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Twice-daily radiotherapy was associated with longer survival in younger limited-stage small cell lung cancer

Among patients under 70, twice-daily chemoradiotherapy was associated with 36.0 versus 22.2 months median survival, without higher acute toxicity.

RadOncToday · ·1 min read

KEY POINTS

  • The Dutch Lung Cancer Audit provided prospectively recorded real-world data from 711 patients with limited-stage small cell lung cancer treated with concurrent chemoradiotherapy between 2016 and 2023. Mean age was 66.7 years, 93.2% had node-positive disease, and 592/711 (83.3%) received twice-daily radiotherapy.
  • Most twice-daily patients received 45 Gy in 30 fractions of 1.5 Gy twice daily. Once-daily treatment included conventional 60–66 Gy in 30–33 fractions and moderately hypofractionated schedules of at least 60 Gy equivalent dose in 24–25 fractions; 96.3% of patients completed the planned treatment.
  • Among 425 patients younger than 70, median overall survival was 36.0 months with twice-daily versus 22.2 months with once-daily treatment. The adjusted hazard ratio was 0.61 (95% CI 0.42–0.90); two-year survival was 63.9% versus 43.9%, and five-year survival 41.8% versus 16.0%.
  • Among 286 patients aged 70 or older, no survival advantage was seen: median overall survival was 21.8 months with twice-daily versus 24.3 months with once-daily radiotherapy, with an adjusted hazard ratio of 1.35 (95% CI 0.77–2.34). Five-year survival was 18.6% versus 29.0%, respectively, without a significant difference.
  • Grade ≥3 non-hematologic toxicity within 90 days occurred in 26.6% overall. Grade ≥3 esophagitis occurred in 13.6%, while grade ≥2 pneumonitis occurred in 2.1%; toxicity did not significantly differ by fractionation schedule.
  • In patients younger than 70, acute toxicity occurred in 26.0% with twice-daily versus 31.1% with once-daily treatment. In older patients, rates were numerically higher with twice-daily treatment (28.1% versus 19.6%), but the adjusted difference was not significant (OR 1.43, 95% CI 0.57–3.77).
  • Treatment selection varied substantially between centres, important pulmonary and dosimetric variables were frequently missing, and prophylactic cranial irradiation data were available for only about half the cohort. Residual confounding therefore remains a major limitation.

CLINICAL TAKEAWAY

These data reinforce twice-daily thoracic radiotherapy as a strong option for fit patients younger than 70 with limited-stage small cell lung cancer. They do not demonstrate that once-daily treatment is superior in older patients, but they question whether the survival advantage associated with twice-daily treatment extends into that population.

SOURCE

International Journal of Radiation Oncology, Biology, Physics