Thirteen is a baker's dozen
but strangely enough an oncologist's dozen may only come
up to nine. An even dozen is typically the benchmark number
of lymph nodes that should be examined to get a
clear prognosis in colorectal cancer. But when put into
practice, a recent study shows that corners are being
cut. On average, US specialists were found to be three
nodes shy of a proper examination.
This is bleak news since this test
— when performed properly — is the most important
predictor of longterm outlooks for folks with colorectal
cancer. Examining all 12 lymph nodes in these patients
helps accurately determine if the cancer is confined
to the immediate area or will spread to other neighborhoods
in the body.
The paper in the February 2 issue
of the Journal of the National Cancer Institute
reports that less than half of the almost 117,000 colorectal
cancer patients included in the study received this
baseline level of lymph node examination. The final
tally is worrisome considering that the discovery of
cancerous lymph nodes not only predicts the spread of
disease, but is also often a deciding factor on when
to bring in the heavy anti-tumour artillery — radiation
treatment and chemotherapy.
Dr Nancy Baxter, a surgeon at the
University of Minnesota in Minneapolis, and colleagues
statistically analyzed data gathered as part of the
National Cancer Institute's Surveillance, Epidemiology
and End Results cancer registry. The registry compiled
information from 116,995 subjects with localized invasive
adenocarcinoma of the colon or rectum. These patients
were treated between 1988 and 2002.
FLYING
BLIND
The bull's-eye of a dozen lymph nodes was hit in only
37% of the patients. In fact, the median number of nodes
examined was far less, at nine. And, most disturbingly,
about 7,600 patients did not have lymph nodes examined
at all. The chances of receiving an adequate lymph node
examination did get better over time. In 1988, the median
numbers of nodes examined was eight, while in 2001 the
number had climbed to 14. Still, even in 2001, the adequate
target of a dozen lymph nodes was achieved in fewer
than 50% of the patients, according to the authors.
"Older patients were less likely to receive adequate
lymph node evaluation than younger patients," say the
researchers. Fifty-one percent
of patients aged less than 50 and
only 35% of those older than 70 received an adequate
exam. Strangely enough, people with right-sided cancers
were also more likely to receive a proper exam. The
quality of care also varied geographically. "Local surgical
and pathology practice patterns may affect adequacy
of lymph node evaluation," according to the authors.
No data is available on how specialists in Canada stack
up. But hopefully the 17,600 Canadian patients diagnosed
with colorectal cancer each year aren't getting short
changed as well.
J Natl Cancer Inst Feb 2,
2005;97(3):219-25
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