HYPOfractionated Whole Pelvic Concurrent Chemoradiotherapy in Cervical Cancer (HYPOCx Trial): A Phase III Randomized Controlled Trial

Cervical cancer remains a major contributor to cancer-related morbidity and mortality among women in low- and middle-income countries, including Thailand. Despite advancements in screening programs and human papillomavirus (HPV) vaccination, a substantial proportion of patients present with locally advanced disease necessitating definitive concurrent chemoradiotherapy.

The established standard of care for locally advanced cervical cancer consists of conventionally fractionated external beam radiotherapy (45 to 50.4 Gy delivered in 25 to 28 fractions) administered concurrently with platinum-based chemotherapy, followed by image-guided adaptive brachytherapy. However, this extended 5-to-7-week regimen imposes significant logistical and financial burdens on patients and healthcare infrastructure, contributing to prolonged overall treatment times, institutional capacity constraints, and restricted access to radiation oncology services. Although hypofractionated radiotherapy has established efficacy and safety in the treatment of breast, prostate, and rectal malignancies, high-level prospective evidence validating its application alongside concurrent chemotherapy in cervical cancer, particularly in the setting of extended-field irradiation, remains limited due to concerns regarding exacerbated gastrointestinal and hematologic toxicities.

To address these therapeutic constraints of conventional fractionation, our group conducted the Phase II HYPOCx-iRex trial (TCTR20210812003). Findings from the HYPOCx-iRex study provided essential clinical proof-of-concept, demonstrating that hypofractionated chemoradiotherapy delivered via advanced delivery techniques, such as IMRT/VMAT with adaptive brachytherapy, achieves acceptable gastrointestinal toxicity rates and promising short-term disease control relative to historical conventional benchmarks.

Building upon the foundation of the Phase II HYPOCx-iRex trial (TCTR20210812003), this multicenter Phase III randomized controlled superiority trial is designed to evaluate this hypofractionated paradigm. Crucially, this trial seeks to address the persistent lack of prospective evidence regarding the safety, feasibility, and oncologic efficacy of hypofractionated extended-field radiotherapy combined with concurrent platinum-based chemotherapy.

In this trial, patients with early-stage node-positive or locally advanced cervical cancer will be randomized to receive either hypofractionated or conventionally fractionated external beam radiotherapy, both administered using high-precision IMRT/VMAT techniques with concurrent chemotherapy and image-guided adaptive brachytherapy. The primary endpoints are nodal control and overall survival. Secondary endpoints encompass tumor response rate, locoregional control, event-free survival, acute and late toxicities, quality of life, and health economic cost-effectiveness. The trial's findings are anticipated to generate high-level clinical evidence capable of demonstrating superior therapeutic and operational value, mitigating treatment delays, and establishing a more accessible, resource-efficient treatment standard.