Purpose: To correlate six-minute walk test (6MWT) and pulmonary function test (PFT) with incidence of radiation pneumonitis (RP) while treating patients with oesophageal cancer with conformal radiotherapy.

Methods: Forty-five patients were selected to the study protocol. Pulmonary evaluation was done objectively by chest x-ray (CXR), 6MWT and PFT and subjectively by symptoms of cough, dyspnoea and fatigue. These tests were performed before radiation and then repeated at 1, 3, 6 and 9 months after treatment. The dose-volume histogram (DVH) was used to derive doses received by lung and organs at risk. χ2-test was used for calculating the p value.

Results: The walk distance change (WDC) correlated with the changes in PFT values (p = 0.001) were done at 3 and 9 months after radiation, respectively. V30 values of ≥20% correlated with the incidence of acute pneumonitis (p = 0.007). 6MVT/vital capacity (VC) values of ≤4 ft/l had a correlation with the incidence of clinically symptomatic RP at 9 months.

Conclusion: 6MWT and PFT are supplementary to each other for assessing the lung function status; but their individual role in predicting RP is weak. However, they are complementary to each other in assessing the risk of radiation-induced lung dysfunction.