Impact of high-dose chemotherapy on the ability to deliver subsequent local-regional radiotherapy for breast cancer: analysis of Cancer and Leukemia Group B Protocol 9082
Department of Radiation Oncology
Medical Subject Headings
Adult; Aged; Analysis of Variance; Antineoplastic Combined Chemotherapy Protocols; effects; Breast Neoplasms; Canada; Carmustine; Cisplatin; Cyclophosphamide; Doxorubicin; Female; Fluorouracil; Follow-Up Studies; Humans; Lymphatic Metastasis; Middle Aged; Multivariate Analysis; Radiotherapy Dosage
Neoplasms | Oncology
PURPOSE: To report, from Cancer and Leukemia Group B Protocol 9082, the impact of high-dose cyclophosphamide, cisplatin, and BCNU (HD-CPB) vs. intermediate-dose CPB (ID-CPB) on the ability to start and complete the planned course of local-regional radiotherapy (RT) for women with breast cancer involving >or=10 axillary nodes.
METHODS AND MATERIALS: From 1991 to 1998, 785 patients were randomized. The HD-CPB and ID-CPB arms were balanced regarding patient characteristics. The HD-CPB and ID-CPB arms were compared on the probability of RT initiation, interruption, modification, or incompleteness. The impact of clinical variables and interactions between variables were also assessed.
RESULTS: Radiotherapy was initiated in 82% (325 of 394) of HD-CPB vs. 92% (360 of 391) of ID-CPB patients (p = 0.001). On multivariate analyses, RT was less likely given to patients who were randomized to HD treatment (odds ratio [OR] = 0 .38, p < 0.001), older (p = 0.005), African American (p = 0.003), postmastectomy (p = 0.02), or estrogen receptor positive (p = 0.03). High-dose treatment had a higher rate of RT interruption (21% vs. 12%, p = 0.001, OR = 2.05), modification (29% vs. 14%, p = 0.001, OR = 2.46), and early termination of RT (9% vs. 2%, p = 0.0001, OR = 5.35), compared with ID.
CONCLUSION: Treatment arm significantly related to initiation, interruption, modification, and early termination of RT. Patients randomized to HD-CPB were less likely to initiate RT, and of those who did, they were more likely to have RT interrupted, modified, and terminated earlier than those randomized to ID-CPB. The observed lower incidence of RT usage in African Americans vs. non-African Americans warrants further study.
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Citation: Int J Radiat Oncol Biol Phys. 2010 Apr; 76(5):1305-13. doi: 10.1016/j.ijrobp.2009.04.013. Epub 2009 Sep 9. Link to article on publisher's site