Estrogen receptors in bilateral breast cancer

Evidence for Etiologic Subtypes of Breast Cancer in the Carolina Breast Cancer Study

BACKGROUND

Distinctions in the etiology of triple-negative versus luminal breast cancer have become well established using immunohistochemical surrogates [notably estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2)]. However, it is unclear whether established immunohistochemical subtypes are the sole or definitive means of etiologically subdividing breast cancers.

METHODS

We evaluated clinical biomarkers and tumor suppressor p53 with risk factor data from cases and controls in the Carolina Breast Cancer Study, a population-based study of incident breast cancers. For each individual marker and combinations of markers, we calculated an aggregate measure to distinguish the etiologic heterogeneity of different classification schema. To compare schema, we estimated subtype-specific case-control odds ratios for individual risk factors and fit age-at-incidence curves with two-component mixture models. We also evaluated subtype concordance of metachronous contralateral breast tumors in the California Cancer Registry.

RESULTS

ER was the biomarker that individually explained the greatest variability in risk factor profiles. However, further subdivision by p53 significantly increased the degree of etiologic heterogeneity. Age at diagnosis, nulliparity, and race were heterogeneously associated with ER/p53 subtypes. The ER-/p53+ subtype exhibited a similar risk factor profile and age-at-incidence distribution to the triple-negative subtype.

CONCLUSIONS

Clinical marker-based intrinsic subtypes have established value, yet other schema may also yield important etiologic insights.

IMPACT

Novel environmental or genetic risk factors may be identifiable by considering different etiologic schema, including cross-classification based on ER/p53.

The prognosis of synchronous and metachronous bilateral breast cancer in Chinese patients

This study was undertaken to determine the differences in the clinicopathology and survival between synchronous bilateral breast cancer (sBBC) and metachronous bilateral breast cancer (mBBC). Additionally, we analyzed the risk factors for single tumors to develop as sBBC or mBBC. Of the 190 bilateral breast cancer (BBC) cases, 84 cases were sBBC and 106 were mBBC. We defined sBBC as two tumors that developed within 12 months, while mBBC was defined as two tumors that developed over more than 12 months. The peak age of onset of the first mBBC tumors was significantly younger than that of sBBC tumors (p = 0.001). There was a higher concordance rate of ER/ER positivity and PR/PR positivity in the first and second tumors of sBBC than mBBC. The two sBBC breast cancers had relatively similar hormone conditions because of the low rate of ER and PR transformation from positive to negative or vice versa. We determined that patients who presented with extracapsular extension (p = 0.008) and ER positivity (p = 0.001) tend to have synchronous cancers, while patients with 3+ HER2 were more likely to develop metachronous tumors. The prognosis for mBBC was better than that for sBBC when the survival time of mBBC was measured from the initial observation of the first tumors.

A strategy for distinguishing optimal cancer subtypes

Much attention is directed currently to identifying subtypes of cancers that are genetically and clinically distinct. The expectation is that subtyping on the basis of somatic genomic characteristics will supplant traditional pathological subtypes with respect to relevance for targeted therapies and clinical course. Less attention has been paid to the goal of validating subtypes on the basis of the distinctiveness of their etiologies. In this article it is shown that studies of individuals with double primary malignancies provide uniquely valuable information for establishing the etiologic distinctiveness of candidate tumor subtypes. Studies of double primaries have the potential to definitively rank candidate taxonomic systems with respect to their etiological relevance by determining which subtypes are most highly correlated in the double primaries. The concept is illustrated with data from studies of the concordance of estrogen and progestin status in bilateral breast cancers, where it is shown that double primaries are much more likely to be concordant with respect to estrogen receptor (ER) status than for PR status. The high concordance of ER status is consistent with a growing literature demonstrating the etiologic distinctiveness of ER+ and ER- tumors.

Concordance in histological and biological parameters between first and second primary breast cancers

BACKGROUND

Women with breast cancer are more likely to have a second breast cancer than women in the general population are to have a primary cancer. However, the biological relationship between primary and second breast cancers is not clear.

