Peritoneal metastases from gastric cancer in a nationwide cohort: Incidence, treatment and survival.

The aims of this study were to investigate incidence, risk factors and treatment of synchronous or metachronous peritoneal metastases (PM) from gastric cancer and to estimate survival of these patients using population-based data. Patients diagnosed with gastric cancer in 2015 to 2016 were selected from the Netherlands Cancer Registry. The incidence of synchronous and metachronous PM were calculated. Multivariable regression analyses were performed to identify factors associated with the occurrence of PM. Treatment and survival were compared between patients with synchronous and metachronous PM. Of 2206 patients with gastric cancer, 741 (34%) were diagnosed with PM. Of these, 498 (23%) had synchronous PM. The cumulative incidence of metachronous PM in patients who underwent potentially curative treatment (n = 675) was 22.8% at 3 years. A factor associated with synchronous and metachronous PM was diffuse type histology. Patients diagnosed with synchronous PM more often received systemic treatment than patients with metachronous PM (35% vs 18%, respectively, P < .001). Median overall survival was comparable between synchronous and metachronous PM (3.2 vs 2.3 months, respectively, P = .731). Approximately one third of all patients with gastric cancer are diagnosed with PM, either at primary diagnosis or during 3-year follow-up after potentially curative treatment. Patients with metachronous PM less often received systemic treatment than those with synchronous PM but survival was comparable between both groups. Future trials are warranted to detect gastric cancer at an earlier stage and to examine strategies that lower the risk of peritoneal dissemination. Also, specific treatment options for patients with gastric PM should be further investigated.

Trends in ovarian, fallopian tube, and primary peritoneal cancer incidence, mortality, and survival: A 15-year population-based analysis.

OBJECTIVE: To characterize trends in ovarian, fallopian tube, and primary peritoneal cancer incidence and incidence-based mortality based on histology and site of origin. METHODS: We obtained age-adjusted incidence and incidence-based mortality for patients with ovarian, fallopian tube, and primary peritoneal cancer from 2000 to 2019 from the US SEER 17 database. Joinpoint 4.9.1.0 was used to characterize log-linear time trends. RESULTS: The incidence and incidence-based mortality of all cancers trended down during the study period. The incidence of epithelial cancers decreased from 2004 to 2019 (AAPC -1.2%, p < 0.001), including that of high-grade (2006-2019: APC -1.2%, p < 0.05) and low-grade (2003-2019: APC -2.4%, p < 0.05) epithelial cancers. There was no change in incidence or incidence-based mortality for ovarian stromal and germ cell cancers. CONCLUSION: There has been a decrease in the incidence and incidence-based mortality of ovarian, fallopian tube, and primary peritoneal cancer, primarily due to reductions in advanced stage epithelial cancers originating in the ovary, fallopian tube, or peritoneum.

Bile Spillage as a Prognostic Factor for Gall Bladder Cancer: A Systematic Review and Meta-Analysis.

INTRODUCTION: Biliary spillage (BS) is a common complication following initial cholecystectomy for gall bladder cancer (GBC). Few studies have explored the importance of BS as a long-term prognostic factor. We perform a meta-analysis of the association between BS and survival in GBC. METHODS: A systematic literature search was performed in February 2023. Studies evaluating the incidence of BS and its association with long-term outcomes in patients undergoing initial laparoscopic or open cholecystectomy for either incidental or resectable GBC were included. Overall survival (OS), disease-free survival (DFS), and rate of peritoneal carcinomatosis (RPC) were the primary end points. Forest plot analyses were used to calculate the pooled hazard ratios (HRs) of OS, DFS, and RPC. Metaregression was used to evaluate study-level association between BS and perioperative risk factors. RESULTS: Of 181 published articles, 11 met inclusion criteria with a sample size of 1116 patients. The rate of BS ranged between 9% and 67%. On pooled analysis, BS was associated with worse OS (HR = 1.68, 95% confidence interval [CI] = 1.32-2.14), DFS (pooled HR= 2.19, 95% CI = 1.30-3.68), and higher RPC (odds ratio = 9.37, 95% CI = 3.49-25.2). The rate of BS was not associated with higher T stage, lymph node metastasis, higher grade, positive margin status, reresection, or conversion rates. CONCLUSIONS: Our meta-analysis shows that BS is a predictor of higher peritoneal recurrence and poor survival in GBC. BS was not associated with tumor characteristics or conversion rates. Further research is needed to identify other potential risk factors for BS and investigate the ideal treatment schedule to improve survival.

