Estimating the magnitude of clinical benefit of systemic therapy in patients with DCIS or pre-invasive disease of the breast

Screen-detected ductal carcinoma in situ, 2008-2020: An observational study

OBJECTIVES

The purpose of this study was to evaluate the grade distribution of screen-detected ductal carcinoma in situ (DCIS) diagnosed in Ireland, in the context of the clinical trials currently underway to determine if active surveillance is a feasible management option for low-risk DCIS.

SETTING

BreastCheck is the national breast screening programme in Ireland, offering screening to women aged 50 to 69 every two years.

METHODS

This study was a secondary analysis of data collected by BreastCheck on all screen-detected DCIS diagnosed in the 12 years of nationwide screening. Incidence and detection rates were calculated. Descriptive analysis of the cases was performed and, for comparative analysis, grade of DCIS was analysed as a binary variable (high vs. low/intermediate) in keeping with the inclusion criteria for active surveillance trials. Analysis was performed in IBM Statistical Package for Social Sciences, version 26.

RESULTS

Between 2008 and 2020, 2240 women were diagnosed with DCIS through BreastCheck; 876 (39.1%) were low/intermediate-grade. The overall incidence rate has remained relatively stable during this period. Women with low/intermediate-grade DCIS were younger than women with high-grade DCIS (56 (interquartile range: 56-61) years v 57 (interquartile range: 53-61) years; p < 0.001). They were also more likely to have been diagnosed at an initial screening episode compared with those who had high-grade lesions (42.5% v 29.0%; p < 0.001).

CONCLUSION

If current clinical trials recommend active surveillance as a feasible option for DCIS, up to 40% of women with screen-detected DCIS may be eligible. These women are younger and often diagnosed on initial screening episode, so may require longer active follow-up.

Tamoxifen and Endometrial Cancer: A Janus-Headed Drug

Simple Summary

Tamoxifen, an antiestrogen, is a potent drug to treat and prevent hormone dependent breast cancer. As it has low toxicity and is widely available, tamoxifen has become one of the most frequently prescribed anticancer drugs worldwide. A major side effect of tamoxifen is to increase the risk of uterine corpus cancer (endometrial cancer). This happens after long-term (>2 years) application, especially in postmenopausal women with preexisting pathologies in the uterus. On the other hand, tamoxifen is an efficacious treatment for certain forms of advanced endometrial cancer, thus making it a Janus-headed drug that can support the development of endometrial cancer on one hand and be used as a remedy for this disease on the other. This article reviews the clinical data on these controversial effects of tamoxifen and the possible explanations.

Abstract

Tamoxifen is a selective estrogen receptor modulator used for the treatment and prevention of estrogen receptor (ER)—positive breast cancer. However, tamoxifen increases the risk of endometrial cancer (EC) by about 2–7 fold, and more aggressive types of EC with poor prognoses are observed in tamoxifen users. On the other hand, tamoxifen is an efficacious treatment for advanced or recurrent EC with low toxicity. The differential agonistic or antagonistic effects of tamoxifen on ERα are explained by the tissue-specific expression profiles of co-activators and co-repressors of the receptor. The estrogen-agonistic effect of tamoxifen in endometrial cancers can also be explained by the expression of G-protein coupled estrogen receptor 1 (GPER-1), a membrane-bound estrogen receptor for which tamoxifen and other “antiestrogens” are pure agonists.