Forgoing hormone therapy did not increase mortality for some older patients with breast cancer

Issue: October 10, 2011

Women aged older than 60 years diagnosed with early-stage, hormone-responsive breast cancer were not at increased risk for death compared with the general population if they did not undergo treatment with adjuvant endocrine therapy.

The mortality risk was 1.02 (95% CI, 0.89-1.16) for women aged 60 to 74 years with tumors smaller than 10 mm, grade 1 ductal carcinoma and grade 1 or 2 lobular carcinoma. Conversely, women aged 35 to 59 years with small tumors and grade 1 ductal carcinoma had a mortality rate 1.26 times more than the general population.

Researchers identified 3,197 patients aged 35 to 74 years with systemically untreated cancer within the Danish Breast Cancer Cooperative Group registry. Patients were node-negative and had ER-positive and/or PR-positive tumors. Patients were grouped by age, tumor size smaller than 20 mm and histopathology. These women compared with age-matched women in the general population.

At a median follow-up after surgery of 14.8 years, there was an excess mortality of 233 deaths in the study population (standardized mortality ratio [SMR]=1.32; 95% CI, 1.24-1.40). The mortality rate was 2,356/100,000 person-years in the study population and 1,790/100,000 person-years in the general population of women.

The excess mortality rate was highest for patients aged 35 to 39 years (SMR=5.53; 95% CI, 3.11-8.95) and lowest for patients aged 60 to 64 years (SMR=1.14; 95% CI, 0.98-1.32).

Mortality rate was also higher for women with tumors 11 mm to 20 mm (SMR=1.42; 95% CI, 1.31-1.53) compared with women with smaller tumors (SMR=1.12; 95% CI, 1.00-1.26).

Writing in an accompanying editorial, Jennifer J. Griggs, MD, MPH, and Daniel F. Hayes, MD, of the University of Michigan, said these results confirm findings from other studies showing that local therapy alone is adequate for treating older women with small tumors. However, this population is a small subset of patients and “in the absence of modern biomarker analysis, there are few patients with invasive breast cancer from whom we can safely withhold adjuvant therapy.”

“The findings of this study are consistent with those of other studies that have demonstrated that, although effective in reducing the risk of ipsilateral and contralateral breast events, adjuvant endocrine therapy does not reduce the risk of mortality in patients with very small, node-negative hormone receptor-positive breast cancer because the risk of mortality is already extremely low,” they wrote. “The study by Christiansen et al further documents the high likelihood of cure of invasive breast cancer by local therapy alone in a small, highly defined group of older women with small, node-negative, hormone receptor-positive low-grade breast cancers. This subset of patients, however, represents only a small fraction of the vast majority of women diagnosed with this disease. We continue to need better prognostic, and in particular, predictive factors to truly personalize our care for our patients.”

Earn CME this spring at the HemOnc Today Breast Cancer Review & Perspective meeting to be held March 23-24, 2012 at the Hilton San Diego Bayfront. See details at HemOncTodayBreastCancer.com.

For more information:

Christiansen P. J Natl Cancer Inst. 2011;doi:10.1093/jnci/djr299.
Griggs JJ. J Natl Cancer Inst. 2011;doi:10.1093/jnci/djr331.

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