Mammography May Be Beneficial To All Women, Regardless of Age
First-of-its-kind study examines the screening modality for women over 80M. D. Anderson News Release 04/21/08
According to researchers at The University of Texas M. D. Anderson Cancer Center, mammography, the gold-standard for breast cancer screening and early detection, has shown to significantly reduce the risk of being diagnosed with advanced stage breast cancer in women over the age of 80, an age group currently without clear guidelines for regular screenings.
The study, published online today (April 21) in the Journal of Clinical Oncology (JCO), is the first to specifically assess the screening modality in women older than 80. It's estimated that approximately 17 percent of breast cancers are diagnosed in women older than 80, and only about one-fifth of women in this age group have routine mammograms.
According to the study's senior author, Gildy Babiera, M.D., the need for this study evolved as she began to notice a growing number of women who were 80-years-old and older in her clinic.
"With an increasing number of people living longer, there's a real dilemma regarding how best to manage the care of breast cancer patients 80 years of age and older, taking into account both their comorbidities and their account their quality of life," said Babiera, associate professor in the Department of Surgical Oncology.
This research follows other M. D. Anderson studies looking at complications associated with surgery and treatment tolerability in elderly patients.
The American Cancer Society recommends annual mammography screening for women starting at age 40 with no age limit for women in good health. Other organizations that recommend screening guidelines differ both in age ceilings as well as how often mammograms should be conducted in older women.
Babiera, Brian Badgwell, M.D., a fellow in M. D. Anderson's Department of Surgical Oncology, and their colleagues used information from the National Cancer Institute SEER (Surveillance, Epidemiology, and End Results) database, the authoritative source of information on cancer incidence and survival in the United States. The researchers analyzed SEER data for the years 1996-2002, and looked at mammography rates in the five years prior to diagnosis.
In total, 12,358 women over age 80 were analyzed. Patients were stratified into nonusers (women who did not have mammograms), 49 percent; irregular users (women who had one or two mammograms), 29 percent; and regular users (women who had three or more mammograms.), 22 percent.
Sixty-eight percent of regular users were more likely to be diagnosed with early disease, stage I while nonusers and irregular users more often were diagnosed with stages II, III or IV, 56 percent and 33 percent respectively.
Five-year survival rate was 94 percent in regular users, compared to 88 percent in irregular users and 82 percent in nonusers. Despite these rates, the researchers were not able to find an increase in overall survival because those getting mammograms were healthier and, therefore, more likely to live longer, said Badgwell, the study's first author.
"For example, in our study, we showed a 12 percent decrease in the risk of breast cancer death for each mammogram. However, in the women who received mammograms, we also showed a 12 percent decrease in non-breast cancer death, thereby showing the bias for women who were healthy and receiving mammograms," said Badgwell.
Babiera and Badgwell acknowledge their studies limitations but feel this type of retrospective data may be the best that can be obtained because it's unlikely a randomized control trial could ever be conducted.
"Now that we have this data and we know that mammography improves survival in the younger population, it would be difficult to conduct a randomized trial and stratify women of any age to a control group to not receive mammography," said Badgwell.
Instead, the researchers stress that physicians should review each woman's situation personally to determine if a mammogram is in her best interest, and if she is found to have breast cancer, could her quality of life be managed appropriately.
"Finding breast cancer early in this age group may not result in survival benefit and it may even increase unnecessary angst in elderly women with other ailments. On the other hand, if the woman is otherwise healthy and could be a surgical candidate, should breast cancer be found by a routine mammogram, perhaps she could be offered less invasive treatment and spared from toxic therapies given to women diagnosed with advanced breast cancer," said Babiera.
In addition to Badgwell and Babiera, other authors on the all-M. D. Anderson study include: Gabriel Hortobagyi, M.D., Sharon Giordano, M.D., Shenying Fang and Zhigang Z. Duan all in the Department of Breast Medical Oncology; Isabelle Bedrosian, M.D., Henry Kuerer, M.D., Ph.D., and Kelly Hunt, M.D., all in the Department of Surgical Oncology. 04/21/08