Stronger Chemotherapy Does Not Help Colon Cancer
Patients 70 or Older in Study
Chemo combo decreases cancer recurrence, promotes
longer survival after surgery for those under 70
May 29, 2009 - The combination of chemotherapies
5FU and oxaliplatin compared to 5FU alone after surgery for colon cancer
decreases colon cancer recurrence and promotes longer survival for
patients under 70 - but not for those who are older, according to Mayo
Clinic and Dana-Farber Cancer Institute scientists who will present
their findings at the American Society of Clinical Oncology's (ASCO)
annual meeting in Orlando, Fla.
"By combining information about many patients from
a collection of studies, our analysis determined that the more
aggressive combination chemotherapy does not benefit older colon cancer
patients as it does for those who are younger," said Nadine Jackson
McCleary, MD, PhD, Dana-Farber gastrointestinal oncologist and the lead
author on the study. Jackson-McCleary is the recipient of a 2008-2009
ASCO Young Investigator's Award.
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Adding oxaliplatin to chemotherapy treatment with
5FU reduces the risk of recurrence among patients less than 70 years of
age who have had their primary cancer removed, the study determined, a
finding that was expected based on the results of previous individual
trials.
Patients under 70 who were treated with 5FU and
oxaliplatin had improved disease-free survival, with the addition of
oxaliplatin relatively reducing the risk of recurrence or death by
approximately 15 percent. Those patients aged 70 and older who were
treated with the combined drug therapy, however, did not have improved
outcomes compared to patients who received 5FU alone.
"We found that adding chemotherapy agents to the
standard 5FU regimen in older patients after surgery did not provide the
benefits that younger patients see," Dan Sargent, PhD, Mayo Clinic, a
collaborator on the study, agreed. "For the older patient, this means
that it is appropriate to choose the better tolerated treatment strategy
of 5FU alone."
The benefit of post-surgical treatment for both
young and older colon cancer patients with 5FU was documented in a 2001
New England Journal of Medicine study by Sargent and colleagues. By
2003, however, oxaliplatin was approved for use in combination with 5FU
because the combination boosted the impact of 5FU on extending
disease-free survival after colon cancer surgery. While the combined
treatment carried additional risk of side effects, physicians prescribed
the treatment strategy to patients of all ages. Initially, studies that
examined age-related impact of the aggressive chemotherapy combination
did not indicate a difference in survival or recurrence related to
patient age.
The current study presented at the ASCO annual
meeting includes a large enough patient base to powerfully discern
differences related to age that are due to treatment regimen.
"The younger patients do get an additional boost
from both drugs used together," Jackson McCleary noted. "Older patients
don't benefit from that combination of treatment."
The findings arise from analysis of combined data
collected within an expanded database by the Adjuvant Colon Cancer End
Points (ACCENT) Group, a consortium of scientists. The ACCENT database
includes data from more than 33,500 patients from the United States,
Canada, Australia, and Europe. ACCENT is supported by the North Central
Cancer Treatment Group (NCCTG); Sargent is chair of ACCENT.
"At this point we can only speculate as to why
older patients do not benefit from combined chemotherapies," Jeffrey
Meyerhardt, MD, MPH, of Dana-Farber and co-investigator on the trial
said. "We do know that a higher number of older patients have to stop
the drug before completing the full six month prescribed course of
treatment."
"These studies add to the knowledge base that
defines how to choose treatment strategies for every individual
patient," Sargent said. "Age may become as important a consideration as
tumor-specific factors when defining individual medical options for
colorectal cancer patients."
Approximately half of all colon cancer patients are
older than 70. While about half of the colon cancer patients over 70
will live for five years, those with recurrence typically develop
additional tumors within three years. The disease is diagnosed in a
million people worldwide every year. In the United States, colorectal
cancer accounts for 10 percent of new cancer cases, as well as 10
percent of cancer-related deaths every year.
Background Information
Jackson McCleary, Meyerhardt, and
Sargent conducted the analysis on the expanded database in concert with
an international team of scientists participating in ACCENT, including
Erin Green, MD, Mayo Clinic; Greg Yothers, PhD, University of
Pittsburgh; Aimery de Gramont, MD, Hopital Saint-Antoine, Paris; Eric
Van Cutsem, MD, PhD, University of Leuven, Belgium; Michael O'Connell,
MD, Mayo Clinic; Chris Twelves, MD, St James University Hospital, Leeds,
England; and Leonard Saltz, MD, Memorial Sloan-Kettering Cancer Center,
New York.
About Dana-Farber Cancer
Institute
Dana-Farber Cancer Institute (www.dana-farber.org)
is a principal teaching affiliate of the Harvard Medical School and is
among the leading cancer research and care centers in the United States.
It is a founding member of the Dana-Farber/Harvard Cancer Center (DF/HCC),
designated a comprehensive cancer center by the National Cancer
Institute.
About Mayo Clinic
Mayo Clinic is the first and largest
integrated, not-for-profit group practice in the world. Doctors from
every medical specialty work together to care for patients, joined by
common systems and a philosophy of "the needs of the patient come
first." More than 3,300 physicians, scientists and researchers and
46,000 allied health staff work at Mayo Clinic, which has sites in
Rochester, Minn., Jacksonville, Fla., and Scottsdale/Phoenix, Ariz.
Collectively, the three locations treat more than half a million people
each year. To obtain the latest news releases from Mayo Clinic, go to
www.mayoclinic.org/news. For information about research and
education, visit
www.mayo.edu. MayoClinic.com is available as a resource for your
health stories.
About NCCTG
NCCTG is a national clinical
research group sponsored by the National Cancer Institute, comprised of
a network of more than 1,000 community-based cancer treatment clinics in
the United States and Canada that work with Mayo Clinic to conduct
clinical studies for advancing cancer treatment.
Keep up with the latest news for senior citizens, baby
boomers
May 29, 2009 - The combination of chemotherapies
5FU and oxaliplatin compared to 5FU alone after surgery for colon cancer
decreases colon cancer recurrence and promotes longer survival for
patients under 70 - but not for those who are older, according to Mayo
Clinic and Dana-Farber Cancer Institute scientists who will present
their findings at the American Society of Clinical Oncology's (ASCO)
annual meeting in Orlando, Fla.