Incidence of incisional hernia in patients undergoing cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: an observational clinical study from a tertiary oncology referral care center in India.

BACKGROUND: An incisional hernia (IH) after major abdominal surgery is an unwanted complication particularly following cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS and HIPEC). The frequency of IH among patients treated with CRS and HIPEC remains unexpectedly high in various studies. This study aimed to analyze the incidence, determine the factors contributing to the occurrence of IH, and develop methods to reduce the incidence of IH. METHODS: We retrospectively analyzed data from a prospectively maintained structured computerized comprehensive database of 360 patients who had undergone CRS and HIPEC after January 2013 and completed two years of follow-up before December 2023. All patients were followed for a minimum period of two years with physical examination and radiological imaging when required and the occurrence of IH was documented. We used SPSS software version 24 to analyze the data using appropriate statistical tests. We set a significance threshold of p < 0.05. RESULTS: Within two years of undergoing CRS and HIPEC, 25 patients (6.9%) out of 360 developed IH, indicating an annual incidence rate of 3.5%. The mean duration of hospitalization for the CRS/HIPEC procedure was 8.4 ± 4.13 days. Fifty-two (14.4%) patients experienced early post-operative surgical complications. The development of IH in our series was significantly associated with obesity (76% vs. 8.4%, P = 0.001), the occurrence of early post-operative surgical complications (48% vs. 12%, P = 0.001), mainly category III complications (44% vs. 7.1%), category IV complications (24% vs. 2.9%) according to Clavien-Dindo classification, post neoadjuvant chemotherapy status (72% vs. 87%, P = 0.045) and need for bowel anastomosis (32% vs. 11%, P = 0.002). CONCLUSION: The lower incidence of IH following CRS and HIPEC in our patient cohort than in the literature can be attributed to a combination of factors, including the use of meticulous surgical techniques and the use of an abdominal binder postoperatively, particularly in obese patients.

Pathological findings and long-term prognosis in Korean BRCA1/2 mutation carriers undergoing risk-reducing salpingo-oophorectomy.

OBJECTIVE: Our study aimed to evaluate the incidence of pathological findings in asymptomatic Korean patients with BRCA1/2 pathogenic variants who underwent risk-reducing salpingo-oophorectomy and to assess their long-term prognosis. METHODS: We retrospectively analyzed the medical records of patients with a germinal BRCA1/2 pathologic variant who had undergone risk-reducing salpingo-oophorectomy at Asan Medical Center (Seoul, Korea) between January 2013 and December 2020. All pathologic reports were made based on the sectioning and extensively examining the fimbriated end of the fallopian tube (SEE/FIM) protocol. RESULTS: Out of 243 patients who underwent risk-reducing salpingo-oophorectomy, 121 (49.8%) had a BRCA1 mutation, 119 (48.9%) had a BRCA2 mutation, and three (1.2%) had both mutations. During the procedure, four (3.3%) patients with a BRCA1 mutation were diagnosed with serous tubal intraepithelial carcinoma (STIC) or serous tubal intraepithelial lesion (STIL), and another four patients (3.3%) were diagnosed with occult cancer despite no evidence of malignancy on preoperative ultrasound. In the BRCA2 mutation group, we found one (0.8%) case of STIC, but no cases of STIL or occult cancer. During the median follow-up period of 98 months (range, 44-104) for STIC and 54 months (range, 52-56) for STIL, none of the patients diagnosed with these precursor lesions developed primary peritoneal carcinomatosis. CONCLUSIONS: Risk-reducing salpingo-oophorectomy, in asymptomatic Korean patients with BRCA1/2 pathogenic variants, detected ovarian cancer and precursor lesions, including STIC or STIL. Furthermore, our follow-up period did not reveal any instances of primary peritoneal carcinomatosis, suggesting a limited body of evidence supporting the imperative need for adjuvant treatment in patients diagnosed with these precursor lesions during risk-reducing salpingo-oophorectomy.

Epidemiology, oncologic results and risk stratification model for metachronous peritoneal metastases after surgery for pT4 colon cancers: results from an observational retrospective multicentre long-term follow-up study.

