Breast cancer in systemic lupus erythematosus (SLE): receptor status and treatment

Objective There is a decreased risk of breast cancer in systemic lupus erythematosus (SLE) versus the general population; little is known regarding the receptor status of breast cancers in SLE, or treatment. Methods Breast cancer cases occurring after SLE diagnosis were ascertained through linkage with tumor registries. We determined breast cancer positivity for estrogen receptors (ER), progesterone receptors (PR), and/or Human Epidermal Growth Factor Receptor 2 (HER2), as well as cancer treatment. Results We obtained information on ER, PR, and/or HER2 status for 63 SLE patients with breast cancer. Fifty-three had information on ER and/or PR status; 36 of these (69%) were ER positive. Thirty-six of the 63 had information on HER2 status; of these, 26 had complete information on all three receptors. Twenty-one of these 26 (81%) were HER2 negative; seven of 26(27%) were triple negative. All but one patient underwent surgery; 11.5% received both non-tamoxifen chemotherapy and radiotherapy, 16.4% radiotherapy without non-tamoxifen chemotherapy, and 14.7% received non-tamoxifen chemotherapy without radiotherapy. Conclusion ER positivity was similar to historical general population figures, with a trend toward a higher proportion of triple-negative breast cancers in SLE (possibly reflecting the relatively young age of our SLE patients).

Breast cancer in systemic lupus erythematosus

OBJECTIVE

Evidence points to a decreased breast cancer risk in systemic lupus erythematosus (SLE). We analyzed data from a large multisite SLE cohort, linked to cancer registries.

METHODS

Information on age, SLE duration, cancer date, and histology was available. We analyzed information on histological type and performed multivariate logistic regression analyses of histological types according to age, SLE duration, and calendar year.

RESULTS

We studied 180 breast cancers in the SLE cohort. Of the 155 cases with histology information, 11 were referred to simply as 'carcinoma not otherwise specified'. In the remaining 144 breast cancers, the most common histological type was ductal carcinoma (n = 95; 66%) followed by lobular adenocarcinoma (n = 11; 8%), 15 cancers were of mixed histology, and the remaining ones were special types. In our regression analyses, the independent risk factors for lobular versus ductal carcinoma was age [odds ratio (OR) 1.07, 95% confidence interval (CI) 1.01-1.14] and for the 'special' subtypes it was age (OR 1.06, 95% CI 1.01-1.10) and SLE duration (OR 1.05, 95% CI 1.00-1.11).

CONCLUSIONS

Generally, up to 80% of breast cancers are ductal carcinomas. Though our results are not definitive, in the breast cancers that occur in SLE, there may be a slight decrease in the ductal histological type. In our analyses, age and SLE duration were independent predictors of histological status.