The Influence of BRCA1/BRCA2 Mutations on Toxicity Related to Chemotherapy and Radiotherapy in Early Breast Cancer Patients

Clinical and Experimental Oncology Department, Maria Skłodowska-Curie Memorial Cancer Center and Institute of Oncology, Gliwice, Poland.
Oncology (Impact Factor: 2.42). 11/2013; 85(5):278-282. DOI: 10.1159/000354834
Source: PubMed


The presence of BRCA gene mutation and low expressions of BRCA proteins are associated with a greater sensitivity of tumor cells to ionizing radiation and to cytostatics damaging the DNA of the cells. The purpose of this study was to estimate the rate of adverse events in BRCA1/2-associated breast cancer patients receiving anthracycline-based chemotherapy compared to patients without mutation. The authors also compared radiotherapy toxicity in these 2 groups.

The analysis included 270 early-stage breast cancer patients treated between 2006 and 2012. All patients were examined for the presence of BRCA1/2 mutations.

BRCA mutation was detected in 41 (15%) patients. Toxicity grade 3, especially nausea and vomiting, was observed more often in noncarriers (7 vs. 13%, p = 0.0008). Neutropenia was detected more frequently in patients with BRCA1/2 mutation (32 vs. 10%), but only after 1 cycle of chemotherapy (p = 0.0007). There was increased radiation toxicity in BRCA1/2 patients who underwent mastectomy and neoadjuvant chemotherapy (p = 0.016).

BRCA1/2 mutation carriers seemed to be more at risk of neutropenia after the first cycle of the treatment. In terms of other side effects, there was a lack of increased toxicity in this group. Mastectomy and neoadjuvant chemotherapy were risk factors for radiation toxicity in mutation carriers.

1 Follower
22 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Chemotherapy-induced nausea and vomiting (CINV) is associated with distressing adverse effects observed in patients during cytotoxic chemotherapy. One of the potential factors explaining suboptimal response to currently used antiemetics is variability in genes encoding enzymes and proteins that play a role in the action of antiemetic drugs. Pharmacogenomics studies of CINV are sparse and focus mainly on polymorphisms associated with serotonin receptor, drug metabolism and drug transport. Currently, the role of pharmacogenetics in mechanisms of CINV has not been fully unraveled, and it is premature to implement results of pharmacogenetic association studies of antiemetic drugs in clinical practice. More uniform studies, with genetic profiles and biomarkers relevant for the proposed target and transporter mechanisms, are needed.
    Pharmacogenomics 01/2015; 16(2):149-160. DOI:10.2217/pgs.14.168 · 3.22 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: DNA repair, in particular, DNA double-strand break (DSB) repair, is essential for the survival of both normal and cancer cells. An elaborate repair mechanism has been developed in cells to efficiently repair the damaged DNA. The pathways predominately involved in DSB repair are homologous recombination and classic nonhomologous end-joining, although the alternative NHEJ pathway, a third DSB repair pathway, could also be important in certain contexts. The protein of BRCA1 encoded by the tumor suppressor gene BRCA1 regulates all DSB repair pathways. Given that DSBs represent the most biologically significant lesions induced by ionizing radiation and that impaired DSB repair leads to radiation sensitivity, it has been expected that cancer patients with BRCA1 mutations should benefit from radiation therapy. However, the clinical data have been conflicting and inconclusive. We provide an overview about the current status of the data regarding BRCA1 deficiency and radiation therapy sensitivity in both experimental models and clinical investigations. In addition, we discuss a strategy to potentiate the effects of radiation therapy by poly(ADP-ribose) polymerase inhibitors, the pharmacologic drugs being investigated as monotherapy for the treatment of patients with BRCA1/2 mutations.
    International journal of radiation oncology, biology, physics 09/2015; 93(2):281-93. DOI:10.1016/j.ijrobp.2015.05.037 · 4.26 Impact Factor