Trends in epidemiology and primary treatment of anal squamous cell carcinoma in the Netherlands (1990-2021).

A rapid increase in the incidence of anal squamous cell carcinoma (SCC) was reported in several countries over the past decades. This study assessed trends in epidemiology and primary treatment over a 32-year period (1990-2021) using the Netherlands Cancer Registry. The study population included 4273 patients, 44.2% male and 55.8% female (median age 63 years). The age-standardised incidence rate (European Standardised Rate, ESR) increased from 0.5 to 1.6 per 100,000, which entailed an average annual percentage change (AAPC) of 5.0% (95% confidence interval [CI]: 4.5%-5.8%). While incidence among females increased continuously over the total period (AAPC 4.9%; 95%CI: 4.4%-5.6%), to 1.8 per 100,000 ESR in 2021, incidence among males increased until 2016 (annual percentage change [APC] of 6.3%; 95%CI: 5.6%-10.7%), after which it seemed to stabilise (APC -2.1%; 95%CI: -16.8%-4.5%). Significant trends were also observed in distribution of age, tumour stage and primary treatment modalities. Five-year relative survival (RS) was estimated using the Pohar-Perme estimator, and this improved from 56.1% in 1990-1997 (95%CI: 49.3%-62.4%) to 67.9% in 2014-2021 (95%CI: 64.7%-70.9%), but remained poor for stage IV disease. Evaluation through a multivariable Poisson regression model demonstrated diagnosis in the most recent period to be independently associated with better RS, in addition to female sex, younger age, early disease stage and any treatment. In conclusion, the rising incidence of anal SCC seems to decline in males, but not in females, and advances in diagnostics and therapeutic management have likely contributed to improved prognosis.

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.

Towards Equal Access to Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy and Survival in Patients with Isolated Colorectal Peritoneal Metastases: A Nationwide Population-Based Study.

BACKGROUND: Before 2016, patients with isolated synchronous colorectal peritoneal metastases (PMCRC) diagnosed in expert centers had a higher odds of undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) and better overall survival (OS) than those diagnosed in referring centers. Nationwide efforts were initiated to increase awareness and improve referral networks. METHODS: This nationwide study aimed to evaluate whether the between-center differences in odds of undergoing CRS-HIPEC and OS have reduced since these national efforts were initiated. All patients with isolated synchronous PMCRC diagnosed between 2009 and 2021 were identified from the Netherlands Cancer Registry. Associations between hospital of diagnosis and the odds of undergoing CRS-HIPEC, as well as OS, were assessed using multilevel multivariable regression analyses for two periods (2009-2015 and 2016-2021). RESULTS: In total, 3948 patients were included. The percentage of patients undergoing CRS-HIPEC increased from 17.2% in 2009-2015 (25.4% in expert centers, 16.5% in referring centers), to 23.4% in 2016-2021 (30.2% in expert centers, 22.6% in referring centers). In 2009-2015, compared with diagnosis in a referring center, diagnosis in a HIPEC center showed a higher odds of undergoing CRS-HIPEC (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.02-2.67) and better survival (hazard ratio [HR] 0.80, 95% CI 0.66-0.96). In 2016-2021, there were no differences in the odds of undergoing CRS-HIPEC between patients diagnosed in HIPEC centers versus referring centers (OR 1.27, 95% CI 0.76-2.13) and survival (HR 1.00, 95% CI 0.76-1.32). CONCLUSION: Previously observed differences in odds of undergoing CRS-HIPEC were no longer present. Increased awareness and the harmonization of treatment for PMCRC may have contributed to equal access to care and a similar chance of survival at a national level.

A propensity score-matched analysis of oncological outcome after systemic therapy for stage IV colorectal cancer: Impact of synchronous ovarian metastases.

