Factors predicting intolerance to definitive conventional radiotherapy in geriatric patients

Although radiotherapy can be administered with a relatively low therapeutic burden, many elderly patients do not complete radiotherapy. In order to predict intolerance during radiotherapy, this study retrospectively analyzed the frequency of and risk factors for radiotherapy interruption among geriatric patients.

From September 2009 to December 2016, 353 patients aged ≥70 years received definitive radiotherapy with a conventionally fractionated schedule. "Total interruption" included completion of ≤90% of a planned radiotherapy, temporary discontinuation, and treatment-related mortality within 2 months. "Early-phase incompletion" and "mid-phase incompletion" represented completion of ≤50 and ≤80% of a planned radiotherapy, respectively.

The median age of patients was 74 years. Early- and mid-phase incompletions and total interruption occurred in 4.2, 9.3, and 19.3% of patients, respectively. Total interruption occurred frequently in cancers involving the thorax (27.4%), head and neck (23.1%), abdomen (20.0%), pelvis (17.4%), and breast/extremity (8.1%). The Eastern Cooperative Oncology Group (ECOG) performance score (P = 0.004 and 0.002), serum albumin level (P = 0.016 and 0.002), and the expected 5‑year survival (P = 0.033 and 0.034) were significant factors for mid-phase incompletion and total interruption. Age ≥ 75 years (P = 0.008), concurrent chemotherapy (P = 0.017), and the extent of radiation field (P = 0.027) were factors associated with total interruption.

Overall, 19.3% of the elderly patients showed treatment intolerance during conventional radiotherapy. Serum albumin level and ECOG performance score should be considered as surrogate markers for radiotherapy interruption prior to the decision regarding definite conventional radiotherapy.