PURPOSE: Metachronous peritoneal metastases (MPM) following a curative surgery procedure for pT4 colon cancer is a challenging condition. Current epidemiological studies on this topic are scarce. METHODS: A retrospective multicentre trial was designed. All consecutive patients who underwent operations to treat pT4 cancers between 2015 and 2017 were reviewed. Demographic, clinical, operative, pathological and oncological follow-up variables were included. MPM were described as any oncological disease at the peritoneum, clearly different from a local recurrence. Univariate and multivariate Cox regression models were constructed. A risk stratification model was created on a cumulative factor basis. According to the calculated hazard ratio (HR), a scoring system was designed (HR < 3, 1 point; HR > 3, 2 points) and a scale from 0 to 6 was calculated for peritoneal disease-free rate (PDF-R). A risk stratification model was also created on the basis of these calculations. RESULTS: Fifty different hospitals were involved, which included a total of 1356 patients. Incidence of MPM was 13.6% at 50 months median follow-up. The strongest independent risk factors for MPM were positive pN stage [HR 3.72 (95% CI 2.56-5.41; p < 0.01) for stage III disease], tumour perforation [HR 1.91 (95% CI 1.26-2.87; p < 0.01)], mucinous or signet ring cell histology [HR 1.68 (95% CI 1.1-2.58; p = 0.02)], poorly differentiated tumours [HR 1.54 (95% CI 1.1-2.2; p = 0.02)] and emergency surgery [HR 1.42 (95% CI 1.01-2.01; p = 0.049)]. In the absence of additional risk factors, pT4 tumours showed 98% and 96% PDF-R in 1-year and 5-year periods based on Kaplan-Meier curves. CONCLUSIONS: Cumulative MPM incidence was 13.6% at 5-year follow-up. The sole presence of a pT4 tumour resulted in high rates of PDF-R at 1-year and 5-year follow-up (98% and 96% respectively). Five additional risk factors different from pT4 status itself were identified as possible MPM indicators during follow-up.

Incidence, treatment and survival of malignant pleural and peritoneal mesothelioma: a population-based study.

INTRODUCTION: Malignant mesothelioma (MM) is an aggressive cancer that primarily arises from the pleura (MPM) or peritoneum (MPeM), mostly due to asbestos exposure. This study reviewed the Dutch population-based incidence, treatment and survival since the national ban on asbestos in 1993. MATERIALS AND METHODS: Patients with MPM or MPeM diagnosed from 1993 to 2018 were selected from the Dutch cancer registry. Annual percentage change (APC) was calculated for (age-specific and sex-specific) revised European standardised incidence rates (RESR). Treatment pattern and Kaplan-Meier overall survival analyses were performed. RESULTS: In total, 12 168 patients were included in the study. For male patients younger than 80 years, the MM incidence significantly decreased in the last decade (APC ranging between -9.4% and -1.8%, p<0.01). Among both male and female patients aged over 80 years, the incidence significantly increased during the entire study period (APC 3.3% and 4.6%, respectively, p<0.01). From 2003 onwards, the use of systemic chemotherapy increased especially for MPM (from 9.3% to 39.4%). Overall, 62.2% of patients received no antitumour treatment. The most common reasons for not undergoing antitumour treatment were patient preference (42%) and performance status (25.6%). The median overall survival improved from 7.3 (1993-2003) to 8.9 (2004-2011) and 9.3 months from 2012 to 2018 (p<0.001). CONCLUSION: The peak of MM incidence was reached around 2010 in the Netherlands, and currently the incidence is declining in most age groups. The use of systemic chemotherapy increased from 2003, which likely resulted in improved overall survival over time. The majority of patients do not receive treatment though and prognosis is still poor.

Occurrence of peritoneal carcinomatosis in patients with rectal cancer undergoing staging pelvic MRI: clinical observations.

