In concurrent CRT for stage III, unresectable NSCLC, performance status is better with proton therapy than photon therapy

In a Dutch study, performance status after concurrent chemoradiotherapy (CRT) was better if patients were treated with protons rather than photons, potentially increasing eligibility for adjuvant durvalumab.

Concurrent CRT followed by adjuvant durvalumab is the current standard of care for patients with stage III, unresectable non-small cell lung cancer (NSCLC). The radiotherapy can be delivered with both protons or photons. Dutch investigators assessed whether the use of intensity-modulated proton therapy (IMPT) compared with intensity-modulated photon therapy (IMRT) affected eligibility for durvalumab (primary endpoint) and occurrence of immune-related adverse events (secondary endpoint) in patients with stage III NSCLC treated with concurrent CRT and adjuvant durvalumab. Dr Francesco Cortiula (Maastricht University Medical Center, the Netherlands) presented the results [1].

Data was collected from 67 patients with stage III, unresectable NSCLC who received concurrent CRT and adjuvant durvalumab; 28 were treated with proton therapy (IMPT) and 39 with photon therapy (IMRT). The median age was 66 years, 52% were male, and 42% had a WHO performance status (PS) of 0 before CRT. All patients received 60–64 Gy of radiotherapy.

On day 21 after CRT, 93% of patients treated with IMPT versus 72% of those treated with IMRT had a WHO PS ≤1 (OR 0.8; P=0.03). The median time between the end of CRT and the start of durvalumab treatment was 32 versus 38 days, respectively (not significant). Immune-related adverse events of any grade were reported in 21% versus 31% of patients treated with IMPT versus IMRT, respectively (not significant). Hypothyroidism accounted for 44% of immune-related adverse events. The occurrence of pneumonitis was also not significantly different (all grade: 25% with IMPT vs 23% with IMRT; grade 3: 7% vs 5%, respectively). At a median follow-up of 9.5 months (IMPT) and 19.5 months (IMRT), 90% of patients were still alive and 73% were disease-free.

Dr Cortiula suggested that IMPT treatment potentially increases eligibility for adjuvant durvalumab, as patients had a better WHO PS score at day 21 after concurrent CRT. Notably, IMPT-treated patients received a significantly lower radiotherapy dose to bone marrow, heart, and lungs, which might explain these findings. IMPT appeared to be as safe as IMRT regarding immune-related adverse events during durvalumab therapy.

1. Cortiula F, et al. Proton-therapy and concurrent chemotherapy in stage III NSCLC: Effects on durvalumab eligibility and safety profile. Abstract 113P. ELCC 2022 Virtual Meeting, 30 March–02 April.

 

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Posted on 25 May, 2022