medwireNews: Visceral pleural invasion (VPI) significantly increases the risk for recurrence and reduces overall survival (OS) in patients with non-small-cell lung cancer (NSCLC), but only for those whose tumors are over 2 cm in diameter, research suggests.
By contrast, VPI has no impact on the outcome of patients with lung adenocarcinoma of less than 2 cm in diameter, report Prasad Adusumilli (Memorial Sloan-Kettering Cancer Center, New York, USA) and co-authors.
They propose that the current TNM classification upstaging of patients with T1 lung adenocarcinoma (defined as 3 cm or smaller in diameter) plus VPI to stage T2a should be revised to reflect this difference.
The investigators reclassified the tumors from 777 patients with node-negative lung adenocarcinoma no larger than 3 cm (stage I) as new stage IA (≤2 cm with or without VPI; 2–3 cm without VPI) or new stage IB (2–3 cm with VPI).
This revealed a significant difference in the outcomes of the two groups: the 5-year cumulative incidence of recurrence (CIR) was 18% for new stage IA patients compared with 40% for new stage IB patients, while OS rates were 76% versus 51%.
Patients with VPI were more likely than those without to have high-grade histology markers, lymphatic invasion, and vascular invasion. There was also no significant difference in the CIR or OS for patients with T2a node-negative tumors of 3 to 5 cm in diameter and for patients with tumors classified as new stage IB.
“These results highlight the finding that the new stage 1B tumors have a natural history similar to that of larger tumors,” Adusumilli et al comment.
Noting that adjuvant chemotherapy has been shown to improve long-term survival in patients who undergo curative resection for NSCLC, the team concludes: “We propose that early-stage tumors (≤2 cm) with VPI should be treated as T1 disease, and not as T2 disease, as they currently are.”
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