Conventionally Fractionationed Volumetric Arc Therapy versus Hypofractionated Stereotactic Body Radiotherapy: Quality of Life, Side Effects, and Prostate-Specific Antigen Kinetics in Localized Prostate Cancer.

OBJECTIVES

To compare conventionally fractionationed volumetric arc therapy (VMAT) and hypofractionated stereotactic body radiotherapy (SBRT) modalities in terms of prostate-specific antigen (PSA) kinetics, toxicity, and quality of life (QOL) in patients with localized prostate cancer.

METHODS

Patients received radical radiotherapy as either 33.5 Gy/5 fr for SBRT or 75.6 Gy/35 fr for VMAT. International Prostate Symptom Score (IPSS) and European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Prostate Cancer Module (QLQ-PR25) forms were used to assess QOL.

RESULTS

Of the 48 patients (28 in SBRT and 20 in VMAT) included in the study, 40 (20 in SBRT and 20 in VMAT) were evaluated for QOL status. PSA control rate was 100% and PSA nadir value was 0.5 ng/dl in both arms during the median follow-up period of 23 months. The magnitude of PSA bounce was higher in the SBRT arm than in the VMAT arm (P = 0.01). The PSA decline rate in the VMAT arm was higher than in the SBRT arm (P = 0.028). Three (10.7%) patients treated with SBRT who had a history of transurethral resection of the prostate (TURP) experienced grade 3 urinary toxicity. No significant difference was observed concerning sexual activity and sexual functioning scores, whereas scores at 10.5 and 13.5 months were decreased in both arms. The SBRT and VMAT arms had similar urinary incontinence, bowel symptoms, and IPSS obstruction scores. The magnitude of increase in IPSS scores at treatment completion was higher in the VMAT arm than in the SBRT arm (P = 0.046). The decrease in hormonal symptom scores at 4.5, 10.5, and 13.5 months was higher in the VMAT arm than in the SBRT arm (P = 0.007, 0.027, and 0.021, respectively).

CONCLUSIONS

Both treatment modalities had similar effectiveness and provided acceptable outcomes in terms of toxicity and QOL. Grade 3 urinary toxicities might be eliminated with careful patient selection for SBRT.