Hypofractionated conformal radiotherapy in combination with chemotherapy in limited disease small cell lung cancer patients

Abstract

Aim: To evaluate the results of hypofractionated conformal radiotherapy (RT) in limited disease small cell lung cancer (LD-SCLC) patients, with particular interest in the value of "early" RT, i.e. given before the 3rd chemotherapy (CHT) cycle.

Material and methods: Outcome of hypofractionated RT (42 Gy, 2.8 Gy/fraction, given over 19-21 days, using "concomitant boost" technique - elective volume [39 Gy, 2.6 Gy/fraction] and tumour volumes treated during the same fraction) combined with CHT in 100 consecutive LD-SCLC patients, was retrospectively assessed. The outcomes were compared with a previously published series of 117 LD-SCLC patients treated in the same institution with hyperfractionated or conventionally fractionated RT.

Results: Forty-two patients (42%) received "early" RT. Grade 3 NCI CTC acute oesophageal toxicity appeared in 5% of patients. There were three treatment-related deaths. Three-year overall survival (OS) rate was 39.4%, median - 24 months in the examined group vs. 26.0%, and 18 months in historical control, P = 0.02. Three-year OS for 78 patients with completed CHT was 42.2%, median - 28 months vs. 30%, and 14 months for 22 patients who received ≤ 3 CHT cycles, (P = 0.03). The actuarial 3-year locoregional failure risk (LRFR) was 34.0% in the examined group vs. 51.0% in the historical control, P = 0.04. Multivariate analysis showed a marginally significant correlation between the "early" use of RT and LRFR: RR = 0.43 (95% CI: 0.17-1.04), P = 0.06, with no significant impact on OS.

Conclusions: Shorter duration of RT using hypofractionation results in encouraging outcomes and acceptable toxicity. Completion of all planned CHT cycles is the most important factor for OS.