Late gastrointestinal morbidity after three-dimensional conformal radiation therapy for prostate cancer fades with time in contrast to genitourinary morbidity.
OBJECTIVE
To investigate the incidence, time course, and relation to irradiated volumes of late morbidity after three-dimensional conformal radiation therapy (RT) for prostate cancer.


METHODS
From January 2000 to December 2001, a total of 247 patients with prostate cancer received a target dose of 70 Gy using conformal RT. Forty-eight patients (20%) received irradiation to the prostate only (Group P), 154 patients (62%) received irradiation to the prostate and seminal vesicles (Group PSV), and 45 patients (18%) received modified pelvic fields (Group MPF). Androgen deprivation was given to 86% of patients. Median follow-up was 62 months. Late gastrointestinal (GI) and genitourinary (GU) morbidity were recorded according to the Radiation Therapy Oncology Group scoring system.


RESULTS
We observed 9%, 7%, and 25% Grade 2 or higher GI morbidity and 36%, 30%, and 21% Grade 2 or higher GU morbidity in Groups P, PSV, and MPF, respectively. In multivariate analyses, age and treatment group were independent predictors for the incidence of late Grade 2 or higher GI morbidity, whereas age and urinary symptoms before treatment were independent predictors for late Grade 2 or higher GU morbidity. Acute side effects predicted for late effects. The rectum dose-volume histogram parameters correlated with the incidence of late Grade 2 or higher GI morbidity, especially the fractional volume receiving more than 40-43 Gy. At 5 years of follow-up, the rate of Grade 2 late GI morbidity was only 1.4%, and Grade 2 or higher GU morbidity was 10.6%.


CONCLUSIONS
The data presented here show that late GI morbidity after prostate RT is low and subsides with time.
Karlsdóttir
Asa
A
Department of Oncology and Medical Physics, Haukeland University Hospital, Bergen, Norway. asa.karlsdottir@helse-bergen.no
Muren
Ludvig Paul
LP
Wentzel-Larsen
Tore
T
Dahl
Olav
O
D000208:Acute Disease; D000368:Aged; D041981:Gastrointestinal Tract / Q000528:radiation effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000150:complications* / Q000503:physiopathology; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D012007:Rectum / Q000528:radiation effects; D012044:Regression Analysis; D012075:Remission, Spontaneous; D013997:Time Factors; D001743:Urinary Bladder / Q000528:radiation effects; D014566:Urogenital System / Q000528:radiation effects*