Effects of circadian rhythms and treatment times on the response of radiotherapy for painful bone metastases.

BACKGROUND: Previous studies have observed how the time of radiotherapy delivery can impact toxicities and outcomes. The goal of this study was to determine whether treatment time influenced radiotherapy response for bone metastases. METHODS: Patients who received radiation treatment to painful bone metastases from January 2000 to December 2010 were included in our analysis. Demographic and treatment information including performance status, primary site, treatment dose and fraction, and response were collected prospectively. Treatment times were extracted from patient medical records. Patients were allocated to 8:00 AM-11:00 AM, 11:01 AM-2:00 PM, or 2:01 PM-5:00 PM cohorts based on their treatment times. To compare treatment response between the three cohorts, the Fisher exact test was used. A two-sided P value of <0.05 was considered statistically significant. Analysis was repeated with males and females separately. RESULTS: A total of 194 patients were included. The median age was 68 years and 55.5% of patients responded to treatment. The dose and fraction of radiation received differed significantly between treatment cohorts using all allocation methods. Females in the 11:01 AM-2:00 PM cohort exhibited a significantly higher response rate (P=0.02) and differing proportions of response types (P=0.03) compared to the 8:00 AM- 11:00 AM and 2:01 PM-5:00 PM cohorts when allocated using all treatment times. No significant differences in response were seen between cohorts when all patients were analysed together or analysed for males only. CONCLUSIONS: Treatment time may affect response in female patients receiving radiotherapy for painful bone metastases. Subsequent chronotherapy studies in radiation should investigate these gender differences.

Could time of whole brain radiotherapy delivery impact overall survival in patients with multiple brain metastases?

OBJECTIVE: Whole brain radiotherapy (WBRT) is commonly used to treat brain metastases. Previous studies have explored how radiotherapy treatment time can affect response. The present study evaluated the influence of treatment time on overall survival (OS) for cancer patients receiving WBRT. METHODS: Patients who received WBRT from 2004 to 2016 were included. Demographic information including age, performance status, primary site, dose, fraction, treatment time, and date of death were collected. Based on different percentages of treatment times falling into one time frame (i.e., 100%, ≥80%, ≥70%, or ≥60%), patients were allocated to three cohorts (8:00-11:00 AM, 11:01 AM-2:00 PM, 2:01-5:00 PM). Demographics were compared among cohorts using the Kruskal-Wallis nonparametric test and Fisher exact test. To control the multiple comparisons on select demographic variables a Bonferroni adjusted P value was considered statistically significant. Kaplan-Meier curves were created for OS. Univariate and multivariate Cox proportional hazard (PH) model were used to find predictive factors of OS in all patients, females and males. RESULTS: A total of 755 patients were included with a median age of 66 years. The actuarial median OS was 2.37 months. Treatment time was not associated with OS for all patients or males only. In elderly female patients (>65 years), a significant difference in OS was found among treatment cohorts (P=0.02). Treatment time (when ≥80% or ≥70% of treatment times were in one time frame), age, and Karnofsky performance status (KPS) were significant predictive factors of OS in univariate analysis for females. Only age and KPS remained significant in multivariate analysis. CONCLUSIONS: Time of WBRT delivery for brain metastases was significantly related to OS upon univariate analyses in females only. Future investigations should be conducted prospectively with homogenous patient groups to elucidate the effect of chronotherapy in palliative brain metastases patients as time of WBRT administration may affect OS in specific subsets of patients.

Randomized, double-blinded, placebo-controlled, trial of risedronate for the prevention of bone mineral density loss in nonmetastatic prostate cancer patients receiving radiation therapy plus androgen deprivation therapy.

PURPOSE: Androgen deprivation therapy (ADT) has been used as an adjuvant treatment to radiation therapy (RT) for the management of locally advanced prostate carcinoma. Long-term ADT decreases bone mineral density (BMD) and increases the risk of osteoporosis. The objective of this clinical trial was to evaluate the efficacy of risedronate for the prevention of BMD loss in nonmetastatic prostate cancer patients undergoing RT plus 2 to 3 years of ADT. METHODS AND MATERIALS: A double-blinded, placebo-controlled, randomized trial was conducted for nonmetastatic prostate cancer patients receiving RT plus 2 to 3 years of ADT. All had T scores > -2.5 on dual energy x-ray absorptiometry at baseline. Patients were randomized 1:1 between risedronate and placebo for 2 years. The primary endpoints were the percent changes in the BMD of the lumbar spine at 1 and 2 years from baseline, measured by dual energy x-ray absorptiometry. Analyses of the changes in BMD and bone turnover biomarkers were carried out by comparing mean values of the intrapatient changes between the 2 arms, using standard t tests. RESULTS: One hundred four patients were accrued between 2004 and 2007, with 52 in each arm. Mean age was 66.8 and 67.5 years for the placebo and risedronate, respectively. At 1 and 2 years, mean (±SE) BMD of the lumbar spine decreased by 5.77% ± 4.66% and 13.55% ± 6.33%, respectively, in the placebo, compared with 0.12% ± 1.29% at 1 year (P=.2485) and 0.85% ± 1.56% (P=.0583) at 2 years in the risedronate. The placebo had a significant increase in serum bone turnover biomarkers compared with the risedronate. CONCLUSIONS: Weekly oral risedronate prevented BMD loss at 2 years and resulted in significant suppression of bone turnover biomarkers for 24 months for patients receiving RT plus 2 to 3 years of ADT.