The influence of age on the delivery, tolerance, and efficacy of thoracic irradiation in the combined modality treatment of limited stage small cell lung cancer

Purpose: To assess the impact of age on the delivery, tolerance, and effica cy of thoracic irradiation (TI) for limited small cell lung cancer (L-SCLC) . Methods and Materials: This is a retrospective review of data from 608 pati ents 80 years or less with L-SCLC, who participated in two previously repor ted randomized trials (BR.3 and BR.6) of the National Cancer Institute of C anada. All patients received the same chemotherapy, consisting of cyclophos phamide, doxorubicin, vincristine (CAV), and etoposide cisplatin (EP) deliv ered either in sequential or alternating sequence. In BR.3, TI was given af ter chemotherapy with randomization to 25 Gy in 10 fractions or 37.5 Gy in 15 fractions. In BR.6, TI (40 Gy in 15 fractions) was given concurrently wi th EP with randomization to either the early (with cycle 2, week 4) or late (with cycle 6, week 16) arm. Results: A total of 665 patients entered these two trials. Of these, 608 pa tients were eligible for analysis, 300 in BR.3 and 308 in BR.6. Five hundre d and twenty patients were under age 70 and 88 patients were 70 years or ol der. Baseline characteristics between the two groups were comparable. In BR .3, 179 patients (60%) participated in radiotherapy randomization (61% youn g, 52% elderly), and 176 patients actually received TI. In BR.6, randomizat ion occurred at study entry for all patients, and 282 (91.6%) patients rece ived TI (92% young, 88% elderly). More patients of both age groups randomiz ed to receive late TI did not receive TI (13% and 14%) than those randomize d to the early TI arm (3%) of BR.6. We could identify no tendency to reduce field sizes to minimize toxicity in either age group at higher doses of TI . Once TI was started, there was no difference between the two age groups w ith regards to the proportion of patients who completed TI, although elderl y patients were less likely to complete high dose TI. Of those who complete d TI, there was no difference in the time to complete TI, mean dose deliver ed or in the incidence of acute and late TI-related toxicities. No statisti cal difference in response rate, local relapse rate, or overall survival wa s seen between young and older age groups. Conclusion: In summary, in the dose range examined, age does not appear to impact on the delivery, tolerance or efficacy of TI in the combined modalit y management of L-SCLC. Potentially curative combined modality treatment sh ould not be withheld on the basis of age. (C) 1998 Elsevier Science Inc.