The reported incidence of synchronous and metachronous ovarian metastases (OM) from colorectal cancer (CRC) is ~3.4%. OM from CRC are often considered sanctuary sites due to their lower sensitivity to systemic treatment. It has thus been hypothesized that the presence of OM decreases overall survival. Therefore, the purpose of our study was to evaluate the impact of synchronous OM on overall survival in female patients with stage IV CRC treated with systemic therapy alone with palliative intent. The present study used data from the Netherlands Cancer Registry and included female CRC patients with synchronous systemic metastases who were treated with systemic therapy between 2008 and 2018. A subsample was created using propensity score matching to create comparable groups. Propensity scores were determined using a logistic regression model in which the dependent variable was the presence of OM and the independent variables were the variables that differed significantly between both groups. Our study included 5253 patients with stage IV CRC that received systemic therapy. Among these patients, 161 (3%) had OM while 5092 (97%) had extra-ovarian metastases only. Three-year overall survival rates did not show a significant difference between patients with OM compared to patients without ovarian metastases. Moreover, the propensity score-matched analysis showed that the presence of OM in patients treated with systemic therapy for stage IV CRC disease was not associated with decreased 3-year overall survival. However, the results of the present study should be interpreted with caution, due to its observational character and used selection criteria.

Locally Recurrent Rectal Cancer: Toward a Second Chance at Cure? A Population-Based, Retrospective Cohort Study.

BACKGROUND: In current practice, rates of locally recurrent rectal cancer (LRRC) are low due to the use of the total mesorectal excision (TME) in combination with various neoadjuvant treatment strategies. However, the literature on LRRC mainly consists of single- and multicenter retrospective cohort studies, which are prone to selection bias. The aim of this study is to provide a nationwide, population-based overview of LRRC after TME in the Netherlands. PATIENTS AND METHODS: In total, 1431 patients with nonmetastasized primary rectal cancer diagnosed in the first six months of 2015 and treated with TME were included from the nationwide, population-based Netherlands Cancer Registry. Data on disease recurrence were collected for patients diagnosed in these 6 months only. Competing risk cumulative incidence, competing risk regression, and Kaplan-Meier analyses were performed to assess incidence, risk factors, treatment, and overall survival (OS) of LRRC. RESULTS: Three-year cumulative incidence of LRRC was 6.4%; synchronous distant metastases (LRRC-M1) were present in 44.9% of patients with LRRC. Distal localization, R1-2 margin, (y)pT3-4, and (y)pN1-2 were associated with an increased LRRC rate. No differences in LRRC treatment and OS were found between patients who had been treated with or without prior n(C)RT. Curative-intent treatment was given to 42.9% of patients with LRRC, and 3-year OS thereafter was 70%. CONCLUSIONS: Nationwide LRRC incidence was low. A high proportion of patients with LRRC underwent curative-intent treatment, and OS of this group was high in comparison with previous studies. Additionally, n(C)RT for primary rectal cancer was not associated with differences in treatment and OS of LRRC.

Locoregionally Recurrent Colon Cancer: How Far Have We Come? A Population-Based, Retrospective Cohort Study.

BACKGROUND: The reported outcomes of locoregionally recurrent colon cancer (LRCC) are poor, but the literature about LRCC is scarce and aged. Recent population-based studies to provide current insight into LRCC are warranted. This study aimed to provide an overview of the incidence, risk factors, treatment, and overall survival (OS) of patients with LRCC after curative resection of stage I-III primary colon cancer. METHODS: Data on disease recurrence were collected for all patients with a diagnosis of non-metastasized primary colon cancer in the Netherlands during the first 6 months of 2015. Patients who underwent surgical resection (N = 3544) were included in this study. The 3-year cumulative incidence, risk factors, treatment, and OS for patients with LRCC were determined. RESULTS: The 3-year cumulative incidence of LRCC was 3.8%. Synchronous distant metastases (LRCC-M1) were diagnosed in 62.7% of the patients. The risk factors for LRCC were age of 70 years or older, pT4, pN1-2, and R1-2. Adjuvant chemotherapy was associated with a decreased risk of LRCC for high-risk stage II and stage III patients [hazard ratio (HR), 0.47; 95% confidence interval (CI) 0.31-0.93]. The median OS for the patients with LRCC was 13.1 months (95% CI 9.1-18.3 months). Curative-intent treatment was given to 22.4% of the LRCC patients, and the subsequent 3 years OS was 71% (95% CI 58-87%). The patients treated with palliative treatment and best supportive care showed 3-year OS rates of 15% (95% CI 7.0-31%) and 3.7% (95% CI 1.0-14%), respectively. CONCLUSIONS: The cumulative incidence of LRCC was low, and adjuvant chemotherapy was associated with a decreased risk for LRCC among targeted patients. Curative-intent treatment was given to nearly 1 in 4 LRCC patients, and the OS for this group was high.