OBJECTIVES: Describe the cumulative incidence (CUIN) of peritoneal carcinomatosis (PC) and survival in patients presenting with advanced rectal cancer at staging pelvic MRI. METHODS: From 2013 to 2018, clinicopathologic records of patients with pretreatment rectal MRI clinical (c)T3c, cT3d, cT4a, and cT4b primary rectal adenocarcinoma were retrospectively reviewed by two radiologists. Standard MRI descriptors and pathologic stages were recorded. Recurrence-free (RFS) and overall survival (OS) were estimated using the Kaplan-Meier method. Development of PC was explored using competing risk analysis. Differences in survival were compared using the log-rank test. Gray's test was used to test for differences in CUIN of PC. RESULTS: Three hundred forty-three patients (147 women; median age, 56 years) had MRI stages cT3cd, n = 170; cT4a, n = 40; and cT4b, n = 133. Median follow-up among survivors was 27 months (0.36-70 months). For M1 patients, OS differed only by cT stage (2-year OS: cT3 88.1%, cT4a 79.1%, cT4b 64.7%, p = 0.045). For M0 patients, OS and RFS differed only by pathological (p)T stage. We observed a statistically significant difference in the cumulative incidence of PC by cT stage (2-year CUIN: cT3 3.2%, cT4a 8.5%, cT4b 1.6%, p = 0.01), but not by pT stage. Seventy-nine patients (23%) presented with metastatic disease (M1), eight with PC (2.3%). Overall, eight patients presented with PC (cT4a: n = 4, other stages: n = 4) and 22 developed PC (cT4a: n = 5, other stages: n = 17). CONCLUSIONS: PC is uncommon in rectal cancer. MRI-based T stage exhibited an overall association with the cumulative incidence of PC, and descriptively, cT4a stage appears to have the highest CUIN. KEY POINTS: • In a retrospective study of 343 patients with rectal cancer undergoing baseline MRI and clinical follow-up, we found that peritoneal carcinomatosis was rare. • We observed a significant overall association between PC at presentation and cT stage that appeared to be driven by the higher proportion of cT4a patients presenting with PC. • Among patients that did not present with PC, we observed a significant overall association between time to PC and cT stage that may be driven by the higher cumulative incidence of PC in cT4a patients.

Addition of sintilimab to nanoparticle albumin-bound paclitaxel and S-1 as adjuvant therapy in stage IIIC gastric cancer.

The prognosis of stage III gastric cancer (GC) is not satisfying and the specific chemotherapy regimens for GC of stage IIIC based on the 8th edition of the UICC/AJCC TNM staging system are still inconclusive. Peritoneal recurrence is the common and severe relapse pattern. Nanoparticle albumin-bound paclitaxel (Nab-PTX) is safer and more effective than PTX in the peritoneal metastasis. Clinical trial has demonstrated the safety and efficacy of sintilimab in GC. A combination of Nab-PTX, S-1 and sintilimab could be a promising triplet regimen as adjuvant therapy for GC. The aim of this article is to describe the design of this prospective Dragon-VII trial, conducted to evaluate the safety and efficacy of the combination of Nab-PTX, S-1 and sintilimab. Clinical trial registration: NCT04781413.

Lay abstract The prognosis of stage IIIC gastric cancer is poor and the treatment for it is not satisfying. This is a clinical trial that aims to explore a more effective therapy in gastric cancer patients of stage IIIC. Patients with stage IIIC gastric cancer must meet all of the inclusion criteria and none of the exclusion criteria to be eligible for this trial. The eligible patients will be given eight cycles of combinatory therapy of albumin-bound paclitaxel, a chemotherapy (day 1 and day 8), and S-1, another chemotherapy (days 1 to 14), plus sintilimab, a type of immunotherapy called an immune checkpoint inhibitor (day 1) every 3 weeks and then sintilimab maintenance for up to 12 months.

Comparison between signet-ring cell carcinoma and non-signet-ring cell carcinoma of the stomach: clinicopathological parameters, epidemiological data, outcome, and prognosis-a cohort study of 123 patients from a non-endemic country.

