Optimal timing for adjuvant radiation therapy in breast cancer: a comprehensive review and perspectives

The optimal sequence of modalities involved in breast cancer treatment with respect to radiotherapy and the maximum acceptable interval between radiotherapy and surgery need to be determined.

This review attempts a critical reading of the literature.

A delay of radiotherapy more than 8-12 weeks after surgery adversely affects local recurrence. Radiotherapy should be administered within 7 months after surgery, when chemotherapy is administered first. Several chemotherapy regimens can be safely administered concurrently with radiotherapy. The concurrent use of tamoxifen with chemotherapy should be avoided, but not with radiotherapy. Data is insufficient with regard to concurrent use of aromatase inhibitors with radiotherapy. The use of trastuzumab concomitantly with radiotherapy may enhance toxicities but may also improve its efficacy.

Although the issue of radiotherapy delay and that of sequence with chemotherapy or tamoxifen are clarified, the sequence of radiotherapy with aromatase inhibitors and trastuzumab needs to be defined. Individual radiosensitivity may influence toxicity. New biologic markers have to be determined in the future for tailoring radiotherapy in breast cancer.