Breast cancer patients who
have mammograms every 12 to 18 months have less chance of lymph node
involvement than those who wait longer, therefore improving their outlook,
according to an early new study.
As breast cancer
progresses, cancer cells may spread to the lymph nodes and other parts of the
body, requiring more extensive treatment.
"We found that doing
mammograms at intervals longer than one and a half years essentially does
affect patient prognosis," said study researcher Dr Lilian Wang. "In
our study, those patients were found to have a significantly greater lymph node
From 2007 to 2010, Wang
evaluated more than 300 women, all of whom were diagnosed with breast cancer
found during a routine mammogram. She divided them into three groups, based on
the interval between mammograms: less than one and a half years, one and a half
to three years or more than three years. Most women were in the first category.
Wang looked to see how many
women had cancer that had spread to their lymph nodes. Although nearly 9% of those in the shortest interval had lymph node involvement, 21% of those in the middle group and more than 15% in the
longest-interval group did.
The stage at which the
cancer was diagnosed did not differ among the groups, she found.
Although the study found an
association between more frequent screenings and less lymph node involvement
among breast cancer patients, it did not establish a cause-and-effect
Wang, an assistant professor
of radiology at Northwestern University's Feinberg School of Medicine, is
scheduled to present the findings at the annual meeting of the
Radiological Society of North America, in Chicago.
The best interval between
routine mammograms has been a point of discussion and debate for years.
In 2009, the US
Preventive Services Task Force, an independent group of experts, changed their
recommendations, which previously advised annual mammograms. The updated
recommendations advised that women begin routine mammograms at age 50, and that
every two years was an acceptable interval. Women aged 40 to 50 were advised to
discuss the pros and cons of screening with their doctors.
The updated guidelines took
into account death from breast cancer with different screening intervals and
the downsides of false positives, which could translate into more testing,
expense and anxiety.
however, including the American Cancer Society and the American College of
Radiology, continue to recommend annual mammograms for women beginning at age
The new results, Wang said,
support the recommendations for annual testing beginning at age 40 for
Analysis of the study
The study disclosed that
another co-author has served on boards or been a speaker for imaging-device
An expert not connected
with the new study said its focus – looking not at the risk of death from
breast cancer, but the chances of cancer spreading to the lymph nodes – is a
"If you catch someone
with early stage cancer, they are going to need less extensive surgery, and
maybe no chemo," said Dr Laura Kruper, director of the Cooper-Finkel
Women's Health Centre at the City of Hope Cancer Centre, in Duarte, California.
"[The new study] adds
more power behind the fact that we do need screening mammograms starting at age
40 and every year," she said.
The second study
In a second study presented
at the meeting, other researchers reported on a new technique that uses focused
ultrasound under the MRI guidance to heat and destroy breast cancer tissue.
Researchers at Sapienza
University, in Rome, evaluated the treatment in 12 breast cancer patients
before surgical removal of their cancer and biopsy of their lymph nodes.
When the researchers looked
at the tissue, no sign of tumour was found in 10 of the 12 patients. More
research is needed, however, before the technique could be considered as a
standalone treatment, the researchers said.
Kruper agreed. The new
technique is far from being ready for clinical use, she said. Among the
unanswered questions are how the results will stand up over time.
Because both studies were
presented at a medical meeting, the data and conclusions should be viewed as
preliminary until published in a peer-reviewed journal.
To learn more about mammograms,
visit the American Cancer Society.