Abstract 233P
Background
Neoadjuvant immunochemotherapy (NICT) has emerged as a promising therapeutic strategy for lung squamous cell cancer (LUSC). However, the response to therapy remains variable. Tumor protein 53 (TP53) mutation has been associated with therapy response and prognosis in lung cancer with controversy. This study investigated the predictive value of immunohistochemistry (IHC) assessment of p53 in LUSC for response to NICT.
Methods
This retrospective study of patients with stage II-III LUSC who received NICT was conducted between 2019-2022. Demographic data and treatment-associated details were collected in predesigned tables. IHC expression level of p53 in pre-treatment biopsy specimens was estimated as the percentage of positive tumor cells within one high-power field and was initially graded as negative (<5% tumor cells, p53-) or positive (≥5% tumor cells, p53+).
Results
Thirty-five patients (97.1% male, median age = 64.5) were included. Significant tumor size regression, clinical downstaging, and pathological downstaging were observed regardless of the p53 status (all Ps < 0.05). p53+ was significantly associated with poor objective response to NICT [52.0% vs. 90.0%, odds ratio (OR) = 9.75, 95% confidence interval (CI) = 1.07-88.87, P = 0.043]. After adjustments, p53+ was significantly associated with worse progress-free survival (PFS) [10.1 months vs. not reached, hazard ratio (HR) = 7.846, 95% CI = 1.04-59.02, P = 0.045]. No differences were observed in overall survival (OS).
Conclusions
Negative expression of p53 by IHC possibly predicts a greater response to NICT and better PFS in stage II-III LUSC.
Legal entity responsible for the study
The authors.
Funding
The National Key Research and Development Program of China; Major Science and Technology Projects of Zhejiang Province; Research Center for Lung Tumor Diagnosis and Treatment of Zhejiang Province.
Disclosure
All authors have declared no conflicts of interest.