Klin Onkol 2006; 19(4): 222-227.
Summary
Backgrounds Three-dimensional conformal radiotherapy (3D-CRT) is an effective treatment method of the localized prostate cancer. Dose escalation is associated with acceptable chronic toxicity.
Design and Subjects Chronic toxicity was retrospectively evaluated in 152 patients with localized prostate cancer (T1-3 N0 M0), treated using 3D-CRT between 1997 and 2000.
Methods and Results The 3-field (0°, 90°, 270°) or 4-field (30°, 90°, 270°, 330°) techniques were used for 3D-CRT. Clinical target volume consisted of prostate and the base of seminal vesicles (SV) in T1-2 tumors and of prostate and SV in T3 tumors. The planning target volume was created with a margin of 10 mm antero-posteriorly and latero-laterally and 15 mm cranio-caudally. Dose was prescribed to the isocenter. 113/152 patients (74%) were treated with 70 Gy and 39/152 patients (26%) received 74 Gy. Chronic toxicity was assessed according to the modified Radiation Therapy Oncology Group and Late Effects Normal Tissue Task Force (RTOG/LENT) scale. Chronic gastrointestinal (GI) toxicity Grades 2 and 3 was observed in 22/152 (14.5%) and 6/152 (3.9%) of patients, respectively. The volume of rectum irradiated to a dose of 60 Gy, 65 Gy, and 70 Gy was significantly greater in patients with chronic GI toxicity Grades 2 or 3 compared to patients with none or Grade 1 toxicity (p=0.04, p=0.01 and p=0.02, respectively). Chronic genitourinary (GU) toxicity Grades 2 and 3 was observed in 16/152 (10.5%) and 15/152 (9.9%) of patients, respectively. Grade 3 GU toxicity was expressed as obstructive symptoms requiring an invasive procedure (n=13), and a total incontinence (n=2). A history of invasive urological procedure (transurethral resection of prostate TURP, transvesical prostatectomy TVPE) was a significant predictor for the development of GU toxicity. Late GU symptoms Grade 2 or 3 were observed in 15/49 patients (30.6%) with a history of TURP/TVPE compared to 16/103 patients (15.5%) without previous invasive procedure (p=0.03) .
Conclusions The incidence of chronic toxicity following 3D-CRT for prostate cancer was acceptable. Invasive urological procedure was a significant predictor for the development of chronic GU toxicity.
