Major Finding: Overall, 65.5% and 29.8% of breast cancers were detected by mammography and palpation, respectively. Among the women younger than age 50, the corresponding values were 48.3% and 46.1%.
Data Source: A retrospective cohort study of 5,628 women given a diagnosis of stage 0 to III breast cancer between 2006 and 2009.
Disclosures: Dr. Caughran and Dr. Seidman reported that they had no relevant conflicts of interest.
SAN FRANCISCO – Many breast cancer patients would have more advanced disease at diagnosis and face harsher treatment if recently updated screening guidelines of the U.S. Preventive Services Task Force were widely adopted, suggests the investigator of a retrospective cohort study of more than 5,000 women with breast cancer in Michigan.
Study results, being reported this week at the symposium, show that nearly a third of the women's cancers were detected by palpation. The guidelines do not advocate for self-exams at all and question the usefulness of clinical breast exams after age 40.
Additionally, nearly half of the cancers in women younger than 50 years were detected by mammography, while the guidelines now recommend against this practice in the 40- to 49-year age group.
Women with palpation-detected cancers had later-stage disease and were significantly more likely to undergo mastectomy and receive chemotherapy than were those with mammography-detected cancers.
“Annual screening mammograms and evaluation of palpable breast masses are important tools in breast cancer detection,” second author Dr. Jamie Caughran said during a premeeting press briefing from the American Society of Clinical Oncology (ASCO).
She declined to say whether the study's results contradict the U.S. Preventive Services Task Force (USPSTF) guidelines, as the investigators did not have adequate information on the women's screening history.
But “we take this data to conclude that you're better off if you can … have your cancer detected by mammography — that you are more likely to have options and less likely to need aggressive treatment. So … we would support the rest of the societies that continue to recommend annual screening mammography starting at age 40,” she said.
Additionally, this study “highlights the still-significant number of women who present with a palpable mass that shouldn't be overlooked by physicians even if they have a negative mammogram,” pointed out Dr. Caughran, medical director of the Comprehensive Breast Center at the Lacks Cancer Center in Grand Rapids, Mich. “So it just continues to reinforce what we believe is inherently true.”
Dr. Andrew Seidman, moderator of the press briefing and a medical oncologist at the Memorial Sloan-Kettering Cancer Center in New York City, commented that the appropriate age for starting screening mammography remains controversial.
“A lot of the debate and focus regarding the utility of mammography have been on overall survival and breast cancer—specific survival, and I certainly think that is the most important end point,” he said, noting that the study speaks to another important end point — reduced intensity of treatment.
“As a medical oncologist or chemotherapist, I think this is a very important gain, independent of any potential survival benefit,” he said. “Having less disfiguring surgery and the ability to deliver less chemotherapy based on the stage at diagnosis are for me a step forward.”
This newest study will not quell the debate, according to Dr. Seidman. “Undoubtedly, this area will continue to remain an area of controversy for some,” he said. “But certainly, women in this age group would be well served to know about this data.”
In the study, Dr. Caughran and her colleagues analyzed data from a statewide breast cancer registry managed by the Michigan Breast Oncology Quality Initiative, identifying 5,628 women who received a diagnosis of stage 0 to III breast cancer between 2006 and 2009. Their average age was 59.4 years.
In the cohort overall, 65.5% of breast cancers were detected by mammography, 29.8% by palpation, and 4.7% by other means.
Fully 90% of the cancers detected by palpation were detected by the patient herself, although “it's unclear if the patients … were practicing regular breast self-examination or if these were incidental findings,” noted Dr. Caughran.
When analyses were restricted to women younger than 50 years of age, 48.3% of breast cancers were detected by mammography, 46.1% by palpation, and 5.6% by other means.
Palpation-detected cancers were of later stages (P less than .0001) — two-thirds were stage II or higher — and were more often treated with mastectomy (45.8% vs. 27.1%, P less than .0001) and with chemotherapy (22.7% vs. 15.7%, P less than .0001).
Nearly half of the cancers in women younger than 50 years were detected by mammography.