A prospective study to evaluate radiation pneumonitis in breast cancer patients after adjuvant conformal radiotherapy

Aim– To study the incidence of radiation pneumonitis (RP) and its association with irradiated lung volumes and various patient and treatment related factors after adjuvant radiotherapy in breast cancer patients.
Material and method- A hospital based prospective quantitative follow up study. Total 80 breast cancer patients who received adjuvant conformal radiation were registered. Clinical assessment including screening for respiratory symptoms, chest radiograph and pulmonary function tests (PFTs) were done at baseline and 12 weeks after the completion of radiotherapy. RP was assessed both clinically using RTOG acute radiation morbidity scoring criteria as well as radiologically using radiological grading scale of radiation induced pneumonitis. Measurement of irradiated lung volume parameters (e.g. central lung distance) were done on simulator film.
Results-Total 76 patients were evaluated for occurrence of RPup to minimum of 12 weeks (1 patient expires and 3 patients not reported for subsequent follow-up). Radiological and clinical RP was seen in 45% (n=34) and 21% (n=16) respectively. Occurrence of RP was significantly higher with age >50 years (p-value 0.025) and higher irradiated lung volume parameters (>3cm).There was no significant difference noticed with other patient and treatment related factors. All pulmonary function parameters including FEV1, FVC, FEV1 ratio and FEF 25-75 were significantly reduced (p<0.001) after 12 weeks of radiotherapy completion except PEF which was reduced non-significantly (p=0.140). FEV1 ratio and FEF 25-75 were significantly reduced in those with RP than without RP group (p<0.001).
Conclusion- Age>50 years and higher irradiated lung volume (>3cm) were associated with increased RP. So, the factors associated with increased RP should be considered for selection of better radiotherapy plan which may subsequently reduce the chances of radiation pneumonitis and helps in maintaining good quality of life in breast cancer survivors.