Changes in lung volume parameters regarding the received dose in the lobes of the lungs after locoregional radiotherapy of breast cancer

Abstract

Aim

The purpose of this study was to evaluate ΔLVP¹1Changes in lung volume parameters and correlate them with MLD²2Mean lung dose and V20³3The percentage of lung volume receiving 20 Gy in the lobes of the lung.

Background

Radiation-induced lung injury after breast irradiation is controversial. The incidence of such an injury could have negative consequences on breast cancer patients.

Materials and Methods

Twenty-three women treated with Breast-conserving surgery, chemotherapy, and locoregional RT⁴4Radiation therapy underwent body plethysmography pre-RT and 3 and 6 months post-RT. Statistical analysis was used to evaluate ΔLVP over time and relate them with MLD, V20, age, and concurrent hormonal therapy.

Results

LVP decreased after 3 months and then showed a slight improvement by returning partially to their pre-RT values after 6 months. The mean ΔLVP was −0.64% for one Gy increase of MLD and −0.34% for one percent increase of V20 after 3 months. After 6 months, only ΔVC⁵5Vital Capacity showed 0.45% reduction with MLD in the upper lobe. Finally, there was no significant correlation between ΔLVP with respect to age and concurrent hormonal therapy.

Conclusions

The results of this study showed that lung volume changes were not a cause for concern in breast cancer patients. There are three reasons to support this conclusion. Lung volume changes and percentage reductions in LVP for each Gy increase of MLD and each percentage increase of V20 in each lobe were small; patients were asymptomatic during the follow-up period; and LVP showed partial improvements after 6 months.