METHODS

A total of 30,617 patients diagnosed with bilateral breast cancers between 1990 and 2007 were identified through 17 cancer registries of the Surveillance, Epidemiology, and End Results program. Logistic regression with odds ratios (ORs) and 95% confidence intervals (CIs) was used to model strength of association in hormone receptor status, grade, and histology between 2 cancers.

RESULTS

There was a strong association in estrogen receptor status between 2 bilateral tumors (OR, 7.64; 95% CI, 7.00-8.35). The strength of association in estrogen receptor status depended on the time interval between the first and second tumors and age at diagnosis. The OR was 25.9 for synchronous tumors (within 1 month) and 3.69 for metachronous tumors separated by ≥10 years. The strength of association was stronger in patients whose first cancer was diagnosed before age 50 (OR, 11.7) versus after age 50 (OR, 5.71). A similar pattern was observed for progesterone receptor, grade, and histological type, but with relatively weaker association.

CONCLUSIONS

The strong concordance in hormone receptor status of primary and second breast cancers suggests that 2 breast cancers arise in a common milieu and that tumor subtypes are predetermined in the early stage of breast carcinogenesis.

Phenotypic similarities in bilateral breast cancer

Bilateral breast cancers that develop at similar times in an individual are likely to have been subjected to similar hormonal, environmental and genetic influences during tumourogenesis compared with metachronous tumours. As such, it is possible that tumour phenotype in synchronous bilateral breast cancer may display similar biological characteristics. The aim of this study was to identify phenotypic similarities between synchronous and metachronous bilateral breast cancers which may suggest a common origin. Thirty-three cases of synchronous and 46 cases of metachronous bilateral breast cancer that displayed similar tumour type were analysed for concordance in relation to various histological and immunohistochemical parameters. A higher level of concordance was demonstrated for synchronous cases with the highest level seen for oestrogen receptor. It is likely that this is related to similar tumourogenic pathways occurring at equivalent exposure times to various environmental and hormonal influences, although, in a proportion of cases, inherited genetic factors may play a role.

Estrogen and progesterone receptor content in bilateral breast cancer

Estrogen and progesterone receptor content was determined in 34 patients with synchronous and 23 patients with asynchronous bilateral breast cancer. Steroid receptor content was measured quantitatively by DCC method. It was shown that progesterone receptor content could not be predicted, as well as, that steroid receptor content of the second tumor significantly influenced the development of asynchronous bilateral breast cancer. The high discordance rate concerning histologic type between two tumors within synchronous as well as asynchronous biopsies was observed. The obtained results indicate that both synchronous and asynchronous bilateral breast tumors may be considered as biologically different tumors whose both steroid receptor levels should be determined whenever possible.

Simultaneous bilateral breast carcinomas: a retrospective review of 149 cases

PURPOSE

To evaluate clinical and biological characteristics as well as treatment outcome in simultaneous bilateral breast carcinomas.

METHODS AND MATERIALS

Between 1981 and 1990, 149 patients were diagnosed to have simultaneous bilateral breast carcinoma, defined as tumor arising in both breasts within a maximum of a 6-month interval, in the absence of distant metastases. The median age was 58. Out of a total of 298 tumors, the clinical tumor size was T0-T1 in 40%, T2 in 45%, and T3-T4 in 15% of tumors. The majority of patients (83%) were clinically node negative. Seventy-eight percent of all tumors were classified ductal invasive; 6% were invasive lobular carcinomas; in situ tumors were present in 9%. More than two-thirds of all tumors were well or moderately well differentiated. Tumors were estrogen positive in 86% and progesterone positive in 69% of 62% of patients for whom this information was available in both tumors. Treatment had been by bilateral mastectomy in 43%, by exclusive irradiation in 16%, and by combined surgery and radiation in 41%.

