Adjuvant chemotherapy is superior to chemoradiation after D2 surgery for gastric cancer in the per-protocol analysis of the randomized CRITICS trial.

BACKGROUND: The Intergroup 0116 and the MAGIC trials changed clinical practice for resectable gastric cancer in the Western world. In these trials, overall survival improved with post-operative chemoradiotherapy (CRT) and perioperative chemotherapy (CT). Intention-to-treat analysis in the CRITICS trial of post-operative CT or post-operative CRT did not show a survival difference. The current study reports on the per-protocol (PP) analysis of the CRITICS trial. PATIENTS AND METHODS: The CRITICS trial was a randomized, controlled trial in which 788 patients with stage Ib-Iva resectable gastric or esophagogastric adenocarcinoma were included. Before start of preoperative CT, patients from the Netherlands, Sweden and Denmark were randomly assigned to receive post-operative CT or CRT. For the current analysis, only patients who started their allocated post-operative treatment were included. Since it is uncertain that the two treatment arms are balanced in such PP analysis, adjusted proportional hazards regression analysis and inverse probability weighted analysis were used to minimize the risk of selection bias and to estimate and compare overall and event-free survival. RESULTS: Of the 788 patients, 478 started post-operative treatment according to protocol, 233 (59%) patients in the CT group and 245 (62%) patients in the CRT group. Patient and tumor characteristics between the groups before start of the post-operative treatment were not different. After a median follow-up of 6.7 years since the start of post-operative treatment, the 5-year overall survival was 57.9% (95% confidence interval: 51.4% to 64.3%) in the CT group versus 45.5% (95% confidence interval: 39.2% to 51.8%) in the CRT group (adjusted hazard ratio CRT versus CT: 1.62 (1.24-2.12), P = 0.0004). Inverse probability weighted analysis resulted in similar hazard ratios. CONCLUSION: After adjustment for all known confounding factors, the PP analysis of patients who started the allocated post-operative treatment in the CRITICS trial showed that the CT group had a significantly better 5-year overall survival than the CRT group (NCT00407186).

Time trends of short-term mortality for octogenarians undergoing a colorectal resection in North Europe.

BACKGROUND: Decreased cancer specific survival in older colorectal patients is mainly due to mortality in the first year, emphasizing the importance of the first postoperative year. This study aims to gain an overview and time trends of short-term mortality in octogenarians (≥80 years) with colorectal cancer across four North European countries. METHODS: Patients of 80 years or older, operated for colorectal cancer (stage I-III) between 2005 and 2014, were included. Population-based cohorts from Belgium, Denmark, the Netherlands, and Sweden were collected. Separately for colon- and rectal cancer, 30-day, 90-day, one-year, and excess one-year mortality were calculated. Also, short-term mortality over three time periods (2005-2008, 2009-2011, 2012-2014) was analyzed. RESULTS: In total, 35,158 colon cancer patients and 10,144 rectal cancer patients were included. For colon cancer, 90-day mortality rate was highest in Denmark (15%) and lowest in Sweden (8%). For rectal cancer, 90-day mortality rate was highest in Belgium (11%) and lowest in Sweden (7%). One-year excess mortality rate of colon cancer patients decreased from 2005 to 2008 to 2012-2014 for all countries (Belgium: 17%-11%, Denmark: 21%-15%, the Netherlands: 18%-10%, and Sweden: 10%-8%). For rectal cancer, from 2005 to 2008 to 2012-2014 one-year excess mortality rate decreased in the Netherlands from 16% to 7% and Sweden: 8%-2%). CONCLUSIONS: Short-term mortality rates were high in octogenarians operated for colorectal cancer. Short-term mortality rates differ across four North European countries, but decreased over time for both colon and rectal cancer patients in all countries.

International comparison of treatment strategy and survival in metastatic gastric cancer.

