126 - A Real-World Comparison of Moderated Hypofractionated Radiotherapy and Conventional Fractionated Radiotherapy in Cervical Cancer

Purpose/Objective(s): Conventional fractionation-based concurrent chemoradiotherapy is one of the standard treatment approaches for cervical cancer, but the role of hypofractionated radiotherapy (MHRT) remains unclear. This study aims to compare the efficacy and safety of MHRT with conventional fractionation radiotherapy (CFRT) in treating cervical cancer.

Materials/Methods: Eligible patients with FIGO stage IB-IIB or IIIC1 cervical squamous cell carcinoma, including those with metastatic lymph nodes =1.5 cm, no iliac node metastasis, and =2 pelvic lymph node metastases, were included. MHRT was delivered in 43.35 Gy over 17 fractions (2.55 Gy/fraction) using daily online adaptive radiotherapy. CFRT was delivered in 50.4 Gy over 28 fractions (1.8 Gy/fraction) with daily image guidance. Both groups received concurrent weekly cisplatin chemotherapy and 30 Gy in 5 fractions of high-dose rate brachytherapy after external beam radiotherapy (EBRT). The primary endpoint was acute toxicity, while secondary outcomes included tumor regression after EBRT, complete clinical response, overall survival (OS), disease-free survival (DFS), and local control (LC) rates. Treatment outcomes and safety profiles were compared before and after 1:1 propensity score matching (PSM).

Results: A total of 192 patients treated between September 2023 and April 2024 were included: 162 received CFRT, and 30 received MHRT. After PSM, the clinical characteristics were balanced between the groups. The MHRT group had significantly shorter treatment durations, with EBRT taking 22 days versus 42 days for CFRT (P < 0.001) and total treatment taking 43 days versus 57 days (P < 0.001). The MHRT group showed significantly higher tumor shrinkage per session and per day before and after PSM. At 3 months, complete response rates were similar (96.2% vs. 100%, P = 0.150), and survival outcomes (OS, DFS, LC) showed no significant differences at 9 months. Before PSM, the incidence of any acute grade 2 or higher toxicities was higher in the CFRT group (98.1% vs. 90%, P = 0.018). After PSM, both groups had similar rates of any acute toxicities, with no significant differences in grade 3 or higher adverse events. Acute grade 3 or higher gastrointestinal toxicity was more common in the MHRT group before PSM (P = 0.028), but this was less pronounced after matching. No grade 3 or higher urinary toxicity was observed in either group. Hematological toxicities were similar between groups before and after PSM.

Conclusion: MHRT demonstrates comparable efficacy and safety to CFRT in treating cervical cancer. MHRT provides the benefit of shorter treatment duration and higher tumor shrinkage rates both per session and per day. These results suggest that MHRT could serve as a promising alternative to CFRT. However, further prospective trials are necessary to validate these findings.