Factors Associated With Radiation Pneumonitis in Patients Receiving Electron Boost Radiation for Breast-Conserving Therapy: A Retrospective Review

Abstract

Purpose This study aimed to investigate risk factors for radiation pneumonitis (RP) caused by electron beam (EB) boost irradiation during breast-conserving therapy. Methods and Materials This single-institution retrospective study included patients with breast cancer treated with breast-conserving therapy from 2013 to 2019. Radiation therapy comprised whole-breast irradiation with a dose of 50 Gy and 10 Gy EB boost dose to the tumor bed. EB energies were 4, 6, 9, 12, and 15 MeV. The lung volume receiving ≥1.25 Gy (V1.25) was calculated and considered because the EB energies have a short range. All patients underwent computed tomography and positron emission tomography/computed tomography within 1 year of irradiation. Imaging evaluation was based on the Common Terminology Criteria for Adverse Events, version 5.0. Results Overall, 105 patients (median age, 62 years; range, 33-85) were included for analysis with a median follow-up period of 5 months. Average area of EB boost irradiation was 72 cm 2 (range, 36-196). Grade 1 RP developed in the EB irradiation field in 22 (20.6%) patients; grade 2 RP developed in 1 (0.93%) patient. Even in patients with central lung distance (CLD) ≥1.8 cm, a positive correlation was found between RP and both energy (r = 0.36; P = .005) and V1.25 (r = 0.26; P = .04). No correlation was found between RP and irradiation field size ( P = .47). The EB energy and V1.25 cutoff values were 12 MeV and 24 cm 3 , respectively. Conclusions CLD of ≥1.8 cm, EB energy of ≥12 MeV, and V1.25 of ≥24 cm 3 were risk factors associated with RP. Although the frequency of severe RP was not high, patients receiving high-energy electron treatment and those with a large CLD should be closely monitored.

The Impact of PM2.5on Radiation-induced Pneumonitis in Patients With Breast Cancer

“…Adjuvant RT for patients with breast cancer is generally well tolerated, but the lung is a major dose-constraint organ for RT planning, since more severe RIP might occur after several weeks after RT (22). Known risk factors for the occurrence of RIP in patients with breast cancer are mainly lung dosimetric parameters in RT plans (23)(24)(25) or other treatments such as chemotherapy (26). There are no studies revealing that air pollution, such as PM, is a risk factor for RIP in patients with breast cancer who receive post-operative RT.…”

An investigation on quantitative detector characteristics of novel flexible skin dosimeter using Monte Carlo simulation method

“…The simulated lead oxide-based flexible dosimeter geometry is illustrated in Figure 1, and the simulated dosimeter structure reported in [8] is schematically depicted on the right bottom of Figure 1. Electron irradiations with various energies are used in electron beam therapy to treat tumour cells [3,6]. Among the different irradiation energies, the 6 MeV electrons are one of the most widely used electron beam therapy [6,26].…”

“…Ionising radiation is a useful tool for cancer treatment. Various photon and particle irradiations with different energies are used in radiation therapy [1][2][3]. The main aim is to prevent the death of cancer cells by protecting healthy tissue [4].…”