Risk of contralateral breast cancer according to first breast cancer characteristics among women in the USA, 1992\u20132016

Cody Ramin,Gretchen L Gierach,Amy Berrington De González,Diana R Withrow,Brittny C Davis Lynn

doi:10.1186/s13058-021-01400-3

Cody Ramin, Gretchen L Gierach + Show 3 more

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https://doi.org/10.1186/s13058-021-01400-3

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Abstract

BackgroundEstimates of contralateral breast cancer (CBC) risk in the modern treatment era by year of diagnosis and characteristics of the first breast cancer are needed to assess the impact of recent advances in breast cancer treatment and inform clinical decision making.MethodsWe examined CBC risk among 419,818 women (age 30–84 years) who were diagnosed with a first unilateral invasive breast cancer and survived ≥ 1 year in the US Surveillance, Epidemiology, and End Results program cancer registries from 1992 to 2015 (follow-up through 2016). CBC was defined as a second invasive breast cancer in the contralateral breast ≥ 12 months after the first breast cancer. We estimated standardized incidence ratios (SIRs) of CBC by year of diagnosis, age at diagnosis, and tumor characteristics for the first breast cancer. Cumulative incidence of CBC was calculated for women diagnosed with a first breast cancer in the recent treatment era (2004–2015, follow-up through 2016).ResultsOver a median follow-up of 8 years (range 1–25 years), 12,986 breast cancer patients developed CBC. Overall, breast cancer patients had approximately twice the risk of developing cancer in the contralateral breast when compared to that expected in the general population (SIR = 2.21, 95% CI = 2.17–2.25). SIRs for CBC declined by year of first diagnosis, irrespective of age at diagnosis and estrogen receptor (ER) status (p-trends < 0.001), but the strongest decline was after an ER-positive tumor. The 5-year cumulative incidence of CBC ranged from 1.01% (95% CI = 0.90–1.14%) in younger women (age < 50 years) with a first ER-positive tumor to 1.89% (95% CI = 1.61–2.21%) in younger women with a first ER-negative tumor.ConclusionDeclines in CBC risk are consistent with continued advances in breast cancer treatment. The updated estimates of cumulative incidence inform breast cancer patients and clinicians on the risk of CBC and may help guide treatment decisions.

Highlights

Estimates of contralateral breast cancer (CBC) risk in the modern treatment era by year of diagnosis and characteristics of the first breast cancer are needed to assess the impact of recent advances in breast cancer treatment and inform clinical decision making
We identified 12,986 cases of CBC among women diagnosed with a first breast cancer between 1992 and 2015 and followed through 2016 (Fig. 1)
Breast cancer patients had approximately a 2-fold increased risk of an incident breast cancer when compared to that expected in the general population (SIR = 2.21, 95% Confidence interval (CI) = 2.17–2.25) (Table 2)

Summary

Introduction

Estimates of contralateral breast cancer (CBC) risk in the modern treatment era by year of diagnosis and characteristics of the first breast cancer are needed to assess the impact of recent advances in breast cancer treatment and inform clinical decision making. In the USA, overall 5-year survival rates for breast cancer exceed 90% [1] and a growing number of breast cancer patients will become long-term survivors at risk for second cancers. The uptake of contralateral prophylactic mastectomies in the USA has nearly tripled in the past decade to over 10% of invasive breast cancer patients undergoing the removal of the unaffected breast [10,11,12]. This increasing uptake of contralateral prophylactic mastectomies has occurred across all ages and stage at diagnosis [11, 12]

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