BARCELONA—Women who develop breast symptoms—especially lumps—between regular mammography screening examinations are up to four times more likely to have a diagnosis of breast cancer soon after than women who do not have symptoms, according to findings of a massive study of routine mammography from Finland reported at the 2018 European Breast Cancer Conference (Abstract 11).
“Women with symptoms should be taken as a different, separate group—a high-risk group. So they will have different screening strategies from women without symptoms [with] more further assessment like ultrasound, further mammography or biopsy, and close monitoring,” said study author Deependra Singh, MPH, who works in the Research Laboratory of the Finnish Cancer Registry in Helsinki, Finland.
Singh's analysis was from Finland's ongoing national screening program in which women between the ages of 50 and 69 are invited for mammographic examinations every 2 years. In Finland, 85 percent of all women in this age group participate. But between 35 and 40 percent of all breast cancer cases have been detected outside the program.
The researchers noted that, because such a substantial proportion of incident breast cancers were not being detected by screening, there was likely to be “room for improvement in detection” in the overall mammography program.
They conducted a “population-based matched cohort study” following up data from the Finnish National Breast Cancer Screening Program (FNBCSP) begun in 1987. In the analysis, women attending for mammography who reported symptoms—including lumps, retraction, and nipple discharge—were assessed for the relationship between their rates of breast cancer diagnosis after the screening visit in comparison with rates of such “interval cancers” among women who were asymptomatic.
“Women without symptoms are our comparison group,” said Singh. “So, we selected women with symptoms and compared their risk of interval breast cancers [with the risk] among women who did not have symptoms. And we found a higher risk of interval breast cancer in those who reported symptoms.”
There was a total of 51,332 visits for mammography at which lumps were reported. Nipple retraction was seen in 40,917 visits and nipple discharge in 9,083 visits. Visits by women with symptoms were then matched with control visits at which women had no symptoms but were otherwise comparable in terms of age, year of the visit, number of invited visits, and geographical location. The primary outcomes were cancers detected during the ensuing interval and at the subsequent visit.
Recall rates were higher in symptomatic women. Those with a lump had a threefold (adjusted HR 3.7) risk for interval cancers and a higher risk (adjusted HR 1.7) of having a breast cancer diagnosis at the subsequent visit compared to those without a lump.
Significantly increased risk of interval breast cancer was also associated with retraction (1.5-fold) and nipple discharge (2.5-fold). For 1,000 screening visits, two interval cancers were diagnosed within 6 months after mammography in patients who had lumps.
Singh said the study findings implied that clinicians needed to check women very carefully during mammography sessions to find out if they had symptoms or not. “And if they suspect symptoms, they should refer [women] for further examination. The strategy is to monitor women with symptoms—especially those with lumps—more closely so that we reduce the chance that those women will have interval cancer diagnoses.”
The study concluded that, since women with breast symptoms had clearly increased risk of breast cancer—even after a negative screening visit—new screening strategies, including shortening the screening interval, were needed for symptomatic women to tailor surveillance and therapy to their needs.
Peter M. Goodwin is a contributing writer.
Read More Articles on Breast Cancer
Oncology Times offers a collection of breast cancer articles all in one place. Visit www.oncology-times.com and click on the Collections tab. There you can sign up to be notified when new breast cancer content goes live. Sign up today!