Background: Complementary therapy (CAM) is common in cancer patients. We undertook this study to assess the association of complementary therapy usage with mortality in glioblastoma (GBM) patients.
Methods: The analysis was based on 470 patients. Information on current use of CAM was collected in structured interviews conducted a median of 6 weeks following GBM diagnosis. Proportional hazards regression was used to estimate hazard ratios (HRs) for GBM-related death according to the use of individual supplements with multivariate adjustment for known prognostic factors including age, KPS, and extent of tumor resection (ESR).
Results: Use of CAM agents was common, with 77% of the cohort reporting CAM usage. No mortality association was observed with the use of multivitamins (HR = 0.91; P = .40) or omega-3 fatty acids (HR = 1.07; P = .69). Patients taking vitamin D as an individual supplement (containing higher dosages than in a multivitamin) had reduced mortality when compared with nonusers (age-adjusted HR = 0.68; P = .02). However, the association was diminished after adjustment for KPS and ESR (HR = 0.74; P = .09). Use of herbal supplements was also associated with reduced mortality (HR = 0.58; P = .04). Vitamin E users had a nonsignificantly higher mortality when compared with nonusers (HR = 1.54; P = .09).
Conclusions: Use of CAM is common in GBM patients. These exploratory analyses suggest no mortality association with the use of multivitamins or omega-3 fatty acids. Associations observed with vitamins D and E merit further investigation.
Keywords: epidemiology; glioblastoma; mortality; supplements; vitamins.