Evaluating the efficacy of statins and ACE-inhibitors in reducing gastrointestinal toxicity in patients receiving radiotherapy for pelvic malignancies.

Introduction: 3-Hydroxy-methylglutaryl coenzyme-a reductase inhibitors (statins) improve survival following pelvic irradiation for cancer. Large studies suggest that patients with hypertension may have reduced gastrointestinal (GI) toxicity. Animal data suggest that statins and ACE inhibitors (ACEi) may protect against normal tissue injury. Their efficacy in humans has not been reported.

Aims/methods: To evaluate the impact of statins and ACEi on normal tissue toxicity during radical pelvic radiotherapy. GI symptomatology was recorded prospectively before radiotherapy, weekly during treatment and 1 year later using the inflammatory bowel disease questionnaire-bowel (IBDQ-B) subset. Cumulative acute toxicity (IBDQ-B AUC) and worst score were determined. Dose, brand and duration of statin and/or ACEi usage were obtained from General Practitioners.

Results: Of 308 patients recruited, 237 had evaluable acute drug and toxicity data and 164 had data at 1year. Acutely, 38 patients (16%) were taking statins, 39 patients (16.5%) were taking ACEi and 18 patients (7.6%) were taking statin+ACEi. Mean changes in acute scores were 7.3 points (non-statin users), 7.3 (non-ACEi users) and 7.0 (non-statin+ACEi users) compared to 4.8 points (statin users), 5.0 points (ACEi users) and 4.9 points (statin+ACEi users). Statin use (p=0.04) and combined statin+ACEi use (p=0.008) were associated with reduced acute IBDQ-B AUC after controlling for baseline scores (ANOVA). At 1 year, users maintained higher IBDQ-B scores than non-users in all user subgroups.

Conclusion: Use of statin or statin+ACEi medication during radical pelvic radiotherapy significantly reduces acute gastrointestinal symptoms scores and also appears to provide longer-term sustained protection.