Background: In the randomized Asian REGATTA trial, no survival benefit was shown for additional gastrectomy over chemotherapy alone in patients with advanced gastric cancer with a single incurable factor, thereby discouraging surgery for these patients. The purpose of this study was to evaluate treatment strategies for patients with metastatic gastric cancer in daily practice in five European countries, along with relative survival in each country. Methods: Nationwide population-based data from Belgium, Denmark, the Netherlands, Norway and Sweden were combined. Patients with primary metastatic gastric cancer diagnosed between 2006 and 2014 were included. The proportion of gastric resections performed and the administration of chemotherapy (irrespective of surgery) within each country were determined. Relative survival according to country was calculated. Results: Overall, 15 057 patients with gastric cancer were included. The proportion of gastric resections varied from 8·1 per cent in the Netherlands and Denmark to 18·3 per cent in Belgium. Administration of chemotherapy was 39·2 per cent in the Netherlands, compared with 63·2 per cent in Belgium. The 6-month relative survival rate was between 39·0 (95 per cent c.i. 37·8 to 40·2) per cent in the Netherlands and 54·1 (52·1 to 56·9) per cent in Belgium. Conclusion: There is variation in the use of gastrectomy and chemotherapy in patients with metastatic gastric cancer, and subsequent differences in survival.

Impact of upfront randomization for postoperative treatment on quality of surgery in the CRITICS gastric cancer trial.

BACKGROUND: Preoperative randomization for postoperative treatment might affect quality of surgery. In the CRITICS trial (ChemoRadiotherapy after Induction chemotherapy In Cancer of the Stomach), patients were randomized before treatment to receive chemotherapy prior to a D1 + gastrectomy (removal of lymph node station (LNS) 1-9 + 11), followed by either chemotherapy (CT) or chemoradiotherapy (CRT). In this analysis, the influence of upfront randomization on the quality of surgery was evaluated. METHODS: Quality of surgery was analyzed in both study arms using surgicopathological compliance (removal of ≥ 15 lymph nodes), surgical compliance (removal of the indicated LNS), and surgical contamination (removal of LNS that should be left in situ). Furthermore, the 'Maruyama Index of Unresected disease' (MI) was evaluated in both study arms, and validated with overall survival. RESULTS: Between 2007 and 2015, 788 patients with gastric cancer were included in the CRITICS study of which 636 patients were operated with curative intent. No difference was observed between the CT and CRT group regarding surgicopathological compliance (74.8% vs 70.9%, P = 0.324), surgical compliance (43.2% vs 39.2%, P = 0.381), and surgical contamination (59.4% vs 59.9%, P = 0.567). Median MI was 1 in both groups (range CT 0-88 and CRT 0-136, P = 0.700). A MI below 5 was associated with better overall survival (CT: P = 0.009 and CRT: P = 0.013). CONCLUSION: Surgical quality parameters were similar in both study arms in the CRITICS gastric cancer trial, indicating that upfront randomization for postoperative treatment had no impact on the quality of surgery. A Maruyama Index below five was associated with better overall survival.

North European comparison of treatment strategy and survival in older patients with resectable gastric cancer: A EURECCA upper gastrointestinal group analysis.

BACKGROUND: As older gastric cancer patients are often excluded from randomized clinical trials, the most appropriate treatment strategy for these patients remains unclear. The current study aimed to gain more insight in treatment strategies and relative survival of older patients with resectable gastric cancer across Europe. METHODS: Population-based cohorts from Belgium, Denmark, The Netherlands, Norway, and Sweden were combined. Patients ≥70 years with resectable gastric cancer (cT1-4a, cN0-2, cM0), diagnosed between 2004 and 2014 were included. Resection rates, administration of chemotherapy (irrespective of surgery), and relative survival within a country according to stage were determined. RESULTS: Overall, 6698 patients were included. The percentage of operated patients was highest in Belgium and lowest in Sweden for both stage II (74% versus 56%) and stage III disease (57% versus 25%). For stage III, chemotherapy administration was highest in Belgium (44%) and lowest in Sweden (2%). Three year relative survival for stage I, II, and III disease in Belgium was 67.8% (95% CI:62.8-72.6), 41.2% (95% CI:37.3-45.2), 17.8% (95% CI:12.5-24.0), compared with 56.7% (95% CI:51.5-61.7), 31.3% (95% CI:27.6-35.2), 8.2% (95% CI:4.4-13.4) in Sweden. There were no significant differences in treatment strategies of patients with stage I disease. CONCLUSION: Substantial treatment differences are observed across North European countries for patients with stages II and III resectable gastric cancer aged 70 years or older. In the present comparison, treatment strategies with a higher proportion of patients undergoing surgery seemed to be associated with higher survival rates for patients with stages II or III disease.

