The ER-/PR+ breast tumor may be the result of a false ER negative result. The aim of this study was to investigate whether there is a difference in patient and tumor characteristics of the ER-/PR+ phenotype in an Asian setting. A total of 2629 breast cancer patients were categorized on the basis of their age, ethnicity, tumor hormonal receptor phenotype, grade and histological type. There were 1230 (46.8%) ER+/PR+, 306 (11.6%) ER+/PR-, 122 (4.6%) ER-/PR+ and 972 (37%) ER-/PR-. ER-/PR+ tumors were 2.5 times more likely to be younger than 50 years at diagnosis (OR: 2.52; 95% CI: 1.72-3.67). Compared to ER+/PR+ tumors, the ER-/ PR+ phenotype was twice more likely to be associated with grade 3 tumors (OR:2.02; 95%CI: 1.00-4.10). In contrast, compared to ER-/PR- tumors, the ER-/PR+ phenotype was 90% less likely to be associated with a grade 3 tumor (OR: 0.12; 95%CI:0.05-0.26), and more likely to have invasive lobular than invasive ductal histology (OR: 3.66; 95%CI: 1.47-9.11). These results show that the ER-/PR+ phenotype occurs in a younger age group and is associated with intermediate histopathological characteristics compared to ER+/PR+ and ER-/PR- tumors. This may imply that it is a distinct entity and not a technical artifact.
INTRODUCTION: The age standardised incidence rate (ASR) of breast cancer in Malaysia which is a high middle- income country is similar to Indonesia, a low middle-income country. (Globocan 2008) It is however unknown whether the presentation of breast cancer differs between these two countries.
OBJECTIVE: We compared the stage, age at presentation, and pathological characteristics of breast cancer between two tertiary hospitals in Indonesia and Malaysia; Dharmais Cancer Centre (DCC), which is the national cancer referral centre in Indonesia, and University Malaya Medical Centre (UMMC), which is an academic hospital with established breast oncology services in Kuala Lumpur. One thousand, one hundred and fourteen consecutive women (477 in UMMC: 637 in DCC) who were newly diagnosed with breast cancer between January and December, 2010 were included. Patient's age, TNM stage at presentation, and pathological characteristics were compared. Estrogen receptor (ER) and progesterone receptor (PR) were considered positive if 10% or greater of invasive cell nuclei were stained while HER2 was considered positive with an immunohistochemistry staining intensity of 3+ . Logistic regression analyses were performed to identify differences.
RESULTS: Median age at diagnosis was 52 years in UMMC and 47 years in DCC, whereby patients in DCC were more likely to be very young at diagnosis (aged < 35 years) compared to their counterparts in UMMC (Odds ratio (OR): 2.09; 95%CI: 1.32-3.31). Approximately one third of patients in UMMC presented with TNM stage III or IV, compared to 63% in DCC. Patients in DCC were three times more likely to present with metastatic breast cancer compared to patients in UMMC (OR: 3.01; 95% CI: 2.02-4.48). The percentage of low grade tumours in DCC was higher than in UMMC (28% vs 11% respectively), and the difference persisted even after multivariate adjustment. Although the frequency of ER and PR positivity appeared to be higher in UMMC (65% and 55% respectively) compared to DCC (48% and 40% respectively), these differences were not statistically significant following adjustment for age, stage, HER2 status and grade. The frequency of HER2 positivity was 45% in DCC compared to 26% in UMMC, and remained significantly higher even after multivariate adjustment (multivariate OR:1.76; 95%CI:1.25-2.47, in DCC compared to UMMC). The proportion of triple negative breast cancer was however similar in the two centres (19% in UMMC vs 21% in DCC).
CONCLUSION: Indonesian women with breast cancer seem to present at a younger age and at later stages compared to Malaysian women. Their tumors were more likely to be of low grade and HER2 positive, even after adjustment for other factors, while hormone receptor positivity proved similar in the two groups. The higher HER2 positivity rate in Indonesian patients warrants further study.
The significance of the single hormone receptor positive phenotype of breast cancer is still poorly understood. The use of hormone therapy has been found to be less effective for this type, which has a survival outcome midway between double positive and double negative phenotypes. The aim of this study was to investigate differences in patient and tumor characteristics and survival between double-receptor positive (ER+PR+), double receptor negative (ER-PR-) and single receptor positive (ER+PR- and ER-PR+) breast cancer in an Asian setting. A total of 1,992 patients with newly diagnosed stage I to IV breast cancer between 2003 and 2008, and where information on ER and PR were available, were included in this study. The majority of patients had ER+PR+ tumors (n=903: 45.3%), followed by 741 (37.2%) ER-PR-, 247 (12.4%) ER+PR-, and 101 (5.1%) ER-PR+ tumors. Using multivariate analysis, ER+PR- tumors were 2.4 times more likely to be grade 3 compared to ER+PR+ tumors. ER+PR- and ER-PR+ tumors were 82% and 86% respectively less likely to be grade 3 compared with ER-PR- tumors. ER-PR+ tumours were associated with younger age. There were no survival differences between patients with ER+PR+ and ER-PR+ tumors. However, ER+PR- tumors have poorer survival compared with ER+PR+ tumours. ER-PR- tumours had the worst survival. Adjuvant hormonal therapy with tamoxifen was found to have identical survival advantage in patients with ER+PR+ and ER-PR+ tumors whereas impact was slightly lower in patients with ER+PR- tumors. In conclusion, we found ER+PR- tumors to be more aggressive and have poorer survival when compared to ER+PR+ tumors, while patients with ER-PR+ tumours were younger, but had a similar survival to their counterparts with ER+PR+ tumours.