Treatment Outcomes of Older Participants in a Randomized Trial Comparing Two Schedules of Twice-Daily Thoracic Radiotherapy in Limited-Stage SCLC.

Introduction: Half of the patients with limited-stage SCLC (LS SCLC) are above or equal to 70 years old, but they account for less than 20% of participants in most trials. Comorbidities and reduced organ and physical function might lead to more treatment toxicity, and population-based studies indicate that fewer older than younger patients with LS SCLC receive standard chemoradiotherapy, although there is limited evidence for such a policy.

Methods: We compared baseline characteristics, comorbidity, survival, treatment completion, toxicity, health-related quality of life, and treatment outcomes between patients above or equal to 70 years old and those younger than 70 years old in an open-label, randomized phase II trial comparing twice-daily thoracic radiotherapy of 45 Gy in 30 fractions with 60 Gy in 40 fractions in LS SCLC. All patients received concurrent i.v. cisplatin (75mg/m) or carboplatin (AUC 5-6 mg/ml x min) day 1 and i.v. etoposide (100 mg/m) day 1-3 chemotherapy. This trial is registered at ClinicalTrials.gov (NCT02041845).

Results: A total of 170 patients who were above or equal to 18 years old and had performance status of 0 to 2 were randomized. Of these, 53 patients (60 Gy: 25, 45 Gy: 28) were above or equal to 70 years old and 117 (60 Gy: 64, 45 Gy: 53) were younger. There were no differences in baseline characteristics, treatment completion rates, toxicity, or response rates across the age groups. Health-related quality of life mean scores were similar during year one, but older patients reported more decline on functional scales than younger patients during year two. Overall survival was shorter for older patients, whereas there was no difference in progression-free survival or time to progression.

Conclusions: Patients above or equal to 70 years old tolerated concurrent twice-daily chemoradiotherapy and achieved similar disease control as younger patients, indicating older patients should receive the same treatment as younger patients.