Mammography Beneficial After 75?, 80?; Breast Cancer
Spreads Faster After 70
Studies of breast cancer in older women point to
extending mammography
April 22, 2008 - A study released yesterday found
mammography, the gold-standard for breast cancer screening, can
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. While a European study
released earlier found it is effective, appropriate and reduces deaths
from the disease in women aged up to 75 years old. Both report to be the
first to study cancer screening at these ages. Another study of breast
cancer in older women found the cancer found in women over age 70 is
more likely to spread.
Study of Women
Over 80
The first study to specifically assess the
screening modality in women older than 80 was released yesterday. 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 researchers at The
University of Texas M. D. Anderson Cancer Center.
The study was published online yesterday in the
Journal of Clinical Oncology (JCO).
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.
Editor's Notes:
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.
About M. D. Anderson
The University of Texas M. D. Anderson Cancer Center in Houston ranks as
one of the world's most respected centers focused on cancer patient
care, research, education and prevention. M. D. Anderson is one of only
39 Comprehensive Cancer Centers designated by the National Cancer
Institute. For five of the past eight years, M. D. Anderson has ranked
No. 1 in cancer care in "America's Best Hospitals," a survey published
annually in U.S. News and World Report.
Mammograms
Benefit Women up to Age 75
Another study presented at the recent 6th European
Breast Cancer Conference (EBCC-6) in Berlin says breast cancer screening
is effective, appropriate and reduces deaths from the disease in women
aged up to 75 years old. The study looked at data from over 860,000
women aged 70-75.
Many countries that run breast cancer screening
programs offer it to women aged between 50 and 70. However, in 1998 in
The Netherlands, the program was extended to women aged up to 75. The
results presented today suggest that this is an appropriate upper age
limit and saves lives without causing substantial harm by subjecting
older women to over-diagnosis and over-treatment.
This is the first study to provide firm support for
the idea that offering mammograms to women up to the age of 75 is
effective, as, until 1998, very few women were screened at this age.
Mr. Jacques Fracheboud, a senior researcher at the
Erasmus Medical Center (Rotterdam, The Netherlands), and his colleagues
found that from 2003, five years after screening was extended to women
aged 70-75, there was a steady decline in deaths from breast cancer
among women aged 75-79. By 2006 breast cancer mortality was 29.5% lower
than the average for the period 1986-1997 for this age group a time
when breast cancer mortality in women aged 75-79 had remained stable. In
1986-1997 the average was 166 deaths per 100,000 women aged 75-79 and in
2006 it was 117 per 100,000.
It takes some years before a significant effect
from screening can be seen; therefore breast cancer mortality was
analyzed for the ages 75-79.
That means that women, aged 70-75 at the time that
screening was extended to this age group, have become five years older
and the reduction in breast cancer mortality shows that the screening
has started to have a statistically significant effect, Mr. Fracheboud
told a news briefing.
Out of the 7.37 million screening examinations
performed between 1998-2006, 862,655 were for women aged 70-75. Among
women aged 50-69, 81.2% participated in the screening program, and 71.9%
of women aged 70-75 took part. However, the participation rate for these
older women increased significantly during this period, rising from
62.5% in 1998 to 77.6% in 2006.
In the 50-69 age group, 12.8 per 1000 women
screened were referred for diagnostic assessment as a result of
screening and breast cancer was detected in 4.5 per 1000, giving a
positive predictive value (percentage of abnormal mammogram findings
that were confirmed as breast cancer) of 36%. In the 70-75 age group,
16.4 per 1000 women screened were referred for diagnostic assessment and
breast cancer was detected in 7.8 per 1000, giving a PPV of 47%.
The difference shows that it is easier to find
breast cancer in older women due to their breast tissue being less
dense, said Mr. Fracheboud. But it is not necessarily an argument for
continuing screening beyond 75 because many tumors found at this stage
are slow growing and may never reach the stage of causing a problem.
He continued: The results of our study suggest
that screening women aged 70-75 has a strong impact on breast cancer
mortality and that it is effective and appropriate up to 75 years. The
cost per mammogram is approximately 50 the same as for younger women.
Before the program was extended up to 75 there was a fear that older
women would be more expensive because fewer would participate and it
might take more time to screen them due to reasons such as lower
mobility. However this seems not to be case and participation rose among
the older women.
Breast Cancers
Behave Differently After the Age of 70
Do the immune defense mechanisms play a role?
Researchers in Belgium have discovered that
increasing age affects the way breast cancer behaves. As women approach
the age of 70, they become less likely to be diagnosed with aggressive
tumors that have spread to the lymph nodes. But after 70, the cancer is
increasingly likely to spread, particularly if the tumors are small.
European Study Defends Mammograms Just
Ever 3 Years
In another study of nearly 100,000 women
aged 50-62, also presented at EBCC-6, researchers found that the
best interval for screening was every three years a finding
that counters arguments that women should have mammograms more
frequently.
