| Background: Radiotherapy plays an important role in the treatment of breast
cancer. In the process of radiotherapy, the underling lung tissue receives higher doses
from treatment field, which led to incidence of radiation pneumonitis.
Objective: The present study aims to evaluate the predictive factors of radiation
pneumonitis and related changes in pulmonary function after 3D-conformal radiotherapy
of breast cancer.
Material and Methods: In prospective basis study, thirty-two patients with
breast cancer who received radiotherapy after surgery, were followed up to 6 months.
Respiratory symptoms, lung radiologic changes and pulmonary function were evaluated.
Radiation pneumonitis (RP) was graded according to common terminology
criteria for adverse events (CTCAE) version 3.0. Dose-volume parameters, which
included percentage of lung volume receiving dose of d Gy (V5-V50) and mean lung
dose (MLD), were evaluated for RP prediction. Pulmonary function evaluated by
spirometry test and changes of FEV1 and FVC parameters.
Results: Eight patients developed RP. Among the dose-volume parameters, V10
was associated to RP incidence. When V10<40% and V10≥40% the incidences of RP
were 5.26% and 61.54%, respectively. The FEV1 and FVC had a reduction 3 and
6 months after radiotherapy, while only FEV1 showed significant reduction. The
FEV1 had more reduction in the patients who developed RP than patients without RP
(15.25±3.81 vs. 9.2±0.93).
Conclusion: Pulmonary function parameters, especially FEV1, significantly decreased
at 3 and 6 months after radiotherapy. Since most patients with breast cancer
who developed RP did not show obvious clinical symptoms, so spirometry test is
beneficial to identify patients with risk of radiation pneumonitis. |