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).Surgical oncolog

Lack of immune potentiation by complexing HBsAg in a heat-inactivated hepatitis B vaccine with antibody in hepatitis B immunoglobulin

In a randomized, dose-response study among 305 health care workers, we examined whether the immunogenicity of a heat-inactivated hepatitis B vaccine could be enhanced when HBsAg was complexed by anti-HBs contained in hepatitis B immunoglobulin either at equivalent proportions or at 10-fold antigen excess. The dose of HBsAg in the control vaccine as well as in the two complexed vaccine preparations could be reduced from the standard value (3 micrograms) to 0.6 micrograms per injection without affecting the antibody response in the vaccinees. Still lower dosages of HBsAg in the three vaccine preparations induced significantly lower but comparable anti-HBs responses. These results indicate that, in man, using a heat-inactivated plasma vaccine, addition of anti-HBs contained in hepatitis B immunoglobulin does not potentiate the immunogenicity of HBsA

Risk Factors for Metachronous Isolated Peritoneal Metastasis after Preoperative Chemotherapy and Potentially Curative Gastric Cancer Resection: Results from the CRITICS Trial

Simple Summary Around 20% of gastric cancer patients develop peritoneal metastasis after preoperative chemotherapy and curative surgery. Patients with peritoneal metastasis as a single site of metastasis may potentially benefit from prophylactic strategies. In this post-hoc analysis of the international phase III CRITICS trial, we aim to identify factors that can distinguish patients at high risk for developing peritoneal metastasis as a single site. Diffuse or mixed histological subtype, tumors with serosal involvement (ypT4) and advanced lymph node stage (ypN3 or a tumor positive lymph node ratio >20%) were independent risk factors for isolated peritoneal metastasis after preoperative chemotherapy and curative surgery. The combination of these risk factors identifies a subgroup that may benefit from treatment strategies that aim to prevent peritoneal metastasis. Gastric cancer (GC) patients at high risk of developing peritoneal metastasis (PM) as a single site of metastasis after curative treatment may be candidates for adjuvant prophylactic strategies. Here we investigated risk factors for metachronous isolated PM in patients who were treated in the CRITICS trial (NCT00407186). Univariable and multivariable analyses on both metachronous isolated PM and 'other events', i.e., (concurrent) distant metastasis, locoregional recurrence or death, were performed using a competing risk model and summarized by cumulative incidences. Isolated PM occurred in 64 of the 606 (11%) included patients. Diffuse or mixed histological subtype, ypT4 tumor stage and LNhigh (ypN3 lymph node stage or a lymph node ratio >20%) were independent risk factors for isolated PM in both univariable and multivariable analyses. Likewise, LNhigh was an independent risk factor for 'other events'. Patients with tumors who were positive for all three independent risk factors had the highest two-year cumulative incidence of 43% for isolated PM development. In conclusion, diffuse or mixed histological subtype, ypT4 and LNhigh were identified as independent risk factors for isolated PM in patients treated with preoperative chemotherapy followed by surgical resection. The combination of these factors may identify a subgroup that may benefit from PM-preventing treatment strategies.Surgical oncolog

Effect of Hospital Volume With Respect to Performing Gastric Cancer Resection on Recurrence and Survival: Results From the CRITICS Trial

OBJECTIVE: We examined the association between surgical hospital volume and both overall survival (OS) and disease-free survival (DFS) using data obtained from the international CRITICS (ChemoRadiotherapy after Induction chemotherapy In Cancer of the Stomach) trial. SUMMARY BACKGROUND DATA: In the CRITICS trial, patients with resectable gastric cancer were randomized to receive preoperative chemotherapy followed by adequate gastrectomy and either chemotherapy or chemoradiotherapy. METHODS: Patients in the CRITICS trial who underwent a gastrectomy with curative intent in a Dutch hospital were included in the analysis. The annual number of gastric cancer surgeries performed at the participating hospitals was obtained from the Netherlands Cancer Registry; the hospitals were then classified as low-volume (1-20 surgeries/year) or high-volume (≥21 surgeries/year) and matched with the CRITICS trial data. Univariate and multivariate analyses were then performed to evaluate the hazard ratio (HR) between hospital volume and both OS and DFS. RESULTS: From 2007 through 2015, 788 patients were included in the CRITICS trial. Among these 788 patients, 494 were eligible for our study; the median follow-up was 5.0 years. Five-year OS was 59.2% and 46.1% in the high-volume and low-volume hospitals, respectively. Multivariate analysis revealed that undergoing surgery in a high-volume hospital was associated with higher OS [HR = 0.69, 95% confidence interval (CI) = 0.50-0.94, P = 0.020] and DFS (HR = 0.73, 95% CI: 0.54-0.99, P = 0.040). CONCLUSIONS: In the CRITICS trial, hospitals with a high annual volume of gastric cancer surgery were associated with higher overall and DFS. These findings emphasize the value of centralizing gastric cancer surgeries in the Western world

Older versus younger adults with gastric cancer receiving perioperative treatment: Results from the CRITICS trial

Aim: To evaluate treatment-related toxicity, treatment compliance, surgical complications and event-free survival (EFS) in older (≥70 years) versus younger (<70 years) adults who underwent perioperative treatment for gastric cancer. Methods: In the CRITICS trial, 788 patients with resectable gastric cancer were randomised before start of any treatment and received preoperative chemotherapy (3 cycles of epirubicin, cisplatin or oxaliplatin and capecitabine), followed by surgery, followed by either postoperative chemotherapy or chemoradiotherapy (45Gy + cisplatin + capecitabine). Results: 172 (22%) patients were older adults. During preoperative chemotherapy, 131 (77%) older adults versus 380 (62%) younger adults experienced severe toxicity (p < 0.001); older adults received significantly lower relative dose intensities (RDIs) for all chemotherapeutic drugs. Equal proportions of older versus younger adults underwent curative surgery: 137 (80%) versus 499 (81%), with comparable postoperative complications and postoperative mortality. Postoperative therapy after curative surgery started in 87 (64%) older adults versus 391 (78%) younger adults (p < 0.001). Incidence of severe toxicity during postoperative chemotherapy was 22 (54%) in older adults versus 113 (59%) in younger adults (p = 0.541); older adults received significantly lower RDIs for all chemotherapeutic drugs. Severe toxicity rates for postoperative chemoradiotherapy were 22 (48%) older adults versus 89 (45%) for younger adults (p = 0.703), with comparable chemotherapy RDIs and radiotherapy dose. Two-year EFS was 53% for older adults versus 51% for younger adults. Conclusion: Perioperative treatment compliance, especially in the postoperative phase, was poorer in older adults compared with younger adults. As comparable proportions of patients underwent curative surgery, future studies should focus on neo-adjuvant treatment. Trial registration: ClinicalTrials.gov identifier: NCT00407186. EudraCT number: 2006–00413032