Quality of Life: A Prospective Randomized Trial of Palliative Volumetric Arc Therapy (VMAT) Versus Conformal Radiation Therapy (CRT)

VMAT spares normal tissues from high/intermediate radiation (RT) doses but increases the volume of tissues receiving low doses of RT as compared to CRT. We hypothesized that palliative VMAT would induce less acute quality of life (QOL) detriment than CRT. This phase 2 trial randomized patients to palliative RT using VMAT or CRT to 1 painful site of metastatic disease in the trunk. Eligible patients were able to complete questionnaires (EORTC QLQ C30 and SF-BPI) and were expected to live >3 months. Patients were ineligible if their KPS<50, they had prior radiation to the same site, there were planned changes in analgesics or cancer therapy within 7 days of the RT. Treating physicians could choose 8Gy in 1 fraction or 20Gy in 5 fractions, a choice used to stratify randomization. The primary endpoint was EORTC QLQ C30 global QOL subscales at 1-week post-RT (QOL at 4 weeks was a secondary endpoint). Paired t-test was used to compare the effect of RT to all patients. Wilcoxon signed-rank test (2-tailed) was used to compare changes in QOL. Only clinically important (≥10 point) QOL differences are reported. From July 2014-November 2017, 72 patients were accrued. Three patients did not receive RT, 12 did not return 1-week post-RT. There were 55 and 46 evaluable patients at 1 and 4 weeks post-RT, respectively. The most common diagnoses were NSCLC, breast, and prostate cancer. Median overall survival was 9 months. Median pain level was 7/10 at baseline and 5/10 at 1 and 4 weeks post-RT (p<0.0001 and p=0.0013). Median time from consultation to RT was 6 days. Baseline characteristics (KPS, pain, QOL subscales and time to 1st RT fraction) were balanced between the groups. At 1 week post-RT, global QOL subscale was not significantly (p=0.46) different between VMAT vs. CRT, but VMAT induced significantly (p= 0.027) less nausea and vomiting than CRT. At 4 weeks post-RT, VMAT induced significantly (p=0.048) less global QOL deterioration. At 4 weeks, patients who received VMAT maintained better role (p=0.022) and social (p=0.018) functions, but reported more diarrhea symptoms (p=0.033) than patients treated with CRT. Patient age, gender, RT dose, PTV size and target location (abdomino-pelvic vs. thoracic) were not associated with global QOL changes at 4 weeks. Palliative VMAT appears to induce less QOL detriments than CRT at 4 weeks post-RT. VMAT reduced iatrogenic nausea and vomiting, which was partially offset by an increase in diarrhea.