Gastrointestinal Symptoms After Resection of Esophagogastric Cancer: A Longitudinal Study on Their Incidence and Impact on Patient-Reported Outcomes.

BACKGROUND: This study assesses the incidence of gastrointestinal symptoms in the first year after resection of esophageal or gastric cancer and its association with health-related quality of life (HRQoL), functioning, work productivity, and daily activities. PATIENTS AND METHODS: Patients diagnosed with esophageal or gastric cancer between 2015 and 2021, who underwent a resection, and completed ≥ 2 questionnaires from the time intervals prior to resection and 0-3, 3-6, 6-9, and 9-12 months after resection were included. Multivariable generalized linear mixed models were used to assess changes in gastrointestinal symptoms over time and the impact of the number of gastrointestinal symptoms on HRQoL, functioning, work productivity, and daily activities for patients who underwent an esophagectomy or gastrectomy separately. RESULTS: The study population consisted of 961 (78.8%) and 259 (21.2%) patients who underwent an esophagectomy and gastrectomy, respectively. For both groups, the majority of gastrointestinal symptoms changed significantly over time. Most clinically relevant differences were observed 0-3 after resection compared with prior to resection and included increased diarrhea, appetite loss, and eating restrictions, and specifically after esophagectomy dry mouth, trouble with coughing, and trouble talking. At 9-12 after resection one or more severe gastrointestinal symptoms were reported by 38.9% after esophagectomy and 33.7% after gastrectomy. A higher number of gastrointestinal symptoms was associated with poorer functioning, lower HRQoL, higher impairment in daily activities, and lower work productivity. CONCLUSIONS: This study shows that gastrointestinal symptoms are frequently observed and burdensome after esophagectomy or gastrectomy, highlighting the importance to address these sequelae for high quality survivorship.

The impact of a multi-hospital network on the inequality in odds of receiving resection or ablation for synchronous colorectal liver metastases.

BACKGROUND: This study investigates whether inequalities in the utilization of resection and/or ablation for synchronous colorectal liver metastases (SCLM) between patients diagnosed in expert and non-expert hospitals changed since a multi-hospital network started. MATERIALS AND METHODS: Patients diagnosed with SCLM between 2009 and 2020 were included. The likelihood of receiving ablation and/or resection was analyzed in the prenetwork (2009-2012), startup (2013-2016), and matured-network (2017-2020) periods. RESULTS: Nationwide, 13.981patients were diagnosed between 2009 and 2020, of whom 1.624 were diagnosed in the network. Of patients diagnosed in the network's expert hospitals, 36.7% received ablation and/or resection versus 28.3% in nonexpert hospitals (p < 0.01). The odds ratio (OR) of receiving ablation and/or resection for patients diagnosed in expert versus nonexpert hospitals increased from 1.38 (p = 0.581, pre-network), to 1.66 (p = 0.108, startup), to 2.48 (p = 0.090, matured-network). Nationwide, the same trend occurred (respectively OR 1.41, p = 0.011; OR 2.23, p < 0.001; OR 3.20, p < 0.001). CONCLUSIONS: Patients diagnosed in expert hospitals were more likely to receive ablation and/or resection for SCLM than patients diagnosed in non-expert hospitals. This difference increased over time despite the startup of a multi-hospital network. Establishing a multi-hospital network did not have an effect on reducing the existing unequal odds of receiving specialized treatment. SYNOPSIS: Specialized oncology treatments are increasingly provided through multi-hospital networks. However, scant empirical evidence on the effectiveness of these networks exists. This study analyzes whether a regional multi-hospital network was able to improve equal access to specialized oncology treatments.

