Study: Paclitaxel Increases Risk of Pneumonitis After Radiation

The addition of paclitaxel to standard chemotherapy significantly increases the risk that patients also receiving radiation treatment for breast cancer will develop pneumonitis, according to researchers at Harvard Medical School in Boston.

Common treatment for breast cancer with lymph node involvement is surgery followed by chemotherapy and radiation therapy. Paclitaxel is often part of the chemotherapy regimen.

Some evidence has shown that paclitaxel may enhance the effectiveness of the radiation therapy, but researchers are unclear as to the actual benefit of the agent in the outcome of the disease.

Researchers analyzed 41 women with breast cancer who were treated with paclitaxel, chemotherapy and radiation, 437 women who received radiation therapy and chemotherapy that did not include paclitaxel, and 849 women who received only radiation therapy.

Of the women taking paclitaxel, 6 developed pneumonitis, a rate of 14.6 percent. The women who were treated with radiation therapy alone and the women who received radiation therapy and chemotherapy that did not include paclitaxel had a 1.1 percent rate of developing pneumonitis, according to the study published in the Journal of the National Cancer Institute.

The average time from the end of radiation to the development of pneumonitis in the non-paclitaxel group was 5 months, compared with 1.9 months in the paclitaxel group.

Researchers conclude that paclitaxel may increase the toxicity of radiation to the lung.

"With the absence of a clear benefit of adding paclitaxel to standard chemotherapy, the use of paclitaxel and radiation therapy in the primary treatment of breast cancer should be undertaken with caution," wrote the authors.

Other Sources: Journal of the National Cancer Institute