Prognostic value of mismatch repair deficiency in patients with advanced gastric cancer, treated by surgery and adjuvant 5-fluorouracil and leucovorin chemoradiotherapy.

OBJECTIVE: The predictive value of mismatch repair protein deficiency (MMRD) for chemoradiotherapeutic outcome has rarely been reported in gastric cancer. This study investigated the clinical significance of MMRD as a prognostic factor for tumor recurrence, and as a predictor of response to adjuvant chemoradiotherapy in advanced gastric cancer patients. METHODS: Between 1995 and 2008, tissue specimens of 881 patients who underwent radical gastrectomy for stage II and III gastric cancer were analyzed. MMRD was assessed using immunohistochemical stains for MLH1, PMS2, MSH2, and MSH6. Patients were divided into two groups according to adjuvant treatment: a 5-fluorouracil/leucovorin (FL) adjuvant chemoradiotherapy group and a surgery alone group. Disease-free survival (DFS) was compared between the two groups correlated to MMRD. Risk factors for tumor recurrence were analyzed using multivariate analysis. RESULTS: Of the 881 gastric cancer patients, 88 (10.0%) exhibited MMRD and 398 (45.2%) patients received adjuvant FL chemoradiotherapy. The multivariate analysis revealed that MMRD was a good independent prognostic factor (hazard ratio, 0.572; 95% confidence interval, 0.370-0.883; P = 0.012). For stage III gastric cancer displaying mismatch repair protein proficiency (MMRP), adjuvant FL chemoradiotherapy after surgery resulted in better DFS than surgery alone (P = 0.001). Among the stage II gastric cancer patients, adjuvant FL chemoradiotherapy did not show survival benefit, regardless of MMRD. CONCLUSION: MMRD is a good independent prognostic factor in advanced gastric cancer. Adjuvant FL chemoradiotherapy was beneficial in patients with stage III gastric cancer with MMRP but not in those with MMRD.

Deep Learning-Based Survival Analysis Identified Associations Between Molecular Subtype and Optimal Adjuvant Treatment of Patients With Gastric Cancer.

PURPOSE: Gastric cancer (GC) is the third-leading cause of cancer-related deaths. Several pivotal clinical trials of adjuvant treatments were performed during the previous decade; however, the optimal regimen for adjuvant treatment of GC remains controversial. PATIENTS AND METHODS: We developed a novel deep learning-based survival model (survival recurrent network [SRN]) in patients with GC by including all available clinical and pathologic data and treatment regimens. This model uses time-sequential data only in the training step, and upon being trained, it receives the initial data from the first visit and then sequentially predicts the outcome at each time point until it reaches 5 years. In total, 1,190 patients from three cohorts (the Asian Cancer Research Group cohort, n = 300; the fluorouracil, leucovorin, and radiotherapy cohort, n = 432; and the Adjuvant Chemoradiation Therapy in Stomach Cancer cohort, n = 458) were included in the analysis. In addition, we added Asian Cancer Research Group molecular classifications into the prediction model. SRN simulated the sequential learning process of clinicians in the outpatient clinic using a recurrent neural network and time-sequential outcome data. RESULTS: The mean area under the receiver operating characteristics curve was 0.92 ± 0.049 at the fifth year. The SRN demonstrated that GC with a mesenchymal subtype should elicit a more risk-adapted postoperative treatment strategy as a result of its high recurrence rate. In addition, the SRN found that GCs with microsatellite instability and GCs of the papillary type exhibited significantly more favorable survival outcomes after capecitabine plus cisplatin chemotherapy alone. CONCLUSION: Our SRN predicted survival at a high rate, reaching 92% at postoperative year 5. Our findings suggest that SRN-based clinical trials or risk-adapted adjuvant trials could be considered for patients with GC to investigate more individualized adjuvant treatments after curative gastrectomy.

