Women diagnosed with breast cancer at a younger age (≤ 40 years of age) may face a more aggressive disease than older women, and are more likely to choose a more aggressive treatment approach, according to two recent studies.
A prospective observational study conducted in the United Kingdom recruited 2,956 women who were 40 years of age or younger when diagnosed with breast cancer and followed them for up to 11 years.1
These women tended to present with advanced disease; the median tumor size was 22 mm, 50% of patients had positive lymph nodes, and 59% of tumors were grade 3.
One-third of tumors were estrogen receptor (ER)–negative and one-fourth were HER2-positive, and the 5-year survival rate was 81.9%. There were 613 (21%) deaths in the study cohort and, as expected, the overwhelming majority of deaths (94%) were due to breast cancer.
A key finding of the study was that patients with ER-positive tumors had better 5-year survival than patients with ER-negative tumors (85.0% vs. 75.7%, respectively); however, by 8 years, survival was the same in the two groups (67.5% vs. 67.7%, respectively).
Among women with ER-negative tumors, the risk of relapse peaked at 2 years, and then showed a steady decline. By contrast, the risk of relapse in women with ER-positive tumors increased throughout the study period. Ten percent of women with ER-positive tumors relapsed between 5 and 8 years after diagnosis. Nevertheless, ER-positive patients had a better outcome even after distant recurrence—their time to death after distant recurrence was 23 months, compared with only 11 months in ER-negative patients.
Regardless of ER-status, women with HER2-positive tumors had worse outcomes.
Responding to the high risk of late recurrence in this population, the researchers suggest that younger women with breast cancer might benefit from extending the standard 5-year course of adjuvant hormonal therapy following initial treatment.
“This study adds to the evidence that breast cancer can behave very differently when diagnosed in younger women,” said senior study author Diana Eccles, MD, FRCP, who heads Cancer Research UK’s Southampton Clinical Trials Unit. “They may require a different approach to treatment, which isn’t necessarily understood from cancer trials in older patients.” She urged that more trials be done in younger women as “research is the key to improving survival” and to developing new treatments specifically for this patient population.
Perhaps in response to their more severe disease, younger women with breast cancer are more likely to choose single or double mastectomy over breast-conserving surgery, according to a different study presented at the 2013 American Society of Clinical Oncology (ASCO) annual meeting.2 Researchers from Dana-Farber Cancer Institute and Harvard School of Public Health evaluated 277 women with stage 1 to 3 breast tumors who had a choice between mastectomy and breast-conserving surgery. Surprisingly, 62% chose mastectomy.
“Women diagnosed with breast cancer at an early age typically have a different set of medical and psychosocial issues and concerns than do older women,” said Shoshana Rosenberg, ScD, who led the study. “We were interested in learning from women who had a choice about surgery what factors were associated with their decisions.”
Women who said that the decision was primarily theirs rather than primarily the physician’s were more likely to choose mastectomy. Women with a BRCA1 or BRCA2 mutation, lymph node involvement, a HER2-positive tumor, a higher-grade tumor, lower body mass index, two or more children, or high levels of anxiety also favored mastectomy over breast-conserving treatment.
“Rates of mastectomy, particularly in young women with breast cancer, are on the rise, and it is not entirely clear why,” said Rosenberg. “Our data suggest that disease and genetic factors may be related to choice, as well as anxiety and how the decision was made. Further research is clearly warranted in an effort to help ensure women can make informed, quality decisions about their breast cancer therapy.”
1. Compson E, Eccles B, Maishman T, et al. Prospective observational study of breast cancer treatment outcomes for UK women aged 18–40 years at diagnosis: the POSH study. J Natl Cancer Inst. 2013; 2013 May 30. [Epub ahead of print]
2. Rosenberg SM, Sepucha K, Ruddy KJ, et al. Choosing mastectomy over lumpectomy: factors associated with surgical decisions in young women with breast cancer. J Clin Oncol 31, 2013 (suppl; abstr 6507).