare the overall survival in colorectal PM patients with PCI >20 and PCI ≤20 treated with CRS and HIPEC to those having open-close/debulking procedure only. METHODS: All patients with colorectal PM and intention to treat with CRS and HIPEC in Uppsala Sweden 2004-2017 were included. Patients scheduled for CRS and HIPEC were divided into three groups, PCI >20, PCI ≤20, and those not operated with CRS and HIPEC stated as open-close including those treated with palliative debulking. RESULTS: Of 201 operations, 112 (56%) resulted in CRS and HIPEC with PCI ≤20, 45 (22%) in CRS and HIPEC with PCI >20 and 44 (22%) resulted in open-close/debulking. Median survival for CRS and HIPEC and PCI >20 was 20 months (95%CI 14-27 months) with 7% surviving longer than 5 years (n = 3). For CRS and HIPEC and PCI ≤20 the median survival was 33 months (95%CI 30-39 months) with 23% (n = 26) surviving >5years. The median survival for open-close was 9 months (95%CI 4-10 months), no one survived >5years. CONCLUSION: Patients with PM from colorectal cancer and PCI >20 that were treated with CRS and HIPEC experience a one year longer and doubled overall survival compared with open-close/debulking patients. In addition to PCI, more factors should be taken into account when a decision about proceeding with CRS or not is taken.

Neutropenia in colorectal cancer treated with oxaliplatin-based hyperthermic intraperitoneal chemotherapy: An observational cohort study.

BACKGROUND: The implications of neutropenia after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) treatment have never been investigated. AIM: To evaluate the occurrence of neutropenia and its effect on the risk of increased Clavien-Dindo morbidity as well as its effect on overall or disease-free survival. METHODS: All patients with colorectal peritoneal metastases (1996-2015) completing cytoreductive surgery and oxaliplatin-based HIPEC treatment from a bi-institutional database (Uppsala and Sydney) were included in the study. Clavien-Dindo grade 3-4 morbidity differences between the neutropenia group vs non-neutropenia group were calculated and Kaplan-Meier curves with log rank test were rendered. Univariate and multivariable Cox regression models for disease-free survival were implemented. RESULTS: Two hundred and forty-six patients were identified - 32 postoperative any-grade neutropenia patients and 214 non-neutropenia patients. The neutropenia group had more combination oxaliplatin + irinotecan treatment than the non-neutropenia group (66% vs 13%, P = 0.0001). The neutropenia group was not associated with increased Clavien-Dindo grade 3-4 morbidity. Median overall survival was 53 mo vs 37 mo for the neutropenia and non-neutropenia group, P = 0.07. Median disease-free survival was 16 mo vs 11 mo, respectively, P = 0.02. Neutropenia was an independent prognostic factor for disease-free survival with hazard ratio: 0.58, 95% confidence interval: 0.36-0.95, P = 0.03. CONCLUSION: 13% of patients developed neutropenia which was not associated with increased Clavien-Dindo grade 3-4 morbidity. Neutropenia was an independent positive prognostic factor for disease-free survival and was associated with more intense HIPEC treatment. This is in direct contrast to the current paradigm of decreasing the treatment intensity.

Prognostic Impact of BRAF and KRAS Mutation in Patients with Colorectal and Appendiceal Peritoneal Metastases Scheduled for CRS and HIPEC.

BACKGROUND: KRAS and BRAF mutations are prognostic and predictive tools in metastatic colorectal cancer, but little is known about their prognostic value in patients scheduled for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Therefore, we analyzed the prognostic impact of KRAS and BRAF mutations in patients with peritoneal metastases scheduled for CRS and HIPEC. PATIENTS AND METHODS: In a consecutive series of 399 patients scheduled for CRS and HIPEC between 2009 and 2017, 111 subjects with peritoneal metastases from primaries of the appendix, colon, or rectum were analyzed for KRAS mutation and 92 for BRAF mutation. RESULTS: Mutation in KRAS was present in 51/111 (46%), and mutated BRAF was found in 10/92 (11%). There was no difference in overall survival between KRAS mutation tumors and KRAS wild type, whereas BRAF mutation was associated with short survival. No subject with BRAF mutation survived 2 years. On multivariate analysis, completeness of cytoreduction score (CCS, p = 0.000001), presence of signet cell differentiation (p = 0.000001), and BRAF mutation (p = 0.0021) were linked with poor prognosis. CONCLUSIONS: BRAF mutation is a marker of poor prognosis in patients with appendiceal and colorectal peritoneal metastases scheduled for CRS and HIPEC, whereas survival outcome in subjects with mutated KRAS does not differ from wild-type KRAS. This finding suggests that those with BRAF mutation should be considered for alternative treatment options.

Gains of Chromosome 1p and 15q are Associated with Poor Survival After Cytoreductive Surgery and HIPEC for Treating Colorectal Peritoneal Metastases.

PURPOSE: Genetic alterations in colorectal peritoneal metastases (PM) are largely unknown. This study was designed to analyze whole-genome copy number alterations (CNA) in colorectal PM and to identify alterations associated with prognosis after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: All patients with PM, originating from a colorectal adenocarcinoma, who were treated with CRS and HIPEC in Uppsala Sweden, between 2004 and 2015, were included (n = 114). DNA derived from formalin-fixed paraffin-embedded (FFPE) specimens were analyzed for CNA using molecular inversion probe arrays. RESULTS: There were extensive but varying degrees of CNA, ranging from minimal CNA to total aneuploidy. In particular, gain of parts of chromosome 1p and major parts of 15q were associated with poor survival. A combination of gains of 1p and 15q was associated with poor survival, also after adjustment for differences in peritoneal cancer index and completeness of cytoreduction score [hazard ratio (HR) 5.96; 95% confidence interval (CI) 2.19-16.18]. These patients had a mean copy number (CN) of 3.19 compared with 2.24 in patients without gains. Complete CN analysis was performed in 53 patients. Analysis was unsuccessful for the remaining patients due to insufficient amounts of DNA and signals caused by interstitial components and normal cells. There was no difference in survival between patients with successful and unsuccessful CN analysis. CONCLUSIONS: This study shows that gains of parts of chromosome 1p and of major parts of chromosome 15q were significantly associated with poor survival after CRS and HIPEC, which could represent future prognostic biomarkers.

