Salvage radiotherapy for limited metastatic relapse in small cell lung cancer after durvalumab.

The ADRIATIC trial demonstrated that consolidation durvalumab after concurrent chemoradiotherapy (cCRT) improves progression-free survival (PFS) and overall survival (OS) in limited-stage small cell lung cancer (LS-SCLC), establishing a new standard of care. However, a proportion of patients still develop distant relapse, and optimal salvage strategies after immunotherapy remain unclear. While metastasis-directed radiotherapy, including stereotactic radiotherapy and hypofractionated radiotherapy, has shown benefit in selected oligometastatic non–small cell lung cancer (NSCLC), evidence in SCLC is limited. Here, we describe two LS-SCLC patients who developed limited metastatic relapse after cCRT followed by durvalumab consolidation: one with a solitary adrenal metastasis and the other with two brain metastases. Both patients received salvage radiotherapy (adrenal hypofractionated radiotherapy: 54 Gy in 15 fractions to GTV and 45 Gy in 15 fractions to PTV; brain lesions treated with whole-brain radiotherapy with simultaneous integrated boost [WBRT-SIB]: 40 Gy in 10 fractions to metastatic foci and 30 Gy in 10 fractions to the whole brain). Both patients experienced durable disease control exceeding four years without additional systemic therapy during follow-up. These two cases provide hypothesis-generating clinical observations suggesting that, in carefully selected LS-SCLC patients with limited metastatic relapse, curative-intent local radiotherapy may be feasible and warrants prospective evaluation.