BACKGROUND: Signet-ring cell carcinoma of the stomach (SRCC) is a particular gastric cancer entity. Its incidence is increasing. Its diagnosis is pathological; it corresponds to adenocarcinoma with a majority of signet-ring cells component (> 50%). These histological features give it its aggressiveness characteristics. This has repercussions on the prognostic level and implications for the alternatives of therapy, especially since some authors suggest a potential chemoresistance. This survey aimed to identify the epidemiological, pathological, therapeutic, and prognostic characteristics of SRCC as a separate disease entity. METHODS: This was a retrospective study of 123 patients admitted for gastric adenocarcinoma to Habib Thameur Hospital in Tunis over 11 years from January 2006 to December 2016. A comparative study was performed between 2 groups: the SRCC group with 62 patients and the non-SRCC (non-signet-ring cell carcinoma of the stomach) with 61 patients. RESULTS: The prevalence of SRCC in our series was 50%. SRCC affected significantly younger patients (55 vs 62 years; p = 0.004). The infiltrative character was more common in SRCC tumors (30.6 vs 14.8%; p = 0.060), whereas the budding character was more often noted in non-SRCC tumors (78.7 vs 58.1%; p = 0.039). There was no significant difference in tumor localization between both groups. Linitis plastica was noted in 14 patients with SRCC against a single patient with non-SRCC (p = 0.001). The tumor size was more important in the non-SRCC group (6.84 vs 6.39 cm; p = 0.551). Peritoneal carcinomatosis was noted in 4.3% of cases in the SRCC group versus 2.2% of cases in the NSRCC group (p = 0.570). Total gastrectomy was more often performed in the SRCC group (87 vs 56%; p = 0.001). Resection was more often curative in the non-SRCC group (84.4 vs 78.3%; p = 0.063). Postoperative chemotherapy was more commonly indicated in the SRCC group (67.4 vs 53.3%; p = 0.339). Tumor recurrence was more common in the non-SRCC group (35.7 vs 32%; p = 0.776). The most common type of recurrence was peritoneal carcinomatosis in the SRCC group (62.5%) and hepatic metastasis in the non-SRCC group (60%; p = 0.096). The overall 5-year survival in the SRCC group was lower than in the non-SRCC group, with no statistically significant difference (47.1 vs 51.5%; p = 0.715). The overall survival was more important for SRCC in early cancer (100 vs 80%; p = 0.408), whereas it was higher for non-SRCC in advanced cancer (48.1 vs 41.9%; p = 0.635). CONCLUSION: Apart from its epidemiological and pathological features, SRCC seems to have a worse prognosis. Indeed, it is diagnosed at a more advanced stage and has a worse prognosis in advanced cancer than non-SRCC. It is therefore to be considered as a particular entity of gastric adenocarcinoma requiring a specific therapeutic protocol where the place of chemotherapy remains to be more investigated.

Estimating the Prevalence of Pseudomyxoma Peritonei in Europe Using a Novel Statistical Method.

BACKGROUND: The determination of the incidence and prevalence of rare diseases is important for economists and health-care providers. Pseudomyxoma peritonei (PMP) is a rare, slow-growing abdominal cancer that represents a substantial burden on both patients and health-care systems. The incidence rate was previously approximated at 1-2 people per million per year; this incidence has never been challenged, and the prevalence has not been estimated. METHODS: Epidemiological data from Norway and England were obtained and analysed to calculate a minimum incidence rate based on the number of patients having a first surgical intervention for PMP. A novel method was then used to determine a prevalence rate for PMP, incorporating incidence, death, and cure rates in a multi-year analysis that accounted for the increasing population of Europe over a 10-year period. RESULTS: An incidence rate of 3.2 people per million per year was calculated, with a corresponding estimated prevalence rate of 22 people per million per year. By this calculation, 11,736 people in Europe were estimated to be living with PMP in 2018. CONCLUSION: Incidence and prevalence are essential tools for assessment of the financial and human cost of a disease. For rare diseases, such as PMP, the lack of accurate registries presents a particular challenge in determining such health-related statistical parameters. Based on our calculations, a significant number of people are living with PMP in Europe, underlining the need for appropriate resource allocation to ensure that adequate health-care measures are provided.

Decision-Making Analysis for Hyperthermic Intraperitoneal Chemotherapy in Ovarian Cancer: A Survey by the Executive Committee of the Peritoneal Surface Oncology Group International (PSOGI).

OBJECTIVES: To assess the individual treatment strategies among international experts in peritoneal carcinosis, specifically their decision-making in the process of patient selection for hyperthermic intraperitoneal chemotherapy (HIPEC) in women suffering from ovarian cancer, to identify relevant decision-making criteria, and to quantify the level of consensus for or against HIPEC. METHODS: The members of the executive committee of the Peritoneal Surface Oncology Group International (PSOGI) were asked to describe the clinical conditions under which they would recommend HIPEC in patients with ovarian cancer and to describe any disease or patient characteristics relevant to their decision. All answers were then merged and converted into decision trees. The decision trees were then analyzed by applying the objective consensus methodology. RESULTS: Nine experts in surgical oncology provided information on their multidisciplinary treatment strategy including HIPEC for patients with advanced ovarian cancer. Three of the total of 12 experts did not perform HIPEC. Five criteria relevant to the decision on whether HIPEC is performed were applied. In patients with resectable disease, a peritoneal cancer index (PCI) <21, and epithelial ovarian cancer without distant metastasis, consent was received by 75% to perform HIPEC for women suffering from recurrent disease. Furthermore, in the primary disease setting, consent was received by 67% to perform HIPEC according to the same criteria. DISCUSSION AND CONCLUSION: Among surgical oncology experts in peritoneal surface malignancy and HIPEC, HIPEC plays an important role in primary and recurrent ovarian cancer, and the PCI is the most important criterion in this decision.

