Risk factors according to estrogen receptor status of breast cancer patients in Trivandrum, South India

Abstract

Estrogen receptor (ER) status is an important biomarker in defining subtypes of breast cancer differing in antihormonal therapy response, risk factors and prognosis. However, little is known about association of ER status with various risk factors in the developing world. Our case-control study done in Kerala, India looked at the associations of ER status and risk factors of breast cancer. From 2002 to 2005, 1,208 cases and controls were selected at the Regional Cancer Center (RCC), Trivandrum, Kerala, India. Information was collected using a standardized questionnaire, and 3-way analyses compared ER1/ER2 cases, ER1 cases/controls and ER2 cases/controls using unconditional logistic regression to calculate odds ratios and 95% confidence intervals. The proportion of ER2 cases was higher (64.1%) than ER1 cases. Muslim women were more likely to have ER2 breast cancer compared to Hindus (OR 5 1.48, 95% CI 5 1.09, 2.02), an effect limited to premenopausal group (OR 5 1.87, 95% CI 5 1.26, 2.77). Women with higher socioeconomic status were more likely to have ER1 breast cancer (OR 5 1.48, 95% CI 5 1.11, 1.98). Increasing BMI increased likelihood of ER2 breast cancer in premenopausal women (p for trend < 0.001). Increasing age of marriage was positively associated with both ER1 and ER2 breast cancer. Increased breastfeeding and physical activity were in general protective for both ER1 and ER2 breast cancer. The findings of our study are significant in further understanding the relationship of ER status and risk factors of breast cancer in the context of the Indian subcontinent. ' UICCKey words: estrogen receptor; breast cancer; India Estrogen receptor (ER) status of breast tumors has been instrumental in defining an important subtype of breast cancer with differences observed in risk factors, treatment and prognosis. [1][2][3][4][5][6][7] Numerous studies in the past have looked at differences in etiology and risk factors pertaining to presence or absence of ER-alpha. Most of these studies were conducted in Western populations as early as 1980s. [1][2][3][4][5] Around the same time, it was also discovered that ER1 tumors that lacked progesterone receptor (PR) expression were less responsive to endocrine therapy compared to tumors that expressed PR. 8 This led to studies in the past decade that looked at the link of various risk factors of breast cancer and combined ER/PR information to better explain the underlying differences between the various subtypes of breast cancer. 9-13 Chen and Colditz 14 have emphasized the importance of taking into account the ER/PR status information of breast tumors both for effective treatment as well as risk prediction for instituting prophylactic measures. Although there might be numerous ways to subtype breast cancer, the classification into ER1 and ER2 cancer remains a key divider. 14 However, information related to ER status is lacking for populations in developing countries. In fact, in most developing countries, determination of hormone receptor status is not a part of standard pro...

Epidemiology, Pathological Characteristics and Estrogen and Progesterone Receptor Status of Operated Cases of Female Breast Cancer: A Retrospective Review of 266 Cases from Kerala

“…At 62 %, ER positivity is low when compared to the West, but similar to the other studies from India [3,[12][13][14]. That the proportion ER-PR-was found to be higher, supports the hypothesis that breast cancer tends to be more aggressive in young individuals [15].…”

Epidemiological Correlates of Breast Cancer in South India

“…After careful and thorough reading, 4 articles have been again excluded for the following reasons Full text article not available (1), Not from South India (1), Study on Families of BC patients (1), and educational intervention on screening (1). Finally 16 articles have been selected for the qualitative synthesis (Gajalakshmi and Shanta, 1991;Nandakumar et al, 1998;Yeole and Kurkure, 2003;Kuraparthy et al, 2007;Ali et al, 2008;Mathew et al, 2008;Syamala et al, 2008a;2008b;Dey et al, 2009;Jayalekshmi et al, 2009;Syamala et al, 2009;Vaidyanathan et al, 2009;Harrison et al, 2010;Surekha et al, 2010;Chauhan et al, 2011) Methodological qualities of included studies: Out of 16 included studies 10 were Case studies, 1 Nested case control study (on a cohort of women), 4 studies were based on Secondary data analysis and 1 (Marmot et al, 2007) was cross-sectional study. Confounding factors were reported and adjusted in 2 out of 10 case control studies, mentioned and not controlled in 3 studies and not mentioned in rest of the studies.…”

Estrogen Receptor Negative Breast Cancer in India: Do We Really Have Higher Burden of this Subtype?

“…Previous Indian studies have documented that rates of ER negativity is high among breast cancers in Indian women [2][3][4]. It has been suggested that factors contributing to this high ER negativity could be technical failures of detection of ER, younger age of patients, and advanced stage at presentation -all of which can increase the proportion of ER negative tumours [2].…”

“…lacking ER, progesterone receptor (PR) as well as HER-2 receptors [1]. Previous data from India show higher proportion of ER negative breast cancer compared to the west [2][3][4]. This higher burden of ER negative disease has been attributed to several factors, including technical failures at detection of ER positivity, younger age of patients, and advanced stage at presentation -all of which can increase the proportion of ER negative tumours [2].…”