Dosimetric and Clinical Outcomes of Volumetric Modulated ArcTherapy for Prostate Cancer

Abstract

Objectives: To evaluate the dosimetric aspects through dose coverage and tolerance as well as the clinical outcomes of radiation therapy for prostate cancer by a technique of Volumetric Modulated Arc Therapy (VMAT).

Methodology: This is a retrospective study of 71 patients treated for prostate cancer consecutively at the International Cancer Center of Dakar (CICD) from July 2020 to December 2023. All patients received radiation therapy in intensity modulation by VMAT technique. The diagnostic data, treatment information including dosimetric and results were collected and analyzed.

Results: The average age was 68.9 ± 6.1 years. The circumstance of discovery was fortuitous by PSA assay in 42.3% and symptomatic in 57.7% of cases. The median initial PSA level was 20 ng/ml (3.7–662). Adenocarcinoma was the histological type in all patients. Pelvic node involvement was found in 12.6% of patients and 5.6% were metastatic. For localized forms, high risk was predominant (49.3%). First-line radiotherapy was performed in 94.4% of cases. The average doses of the D95% and Dmax of the high-risk forecast target volume were 70.69 ± 5.2Gy and 77.06 ± 5.88Gy, respectively. All dose constraints have been met on the target volumes and organs at risk. No Grade 3 acute toxicity was observed. With a median follow-up of 20.67 months, the overall survival (OS) and biochemical relapse-free survival (BFS) rates at 2 years were 98.6% and 92.9%, respectively.

 Conclusion: Radiotherapy occupies a prominent place in the treatment of prostate cancer. New techniques by intensity modulation allow better oncological results and improve the tolerance of treatments.