In the UK Breast Screening Frequency Trial
researchers randomized nearly 100,000 women to have either an
annual or a three-yearly mammogram after the date of the first
screening to which they were invited after their 50th birthday.
In an earlier paper (European Journal of
Cancer 2002), the researchers had predicted that annual
screening would not result in a further reduction in breast
cancer mortality over the three-year interval standard in the
UK. The actual mortality rates presented today confirm this to
be the case.
After an average follow-up time of over 13
years (the trial started in 1989), there were 373 breast cancer
deaths (out of a total of 49,173) among the study group of women
invited to attend annual screening, and 374 (out of a total of
50,162) in the control group of women invited to three-yearly
screening.
Among those women who actually attended the
screening (as opposed to the whole group of women, including
non-attendees), there were 209 breast cancer deaths in the study
group and 231 in the control group. The researchers found no
difference in mortality rates when they looked at only those
cancers diagnosed during the three-year screening periods.
The absolute risk of dying from breast
cancer was statistically insignificant between the two groups,
with the control group having an absolute risk of only two per
cent more than the study group.
One of the authors of the study, Professor
Roger Blamey, a breast surgeon at Nottingham City Hospital
(Nottingham, UK), told the news briefing: There was a lot of
criticism of the UK for having a three-yearly interval when
breast screening was set up screeners and advocacy groups
said, without evidence, that it was too long an interval.
Population screening in the UK costs around 100m a year.
"These results indicate that our earlier
predicted mortality figures were accurate and that there is no
evidence in favor of shortening the current three-year screening
interval.
Until now, there has been conflicting evidence on
aging and lymph node involvement and this study is the first to show
clearly how the link between the two changes before and after the age of
70.
Professor Hans Wildiers told the 6th European
Breast Cancer Conference (EBCC-6), that he suspects that women older
than 70 have decreased immune defense mechanisms, which are less able to
deal with tumors that are likely to metastasize to other sites in the
body.
The effect of age of lymph node positivity is not
straightforward. There seems to be a different effect between women aged
up to 70 years and women older than 70. For the younger group of women,
age appears to have a negative effect on lymph node status the older
they become, the less likely the cancer is to have spread to the lymph
nodes.
"For the older group of women (aged over 70), age
appears to influence lymph node status in the opposite way the older
they become, the more likely they are to have cancer cells in the lymph
nodes if the tumor is small, said Prof Wildiers, who is adjunct head of
clinic in the department of general medical oncology at the
Multidisciplinary Breast Centre, University Hospitals Leuven, Belgium.
There is an interaction between age and tumor
size, suggesting that, up to the age of 70, age mainly has a positive
effect on lymph node status for older women with small tumors. A likely
explanation is that breast tumors metastasize less frequently to lymph
nodes with increasing age due to the decreased biological aggressiveness
in these tumors. On the other hand, over the age of 70, if the tumors
have the potential to metastasize to lymph nodes, this occurs more
rapidly in smaller tumors and this might be related to decreased immune
defense mechanisms in elderly patients.
Wildiers and his colleagues investigated 2,227
women who had been treated for breast cancer between 2000 and 2006 at
the University Hospitals Leuven. Then they compared the results with a
separate database of over 11,000 breast cancer patients on the Eindhoven
Cancer Registry.
They found that for women aged 70 or younger,
increasing age was associated with a decreased prevalence of cancer
spreading to the lymph nodes.
The womens risk of having positive lymph nodes
decreased by 13% for every decade they aged, up to age 70.
Once aged 70 and over, the odds of lymph node
involvement doubled with every 10-year increase in age for women who had
tumors that were no bigger than 15mm across. If the tumors were larger
than 42-43 mm, then risk of lymph node involvement continued to
decrease.
Wildiers said: We know that the elderly have
depressed immune defenses, and, therefore, it is possible that these
decreased defenses are unable to prevent invasion of the lymph nodes by
metastases in a subset of breast tumors in elderly women.
"Although breast cancer survival in older women
appears to be similar to survival in the general population irrespective
of disease status, it might well be that there is a balance in the
elderly between, on the one hand, a less aggressive type of tumor, and,
on the other hand, their decreased immunological defenses.
He said the findings supported the idea that there
are two types of tumor in elderly women: ones that are slow-growing and
dont invade the lymph nodes even if the tumors are larger, and ones
that are aggressive and metastasize very early to the lymph nodes. Women
with slow-growing tumors might benefit from less aggressive treatment,
while the smaller tumors in the women aged over 70 might need to be
treated more aggressively.
Further research now needs to be conducted into
the role the immune system plays in lymph node invasion, he concluded.
Keep up with the latest news for senior citizens, baby
bommers
April 22, 2008 - A study released yesterday found
mammography, the gold-standard for breast cancer screening, can
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. While a European study
released earlier found it is effective, appropriate and reduces deaths
from the disease in women aged up to 75 years old. Both report to be the
first to study cancer screening at these ages. Another study of breast
cancer in older women found the cancer found in women over age 70 is
more likely to spread.