PHOENIX—Breast cancer patients age 40 and younger treated with breast conservation and irradiation have a significantly increased risk of breast recurrence and distant metastases, compared with older patients, a large retrospective French study has shown.
The study included 1,425 premenopausal patients with unilateral invasive clinical stage I or II breast cancer treated with breast-conserving surgery and radiation therapy at the Institut Curie, Anne de la Rochefordiere, MD, reported at the annual meeting of the American Society of Therapeutic Radiology and Oncology.
Patients were stratified into three age groups: very young (35 or less, 128 patients); intermediate age (36 to 40, 226 patients); and older age (over 40, 1,071 patients). “We observed no significant differences among the three groups in terms of tumor size or clinical nodal stage,” Dr. de la Rochefordiere said.
At median follow-up of 10 years, 85% of patients older than 40 were free from breast failure, compared with only 57% of patients 35 or younger and 70% of patients age 36 to 40.
In addition, the younger patients were more likely to have early breast recurrence. “In all age groups,” Dr. de la Rochefordiere said, “the annual hazard rate for breast failure increased in the early years following primary treatment and decreased subsequently.” This early increase was significantly higher in the two younger age groups.
When adjusted for other confounding variables, age was the only independent prognostic factor for breast failure. “The relative risk of local relapse decreased by 8% for every increasing year of age in the study population, that is, between 23 and 55 years,” she said. Factors found to have no impact on the risk of breast failure included tumor size, margin status, vascular invasion, or the use of adjuvant chemotherapy.
Similarly, using multivariate analysis, age was an independent prognostic factor for the risk of distant metastases. At 10 years, 87% of patients older than 40 were free of metastatic disease, compared with 69% and 64%, respectively, of the intermediate age and very young patient groups. Patients under age 40 were also at increased risk for distant metastases as a first event, but this was significant only in the first 2 years after primary treatment.
Multivariate analysis also showed an association between early breast recurrence (within 4 years of primary treatment) and a higher risk of distant metastases.
Finally, the researchers examined the adverse impact of young age on outcome over time by assessing the odds ratios at 2-year intervals from primary treatment. For this analysis, patients were regrouped into two age groups: patients older than 40 and younger than 40.
“The adverse impact of young age (age less than 40) on the relative risk of breast failure lasted up to 4 years after primary treatment and even up to 6 years,” Dr. de la Rochefordiere said.
She noted that although mastectomy would probably decrease the rate of local failure in these patients, “it may not be the proper answer to the poor prognosis of breast cancer in young patients. The problem might be that young patients have a more aggressive biology.” Thus, she emphasized, “significant effort should be made to understand the biological patterns of breast cancer in this age group in order to improve treatment selection and treatment efficacy.”
