Background: Acute hematologic toxicity (HT) during concurrent chemoradiotherapy (CCRT) for cervical cancer is strongly associated with pelvic bone marrow (PBM) irradiation. While prior randomised and multicenter studies have evaluated PBM sparing, limited prospective data exist in homogeneous cohorts assessing dosimetric, clinical and treatment compliance outcomes.
Methods: In this prospective study conducted at a single tertiary center, 50 women with International Federation of Gynecology and Obstetrics stage IB2–IVA cervical cancer (locally advanced: n =33, 66%; early stage: n =17, 34%) undergoing definitive pelvic CCRT were assigned to bone marrow–sparing intensity-modulated radiation therapy (BM-IMRT, n = 25) or without bone marrow-sparing IMRT (n = 25). All patients received 50 Gy in 25 fractions with weekly cisplatin, followed by brachytherapy. PBM was delineated as the pelvic bones and proximal femur. Primary endpoints included PBM dose-volume parameters (V10–V50, mean dose), and secondary endpoints included acute HT (Common Terminology Criteria for Adverse Events v5.0), Gastrointestinal (GI)/Genitourinary (GU) toxicity, chemotherapy delivery and target coverage.
Results: BM-IMRT achieved significant reductions in PBM dose, including V20 (77.2% versus 83.4%, p = 0.03) and mean dose (31.2 versus 35.9 Gy, p = 0.01), with comparable target coverage and organ at risk doses. Clinically, BM-IMRT was associated with significantly fewer ≥grade 2 HTs (0% versus 20%, p < 0.05), driven by reductions in leukopenia and anemia (0% versus 20% each) and fewer chemotherapy interruptions. No significant differences were observed in GI or GU toxicity (p > 0.05).
Conclusion: Incorporation of explicit PBM constraints in pelvic IMRT for cervical cancer reduces marrow dose and acute HT without compromising target coverage or increasing GI/GU toxicity. These findings suggest that PBM-based planning objectives may improve treatment adherence; however, further validation in larger studies is required before routine clinical implementation.