Association between hospital volume and quality of gastric cancer surgery in the CRITICS trial.

BACKGROUND: Studies investigating the association between hospital volume and quality of gastric cancer surgery are lacking. In the present study, the effect of hospital volume on quality of gastric cancer surgery was evaluated by analysing data from the CRITICS (ChemoRadiotherapy after Induction chemotherapy In Cancer of the Stomach) trial. METHODS: Patients who underwent gastrectomy with curative intent in the Netherlands were selected from the CRITICS trial database. Annual hospital volume of participating centres was derived from the Netherlands Cancer Registry. Hospital volume was categorized into very low (1-10 gastrectomies per year per institution), low (11-20), medium (21-30) and high (31 or more), and linked to the CRITICS database. Quality of surgery was analysed by surgicopathological compliance (removal of at least 15 lymph nodes), surgical compliance (removal of indicated lymph node stations) and the Maruyama Index. Postoperative morbidity and mortality were also compared between hospital categories. RESULTS: Between 2007 and 2015, 788 patients were included in the CRITICS study, of whom 494 were analysed. Surgicopathological compliance was higher (86·7 versus 50·4 per cent; P < 0·001), surgical compliance was greater (52·9 versus 19·8 per cent; P < 0·001) and median Maruyama Index was lower (0 versus 6; P = 0·006) in high-volume hospitals compared with very low-volume hospitals. There was no statistically significant difference in postoperative complications or mortality between the hospital volume categories. CONCLUSION: Surgery performed in high-volume hospitals was associated with better surgical quality than surgery carried out in lower-volume hospitals.

Surgical morbidity and mortality after neoadjuvant chemotherapy in the CRITICS gastric cancer trial.

BACKGROUND: In order to determine the optimal combination of perioperative chemotherapy and chemoradiotherapy for Western patients with advanced resectable gastric cancer, the international multicentre CRITICS trial (ChemoRadiotherapy after Induction chemotherapy In Cancer of the Stomach) was initiated. In this trial, patients with resectable gastric cancer were randomised before start of treatment between adjuvant chemotherapy or adjuvant chemoradiotherapy following neoadjuvant chemotherapy plus gastric cancer resection. The purpose of this study was to report on surgical morbidity and mortality in this trial, and to identify factors associated with surgical morbidity. METHODS: Patients who underwent a gastrectomy with curative intent were selected. Logistic regression analyses were used to assess risk factors for developing postoperative complications. RESULTS: Between 2007 and 2015, 788 patients were included in the CRITICS trial, of whom 636 patients were eligible for current analyses. Complications occurred in 296 patients (47%). Postoperative mortality was 2.2% (n = 14). Complications due to anastomotic leakage was cause of death in 5 patients. Failure to complete preoperative chemotherapy (OR = 2.09, P = 0.004), splenectomy (OR = 2.82, P = 0.012), and male sex (OR = 1.55, P = 0.020) were associated with a greater risk for postoperative complications. Total gastrectomy and oesophago-cardia resection were associated with greater risk for morbidity compared with subtotal gastrectomy (OR = 1.88, P = 0.001 and OR = 1.89, P = 0.038). CONCLUSION: Compared to other Western studies, surgical morbidity in the CRITICS trial was slightly higher whereas mortality was low. Complications following anastomotic leakage was the most important factor for postoperative mortality. Important proxies for developing postoperative complications were failure to complete preoperative chemotherapy, splenectomy, male sex, total gastrectomy, and oesophago-cardia resection.