Survival impact of pathologic features after salvage lung resection following definitive chemoradiotherapy or systemic therapy for initially unresectable lung cancer.

Purpose: Salvage surgery for primary lung cancer is expected to become increasingly common. This study aimed to clarify the survival impact of pathologic characteristics after salvage surgery.

Methods: Consecutive patients who underwent salvage surgery following definitive chemoradiotherapy or systemic therapy for initially unresectable lung cancer from 2010 to 2020 were enrolled in this study. The tumor slides were reviewed to determine the size of the tumor bed and the proportions of viable tumor, necrosis, and stroma.

Results: A total of 23 patients were evaluated, and 18 had clinical stage IIIB-IV disease. Six received chemoradiotherapy and 17 received systemic therapy alone. A major pathologic response (MPR, ≤ 10% of viable tumor) was observed in 6 patients, and 4 patients achieved a pathological complete response. The 3-year overall and recurrence-free survival rates (OS and RFS) were 78.6% and 59.2%, respectively. There was no significant difference in OS between patients with and without MPR, and even non-MPR patients achieved a favorable 3-year OS of 70.2%. Meanwhile, patients with high (≥ 30%) stroma showed significantly better OS than those with low (< 30%) stroma (3-year OS: 100% vs. 23.3%, p < 0.001).

Conclusions: This study showed that the proportion of stroma can be useful for predicting long-term survival after salvage surgery. Further large-scale studies are warranted to confirm the current findings.