Adjuvant chemoradiation with 5-fluorouracil/leucovorin versus S-1 in gastric cancer patients following D2 lymph node dissection surgery: a feasibility study.

PURPOSE: We retrospectively analyzed the feasibility and adverse events for two regimens, postoperative chemoradiation (CRT) with 5-fluorouracil/leucovorin (5-FU/LV) compared to S-1 in D2-resected gastric cancer patients. PATIENTS AND METHODS: The study included 405 gastric cancer patients who underwent curative gastrectomy with D2 lymph node dissection and received adjuvant therapy between January 2008 and July 2009. Feasibility and adverse events for the CRT and S-1 regimens were analyzed. RESULTS: Out of the 405 patients, 244 (60.2%) had CRT and 161 (39.8%) had S-1 treatment. The regimen was selected based on the preferences of the physician and the patient. S-1 was more frequently administered to patients with older age (age≥70) and those with early-stage disease (stage II). The stage was significantly more advanced in the CRT group compared to the S-1 group (S-1 vs. CRT: stage II, 59.6% vs. 36.1%; stage III/IV, 28.0% vs. 48.3%, respectively; p<0.001). The completion rate of the planned therapy was significantly higher in the CRT group than in the S-1 group (95.1% vs. 72.8%, respectively; p<0.001). Regarding severe adverse events (grade 3-4), neutropenia (CRT vs. S-1; 40.2% vs. 8.7%, respectively, p<0.001), nausea (CRT vs. S-1; 5.7% vs. 0%, respectively; p=0.002) and stomatitis (CRT vs. S-1; 7.4% vs. 2.5%, respectively; p=0.034) were significantly more frequent in the CRT cohort compared to the S-1 group. CONCLUSION: Both adjuvant CRT with 5-FU/LV and adjuvant S-1 are safe and feasible in D2-resected gastric cancer patients. Patients with old age or early stage disease tend to prefer S-1 therapy to chemoradiation.

Phase III trial comparing capecitabine plus cisplatin versus capecitabine plus cisplatin with concurrent capecitabine radiotherapy in completely resected gastric cancer with D2 lymph node dissection: the ARTIST trial.

PURPOSE: The ARTIST (Adjuvant Chemoradiation Therapy in Stomach Cancer) trial was the first study to our knowledge to investigate the role of postoperative chemoradiotherapy therapy in patients with curatively resected gastric cancer with D2 lymph node dissection. This trial was designed to compare postoperative treatment with capecitabine plus cisplatin (XP) versus XP plus radiotherapy with capecitabine (XP/XRT/XP). PATIENTS AND METHODS: The XP arm received six cycles of XP (capecitabine 2,000 mg/m2 per day on days 1 to 14 and cisplatin 60 mg/m2 on day 1, repeated every 3 weeks) chemotherapy. The XP/XRT/XP arm received two cycles of XP followed by 45-Gy XRT (capecitabine 1,650 mg/m2 per day for 5 weeks) and two cycles of XP. RESULTS: Of 458 patients, 228 were randomly assigned to the XP arm and 230 to the XP/XRT/XP arm. Treatment was completed as planned by 75.4% of patients (172 of 228) in the XP arm and 81.7% (188 of 230) in the XP/XRT/XP arm. Overall, the addition of XRT to XP chemotherapy did not significantly prolong disease-free survival (DFS; P = .0862). However, in the subgroup of patients with pathologic lymph node metastasis at the time of surgery (n = 396), patients randomly assigned to the XP/XRT/XP arm experienced superior DFS when compared with those who received XP alone (P = .0365), and the statistical significance was retained at multivariate analysis (estimated hazard ratio, 0.6865; 95% CI, 0.4735 to 0.9952; P = .0471). CONCLUSION The addition of XRT to XP chemotherapy did not significantly reduce recurrence after curative resection and D2 lymph node dissection in gastric cancer. A subsequent trial (ARTIST-II) in patients with lymph node-positive gastric cancer is planned.