The impact of body weight on the development of peritoneal metastases in colorectal cancer patients: results from a nationwide cohort study.

BACKGROUND: Obesity is a major global health problem and an important risk factor for colorectal cancer (CRC) is increased body weight. Obesity plays a role in the peritoneal dissemination of cancer; however, it is unclear whether this also applies for peritoneal dissemination of CRC. The purpose of this study was to provide insight in the role of obesity on the peritoneal dissemination of colorectal cancer. METHODS: Of all patients diagnosed with CRC in the Netherlands in the first half of 2015, follow-up data was completed in 2019. Weight at time of primary diagnosis was categorized as underweight, normal weight, overweight, or obese. Logistic regression modelling was used to assess the association between weight and the presence of synchronous colorectal peritoneal metastases (CPM), and Cox regression modelling was used to assess the association between weight and metachronous CPM. Patient and tumor characteristics were taken into account. The analyses were adjusted for tumor stage, nodal stage, tumor location, and tumor histology. RESULTS: In total, 6436 patients were included in this study. Two-hundred ninety-three (4.6%) patients presented with synchronous CPM at the time of primary diagnosis, while another 278 (5.1%) patients developed metachronous CPM after a median time of 16.5 months. Univariable and multivariable logistic regression modelling did not identify an effect of weight on the presence of synchronous CPM. Neither underweight (odds ratio [OR] 1.10, 95% CI 0.48-2.54), nor overweight (OR 0.96, 95% CI 0.71-1.29), or obesity (OR 0.84, 95% CI 0.56-1.26) was either positively or negatively associated with the presence of synchronous peritoneal metastases as compared to normal weight. Univariable and multivariable Cox regression modelling did not identify an effect of weight on the development of metachronous CPM. Neither underweight (HR 0.162, 95% CI 0.02-1.16), nor overweight (HR 1.07, 95% CI 0.82-1.39), or obesity (HR 1.02, 95% CI 0.73-1.16) was either positively or negatively associated with the presence of synchronous peritoneal metastases as compared to normal weight. CONCLUSION: CRC patients who are overweight or obese are not more at risk for the presence of synchronous CPM nor development of metachronous CPM than their normal-weight counterparts.

Evaluation of an individual feedback report on patient-reported outcomes in the Prospective Dutch ColoRectal Cancer cohort.

PURPOSE: Returning patient-reported outcomes to patients might aid patients in detecting symptoms and might facilitate early intervention. This descriptive study evaluates the use of an individual feedback report on patient-reported outcomes for colorectal cancer patients and aims to assess differences in patient, tumor, and treatment characteristics and cohort retention between patients who opt and do not opt for the feedback report. METHODS: Patients with colorectal cancer participating in the nationwide Prospective Dutch ColoRectal Cancer Cohort, who filled in questionnaires digitally between June 2018 and January 2019, were included. Participants were given the option to receive a feedback report at baseline, 3, 6, and 12 months. The usefulness, content, and layout of the feedback report were evaluated. Differences in patient, tumor, and treatment characteristics, patient-reported outcomes, and cohort retention at subsequent questionnaires between participants who did and did not opt for feedback were assessed. RESULTS: A total of 484 participants were included of whom 293 (61%) opted for feedback. The feedback report was considered useful by 92%. No differences in patient, tumor, and treatment characteristics, and patient-reported outcomes were found between participants who did and did not opt for feedback. The response rate was higher among patients who opted for feedback compared to patients who did not opt for feedback at T3 (84 vs 74%), but not at T6 and T12. CONCLUSION: The feedback report was used by 6 out of 10 patients. The feedback report was considered valuable and associated with a higher subsequent response rate.

The impact of an open or laparoscopic approach on the development of metachronous peritoneal metastases after primary resection of colorectal cancer: results from a population-based cohort study.

