Fractionated perineal high-dose-rate temporary brachytherapy combined with external beam radiation in the treatment of localized prostate cancer: is lymph node sampling necessary?

Purpose. – To study the influence of imaging based nodal staging and local dose escalation by a high-dose-rate brachytherapy (HDR-BT) boost in the treatment of locally confined prostate cancer in terms of prostate specific antigen (PSA) recurrence-free survival (biochemical non-evidence of disease (bNED)), treatment toxicity and prognostic variables. ts and Methods. – The prospectively recorded files of 144 men aged in a median of 68 years with a mean follow-up of 8 years (60–171 months) receiving curatively intended, transrectal ultrasound guided high-dose-rate 192-iridium-brachytherapy (HDR-BT) combined with external beam radiation therapy (EBRT) for locally confined prostate cancer were analyzed. T-stages were defined by digital rectal investigation and transrectal sonography (TRUS), nodal staging was performed with computed tomography(CT)/magnetic resonance imaging (MRI) (UICC/AJCR 1992). Twenty-nine patients (20.1%) had T1b-T2a tumors, and 115 patients had T2b-T3 tumors. Median initial PSA (iPSA) was 12.15 ng mL–1 (mean 25.61 ng mL–1). The total planned dose applied by external beam radiation was 50 Gy in the pelvis, and 40 Gy in the prostate by in-field-dose modification by individual compensators. The perineal, TRUS guided HDR-BT was delivered in two fractions of 15 Gy each. The target of BT boost was the peripheral zone of the prostate. s. – the overall survival was 71.5% and that of the disease free survival 82.6%. Freedom from distant metastases in T3 stage was 91.3%, whereas for G3 lesions, it was 88.23%. The bNED rate was 72.9%. Regarding treatment related late toxicity according to the EORTC/RTOG score, we observed grade 1, 2, 3 proctitis in 9.72%, 6.94%, 4.10% as well as grade 1, 2, 3 cystitis in 12.5%, 4.16%, 2.08%, respectively. Grade 4 and 5 proctitis or cystitis were not registered. sion. – The minimum 5-year and mean 8-year results confirm that local dose escalation by TRUS guided perineal HDR-BT and complementary external beam radiation of the pelvic lymphatics has curative potential in men with locally confined high-risk prostate cancer, although surgical staging results in the literature suggest a high probabilityof microscopic nodal involvements at the level of 25.61 ng mL–1 mean PSA. The influence of additional short-term (< 6 months) hormonal ablation on the treatment results could not be stated.