Planning Target Volume and Nodal Status Predict Clinical Outcomes After Chemoradiation and Durvalumab in Stage III...

Unresectable Stage III non-small cell lung cancer (NSCLC) presents a major clinical challenge due to its heterogeneous nature and poor prognosis. Despite aggressive treatment with concurrent chemoradiation (CRT) and the introduction of Durvalumab consolidation therapy, the risk of recurrence remains high, necessitating research into predictors of clinical outcomes.

In this retrospective, two-center study, we reviewed cases of 141 patients with Stage III unresectable NSCLC, treated with CRT followed by Durvalumab between 2017 and 2023. We retrieved clinical and treatment characteristics and analyzed associations with clinical outcomes.

Utilizing a binary threshold for planning target volume (PTV), patients with PTV ≥ 350 cm³ had significantly worse progression-free survival (PFS) compared to those with PTV < 350 cm³, with a median PFS of 16.2 months compared with 30.9 months, respectively, HR 1.78 (95% CI 1.14-2.68), p = 0.01. Nodal status was also associated with worse PFS, with patients having N3 disease exhibiting a median PFS of 5.1 months compared to 15.2 months for N0-N2 disease, HR 2.09 (95% CI 1.28-3.41), p = 0.003. PTV ≥ 350 cm³ and N3 involvement remained significantly associated with PFS in multivariable analysis. Both variables were associated with early and distant recurrence patterns, and PTV ≥ 350 cm³ was associated with worse survival.

This study identifies PTV ≥ 350 cm³ and nodal involvement as key predictors of worse clinical outcomes in patients with Stage III NSCLC treated with CRT and Durvalumab. The PTV threshold of 350 cm³ provides a practical, clinically applicable tool for risk stratification that could guide intensification of treatment and surveillance to improve outcomes in high-risk patients.