# Gemcitabine-Induced Myonecrosis Following Hypofractionated Radiation

## TL;DR

A 41-year-old woman with breast cancer developed muscle damage after gemcitabine and hypofractionated radiation, highlighting a rare side effect called radiation recall phenomenon.

## Contribution

This case report documents myonecrosis as a rare manifestation of radiation recall phenomenon after hypofractionated radiation and gemcitabine.

## Key findings

- Myonecrosis occurred four months after hypofractionated radiation and six cycles of gemcitabine and cisplatin.
- Symptoms improved after stopping gemcitabine and using anti-inflammatory drugs.
- This case highlights the need for awareness of RRP in hypofractionated radiation settings.

## Abstract

Palliative radiation is often used to abate pain and prevent bone fractures in patients with metastatic cancer. Hypofractionation, meaning delivery of larger doses of radiation in each treatment session (fraction), has become the standard of care in most cases. It not only reduces the burden on the medical system and facilitates the relief of symptoms but also enables the maintenance of the continuity of systemic therapy. Radiation recall phenomenon (RRP) is an acute inflammatory reaction in previously irradiated tissues that is provoked by chemotherapeutic drug administration. The incidence, severity, and prognosis of RRP following hypofractionated radiation therapy have not been studied. The symptoms of RRP depend on the radiation field, with the greatest concern associated with mucosal and dermal damage, though other symptoms have also been reported. Here, we describe a case of a 41-year-old woman with metastatic breast cancer (hormone receptor-positive, HER2/neu negative), who received palliative radiation to four other fields along the course of her disease, before her presentation with isolated myonecrosis of the thigh muscles. This RRP occurred four months following the last of two fractions of 8 Gy radiation to this region, given three months apart, and after six courses of cisplatin + gemcitabine. The symptoms improved with cessation of gemcitabine and prolonged administration of non-steroidal anti-inflammatory medications.