BACKGROUND: This study aimed to assess the impact of open or laparoscopic resection of primary colorectal cancer (CRC) on the development of metachronous colorectal peritoneal metastases (CPM) in a population-based cohort. MATERIALS AND METHODS: This was a retrospective, population-based study of CRC patients who underwent open or laparoscopic resection of the primary tumour in the Netherlands between January 1st and June 30th 2015. Patients with synchronous metastases were excluded. CPM were considered metachronous if diagnosed ≥ 90 days after resection of primary CRC. Multivariable cox regression analysis was performed to correct for tumour location, histology, differentiation, and stage, nodal stage, tumour perforation, primary surgery type, and unclear resection margins. RESULTS: In total, 1516 CRC patients underwent open resection and 3236 CRC patients underwent laparoscopic resection, with a 3-year cumulative incidence of metachronous CPM of 7.3% and 3.7%, respectively (p < 0.001), after median follow-up of 42 months. Open surgical approach was significantly associated with the development of metachronous CPM: HR 1.4 [95%CI 1.1-1.8]. Other prognostic factors were mucinous adenocarcinoma histology (HR 1.6, 95%CI 1.0-2.5), T4 stage (HR 3.2, 95%CI 2.3-4.5), N1 stage (HR 2.9, 95%CI 2.1-4.0), and N2 stage (HR 4.2, 95%CI 2.9-6.1). CONCLUSIONS: Patients treated with open resection had a significantly higher risk to develop metachronous CPM than patients treated with laparoscopic resection. The mechanisms underlying this phenomenon remain unknown but might be related to differences in per-operative specimen handling, tumour spill, surgical trauma and pro-inflammatory response. This finding might imply the need for a personalized follow-up after primary resection of CRC.

Longitudinal effects of adjuvant chemotherapy and related neuropathy on health utility in stage II and III colon cancer patients: A prospective cohort study.

Patient's quality of life should be included in clinical decision making regarding the administration of adjuvant chemotherapy (ACT) in stage II/III colon cancer. Therefore, quality of life, summarized as health utility (HU), was evaluated for patients treated with and without ACT. Furthermore, the role of chemotherapy-induced peripheral neuropathy (CIPN) on HU was evaluated. Patients diagnosed with stage II/III colon cancer between 2011 and 2019 and participating in the Prospective Dutch ColoRectal Cancer cohort were included (n = 914). HU scores were assessed with the EQ-5D-5L at baseline, 3, 6, 12, 18, and 24 months. Patients treated with ACT received mainly capecitabine and oxaliplatin (57%) or capecitabine monotherapy (40%) (average duration: 3.5 months). HU 3 to 18 months after diagnosis (potential ACT period + 12 months follow-up) was compared between patients treated with and without ACT using a mixed model adjusted for age, sex and education level. Subsequently, the CIPN sensory, motor and autonomy scales, measured using the EORTC QLQ-CIPN20, were independently included in the model to evaluate the impact of neuropathy. Using a mixed model, a significant difference of -0.039 (95% confidence interval: -0.062; -0.015) in HU was found between patients treated with and without ACT. Including the CIPN sensory, motor and autonomy scales decreased the difference with 0.019, 0.015 and 0.02, respectively. HU 3 to 18 months after diagnosis is significantly lower in patients treated with ACT vs without ACT. This difference is on the boundary of clinical relevance and appears to be partly related to the sensory and motor neuropathy-related side effects of ACT.

Heterogeneity in Quality of Life of Long-Term Colon Cancer Survivors: A Latent Class Analysis of the Population-Based PROFILES Registry.

