Postoperative irradiation of left-sided breast cancer patients and cardiac toxicity. Does deep inspiration breath-hold (DIBH) technique protect the heart?

PURPOSE: To evaluate the impact of deep inspiration breath-hold (DIBH) technique during postoperative left-sided tangential breast irradiation on minimizing irradiated heart amount compared to normal breathing.

PATIENTS AND METHODS: In 22 patients with left-sided breast cancer, postoperative CT scanning was performed in different respiratory phases using the Varian Real-time Position Management System for monitoring of respiratory chest wall motion. Each patient underwent two CT scans: during normal breathing and DIBH. For each scan, an optimized plan was designed with tangential photon fields encompassing the clinical target volume after breast-conserving surgery or modified radical mastectomy. The resulting dose-volume histograms were compared between both breathing techniques for irradiated volume and dose to the heart.

RESULTS: The mean patient age was 51 years (range: 34-77 years). The DIBH-gated technique was well accepted by all patients. The significant reduction in dose to the irradiated heart volume for the DIBH technique compared to the normal breathing was 56% (mean heart dose: 2.3 Gy vs. 1.3 Gy; p = 0.01).

CONCLUSION: This study demonstrates that irradiated cardiac volumes can significantly be reduced in left-sided breast cancer patients using DIBH technique for postoperative tangential radiotherapy. Moreover, the technique is safe and feasible in daily routine.