Risk factors for appendiceal and colorectal peritoneal metastases.

BACKGROUND: Early diagnosis to target minimal volume disease has received increased attention in the management of appendiceal and colorectal peritoneal metastases (PM). This study aimed to identify risk factors for appendiceal, colon and rectal PM. METHODS: Data were retrieved from the Swedish Colorectal Cancer Registry for all patients undergoing bowel resection of appendiceal and colorectal tumours, in Sweden, 2007-2015. Risk factors for synchronous and metachronous PM were analysed with multivariate logistic and Cox proportional hazard regression models. RESULTS: Synchronous PM was most common in appendiceal cancer (23.5%), followed by colon (3.1%) and rectal (0.6%) cancer. The 5-year cumulative incidence was 9.0% for appendiceal, 2.5% for right colon, 1.8% for left colon and 1.2% for rectal cancer. In appendiceal cancer (n = 327), T4, N2, mucinous tumour, and non-radical surgery were associated with PM. In colon cancer (n = 24,399), synchronous PM were primarily associated with T4 (OR 18.37, 95% CI 8.12-41.53), T3 and N2 but also with N1, right-sided tumour, mucinous tumour, vascular and perineural invasion, female gender, age <60 and emergency surgery. These factors were also associated with metachronous PM. In rectal cancer (n = 10,394), T4 (OR 19.12, 95% CI 5.52-66.24), proximal tumour and mucinous tumour were associated with synchronous PM and T4 and mucinous tumour with metachronous PM. CONCLUSIONS: This study shows that appendiceal cancer, right-sided colon cancer, advanced tumour and node stages and mucinous histopathology are the main high-risk features for PM and should increase the awareness of current or future PM.

Increased incidence of bowel cancer after non-surgical treatment of appendicitis.

BACKGROUND: There is an ongoing debate on the use of antibiotics instead of appendectomy for treating appendicitis but diagnostic difficulties and longstanding inflammation might lead to increased incidence of bowel cancer in these patients. The aim of this population-based study was to investigate the incidence of bowel cancer after non-surgical treatment of appendicitis. PATIENTS AND METHODS: Patients diagnosed with appendicitis but lacking the surgical procedure code for appendix removal were retrieved from the Swedish National Inpatient Register 1987-2013. The cohort was matched with the Swedish Cancer Registry and the standardised incidence ratios (SIR) with 95% confidence interval (95% CI) for appendiceal, colorectal and small bowel cancers were calculated. RESULTS: Of 13 595 patients with non-surgical treatment of appendicitis, 352 (2.6%) were diagnosed with appendiceal, colorectal or small bowel cancer (SIR 4.1, 95% CI 3.7-4.6). The largest incidence increase was found for appendiceal (SIR 35, 95% CI 26-46) and right-sided colon cancer (SIR 7.5, 95% CI 6.6-8.6). SIR was still elevated when excluding patients with less than 12 months since appendicitis and the incidence of right-sided colon cancer was elevated five years after appendicitis (SIR 3.5, 95% CI 2.1-5.4). An increased incidence of bowel cancer was found after appendicitis with abscess (SIR 4.6, 95% CI 4.0-5.2), and without abscess (SIR 3.5, 95% CI 2.9-4.1). CONCLUSION: Patients with non-surgical treatment of appendicitis have an increased short and long-term incidence of bowel cancer. This should be considered in the discussion about optimal management of patients with appendicitis.

Importance of Absent Neoplastic Epithelium in Patients Treated With Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: The importance of absent neoplastic epithelium in specimens from cytoreductive surgery (CRS) is unknown. This study aimed to investigate the prevalence and prognostic value of histopathology without neoplastic epithelium in patients treated with CRS and hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: Data were extracted from medical records and histopathology reports for patients treated with initial CRS and HIPEC at Uppsala University Hospital, Sweden, between 2004 and 2012. Patients with inoperable disease and patients undergoing palliative non-CRS surgery were excluded from the study. Patients lacking neoplastic epithelium in surgical specimens from CRS, with or without mucin, were classified as "neoplastic epithelium absent" (NEA), and patients with neoplastic epithelium were classified as "neoplastic epithelium present" (NEP). RESULTS: The study observed NEA in 78 of 353 patients (22 %). Mucin was found in 28 of the patients with NEA. For low-grade appendiceal mucinous neoplasms and adenomas, the 5-year overall survival rate was 100 % for NEA and 84 % for NEP, and the 5-year recurrence-free survival rate was 100 % for NEA and 59 % for NEP. For appendiceal/colorectal adenocarcinomas (including tumors of the small intestine), the 5-year overall survival rate was 61 % for NEA and 38 % for NEP, and the 5-year recurrence-free survival rate was 60 % for NEA and 14 % for NEP. Carcinoembryonic antigen level, peritoneal cancer index, and completeness of the cytoreduction score were lower in patients with NEA. CONCLUSIONS: A substantial proportion of patients undergoing CRS and HIPEC have NEA. These patients have a favorable prognosis and a decreased risk of recurrence. Differences in patient selection can affect the proportion of NEA and hence explain differences in survival rates between reported series.