Although population-based cancer registries data are useful in tracking and reporting the evolving burden of cancer in the population, the information they capture reflects the outcomes of diagnosis and death, regardless of whether the death is due to the disease or to other causes, and not data on the risk of recurrence. A population-based study by Mariotto et al evaluating a statistical model to estimate the risk of recurrence of hormone receptor (HR)-positive and HR-negative breast cancers has found that although women with HR-positive cancer have a lower risk of recurrence soon after diagnosis, their risk persists for several years. Conversely, for women diagnosed with HR-negative disease, the risk of progression to metastatic disease is high soon after the diagnosis, but diminishes over time. The study’s findings suggest that it is possible to extract information about the risk of breast cancer recurrence using disease-specific survival, and that the approach may be applicable to other cancers. The study is published inCancer Epidemiology, Biomarkers & Prevention.
To estimate the rate of breast cancer recurrence, the researchers analyzed data from the Surveillance, Epidemiology, and End Results Program (SEER) on a cohort of 381,430 women, ages 15–84, diagnosed with invasive breast cancer from 1992–2013. They then applied a statistical modeling technique called the “mixture-cure model” to the survival data, which included complete stage and hormone receptor status, to identify the cure fraction (the fraction of women whose cancer did not progress) and used two pieces of information available in the SEER database, Weibull and log-logistic parametric survival function, to estimate the time to metastasis for women in the “noncured” fraction (the fraction of women whose cancer progressed).
The researchers found that the risk of recurrence is higher for women diagnosed with breast cancer at older age, earlier period, more advanced stage of disease, and HR-negative tumors. For women diagnosed at ages 60–74 in 2000–2013, the projected percent recurring within 5 years is 2.5%, 9.6%, and 34.5% for stages I, II, and III HR-positive breast cancer, and 6.5%, 20.2%, and 48.5% for stages I, II, and III HR-negative tumors.
Although the women with HR-positive cancer have a lower risk of recurrence soon after diagnosis, their risk persists longer than for women with HR-negative breast cancer.
“The results show that it is possible to extract information about the risk of recurrence using disease-specific survival, and the methods can in principle be extended to other cancer sites,” concluded the study authors.
“We were surprised by the insights the estimates provided into how the risk of recurrence for women diagnosed with early breast cancer in the United States varies with stage, HR status, age, year of diagnosis, and time since diagnosis,” said Angela B. Mariotto, PhD, Chief of Data Analytics Branch at the National Cancer Institute and lead author of this study, in a statement. “We found that the risks of progressing to metastasis were lower for women diagnosed with breast cancer more recently, at younger ages, at early stage, and with HR-positive disease.”
Dr. Mariotto is the corresponding author of this study.
This study was sponsored by the National Cancer Institute.
The study authors declared no conflicts of interest.
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