Schmiegel, Wolff

Background. Lynch syndrome is the most common genetic predisposition for hereditary cancer. Carriers of pathogenic changes in mismatch repair (MMR) genes have an increased risk of developing colorectal (CRC), endometrial, ovarian, urinary tract, prostate, and other cancers, depending on which gene is malfunctioning. In Lynch syndrome, differences in cancer incidence (penetrance) according to the gene involved have led to the stratification of cancer surveillance. By contrast, any differences in penetrance determined by the type of pathogenic variant remain unknown. Objective. To determine cumulative incidences of cancer in carriers of truncating and missense or aberrant splicing pathogenic variants of the MLH1 and MSH2 genes. Methods. Carriers of pathogenic variants of MLH1 (path_MLH1) and MSH2 (path_MSH2) genes filed in the Prospective Lynch Syndrome Database (PLSD) were categorized as truncating or missense/aberrant splicing according to the InSiGHT criteria for pathogenicity. Results. Among 5199 carriers, 1045 had missense or aberrant splicing variants, and 3930 had truncating variants. Prospective observation years for the two groups were 8205 and 34,141 years, respectively, after which there were no significant differences in incidences for cancer overall or for colorectal cancer or endometrial cancers separately. Conclusion. Truncating and missense or aberrant splicing pathogenic variants were associated with similar average cumulative incidences of cancer in carriers of path MLH1 and path_MSH2.

Purpose Six randomized phase II and III trials have investigated the role of oxaliplatin (OX) in combination with capecitabine (CAP) or infusional fluorouracil (FU) in metastatic colorectal cancer. This meta-analysis compared the efficacy of CAP/OX compared with infusional FU/OX. Patients and Methods This analysis compared all published CAP/OX versus infusional FU/OX regimens. A total of 3,494 patients (FU, n = 1,737; CAP, n = 1,757) were analyzed for response rate (RR), progression-free (PFS), overall survival (OS), and toxicity. Results The fixed-effect pooled estimate for RR showed higher RR for FU-based regimens (Odds ratio [OR] = 0.85; 95% CI, 0.74 to 0.97; P = .02) whereas the analysis of chemotherapy-only trials, excluding the bevacizumab containing NO16966 and TREE 2 trials, led to an OR of 0.74 (95% CI, 0.60 to 0.92; P = .007). However, for PFS (hazard ratio [HR] = 1.04; 95% CI, 0.96 to 1.12; P = .17) and OS (HR = 1.04; 95% CI, 0.95 to 1.12; P = .41) all models suggested similar outcome within the range of noninferiority. Grade 3/4 toxicities (thrombocytopenia—HR = 2.07, 95% CI, 1.42 to 3.03; P < .0002; diarrhea—HR = 1.34; 95% CI, 1.08 to 1.66; P < .0009; and grade 2/3 hand-foot-syndrome [HFS]—HR = 3.54; 95% CI, 2.07 to 6.05; P < .00001) were less prominent with FU-based regimens whereas neutropenia (HR = 0.15; 95% CI, 0.11 to 0.19; P < .00001) was lower in the CAP regimens. Conclusion The combination of CAP and OX resulted in lower RR, but this did not affect PFS and OS, which were similar in both treatment arms. The toxicity analysis showed the characteristic toxicity of each of the different FU schedules, with thrombocytopenia and HFS consistently more prominent in the CAP regimens.

Purpose To compare the use of capecitabine plus oxaliplatin (CAPOX) with infusional fluorouracil (FU)/folinic acid plus oxaliplatin (FUFOX) as first-line therapy for patients with metastatic colorectal cancer (MCRC). Patients and Methods A total of 474 patients with MCRC received either CAPOX (capecitabine 1,000 mg/m2 bid, days 1 to 14 plus oxaliplatin 70 mg/m2 days 1 and 8, repeated every 22 days) ) or FUFOX (oxaliplatin 50 mg/m2 followed by leucovorin 500 mg/m2 plus FU 2,000 mg/m2 as a 22-hour infusion days 1, 8, 15, and 22, repeated every 36 days). The primary end point was progression-free survival (PFS). Secondary end points were response rate (RR), overall survival (OS), time to treatment failure, and toxicity. The study was designed to determine noninferiority for the CAPOX regimen. Results Median PFS was 7.1 months in the CAPOX arm and 8.0 months in the FUFOX arm (hazard ratio [HR], 1.17; 95% CI, 0.96 to 1.43; P = .117). Median OS was 16.8 months (CAPOX) and 18.8 months (FUFOX; HR, 1.12; 95% CI, 0.92 to 1.38; P = .26). Overall RRs were 48% for CAPOX (95% CI, 41% to 54%) and 54% for FUFOX (95% CI, 47% to 60%). Both regimens were generally well tolerated, although there was a significantly higher incidence of grade 2/3 hand-foot syndrome (HFS) in the CAPOX arm (P = .028). Conclusion CAPOX resulted in a slightly inferior efficacy than FUFOX. With respect to PFS, the best estimate of the HR of 1.17 was within the prespecified equivalence range. However, a relevant inferiority cannot be excluded. Both regimens were generally well tolerated but there was a significantly higher rate of grade 2/3 HFS in the CAPOX arm.