A Phase II Study to Prevent Radiation-induced Rectal Injury With Lovastatin

Physician reported symptomatic late rectal injury occurs in about 5% to 25% of patients treated with radiation therapy for prostate cancer, depending on the treatment technique. Patients, however, report clinically meaningful declines in bowel/rectal function regardless of the technique used. Lovastatin has been shown to protect mice from late radiation injury. This study was designed to determine if lovastatin might reduce the incidence of late rectal injury in patients receiving radiation therapy for prostate cancer.

Patients with adenocarcinoma of the prostate receiving radiotherapy with curative intent were eligible. A portion of the rectum had to receive at least 60 Gy. Gastrointestinal functioning was assessed using both physician-reported and patient-reported instruments at baseline and at prescribed intervals during and after treatment. Lovastatin (20 to 80 mg/d) was started on day 1 of radiation and continued for 12 months. Patients were followed for an additional 12 months. The primary endpoint was physician-reported rectal toxicity ≥grade 2 during the first 2 years after treatment.

A total of 20/53 (38%) patients developed grade 2 or higher toxicity during the 2-year follow-up period. Seventeen patients had 1 or more unresolved gastrointestinal symptom at the end of 2 years, 3 (6%) of which were grade 2 and none were of higher grade.

The primary endpoint of the study was not met. Lovastatin, as administered in this trial, did not reduce the incidence of grade 2 or higher rectal toxicity compared with historical controls.