Incidence and survival of epithelial ovarian, fallopian tube, peritoneal, and undesignated abdominal/pelvic cancers in Sweden 1960-2014: A population-based cohort study.

BACKGROUND: Despite improved surgical and oncological treatment, ovarian cancer continues to be the most lethal of the gynecologic malignancies. We aimed to analyze survival trends in epithelial ovarian cancer with regard to age, tumor site, and morphology in Sweden 1960 to 2014. METHODS: A nationwide population-based study was conducted using data from the Swedish Cancer Registry on 46,350 women aged 18 or older with a diagnosis of epithelial ovarian, fallopian tube, peritoneal, or undesignated abdominal/pelvic cancer 1960 to 2014. Analyses of age-standardized incidence and relative survival (RS) were performed and time trends modelled according to age, tumor site, and morphology. RESULTS: Overall incidence of ovarian, tubal, peritoneal, and undesignated abdominal/pelvic cancers declined since 1980. Median age at diagnosis increased. Serous carcinoma increased in incidence. RS at 1, 2 and 5 years from diagnosis improved since 1960, although not for the youngest and the oldest patients. Ten-year RS did not improve. The best RS was found for fallopian tube cancer and the worst RS for undesignated abdominal/pelvic cancer. Among the morphologic subgroups, endometrioid carcinoma had the best RS. CONCLUSIONS: Survival in epithelial ovarian, tubal, peritoneal, and undesignated abdominal/pelvic cancers in Sweden has improved over the last six decades. Advances in epithelial ovarian cancer treatment have extended life for the first 5 years from diagnosis but 10-year survival remains poor.

Metastatic colo-rectal cancer: real life experience from an Indian tertiary care center.

BACKGROUND: No data exist for the long-term outcome of metastatic colorectal cancer (mCRC) from the Southern part of Asia. The primary objective of the study is to evaluate the survival outcome of mCRC from an Indian tertiary care center. The study also aims to highlight the treatment pattern practiced and the unique clinico-pathologic characteristics. METHODS: This is a single-center retrospective observational study done at a large referral tertiary care center in North India. All patients with synchronous or metachronous mCRC who received at least one dose of chemotherapy for metastatic disease, registered between 2003 to 2017 were included. Primary outcome measures were overall survival and progression-free survival and prognostic factors of overall survival. Descriptive analysis was done for the clinicopathological characteristics and treatment patterns. Kaplan Meier method for overall survival and progression-free survival. Cox regression analysis was performed for the determination of the prognostic factors for overall survival. RESULT: Out of 377 eligible patients, 256 patients (68%) had de novo metastatic disease and the remaining 121 (32%) progressed to metastatic disease after initial treatment. The cohort was young (median age, 46 years) with the most common primary site being the rectum. A higher proportion of signet (9%) and mucinous histology (24%). The three common sites of metastasis were the liver, peritoneum, and lung. In the first line, most patients received oxaliplatin-based chemotherapy (70%). Only 12.5% of patients received biologicals in the first-line setting. The median follow-up and median overall survival of study cohort were 17 months and 18.5 months. The factors associated with poor outcome for overall survival on multivariate analysis were ECOG performance status of > 1, high CEA, low albumin, and the number of lines of chemotherapy received (< 2). CONCLUSION: The outcome of mCRC is inferior to the published literature. We found a relatively higher proportion of patients with the following characteristics; younger, rectum as primary tumor location, the signet, and mucinous histology, higher incidence of peritoneum involvement. The routine use of targeted therapies is limited. Government schemes (inclusion of targeted therapies in the Ayushman scheme), NGO assistance, and availability of generic low-cost targeted drugs may increase the availability.

Metachronous peritoneal metastases following curative resection for colon cancer: Understanding risk factors and patterns of recurrence.

BACKGROUND: A subset of metachronous colon cancer recurrence manifests as peritoneal metastases (PM). Risk factors for metachronous PM recurrence are not well-defined in patients with stage II or III colon cancers after curative resection and standard adjuvant treatments. METHODS: Population data from the California Cancer Registry for patients with Stage II or III colon cancer were collected between 2004 and 2012. Multivariate analysis was used to identify factors associated with metachronous PM. RESULTS: Of the 2077 patients with stage II or III colon cancer, female patients (odds ratio [OR] = 1.84, p = 0.02), T4 primary tumor (OR = 2.36, p = 0.02), mucinous (OR = 3.97, p < 0.01) or signet-ring histology (OR = 6.01, p = 0.01), and right-sided cancer (OR = 2.2, p < 0.01) were found with increased risk of metachronous isolated PM recurrence after curative resection. Median survival after diagnosis for patients without PM recurrence was 22 months, compared with 12 months for PM recurrence (p < 0.001). CONCLUSION: PM recurrence groups have a worse overall survival than patients with recurrent disease in other sites. A better understanding of the tumor biology and molecular characteristics of colon cancers likely to recur as PM is needed to explain behavior and identify potential targeted therapy.

