THE FREQUENCY OF ACUTE PNEUMONITIS AS COMPARED TO IPSILATERAL LUNG DOSE IN PATIENTS OF BREAST CANCER RECEIVING POST-OPERATIVE RADIOTHERAPY INCLUDING INTERNAL MAMMARY NODES

Abstract

Objectives: To determine the frequency of acute pneumonitis in patients of breast including internal mammary nodal irradiation receiving Post-operative Radiotherapy.     

Materials and Methods:  After ethical approval, 57 patients were enrolled with informed consent and received post-operative radiotherapy (3D-CRT/IMRT). Ipsilateral lung dosimetric parameters (V5, V10, V20, MLD) were calculated. Patients were followed for three months to assess acute pneumonitis, which was graded using CTCAE v5.0. Data were collected via a structured questionnaire and analyzed using SPSS Version 25.

Results: The mean age was 53.64±12.06 years, with most patients aged 41–60 years. Mean dosimetric values were V5: 42.1±7.3%, V10: 30.2±6.1%, V20: 20.3±4.5%, and MLD: 12.8±2.6 Gy. Acute pneumonitis occurred in 33.3% of patients, mostly Grade 1, and all participants were non-smokers. Higher dosimetric values were significantly associated with pneumonitis (p=0.00), while age showed no significant association (p=0.13).

Conclusion: It was concluded that a significant association was found between higher ipsilateral lung radiation dose and acute radiation pneumonitis in breast cancer patients, while age had no significant effect, highlighting the importance of limiting lung dose (V5, V10, V20, MLD) to reduce risk.