Background: This study aims to test the efficacy of single-photon emission computed tomography (SPECT)-defined active bone marrow-sparing (ABMS) volumetric-modulated arc therapy (VMAT) in reducing grade 3+ acute hematologic toxicity (HT) in locally advanced cervical cancer patients treated with chemoradiotherapy.
Methods: This was a prospective, single-center, open label, randomized clinical trial that enrolled locally advanced cervical cancer patients. Participants were randomized to the 99m Tc sulfur colloid SPECT-defined ABMS VMAT (ABMS group) or control group, who received weekly cisplatin concurrently with VMAT followed by high-dose-rate intracavitary brachytherapy. The ABMS group additionally received SPECT-defined ABM dose constraints. The primary end point was the incidence of grade 3+ acute HT.
Results: A total of 192 Federation of Gynaecology and Obstetrics stage IB-IIIB patients were randomly treated (96 each in the ABMS control groups). The median follow-up was 24.0 months. The incidence of grade 3+ acute HT in the ABMS group was significantly lower than that in the control group (32.3% vs. 53.1%, p < .01). The number of patients completing five cycles of cisplatin was 88.5% in the ABMS group and 75% in the control group, and the difference was significant (p = .02). There were no differences in planning target value coverage, organs at risk dosimetric parameters, 2-year progression-free survival, or 2-year overall survival between the two groups. Patients in the control group had nonsignificantly worse 2-year distant metastasis than patients in the ABMS group (17.8% vs. 11.1%, p = .19).
Conclusions: ABMS VMAT significantly reduced grade 3+ acute HT and improved chemotherapy delivery compared with the control treatment. We found weak evidence of the effect of ABMS VMAT on distant metastasis.
Keywords: active bone marrow; cervical cancer; chemoradiotherapy; hematologic toxicity; single-photon emission computed tomography.
© 2023 American Cancer Society.