Sep 29

QP 29 - Response Assessment and Risk Stratification in Gynecologic Cancers: Biomarkers, Imaging, and Outcomes

1172 - Exploring the Association Between Pre-Treatment Cell Cycle Profiling and Chemoradiation Outcomes in Cervical Cancer

05:35pm - 05:40pm ET

Room 257

Presenter(s)

Nilanjana Dahiya, MD - Kidwai Memorial Institute of Oncology, Bangalore, Karnataka

N. Dahiya¹, L. Viswanath², S. RA¹, U. Amirtham¹, and S. Pasupathy¹; ¹Kidwai Memorial Institute of Oncology, Bengaluru, India, ²Kidwai Institute Institute Of Oncology, Bengaluru, India

Purpose/Objective(s): Cervical cancer response to chemoradiation may depend on tumor cell cycle characteristics. Cells in G2/M-phase are more radiosensitive than those in S-phase, which are relatively radioresistant. We evaluated whether pre-treatment tumor cell cycle distribution correlates with chemoradiation outcomes and could serve as a predictive biomarker.

Materials/Methods: Thirty-two patients with locally advanced cervical carcinoma received definitive chemoradiation (external-beam radiotherapy with concurrent cisplatin). Pre-treatment tumor biopsies underwent flow cytometry to measure the percentage of cells in G0/G1, S, and G2/M phases. Tumors were grouped by cell cycle profile: high G2/M fraction with low S-phase fraction (High G2M+Low S) versus low G2/M with high S-phase (Low G2M+High S). Response was assessed ~2 months post-therapy (via MRI and clinical exam) as complete response (CR), partial response (PR), or progressive disease (PD).

Results: Tumors with a High G2M+Low S profile showed significantly better responses, with 75% of patients achieving CR and 0% PD (p<0.01), along with favorable survival outcomes. In contrast, the Low G2M+High S group had poor outcomes: only 57.14% achieved a CR, with a concerning14.3% progressing to PD, although statistical significance was not achieved (Fisher’s exact p=0.46), likely due to limited sample size. MRI and clinical evaluations confirmed persistent tumor or progression in this poor-response cohort.

Conclusion: Pre-treatment cell cycle profiling has prognostic and potential therapeutic value. Tumors dominated by G2/M-phase cells responded more favorably to chemoradiation, whereas S-phase–dominant tumors were treatment-resistant. This translational insight indicates that cell cycle analysis could inform personalized treatment planning by identifying high-risk patients who may benefit from intensified or alternative strategies. These results warrant validation in larger cohorts for clinical integration.