A study of 7,300 breast cancer patients revealed that more than two-thirds of breast cancer deaths occur in younger women with no indication of mammography or with time-period of two years or more between mammograms.
Over a span of 18 years, it was reported that 71% of breast cancer deaths were associated with mammographically unscreened women. The average age at the time of diagnosis and consequent death was 49 years, compared to 72 women who died of other causes.
Based on the studies findings, Blake Cady, MD, of Massachusetts General Hospital in Boston, and coauthors are vying for mammographic screening prior to age 50, as detailed on the online journal, Cancer.
"Even with effective adjuvant therapies, the best method for women to avoid death from breast cancer is to participate in regular mammography screening. Regular screening increases the likelihood of detecting nonpalpable cancers, and annual screening further increases the likelihood relative to biennial screening,” the authors determined.
"Furthermore, detecting and treating breast cancer in younger women to prevent death may further increase the disease-free life years saved. Our findings suggest decreasing the intensity of efforts to screen women older than 69 years while concomitantly emphasizing efforts to screening young women in particular,” they added.
The history of breast cancer screenings via mammographies is one that has been riddled with controversy. Studies have indicated that early detection of the disease helps diminish the risk of mortality. Yet, the best and most suitable age to administer the procedure and the time intervals between screenings has gone unanswered.
The debate surrounding mammographies reached new heights in 2009 when the United States Preventive Services Task Force (USPSTF) suggested that routine screening mammography commence at the age of 50 and that screening should be made elective for younger women.
The USPSTF also recommended biennial screenings over annual ones, as a choice for women at an average risk.
The USPSTF recommendations were met by fierce criticism from the American Cancer Society, American College of Radiology, and other organizations with a say in breast cancer diagnosis and management. For the most parts, naysayers agreed on the annual screening and launch of screening at a younger age.
Randomized trials have downplayed the usefulness of screening mammography because of their focus on women who are offered mammography instead of women who are actually screened, the authors noted in their introduction. As a result, the suggestions do not coincide with the survival advantage presented in the long-term follow-up of patients who go through the screening.
In order to assess the survival benefit of women who have been screened, Cady and the team examined data on 7,703 patients who were newly diagnosed with breast cancer from 1991 to 1999; with a follow-up continuation to 2007.
The study also analyzed the time between screening intervals, stipulating that biennial screening should be intervals of no more than two years. Women who had their last screen more than two years ago were accounted for in the unscreened group.
The information consisted of demographics, use of mammography, surgical and pathology reports, disease recurrence, and death. Researchers credited mammograms as screening or diagnostic on the basis of nonexistence or presence of signs and symptoms of breast cancer.
The researchers calculated that 1,705 out of 7,703 women died during follow-up, 609 of which were related to breast cancer deaths. Analysis of breast cancer deaths based on screening rate revealed that tumors identified via screen contributed to 118 deaths, most of which (111) included women whose tumors were spotted following two mammogram screening that took place no more than two years apart.
Furthermore, 60 deaths were caused by ‘interval cancers,’ a term used to describe tumors that occurred in women who had one negative mammogram performed no more than two years previously.
Unscreened women were the result of 395 breast cancer deaths. Another 36 deaths were due to ‘off-program’ women, a term used to describe patients who had a history of mammography, but had not been screened for more than two years.
All in all, interval cancers contributed to 34% of breast cancer deaths in screened women. However, researchers discovered an inverse relationship among age during the time of diagnosis and the percentage of deaths involving interval cancers, diminishing to 47% among women aged 40 to 49, 28% in women aged 50 to 59, 26% in women aged 60 to 69, and 24% in women aged 70 or older.
Researchers also examined breast cancer and non-breast cancer deaths by the factor of age. Half of all breast cancer deaths happened in women younger than 50 and 69% prior to 60. The results fall in line with the controversy that argues whether mammography screenings should take place at age 50 or earlier.
President of the American Society of Clinical Oncology, Clifford Hudis, MD, said that the results are in agreement with much of the writing detailing that mammography screenings lowers the stage at cancer recognition. Earlier stage, smaller tumors, and lower nodal involvement are all connected with improved outcomes in breast cancer.
"Some would argue that cancers are cancers, and whether they are detected early or late, the outcome is the same. This study suggests that is not true, that the stage really matters, even if you have changed the stage at detection,” said Hudis.
"This provides a little more support for the routine use of mammography, which is important because of the ongoing circular debates about screening," he concluded.