Changes in pulmonary function up to 10 years after locoregional breast irradiation

Area of Science:

• Oncology
• Pulmonology
• Radiotherapy

Background:

• Locoregional radiotherapy (RT) is a standard treatment for breast cancer.
• Long-term effects of RT on pulmonary function are not fully understood.

Purpose of the Study:

• To evaluate the long-term impact of locoregional breast radiotherapy (RT) on pulmonary function tests (PFTs).

Main Methods:

• Seventy-five women undergoing postoperative locoregional breast RT had PFTs assessed before RT and at 3, 6, 12 months, and 8-10 years post-RT.
• Univariate and multivariate analyses identified factors influencing late PFT changes.

Main Results:

• PFTs significantly worsened at 3-6 months post-RT, with partial recovery by 12 months.
• At 8-10 years, mean reductions were observed in forced expiratory volume in 1 second (FEV(1)) (4%), vital capacity (VC) (5%), diffusion capacity of carbon monoxide (DL(CO)) (9%), and total lung capacity (TLC) (11%).
• Tamoxifen use was linked to reduced TLC, and right-sided RT to reduced FEV(1). Early PFT decrease predicted late decline.

Conclusions:

• Locoregional RT for breast cancer induces a biphasic PFT decline: an early reduction followed by a more significant late reduction up to 10 years.
• Tamoxifen use may contribute to the late decline in pulmonary function.