Epidemiology and outcome of peritoneal and pleural mesothelioma subtypes in Norway. A 20 year nation-wide study.

BACKGROUND: Mesothelioma of the pleural or peritoneal cavities is one of the deadliest cancer types. The incidence of pleural subtypes has decreased over time due to decrease in asbestos exposure, and the current treatment landscape is changing due to introduction of novel therapies. In this study we have analysed contemporary epidemiological data of mesothelioma on a national level before the advent of immunotherapy. MATERIAL AND METHODS: Complete national data on 1509 pleural and peritoneal malignant mesothelioma from the Cancer Registry of Norway from 2000 to 2019 are presented. Age standardised incidence and median survival were calculated. RESULTS: The age-standardised incidence of pleural mesothelioma among males has decreased from 1.7 per 100 000 in 2000-2004 to 1.1 in 2015-2019, whereas the incidence for females has been stable, lower than 0.3 per 100 000 throughout the period. Incidence of peritoneal mesotheliomas remained low, below 0.08 per 100 000. The female to male ratio among pleural mesotheliomas was 1:7 with no differences among morphological subtypes, whereas this ratio was 1:1.2 in peritoneal mesotheliomas. Median age at diagnosis for pleural mesothelioma was 73 years and 76 years for females and males respectively in the last 5-year period, and 67 years for peritoneal mesotheliomas of both sexes. Median survival among pleural mesotheliomas has been stable, with significantly worse prognosis among sarcomatoid subtype (5.4 months) compared to epithelioid subtype (15.8 months). Peritoneal mesothelioma of the epithelioid subtype, representing 38% of cases, had a median survival of 43.3 months, contrasting the non-epithelioid subtype of 5.1 months. DISCUSSION: Mesothelioma is still a significant disease with a dismal prognosis. Improvement in treatment is warranted.

Differences in Metastatic Pattern in Patients Presenting With or Without Obstructing Colorectal Cancer: A Retrospective Observational Study of 2595 Patients.

BACKGROUND: Little is known about metastatic patterns in patients with obstructing colorectal cancer (CRC). OBJECTIVE: The aim of this study was to determine if metastatic patterns in patients with CRC differ between patients with or without obstruction. METHODS: This single-center, observational, retrospective cohort study includes patients who underwent surgery for CRC between 2004 and 2015 in our hospital. Patients were divided into two groups-patients with or without obstructing CRC. All anatomic sites of distant metastases were reported. Differences in synchronous and metachronous metastases were compared between both groups. RESULTS: A total of 2595 patients were included for analysis, of whom 315 (12%) presented with obstructing CRC. Synchronous metastases were diagnosed in 483 patients (19%). Patients with obstructing CRC and synchronous metastases, were diagnosed with peritoneal metastases more often than patients without obstruction (37% vs. 16%; p < 0.01). With regard to the location of the tumor, obstructing right-sided CRC patients were diagnosed with peritoneal metastases more often than patients without obstruction (52% vs. 21%; p < 0.01). Additionally, metachronous metastases were found significantly more often in patients with obstructing CRC (27%) compared with patients without obstruction (15%; p < 0.01). CONCLUSIONS: Patients with obstructing CRC have more advanced tumor stage compared with patients without obstructing CRC. Synchronous peritoneal metastases are more often encountered in patients with obstructing CRC compared with patients without obstruction. This difference is due to the raised presence of synchronous peritoneal metastases in patients with obstructed right-sided colonic cancer. Furthermore, metachronous metastases are more often found in patients with obstructing CRC.

Prophylactic HIPEC in pT4 Colon Tumors: Proactive Approach or Overtreatment?

