Hematologic Toxicity in RTOG 0418: A Phase 2 Study of Postoperative IMRT for Gynecologic Cancer

The University of Texas MD Anderson Cancer Center, Houston, Texas. Electronic address: .
International journal of radiation oncology, biology, physics (Impact Factor: 4.26). 05/2013; 86(1):83-90. DOI: 10.1016/j.ijrobp.2013.01.017
Source: PubMed


Intensity modulated radiation therapy (IMRT), compared with conventional 4-field treatment, can reduce the volume of bone marrow irradiated. Pelvic bone marrow sparing has produced a clinically significant reduction in hematologic toxicity (HT). This analysis investigated HT in Radiation Therapy Oncology Group (RTOG) 0418, a prospective study to test the feasibility of delivering postoperative IMRT for cervical and endometrial cancer in a multiinstitutional setting.
Patients in the RTOG 0418 study were treated with postoperative IMRT to 50.4 Gy to the pelvic lymphatics and vagina. Endometrial cancer patients received IMRT alone, whereas patients with cervical cancer received IMRT and weekly cisplatin (40 mg/m(2)). Pelvic bone marrow was defined within the treatment field by using a computed tomography density-based autocontouring algorithm. The volume of bone marrow receiving 10, 20, 30, and 40 Gy and the median dose to bone marrow were correlated with HT, graded by Common Terminology Criteria for Adverse Events, version 3.0, criteria.
Eighty-three patients were eligible for analysis (43 with endometrial cancer and 40 with cervical cancer). Patients with cervical cancer treated with weekly cisplatin and pelvic IMRT had grades 1-5 HT (23%, 33%, 25%, 0%, and 0% of patients, respectively). Among patients with cervical cancer, 83% received 5 or more cycles of cisplatin, and 90% received at least 4 cycles of cisplatin. The median percentage volume of bone marrow receiving 10, 20, 30, and 40 Gy in all 83 patients, respectively, was 96%, 84%, 61%, and 37%. Among cervical cancer patients with a V40 >37%, 75% had grade 2 or higher HT compared with 40% of patients with a V40 less than or equal to 37% (P =.025). Cervical cancer patients with a median bone marrow dose of >34.2 Gy also had higher rates of grade ≥2 HT than did those with a dose of ≤34.2 Gy (74% vs 43%, P=.049).
Pelvic IMRT with weekly cisplatin is associated with low rates of HT and high rates of weekly cisplatin use. The volume of bone marrow receiving 40 Gy and the median dose to bone marrow correlated with higher rates of grade ≥2 toxicity among patients receiving weekly cisplatin (cervical cancer patients). Evaluation and limitation of the volume of bone marrow treated with pelvic IMRT is warranted in patients receiving concurrent chemotherapy.

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Available from: Mohammad Reza Salehpour
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    • "L'étude de phase II du RTOG 0418, évaluant l'intérêt de la RCMI en situation postopératoire dans les cancers du col et de l'endomètre, a conclu à une corrélation entre le volume de moelle osseuse irradié à plus de 40 Gy et le risque de toxicité de grade 2 ou plus, dans le groupe des patientes atteintes d'un cancer du col (n = 40) et dont le traitement était une chimioradiothérapie avec chaque semaine 40 mg/m 2 de cisplatine. Un volume recevant 40 Gy (V40 Gy) de plus de 37 % engendrait ainsi un risque significatif 4,5 fois supérieur [24]. La toxicité hématologique rapportée dans cette publication était encourageante par rapport à la série historique de l'étude du RTOG 9708 : 25 % d'effets de grade 2 et 3,0 % de grade 4, contre respectivement 31 et 18 %. "
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