BACKGROUND: Long-term colon cancer survivors present heterogeneous health-related quality of life (HRQOL) outcomes. We determined unobserved subgroups (classes) of survivors with similar HRQOL patterns and investigated their stability over time and the association of clinical covariates with these classes. MATERIALS AND METHODS: Data from the population-based PROFILES registry were used. Included were survivors with nonmetastatic (TNM stage I-III) colon cancer (n = 1,489). HRQOL was assessed with the Dutch translation of the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 version 3.0. Based on survivors' HRQOL, latent class analysis (LCA) was used to identify unobserved classes of survivors. Moreover, latent transition analysis (LTA) was used to investigate changes in class membership over time. Furthermore, the effect of covariates on class membership was assessed using multinomial logistic regression. RESULTS: LCA identified five classes at baseline: class 1, excellent HRQOL (n = 555, 37.3%); class 2, good HRQOL with prevalence of insomnia (n = 464, 31.2%); class 3, moderate HRQOL with prevalence of fatigue (n = 213, 14.3%); class 4, good HRQOL with physical limitations (n = 134, 9.0%); and class 5, poor HRQOL (n = 123, 8.3%). All classes were stable with high self-transition probabilities. Longer time since the diagnosis, no comorbid conditions, and male sex were associated with class 1, whereas older age was associated with class 4. Clinical covariates were not associated with class membership. CONCLUSION: The identified classes are characterized by distinct patterns of HRQOL and can support patient-centered care. LCA and LTA are powerful tools for investigating HRQOL in cancer survivors. IMPLICATIONS FOR PRACTICE: Long-term colon cancer survivors show great heterogeneity in their health-related quality of life. This study identified five distinct clusters of survivors with similar patterns of health-related quality of life and showed that these clusters remain stable over time. It was also shown that these clusters do not significantly differ in tumor characteristics or received treatment. Cluster membership of long-term survivors can be identified by sociodemographic characteristics but is not predetermined by diagnosis and treatment.

Primary Anastomosis Versus End-Ostomy in Left-Sided Colonic and Proximal Rectal Cancer Surgery in the Elderly Dutch Population: A Propensity Score Matched Analysis.

BACKGROUND: Primary anastomosis (PA) in left-sided colorectal cancer (CRC) surgery in elderly patients is disputed. The aim of our study was to evaluate the differences in postoperative outcomes after left-sided CRC surgery in elderly patients in The Netherlands, comparing patients with PA and those who underwent end-ostomy (EO). METHOD: Patients aged ≥ 75 years with stage I-III left-sided CRC, diagnosed and surgically treated in 2015-2017 were selected from the Netherlands Cancer Registry (n = 3286). Postoperative outcomes, short-term (30-, 60-, and 90-day) mortality and 3-year overall and relative survival were analyzed, stratified by surgical resection with PA versus EO. Propensity score matching (PSM) and multivariable logistic regression analysis were conducted. RESULTS: Patients with higher age, higher American Society of Anesthesiologists classification and higher tumor stage, a perforation, ileus or tumor located in the proximal rectum, and after open or converted surgery were more likely to receive EO. No difference in anastomotic leakage was seen in PA patients with or without defunctioning stoma (6.2% vs. 7.0%, p = 0.680). Postoperative hospital stay was longer (7.0 vs. 6.0 days, p < 0.0001) and more often prolonged (19% vs. 13%, p = 0.03) in EO patients. Sixty-day mortality (2.9% vs. 6.4%, p < 0.0001), 90-day mortality (3.4% vs. 7.7%, p < 0.0001), and crude 3-year survival (81.2% vs. 58.7%, p < 0.0001) were significantly higher in EO patients, remaining significant after multivariable and PSM analysis. CONCLUSION: There are significant differences between elderly patients after left-sided CRC surgery with PA versus EO in terms of postoperative length of stay, short-term survival, 3-year overall survival, and relative survival at disadvantage of EO patients. This information could be important for decision making regarding surgical treatment in the elderly.

Disease recurrence after colorectal cancer surgery in the modern era: a population-based study.

