Clinically relevant pneumonitis after sequential paclitaxel-based chemotherapy and radiotherapy in breast cancer patients

Abstract

Background: Taxane-based chemotherapy has been associated with an increased risk of radiation pneumonitis in patients with breast cancer. To obtain additional information about this association, we investigated the association between paclitaxel chemotherapy and radiation pneumonitis in patients participating in a phase III randomized study.

Methods: Five hundred and twenty-four breast cancer patients were prospectively and randomly assigned to receive either four cycles of paclitaxel followed by four cycles of 5-fluorouracil, doxorubicin, cyclophosphamide (FAC) or eight cycles of FAC. One hundred and eighty-nine of these patients (100 in the paclitaxel-FAC group and 89 in the FAC group) subsequently underwent radiation therapy in our institution and had medical records available to review for pulmonary symptoms. In addition, a radiologist who was unaware of the type of treatment scored chest x-ray changes after radiation treatment. Crude rates of radiation pneumonitis were compared with chi-square or Fisher's exact test, and actuarial rates were assessed with Kaplan-Meier and log-rank tests. All statistical tests were two-sided.

Results: No difference in the rate of clinically relevant radiation pneumonitis was observed between the two groups (5.0% in the paclitaxel-FAC group versus 4.5% in the FAC group; difference = 0.5%, 95% CI = -6.6% to 5.5%; P = 1.00). Oral steroids for pneumonitis were taken by two patients in the paclitaxel-FAC group but by none in the FAC group, and no patient was hospitalized for or died of radiation pneumonitis. The paclitaxel-FAC group (39.3%) had a higher rate of radiographic changes after irradiation than the FAC group (23.7%; difference = 15.6%, 95% CI = -0.11% to 28.8%; P = .034).

Conclusion: Patients with breast cancer treated with sequential paclitaxel, FAC, and radiation therapy appeared to have a very low rate of clinically relevant radiation pneumonitis that was no different from that of patients treated with FAC alone.