Acute and late radiation toxicities of proton beam radiation therapy
Posted Oct 05 2010 12:00am
Over the years there have been almost no publications addressing the complications of proton beam radiation therapy (PBRT) among well-defined series of prostate cancer patients. With the number of PBRT centers now growing fast, good data on the side effects of PBRT are an urgent priority.
Nihei et al. have conducted a prospective Phase II study in Japan, designed to assess the incidence of late rectal toxicities after PBRT among patients with organ-confined prostate cancer. Their study also provides us with information about acute rectal toxicities as well as acute and late bladder toxicities.
The study was carried out by a consortium of three Japanese PBRT facilities. Patients were all intended to be clinical stage T1 or T2, with PSA levels of ≤ 20 ng/ml and Gleason scores ≤ 7. Patients received no hormone therapy either while on study or for 12 months prior to enrollment in the study. The patients were all treated between 2004 and 2007 and received a total dose of 74 GyE in 37 fractions.
The results of the study showed the following:
151 patients were enrolled in the study.
The clinical stages of the patients were T1c (n = 75), T2a (n = 49), T2b (n = 9), T2c (n = 17), and T3a (n = 1).
The Gleason scores of the patients were 4 (n = 5), 5 (n = 15), 6 (n = 80), and 7 (n = 51).
The initial PSA level was < 10 ng/ml in 102 patients and 10-20 ng/ml in 49 patients, respectively.
42 patients (28 percent) had previously received hormonal therapy.
Median follow-up was 43.4 months.
Acute (temporary) Grade 2 rectal toxicity developed in 0.7 percent of patients (2/151).
Acute (temporary) Grade 2 bladder toxicity developed in 12 percent of patients (18/151).
Late rectal toxicity of Grade 2 or higher was observed in 2 percent of patients (3/147) followed for > 2 years.
Late bladder toxicity of Grade 2 or higher was observed in 4.1 percent of patients (6/147) at 2 years post-treatment.
In this cohort of Japanese patients, the incidence of acute and late rectal toxicities following PBRT for localized prostate cancer was extremely low. The incidence of acute and late bladder toxicities is clearly higher. The abstract does not provide us with detail about the incidence of late bladder toxicities of Grade 3 or Grade 4. Grade 2 toxicities are generally considered to be mild to moderate.
The “New” Prostate Cancer InfoLink looks forward to seeing data on other complications of PBRT in comparable patient cohorts most particularly the incidence of erectile dysfunction in men who had high erectile function immediately prior to treatment.
Over the years there have been almost no publications addressing the complications of proton beam radiation therapy (PBRT) among well-defined series of prostate cancer patients. With the number of PBRT centers now growing fast, good data on the side effects of PBRT are an urgent priority.
Nihei et al. have conducted a prospective Phase II study in Japan, designed to assess the incidence of late rectal toxicities after PBRT among patients with organ-confined prostate cancer. Their study also provides us with information about acute rectal toxicities as well as acute and late bladder toxicities.
The study was carried out by a consortium of three Japanese PBRT facilities. Patients were all intended to be clinical stage T1 or T2, with PSA levels of ≤ 20 ng/ml and Gleason scores ≤ 7. Patients received no hormone therapy either while on study or for 12 months prior to enrollment in the study. The patients were all treated between 2004 and 2007 and received a total dose of 74 GyE in 37 fractions.
The results of the study showed the following:
In this cohort of Japanese patients, the incidence of acute and late rectal toxicities following PBRT for localized prostate cancer was extremely low. The incidence of acute and late bladder toxicities is clearly higher. The abstract does not provide us with detail about the incidence of late bladder toxicities of Grade 3 or Grade 4. Grade 2 toxicities are generally considered to be mild to moderate.
The “New” Prostate Cancer InfoLink looks forward to seeing data on other complications of PBRT in comparable patient cohorts most particularly the incidence of erectile dysfunction in men who had high erectile function immediately prior to treatment.