PURPOSE: This population-based study determined the cumulative incidence (CI) of local, regional, and distant recurrences, examined metastatic patterns, and identified risk factors for recurrence after curative treatment for CRC. METHODS: All patients undergoing resection for pathological stage I-III CRC between January 2015 and July 2015 and registered in the Netherlands Cancer Registry were selected (N = 5412). Additional patient record review and data collection on recurrences was conducted by trained administrators in 2019. Three-year CI of recurrence was calculated according to sublocation (right-sided: RCC, left-sided: LCC and rectal cancer: RC) and stage. Cox competing risk regression analyses were used to identify risk factors for recurrence. RESULTS: The 3-year CI of recurrence for stage I, II, and III RCC and LCC was 0.03 vs. 0.03, 0.12 vs. 0.16, and 0.31 vs. 0.24, respectively. The 3-year CI of recurrence for stage I, II, and III RC was 0.08, 0.24, and 0.38. Distant metastases were found in 14, 12, and 16% of patients with RCC, LCC, and RC. Multiple site metastases were found often in patients with RCC, LCC, and RC (42 vs. 32 vs. 28%). Risk factors for recurrence in stage I-II CRC were age 65-74 years, pT4 tumor size, and poor tumor differentiation whereas in stage III CRC, these were ASA III, pT4 tumor size, N2, and poor tumor differentiation. CONCLUSIONS: Recurrence rates in recently treated patients with CRC were lower than reported in the literature and the metastatic pattern and recurrence risks varied between anatomical sublocations.

Estimating adjuvant treatment effects in Stage II colon cancer: Comparing the synthesis of randomized clinical trial data to real-world data.

There is an ongoing discussion regarding the impact of adjuvant chemotherapy in Stage II colon cancer. We therefore estimated adjuvant treatment effect in Stage II colon cancer using pooled disease-free survival (DFS) data from randomized clinical trials (RCT approach) and compared this to real-world data (RWD approach) estimates. First, we estimated the treatment effect in RCTs by (i) searching relevant trials reporting DFS data, (ii) generating patient-level data from reported DFS data and (iii) estimating treatment effect in the patient-level data. Second, the treatment effect was estimated in an observational cohort of 1,947 patients provided by the Netherlands Cancer Registry using three propensity score methods; matching, weighting and stratification. In the RCT approach, patient-level data of 4,489 patients (events: 853) were generated from seven trials which compared two of the following treatment arms: control, 5FU/LV or FOLFOX. A Cox model was used to estimate a hazard ratio (HR) of 0.77 (0.43;1.10) for 5FU/LV vs. control and 0.93 (0.72;1.15) for FOLFOX vs. 5FU/LV. In the RWD approach, HRs for any adjuvant treatment vs. control were 0.95 (0.50;1.80), 0.88 (0.24;3.21) and 1.05 (0.04;2.06) using matching, weighting and stratification, respectively. There was no significant difference with the estimates from the RCT approach (interaction test, p > 0.10). The RCT data suggest a clinically relevant benefit of adjuvant chemotherapy in terms of DFS, but the estimate did not reach statistical significance. Stratified analyses are required to evaluate whether treatment effect differs in specific subgroups.

Administration of adjuvant chemotherapy for stage II-III colon cancer patients: An European population-based study.

The advantage of adjuvant chemotherapy (ACT) for treating Stage III colon cancer patients is well established and widely accepted. However, many patients with Stage III colon cancer do not receive ACT. Moreover, there are controversies around the effectiveness of ACT for Stage II patients. We investigated the administration of ACT and its association with overall survival in resected Stage II (overall and stratified by low-/high-risk) and Stage III colon cancer patients in three European countries including The Netherlands (2009-2014), Belgium (2009-2013) and Sweden (2009-2014). Hazard ratios (HR) for death were obtained by Cox regression models adjusted for potential confounders. A total of 60244 resected colon cancer patients with pathological Stages II and III were analyzed. A small proportion (range 9-24%) of Stage II and over half (range 55-68%) of Stage III patients received ACT. Administration of ACT in Stages II and III tumors decreased with higher age of patients. Administration of ACT was significantly associated with higher overall survival in high-risk Stage II patients (in The Netherlands (HR; 95%CI = 0.82 (0.67-0.99), Belgium (0.73; 0.59-0.90) and Sweden (0.58; 0.44-0.75)), and in Stage III patients (in The Netherlands (0.47; 0.43-0.50), Belgium (0.46; 0.41-0.50) and Sweden (0.48; 0.43-0.54)). In Stage III, results were consistent across subgroups including elderly patients. Our results show an association of ACT with higher survival among Stage III and high-risk Stage II colon cancer patients. Further investigations are needed on the selection criteria of Stages II and III colon cancer patients for ACT.