RESULTS

Median follow-up was 68 months (11-141). A number of positive correlations existed between the tumors in both breasts more often than by chance alone: These were the presence of lobular carcinomas in both breasts (p = 0.06), the same histological grade (p = 0.002), similar ER (p = 0.03) and PR (p = 0.01) status. Five-year rates for survival and disease-free interval were 86% (80-92) and 70% (62-78), respectively. For each patient the stage of the largest tumor at diagnosis was defined as maximum stage. When survival figures were compared between each maximum stage and matched stages of a group of unilateral breast cancer patients treated during the same time interval in our institute, bilateral breast cancer fared not worse than unilateral breast tumors. Treatment related complications occurred in eight patients (5%).

CONCLUSION

Simultaneous bilateral breast carcinomas have similar biological, but not clinical, features more frequently than would be predicted by chance alone. So far, the number of patients is too small, and the follow-up is too short to determine whether or not the prognosis is equivalent to that of unilateral breast cancer patients of equal stage. Bilateral conservative treatment is feasible with acceptable cosmetic results and toxicity by using carefully designed radiotherapy techniques.

Variations in the content of steroid receptors in breast cancer. Comparison between primary tumors and metastatic lesions

Steroid receptors were determined by the dextran-coated charcoal method in 193 breast cancer patients in different clinical stages of disease. Quantitative estrogen and progesterone values in primary tumors (n = 69) were compared with receptors in regional lymph node metastases (n = 28) and in distant malignant deposits (n = 65). The groups including receptor values from primaries and regional lymph node metastases (n = 15) and from primaries and distant metastatic lesions (n = 16) in the same patients were also analyzed. The obtained results indicated relative stability of both receptors in loco-regional disease, but with a tendency towards lower receptor values in lesions from advanced disease. This tendency is probably caused by the disease progression itself, but the influence of radio- or chemotherapy cannot be excluded.

Bilateral breast cancer: one disease or two?

Our purpose was to determine whether bilateral breast cancer depends upon genetic predisposition to multiple tumors or, alternatively, represents two independent sporadic events. Biological concordance of hormone receptors and histopathology in bilateral tumors, family history of breast cancer, age at diagnosis, and survival were evaluated in 88 patients. The immunoreactivity of paired tumors from 51 patients to six different immunocytochemical markers was compared. Neither histologic patterns nor immunocytochemical reactions showed concordance between bilateral tumors. Absence of concordance (other than for estrogen receptors) and lack of associations with positive family history and early age of onset support an interpretation of independent tumor origins and does not suggest a major role for genetic determinants in the majority of cases of bilateral breast cancer.

Differential response to chemotherapy in metastatic breast cancer in relation to estrogen receptor level. Results of a prospective randomized study

The predictive value of estrogen receptor (ER) level for response to chemotherapy was studied in 182 patients with metastatic breast cancer in a prospective study. Patients were stratified according to ER status and dominant site of disease and randomized to one of three regimens: cyclophosphamide, 5-Fluorouracil, and prednisone (CFP) versus CFP, methotrexate, and vincristine (CFPMV) versus doxorubicin and cyclophosphamide (AC). There was no significant differences in all response categories (P = 0.21), was taken as a predictor for response to chemotherapy, there was no significant difference in overall response (P = 0.61) between ER+ (62/108, 57%) and ER- patients (31/49, 63%). However, there was a significant trend toward a higher degree of response in ER- patients (more complete response [CR] nine of 49, 18%, and fewer failures six of 49, 12%) than in ER+ (less CR seven of 108, 7%, and more failures 37/108, 34%) (P = 0.006). Patients with higher measured levels of ER showed worse response (Kendall's tau C, P = 0.026). This trend for ER- patients to have better response than ER+ patients was generally consistent, regardless of the predominant site of metastases or chemotherapy regimen (P = 0.04 for CFP; P = 0.08 for CFPMV; and P = 0.20 for AC). The advantage of a better response for ER- patients was nullified by an earlier relapse which was reflected in longer duration of remission, time to treatment failure, and survival in favor of ER+ patients (12.3 months versus 7.3 months remission duration, 18.7 months versus 13.6 months survival in partial responders). These data suggest that ER- patients respond to a higher extent to chemotherapy but relapse sooner than ER+ patients, suggesting a more rapid growth for ER- tumors. In patients with ER- tumors and poorer prognosis on conventional chemotherapy, new trials of intensive consolidation after response should be considered.