Biochemical outcome after curative treatment for localized prostate cancer with external beam radiotherapy: a cross-sectional study

Although many patients who receive definitive radiotherapy (RT) for localised prostate cancer (CaP) experience long-term disease-free survival and better quality of life, some also have biochemical progression during follow-up. Oftentimes this implies additional treatment for patients with the accompanying challenges of cumulative treatment side effects, inconvenience and financial toxicity. This study retrospectively assessed the clinicopathological characteristics and biochemical outcomes of patients treated for localised CaP with external beam radiotherapy (EBRT) between 2015 and 2020 at a major cancer treatment centre in Accra, Ghana. Patients' socio-demographic and clinical data were collected from their hospital records and analysed with the Statistical Package for Social Sciences version 26. Biochemical failure (BCF) was defined as an increase in the level of serum prostate-specific antigen (PSA) >2 ng/mL above the nadir after curative therapy based on the Phoenix definition. The mean age was 67.6 years (SD +/- 6.2). The majority of the study participants (n = 79, 64.8%) had initial PSA >20 ng/mL, with the highest recorded value of 705 ng/mL. All the patients had biopsy-proven adenocarcinoma of the prostate gland. Some patients received 3-dimensional conformal radiotherapy (3DCRT) on a cobalt-60 teletherapy machine whereas others were treated with either 3DCRT or intensity-modulated radiotherapy (IMRT) on a 6 MV Linac. In all, 13.1% of the patients experienced BCF after receiving EBRT after an average follow-up of 31.3 months. This study demonstrated a low rate of BCF among patients treated with EBRT for localised CaP in Ghana. Strong prognostic factors of biochemical outcome demonstrated in this study were the percentage of cores positive, grade group, and risk stratification. Diar-rhaea and desquamation experienced by treated CaP patients were exclusively attribut-able to EBRT. RT produced a complete resolution of symptoms in some of the patients.