Impact of Metformin Use and Diabetic Status During Adjuvant Fluoropyrimidine-Oxaliplatin Chemotherapy on the Outcome of Patients with Resected Colon Cancer: A TOSCA Study Subanalysis.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is associated with increased risk of colon cancer (CC), whereas metformin use seems to be protective. However, the impact of metformin use on the risk of death or disease recurrence after radical surgery for CC remains uncertain. MATERIALS AND METHODS: This is a substudy conducted in patients with high-risk stage II or stage III CC randomized in the TOSCA trial, which compared 3 versus 6 months of fluoropyrimidine-oxaliplatin adjuvant chemotherapy. Objective of the study was to investigate the impact of metformin exposure during adjuvant chemotherapy on overall survival (OS) and relapse-free survival (RFS). We also evaluated the impact of T2DM or metformin dosage on clinical outcomes. RESULTS: Out of 3,759 patients enrolled in the TOSCA trial, 133 patients with diabetes (9.2%) and 1,319 without diabetes (90.8%) were recruited in this study. After excluding 13 patients with diabetes without information on metformin exposure, 76 patients with T2DM (63.3%) were defined as metformin users and 44 (36.7%) as metformin nonusers. After a median follow-up of 60.4 months, 26 (21.7%) patients relapsed and 16 (13.3%) died. Metformin use was neither associated with OS (adjusted hazard ratio [HR], 1.51; 95% confidence interval [CI], 0.48-4.77; p = .4781) nor with RFS (HR, 1.56; 95% CI, 0.69-3.54; p = .2881). Similarly, we found no association between T2DM or metformin dosage and OS or RFS. CONCLUSIONS: Metformin use and T2DM did not impact on OS or RFS in patients with resected CC treated with adjuvant fluoropyrimidine-oxaliplatin chemotherapy. Larger studies and longer follow-up are required to clarify the potential efficacy of metformin in improving the prognosis of patients with CC. IMPLICATIONS FOR PRACTICE: The role of the antidiabetic drug metformin in colon cancer prevention and treatment is highly debated. While low-dose metformin reduced the incidence of colorectal adenomas in two prospective studies, its effect in patients with already established colon cancer remains unclear. In this study, the potential impact of metformin on the survival of resected colon cancer patients who received adjuvant chemotherapy was investigated in the context of the TOSCA study. We did not find any association between metformin use or dosages and patient survival. Prospective studies are required to draw definitive conclusions about metformin impact on colon cancer recurrence and survival.

Khorana score and thromboembolic risk in stage II-III colorectal cancer patients: a post hoc analysis from the adjuvant TOSCA trial.

BACKGROUND: The risk of venous thromboembolic events (VTE) during adjuvant chemotherapy for colorectal cancer (CRC) is unknown. We aim to evaluate if the Khorana score (KS) can predict this risk, and if it represents a prognostic factor for overall survival (OS) through a post hoc analysis of the phase III TOSCA trial of different durations (3- versus 6-months) of adjuvant chemotherapy. METHODS: A logistic regression model was used to test the associations between the risk of VTE and the KS. The results are expressed as odds ratios (OR) with 95% confidence intervals (95% CI). To assess the effect of the KS on OS, multivariable analyses using Cox regression models were performed. The results are expressed as hazard ratios (HR) with 95% CI. RESULTS: Among 1380 CRC patients with available data, the VTE risk (n = 72 events: 5.2%) was similar in the two duration arms (5.5% versus 4.9%), with 0.2% of patients belonging to the high-risk KS group. Rates of VTE were similar in the low- and intermediate-risk groups (4.8% versus 6.4%). KS did not represent an independent predictive factor for VTE occurrence. Chemotherapy duration was not associated with VTE risk. In addition, KS was not prognostic for OS in multivariate analysis (HR: 0.92, 95% CI, 0.63-1.36; p = 0.6835). CONCLUSIONS: The use of the KS did not predict VTEs in a low-moderate thromboembolic risk population as CRC. These data did not support the use of KS to predict VTE during adjuvant chemotherapy, and suggest that other risk assessment models should be researched.

Chronomodulated capecitabine and adjuvant radiation in intermediate-risk to high-risk rectal cancer: a phase II study.

OBJECTIVES: The aim of this study was to evaluate the feasibility and tolerability of capecitabine administration according to a specific time schedule, combined with adjuvant radiation therapy, in intermediate-risk to high-risk rectal cancer patients treated with an upfront surgery. The primary endpoint was the rate of grade 3 to 4 diarrhea during chemoradiation (CRT). MATERIALS AND METHODS: Stage II and III rectal cancer patients received, after total mesorectal excision, 2 cycles of XELOX regimen (oxaliplatin 130 mg/m(2) on day 1; capecitabine 1000 mg/m(2) bid on day 1 to 14, q21), followed by capecitabine (800 mg/m(2) bid daily; 20% dose at 12:00 AM and 80% dose at 12:00 PM) administered continuously during pelvic radiation (total 50.4 Gy in 28 fractions, 1.8 Gy daily dose between 2:00 and 4:00 PM). Four additional cycles of XELOX were administered after chemoradiotherapy. RESULTS: Fifty-one radically resected rectal cancer patients were enrolled. All, but one, cases were evaluated for safety of CRT. We reported a grade 3 and 4 diarrhea rate of 14% (7 of 50 patients), whereas no grade 3 and 4 leukopenia was observed. Grade 1 and 2 proctitis was observed in 26 (52%) cases, whereas grade 1 and 2 cystitis in 5 (10%) patients. Only 2 cases of grade 3 proctitis and cystitis were reported, respectively. The CRT phase was feasible and was completed by 43 (84%) patients. Three patients developed actinic enteritis 60 days after the end of the radiotherapy program. CONCLUSIONS: Capecitabine timetable administration combined with adjuvant radiation therapy of rectal cancer is well tolerated and feasible. Further investigation of this chronomodulated schedule in terms of efficacy is warranted in neoadjuvant setting.

Dose finding study of erlotinib combined to capecitabine and irinotecan in pretreated advanced colorectal cancer patients.

PURPOSE: This study evaluated the maximum tolerated dose (MTD) and the dose limiting toxicity (DLT) of erlotinib when combined to irinotecan and capecitabine in pre-treated metastatic colorectal cancer patients. METHODS: Five dose level combinations with irinotecan (from 180 to 240 mg/m(2), day 1, q21), capecitabine (1,500-2,000 mg/m(2) per day, days 2-15, q21) and erlotinib (50-150 mg per day, continuously) were planned. Patients were enrolled in cohorts of three, and evaluated for first cycle acute toxicity. RESULTS: Twenty-one patients were treated. In the first cohort, no DLT was reported, in the second: one DLT (G4 neutropenic fever associated with G3 cutaneous rash and mucositis); in the third dose level: two DLT (G3 diarrhea and G4 neutropenic fever). To confirm these results, other six patients were additionally included and no DLT was observed. CONCLUSIONS: The results documented that erlotinib at the dose of 100 mg per day, irinotecan 180 mg/m(2) and capecitabine 1,500 mg/m(2) per day for 14 days has an acceptable safety profile and appears suitable for further phase II studies.