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A recent review, written about the use of radiation therapy together with the administration of certain hormones has been a topic of late. The review states that Endocrine therapy is utilized to treat patients synchronously with radiation treatment but the authors ask the question, why?

Especially without a body of studies on such a combination, it sought answers for such procedures.  This review, called Concurrent hormone and radiation therapy in patients with breast cancer: what is the rationale? states that “although data from in-vitro studies support the notion of antagonistic effects of concurrent tamoxifen and radiotherapy on tumour cells, in-vivo research suggests a synergistic effect that could be attributable to microenvironmental changes in tumour responsiveness to ionising radiation and hormone therapy.”

The review goes on to say “concurrent administration of tamoxifen with radiotherapy does not compromise local control but might increase toxicity.” Further studies are recommended by the reviewers before physiological responses will be better understood, especially given that very little data has been compiled on the timing of the hormone treatment, whether given during or after radiation therapy.  So far, no studies have been clinically explored for such timing, however, reports show an increase in local control had been attained when given tamoxifen rather than given no hormone.

A rare study, on hormone therapy with radiotherapy, by Ahn and colleagues (Ahn PH, Vu HT, Lannin D, et al. Sequence of radiotherapy with tamoxifen in conservatively managed breast cancer does not affectlocal relapse rates. J Clin Oncol 2005; 23: 17–23) assessed the timing of tamoxifen relative to radiotherapy.  “Although this study is the largest published investigation of the sequencing of radiotherapy and tamoxifen therapy, the small sample size limits the ability to detect small difference in outcomes,” states the review.  The authors go on to say it is also “a retrospective study and is subject to inherent biases and limitations therein.” Because there is no proof that administering hormone therapy in conjunction with radiotherapy provides any advantageous benefit, the conclusion of the review recommended delaying the use of hormone therapy until after radiation treatment.