Mild Lung Restriction in Breast Cancer Patients after Hypofractionated and Conventional Radiotherapy : a 3-year Follow-up

Publication date: Available online 6 February 2016
Source:International Journal of Radiation Oncology*Biology*Physics
Author(s): Sylvia Verbanck, Shane Hanon, Daniel Schuermans, Hilde Van Parijs, Vincent Vinh-Hung, Geertje Miedema, Dirk Verellen, Guy Storme, Christel Fontaine, Jan Lamote, Mark De Ridder, Walter Vincken
PurposeRadiotherapy treatments for early stage breast cancer patients potentially affect the lung parenchyma. Previous studies have shown acute effects on the lung diffusing capacity, essentially due to lung volume restriction. We aimed to assess the effect of radiotherapy on lung function over the course of 3 years.Methods and MaterialsEvolution of restrictive and obstructive lung function parameters was investigated in 108 breast cancer participants in a randomized controlled trial comparing conventional radiotherapy (CR) and hypofractionated tomotherapy (TT) (age at inclusion ranging 32-81yr). Spirometry, plethysmography and haemoglobin-corrected diffusing capacity was assessed at baseline, after 3 months, 1, 2 and 3 years. Natural ageing was accounted for by considering all lung function parameters in terms of %predicted values using the most recent reference values for women up to 80 years.ResultsIn the patients with negligible history of respiratory disease or smoking (n=77), the greatest rate of functional decline was observed during the initial 3 months, this acute decrease being more marked in the CR vs the TT arm. During the remainder of the 3-year follow-up period, values (in terms of %predicted) were maintained (diffusing capacity) or continued to decline at a slower rate (forced vital capacity). However, the average decline of the restrictive lung function parameters over a 3-year period did not exceed 9%predicted in either TT or CR arm. Obstructive lung function parameters remained unaffected throughout. Including also the 31 patients with a history of respiratory disease or more than 10 packyears showed a very similar restrictive pattern.ConclusionsIn women with breast cancer, both conventional radiotherapy and hypofractionated tomotherapy induce small but consistent restrictive lung patterns over the course of a 3-year period, irrespective of baseline respiratory status or smoking history. The fastest rate of lung function decline generally occurred in the first 3 months.

Teaser

Acute effects of radiotherapy in breast cancer patients include a small but consistent degree of lung restriction and associated decrease in its diffusing capacity. When accounting for the natural decline in lung function over a 3-year period, the restrictive changes observed after 3 months were either sustained or slowly deteriorated. However, the overall decline over the 3-year period never exceeded 9%predicted, irrespective of radiotherapy modality or respiratory status at baseline. There was no airway obstruction following radiotherapy.


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