Women who receive at least three screening mammograms have a 49 percent lower risk of dying from breast cancer, according to a new study. Researchers identified 755 patients who died from breast cancer between 1995 and 2003 and matched them with 3,739 controls. When the U.S. Preventive Services Task Force recommended in 2009 that routine breast cancer screenings should begin at age 50 instead of 40, controversy ensued about the benefits of screening for breast cancer and the age a woman should have her first mammogram.
Now a new study, presented at the Radiological Society of North America’s annual meeting in Chicago, found that women between the ages of 40 to 49 do have a high rate of developing breast cancer even if they don’t have a family history of the illness.
The study authors believe their results support the recommendation that annual screening mammograms begin at age 40, which other organizations like the American Cancer Society and American College of Obstetricians and Gynecologists also endorse.
The study looked at patient’s records from the database at the Elizabeth Wende Breast Care clinic in Rochester, New York, over a 10-year period. (2000-2010) They found 1,071 of more than 6,000 patients were between the ages of 40-49. Of those, 373 patients were screened for breast cancer.
The researchers found 144, or 39 percent, of those women had a family history of breast cancer, while 228 (61 percent) did not, with one patient whose history was unknown.
“There’s been a lot of talk about who should get mammograms, especially the 40 age group, and we found these women were indeed being diagnosed with breast cancer,” said Dr. Stamatia Destounis, lead author of the paper and a doctor at the breast care clinic. “And even worse, many of the cases had spread to the lymph nodes, which means early detection is important.”
The data showed invasive cancer was diagnosed in 64 percent of cases presenting without family history and 63 percent with family history. The lymph node metastatic rate was similar, at 29 percent without and 31 percent with family history.
“Family history does not seem to impact the rate of invasive disease in this particular patient group,” Destounis said. “Which leads us to believe that women, even those who don’t have a family history, could greatly benefit from a mammogram beginning in their early forties.”
Comparison Mammography Sways Direction of Diagnosis
Research was conducted to assess the impact of comparison mammograms on the accuracy, sensitivity, specificity, positive predictive value (PPV1), and cancer detection rate (CDR) of screening mammography to determine the contribution of identification of change on comparison mammograms. The study included 1,157,980 screening mammograms obtained between 1994 and 2008 in 435,183 women at least 40 years old. Radiologists recorded presence of comparison mammograms and change, if observed. Patients were tracked for 12 months to monitor cancer occurrence. Performance measurements were estimated for screening with comparison mammograms versus screening without comparison mammograms and for screening with comparison mammograms that exhibited a change versus screening with comparison mammograms that did not show a change while controlling for age, breast density, and data clustering. For screening with comparison mammograms versus screening without comparison mammograms, the CDR per 1,000 women was 3.7 compared to 7.1; recall rate, 6.9 percent compared to 14.9 percent; sensitivity, 78.9 percent versus 87.4 percent; specificity, 93.5 percent versus 85.7 percent; and PPV1, 5.4 percent versus 4.8 percent. For screening with comparison mammograms that displayed a change versus screening with comparison mammograms that did not show a change, the CDR per 1,000 women was 25.4 versus 0.8; recall rate, 41.4 percent versus 2 percent; sensitivity, 96.6 percent versus 43.5 percent; specificity, 60.4 percent versus 98.1 percent; and PPV1, 6 percent versus 3.9 percent. Detected cancers with change were 21.1 percent ductal carcinoma in situ and 78.9 percent invasive carcinoma, while detected cancers with no change were 19.3 percent ductal carcinoma in situ and 80.7 percent invasive carcinoma. The researchers concluded that performance is affected when change from comparison mammograms is noted. Without change, sensitivity is low and specificity is high. Change translates into high sensitivity, with a high false-positive rate. The research was published online Oct. 26 in the journal Radiology.
From “Effect of Observing Change From Comparison Mammograms on Performance of Screening Mammography in a Large Community-based Population” Radiology (10/26/11) Yankaskas, Bonnie C.; May, Ryan C.; Matuszewski, Jeanine; et al.
Breast Cancer Studies Spotlight ‘False Positive’ Mammograms, Digital Scans
Researchers analyzed about 170,000 women who had their first screening mammogram in their 40s or 50s and roughly 4,500 women who had been diagnosed with breast cancer in order to determine the frequency of false positives. They found that more than 50 percent of women who start getting yearly annual mammograms in their 40s can expect to have a false positive. Of the women who are called back for additional screening, some 7 percent are advised to undergo a breast biopsy that ends up being negative. The researchers learned that screening every other year, rather than annually, can reduce the risk of getting a false positive by about 33 percent; but biennial screening was linked to a slight increase in the risk that a tumor would be missed until it became advanced. The researchers concluded that “mammography every year is less efficient than screening every two years or more.” “We hope that by helping women know what to expect in terms of false-positive results, they’ll be less likely to experience anxiety when they are called back for a repeat screening or biopsy,” noted study author Rebecca Hubbard in a written statement. A related study involved the analysis of over 300,000 women who had undergone mammography between 2000 and 2006 to assess the accuracy of traditional film mammography and digital mammography, and the researchers found that for most women, accuracy was about equal for both methods. Still, digital scans were determined to be more accurate at spotting estrogen receptor-negative cancer in extremely dense breasts, and the researchers suggested that digital may be better for women 50 to 79 years old because dense breasts and estrogen receptor-negative tumors are more common in younger women. Both studies were published in the Oct. 18 issue of Annals of Internal Medicine.
From “Breast Cancer Studies Spotlight ‘False Positive’ Mammograms, Digital Scans”
CBS News (10/17/11) Freeman, David W.