ABSTRACT
BACKGROUND: The most common malignancy among Indian women is carcinoma of the breast. In the management of breast cancer (BC), radiation therapy (RT) is given to breast or chest wall and supraclavicular lymph nodal (SCLN) area, with at least part of the thyroid receiving RT dose.There is an increased incidence of hypothyroidism (HT) among BC patients after RT involving the SCLN area. Moreover, the incidence of HT in India is higher than in the West. The aim of our study is to dosimetrically evaluate the thyroid doses during RT for BC. METHODS: This is a single institute prospective study (n = 131). Radiation was planned by three-dimensional conformal radiation therapy (3D-CRT) technique and dose-volume parameters for thyroid gland were noted. RESULTS: The median thyroid gland volume was 7.4 cc. The median of the mean dose to thyroid gland was 2068 cGy, V10 was 42%, and V40 was 33%. In other studies, BC patients with smaller thyroid gland were more prone to HT (volume <8 cc). In our study, we have seen that the median thyroid volume was 7.4 cc. CONCLUSION: Our study showed a lower mean dose to the thyroid gland and smaller volume thyroid glands than in the literature. As the incidence of HT is higher in India, compared to the west and our patients had small volume thyroid glands, they could be at higher risk of developing HT RT. So BC patients should be monitored for HT and should be given a dose constraint while planning RT.
Subject(s)
Breast Neoplasms/radiotherapy , Organs at Risk/radiation effects , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Conformal/methods , Thyroid Gland/radiation effects , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Middle Aged , Prognosis , Prospective Studies , Radiotherapy Dosage , Radiotherapy, Adjuvant , Young AdultABSTRACT
BACKGROUND: Oxidative stress (OS) is a key characteristic feature in cancer initiation and progression. Among multiple cancers, NADPH oxidase (NOX) dependent free radical production is implicated in oxidative stress. P22phox, a subunit of NADPH oxidase encoded by the CYBA gene has functional polymorphisms associated with various complex diseases. The present study was aimed to examine the importance and association of the functional polymorphisms of CYBA gene (-930 A/G and 242 C/T) with the oxidative stress in breast cancer (BC) development and progression. MATERIALS AND METHODS: We have performed a case-control study on 300 breast cancer patients and 300 healthy individuals as controls to examine the role of CYBA gene -930 A/G and 242 C/T single nucleotide polymorphisms (SNPs) using As-PCR and PCR-RFLP assays and its association with OS as measured by plasma MDA levels. Linkage disequilibrium (LD) plots were generated using Haploviewtool and Multifactor dimensionality reduction (MDR) analysis was applied to assess high-order interactions between the SNPs. The Insilco analysis has been performed to predict the effect of SNPs on the gene regulation using online tools. RESULTS: We have found that genotype frequencies of CYBA gene -930 A/G and 242C/T polymorphism were significantly different between controls and BC patients (p < 0.05). The haplotype combination -930G/242C and -930G/242T were associated with 1.44 & 1.56 folds increased risk for breast cancer respectively. Further, the MDA levels were higher in the patients carrying -930G/242C and -930G/242T haplotype (p < 0.001). Our results have been substantiated by Insilco analysis. CONCLUSION: Results of the present study suggest that GG genotype of -930 A/G polymorphism, -930G/242C and -930G/242T haplotypes of CYBA gene polymorphisms have shown association with higher MDA levels in breast cancer patients, signify that elevated oxidative stress might aid in increased risk for breast cancer initiation and progression.
