CODE: 7.3 - Toxicity related to conformal radiotherapy of prostate cancer
Article published in Urologia Polska 2006/59/Suplement 1.

authors

Piotr Milecki ¹, Tomasz Piotrowski ¹, Andrzej Antczak ², Zbigniew Kwias ², Tomasz Stachowski ³

¹ Wielkopolskie Centrum Onkologii w Poznaniu
² Katedra Urologii AM w Poznaniu
³ Szpital MSW w Poznaniu

summary

Introduction. The evaluation of toxicity level related to radiotherapy and analysis of predictive factors that correlate with, and ideally predict for, acute and late side effects has become a crucial point for many clinical trials and should result in benefit for the patient.

Objectives. Aim of this work was to evaluate the acute and late toxicity profile of prostate cancer patients treated with external beam radiotherapy and to investigate the possible risk factors for acute and late toxicities.

Materials and methods. The study population consisted of 432 patients with diagnosis of prostate adenocarcinoma treated between June 1999 and December 2004 with conformal radiotherapy. The median age of patients was 69 years (range 51- 81 years). The patient's T stage was as follows: T1 (n=58), T2 (n=238), T3 (n=136). Median PSA level was 22.2 ng/ml (0.2-99 ng/ml). All patients were treated with external beam radiotherapy with median total dose of 70 Gy (range 60 to 74 Gy) using three-dimensional conformal techniques (3D CRT). Of the 432 patients, 377 patients (87%) received hormonal therapy (neoadjuvant or adjuvant). Acute toxicity (<120 days) and late toxicity (>120 days) from genitourinary tract (GU) and gastrointestinal tract (GI) were scored with a modified RTOG/EORTC scoring classification. Risk factors investigated for their possible relationship with the acute and late GU or GI grade 2 toxicity were age, past medical history, T stage, initial PSA, Gleason score, use of pelvic fields, total dose, use and duration of neo- and adjuvant androgen ablation, and acute toxicity (Grade 2 or greater). The minimum follow-up for the entire group of patients was of 12 months. Kaplan-Meier curves were to calculate the cumulative incidences of late side effects.

Results. The GI and GU scores gradually increased during treatment with maximum incidence of GU grade 2 was 7% and GI grade 2 was 6%. Overall, 93% of the patients experienced no or mild (grade 0/1) GU toxicity. GI toxicity grade 0/1 was observed for 94% of patients. No grade 3 or 4 toxicity occurred. The incidence of late grade 2 GI and GU toxicity was 16% at 4 years (GI 8% and GU 8%). No Grade 4 toxicity occurred. The risk factors of significance in relation to the development of late Grade 2 GU toxicity was presence of acute grade 2 GU toxicity. For late grade 2 GI toxicity pelvic radiotherapy was related to higher incidence of such side effects. On the other hand, neoadjuvant hormonal therapy is correlated with decreasing the acute and late toxicity for GU and GI tracts.

Conclusions. Conformal radiotherapy is related with mild toxicity from GU and GI. Neoadjuvant hormonal therapy is related to lower acute and late side effects of radiotherapy.