BACKGROUND: The peritoneum is the second most common site for metastasis in patients with colorectal cancer. Various factors have been studied to identify patients at risk of developing peritoneal carcinomatosis (PC), including T4 tumors. The objectives were to assess the incidence of synchronous and metachronous PC, explore potential risk factors for developing PC as the only site of metastasis, and identify which patients might be candidates for prophylactic hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: We conducted a retrospective analysis of 125 patients with pT4 colon cancer who underwent surgery in a single center between January 2010 and December 2014. RESULTS: Of the 947 colon cancer patients who underwent surgery, 125 (13.2%) were diagnosed with pT4a or b colon carcinoma. The median follow-up was 3.7 years. The overall rate of PC was 34.3%, being synchronous in 12% and metachronous in 22.3% of cases. The 8% and 6% of synchronous and metachronous cases of PC respectively were isolated (single site) metastasis. The incidence of PC was 6.1% at 1 year and 14.5% at 3 years after surgery. pT4 was not found to be an independent risk factor for the development of PC (p = 0.231). Nonetheless, the rate of metachronous PC as a single site of metastasis was higher in patients with pT4 tumors and peritoneal nodules around the primary tumor and/or tumor perforation (p = 0.027) and/or who underwent emergency surgery (p = 0.043) than other patients. CONCLUSIONS: Considering pT4 tumor stage as the only risk factor for the development of PC in deciding whether to administer prophylactic HIPEC would lead to unjustified overtreatment.

Synchronous and Metachronous Peritoneal Metastases in Patients with Left-Sided Obstructive Colon Cancer.

BACKGROUND: Controversy exists on emergency setting as a risk factor for peritoneal metastases (PM) in colon cancer patients. Data in patients with obstruction are scarce. The aim of this study was to determine the incidence of synchronous and metachronous PM, risk factors for the development of metachronous PM, and prognostic implications within a large nationwide cohort of left-sided obstructive colon cancer (LSOCC). METHODS: Patients with LSOCC treated between 2009 and 2016 were selected from the Dutch ColoRectal Audit. Additional treatment and long-term outcome data were retrospectively collected from original patient files in 75 hospitals in 2017. RESULTS: In total, 3038 patients with confirmed obstruction and without perforation were included. Synchronous PM (at diagnosis or < 30 days postoperatively) were diagnosed in 148/2976 evaluable patients (5.0%), and 3-year cumulative metachronous PM rate was 9.9%. Multivariable Cox regression analyses revealed pT4 stage (HR 1.782, 95% CI 1.191-2.668) and pN2 stage (HR 2.101, 95% CI 1.208-3.653) of the primary tumor to be independent risk factors for the development of metachronous PM. Median overall survival in patients with or without synchronous PM was 20 and 63 months (p < 0.001) and 3-year overall survival of patients that did or did not develop metachronous PM was 48.1% and 77.0%, respectively (p < 0.001). CONCLUSION: This population based study revealed a 5.0% incidence of synchronous peritoneal metastases in patients who underwent resection of left-sided obstructive colon cancer. The subsequent 3-year cumulative metachronous PM rate was 9.9%, with advanced tumor and nodal stage as independent risk factors for the development of PM.

The Impact of Primary Tumor Location in Synchronous Metastatic Colorectal Cancer: Differences in Metastatic Sites and Survival.

PURPOSE: We explored differences in survival between primary tumor locations, hereby focusing on the role of metastatic sites in synchronous metastatic colorectal cancer (mCRC). METHODS: Data for patients diagnosed with synchronous mCRC between 1989 and 2014 were retrieved from the Netherlands Cancer registry. Relative survival and relative excess risks (RER) were analyzed by primary tumor location (right colon (RCC), left colon (LCC), and rectum). Metastatic sites were reported per primary tumor location. Survival was analyzed for metastatic sites combined and for single metastatic sites. RESULTS: In total, 36,297 patients were included in this study. Metastatic sites differed significantly between primary tumor locations, with liver-only metastases in 43%, 54%, and 52% of RCC, LCC, and rectal cancer patients respectively (p < 0.001). Peritoneal metastases were most prevalent in RCC patients (33%), and lung metastases were most prevalent in rectal cancer patients (28%). Regardless of the location of metastases, patients with RCC had a worse survival compared with LCC (RER 0.81, 95% CI 0.78-0.83) and rectal cancer (RER 0.73, 95% CI 0.71-0.76). The survival disadvantage for RCC remained present, even in cases with metastasectomy for liver-only disease (LCC: RER 0.66, 95% CI 0.57-0.76; rectal cancer: RER 0.84, 95% CI 0.66-1.06). CONCLUSIONS: This study showed significant differences in relative survival between primary tumor locations in synchronous mCRC, which can only be partially explained by distinct metastatic sites. Our findings support the concept that RCC, LCC and rectal cancer should be considered distinct entities in synchronous mCRC.