Changes in Pulmonary Function Tests in Breast Carcinoma Patients Treated With Locoregional Post-mastectomy Radiotherapy: Results of a Pilot Study
Breast Cancer: Targets and Therapy
Background: The aim of present pilot study was to evaluate the changes in pulmonary function tests (PFTs) after locoregional post-mastectomy radiotherapy (PMRT) in breast cancer patients.
Materials and methods: Twenty consecutive patients with histopathologically confirmed breast carcinoma stages T1–T4, N1–N2, who were treated with modified radical mastectomy with neoadjuvant or adjuvant chemotherapy underwent PFTs, including forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced expiratory flow at 50%, and peak expiratory flow rate, maximum mid expiratory flow (MMEF25–75), maximal oxygen consumption (VO2max), and carbon monoxide diffusing capacity (DLCO) before, at 30 days, and at 90 days after locoregional PMRT. A two-tailed paired Student's t-test was used to compare mean values among the variables between the groups
Results: A significant drop in FVC, FEV1, and DLCO was noticed at day 90 after the completion of locoregional PMRT with P-values 0.033, 0.042, and 0.031, respectively, while MMEF25–75 and VO2max were not significantly affected (P-values 0.075 and 0.062, respectively) favoring a restrictive lung injury pattern. However, no patient was found to be symptomatic.
Conclusion: A significant drop in reduction in PFTs occurred at day 90 after the completion of locoregional PMRT. PFTs shall be performed in all breast cancer patients receiving locoregional PMRT for early detection of radiation-induced lung toxicity as all patients in our cohort were found asymptomatic.
Keywords: breast carcinoma, locoregional, post-mastectomy radiotherapy, changes in pulmonary function tests
During the post-mastectomy radiotherapy (PMRT) with tangential fields, usually a small portion of the underlying lung is included within the radiation portals, which may result in potential risk of radiation-induced lung toxicity (RILT).1 RILT is typically manifested clinically either as acute radiation-induced pneumonitis (RIP), or late radiation-induced fibrosis (RIF).2,3 RIP usually occurs 4–12 weeks after the completion of PMRT and in most of the patients it is often indolent, although in few it can present as cough and shortness of breath. In most of cases, RIP is regressed spontaneously or with use of steroids; however, it can also evolve into RIF as consequential late toxicity.4,5 RIP and RIF are mainly related to 1) the volume of irradiated lung parenchyma, 2) mean lung dose, 3) fractionation schedule, and 4) concurrent chemotherapy.6,7 However, pulmonary functional reserve is not only limited by previously mentioned factors, but also affected by 1) involvement or not of supraclavicular (SC) region,8 2) radiotherapy techniques,9 3) smoking habits,10 and 4) the use of concurrent tamoxifen.11Although RILT may not increase the risk of death, it has a negative impact on quality of life, and breast carcinoma patients with compromised pulmonary functional reserve may have relatively inferior long-term treatment outcomes.3,8 There is limited data available regarding the changes in pulmonary function tests (PFTs) in breast carcinoma patients receiving PMRT. Few studies have documented a significant decrement in PFTs in breast carcinoma patients who were treated with PMRT including SC region and were given adjuvant chemotherapy.3,9,12
In the present study, we aimed to evaluate the acute changes in PFTs in breast carcinoma patients who received adjuvant chemotherapy and were treated with PMRT including SC regions.