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Introduction: Concurrent chemoradiation therapy (CCRT) is the standard of care in the management of cervical cancer (International Federation of Gynecology and Obstetrics [FIGO] 2008 Stages IB2-IVA). Apart from the myelotoxic effects of chemotherapy, irradiation of pelvic bone marrow (BM) in the radiation field, can also contribute to hematological toxicity. Objectives: We examined the relationship of irradiated BM volume and neutropenia in cervical cancer patients undergoing CCRT. Materials and Methods: This prospective study was conducted in a tertiary cancer center with a longitudinal study design. A total of 43 patients undergoing CCRT for cervical cancer were included. Using auto bone segmentation, the external contour of pelvic bones from L4 vertebral body to ischial tuberosities were delineated as BM. The volume of BM receiving 10, 20, 40, 50 Gy was calculated. Complete blood counts were done weekly to evaluate the neutropenia and were graded according to Common Terminology Criteria for Adverse Events, version 3.0. The risk of developing neutropenia was analyzed using logistic regression. Results: Twenty-seven patients (62.8%) received 5 cycles of chemotherapy, 14 patients (32.6%) received 4 cycles of chemotherapy and 2 patients (4.7%) received 3 cycles of chemotherapy. Overall, 22 patients (51.2%) experienced acute neutropenia. On multivariate analysis increased BM V50Gy had a statistically significantly odds of developing any grade of neutropenia (odds ratio [OR] =1.43; 95% confidence interval [CI], 1.03–1.97; P = 0.028). When comparing patients receiving BM V40Gy ≥40% with BM V40Gy <40% odds of any grade of neutropenia was increased (OR = 2.03; 95% CI, 0.55–7.42; P = 0.28). Moreover, when comparing patients receiving BM V50Gy ≥15% with BM V50Gy <15% odds of any grade of neutropenia was increased (OR = 2.13; 95% CI, 0.57–7.97; P = 0.26). Conclusions: High-dose irradiation to the larger volume of BM prevents compensatory hyperplasia which leads to neutropenia in patients undergoing CCRT for cervical cancer.

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Three-dimensional conformal radiation therapy (3DCRT), intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) are the three main radiotherapy treatment techniques for cervical cancer. Whether either technique significantly reduces the radiation exposure to organs at risk remains unclear. We dosimetrically compared the irradiated volumes of bone marrow, bladder and rectum in cervical cancer patients using 3DCRT, IMRT and VMAT techniques in those patients with FIGO stage IIIB cervical cancer, receiving chemo irradiation at our institute.  A total of 10 patients were dosimetrically compared. Significant reduction in V10, V20, V30, V40, V50 Gy of bone marrow was observed with IMRT and VMAT when compared to 3DCRT. Similar results were seen with V20, V30, V40, V50 Gy of bladder, and V40, V50 Gy of rectum. While comparing IMRT and VMAT, statistically significant dose reduction was noted in V20 Gy of bone marrow and V20 and V30 Gy of bladder with VMAT. When compared with 3DCRT the use of IMRT and/or VMAT reduced the radiation exposure to bone marrow, bladder, and rectum volumes at various radiation dose levels. VMAT can further reduce the radiation exposure to bone marrow and bladder when compared with IMRT. Thus, we propose the use of VMAT in cervical cancer to reduce the OAR toxicities.

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