Risk of radiation pneumonitis in breast cancer patients treated with adjuvant taxanes and radiation

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624 Background: In 2001, Taghian et al (JNCI 2001;93:1806–11) published a retrospective cohort study of 41 breast cancer patients treated with adjuvant paclitaxel and radiotherapy (RT). The crude rate of radiation pneumonitis was 15%, significantly higher than the expected rate of 1%. This result raised considerable concern regarding the safety of this treatment. The goal of this study was to conduct a review of breast cancer patients treated with paclitaxel and RT at the BC Cancer Agency, and to determine the risk of radiation pneumonitis at this institution. The results of this study can be used to develop safe guidelines for use of this treatment. Methods: This study is a retrospective review of breast cancer patients treated with adjuvant paclitaxel and radiotherapy at the BCCA. Patients received 4 cycles of adjuvant AC and then 4 cycles of paclitaxel, RT is usually given sequentially after paclitaxel. All patients had stage II-III, node positive, and ER- breast cancer. The number of chemotherapy cycles, RT technique and dose, and pulmonary symptoms 1–12 months following RT were recorded. Radiation pneumonitis is defined as Grade 2 or 3 toxicity on the RTOG scale. Results: A total of 77 women who initiated treatment from Apr. 2000 –Jun. 2002 were identified. Of these 77 women, 53 received sequential adjuvant RT. 91% completed all 4 cycles of paclitaxel, 100% received the prescribed dose of radiation. All patients had at least 3 months of follow-up following completion of RT. With this sample size, the power to detect a change in pneumonitis risk from 1% to 15% exceeds 80% (alpha = 0.05). 10 patients (19%) reported pulmonary symptoms within a year of RT. 1 patient was diagnosed with heart failure from anthracycline. 1 patient had pleural effusions from metastases. 1 patient was diagnosed with radiation pneumonitis and improved with steroids. 7 patients had episodes of dyspnea or dry cough that resolved without treatment. Thus, the crude rate of Grade 1 and Grade 2–4 pulmonary toxicity was 13% and 2% respectively. Conclusions: The incidence pneumonitis is not significantly increased for breast cancer patients treated with adjuvant paclitaxel and adjuvant sequential RT. No significant financial relationships to disclose.