Not All Colon Cancer Patients Need Chemotherapy: Study - OAWHealth

Not All Colon Cancer Patients Need Chemotherapy: Study

Not All Colon Cancer Patients Need Chemotherapy: S...

Not All Colon Cancer Patients Need Chemotherapy: Study

Amanda Gardner


May 16, 2008 (HealthDay News) — Colon cancer patients with a specific subset of the disease don't need to receive chemotherapy. In fact, not only does chemotherapy not benefit this group of patients, it may actually harm them, a new study found.

"If you are found to have [this type of colon cancer], then you should not be treated with chemotherapy. Surgery alone would be standard treatment," said Daniel Sargent, lead author of the study and a professor of biostatistics at the Mayo Clinic in Rochester, Minn.

"In our data, patients who have [this type of cancer] who had surgery alone had a 93 percent survival at five years. In our study, chemotherapy actually lowered survival to 75 percent. So, we have a group of patients who can be spared the toxicity, the expense and the inconvenience of treatment and have a very good outcome even without any [chemotherapy] treatment," Sargent said.

The findings, presented Thursday at the American Society of Clinical Oncology annual meeting, in Chicago, confirm previous research and now give physicians a clearer roadmap for treatment, the study authors said.

About 15 percent of colon cancer tumors are known as deficient DNA mismatch repair (dMMR) tumors, because they have lost the ability to repair DNA damage. This particular type of tumor seems to be less aggressive than other forms of colon cancer, the researchers said.

A study published by the same group of researchers in 2003 in the New England Journal of Medicine also found that this subset of patients did not benefit from standard chemotherapy for colon cancer. Because the finding was so novel, the results needed confirmation before they could be incorporated into clinical practice. This new study offers that confirmation, the researchers said.

"We're talking about patients with early stage colon cancer. These are patients who sometimes get chemo and sometimes do not," Sargent said. "We have sought for a long time to try to determine if there was a way to predict which patients might benefit from chemo and which might not."

But, Sargent added, "we felt that in order to really recommend this in clinical practice, we needed to validate it."

The new study analyzed data from 1,027 patients in the United States as well as Canada, France and Italy who had participated in previous trials. Sixteen percent had dMMR.

"The goal was to validate that the 15 percent of patients who have defective mismatch repair did not receive any benefit from 5-FU therapy, and that is indeed exactly what we found," Sargent said.

"We now feel this is appropriately validated for clinical use," he added.

In fact, there is already a simple test for this type of cancer.

"The test is available and, in a patient with stage 2 disease being considered for treatment with chemotherapy, we think that this test would be useful," Sargent said.

SOURCE: www.medicinenet.com

Comment:
The new study analyzed data from 1,027 patients in the United States, Canada, France and Italy. The lead author said in his study, people with a specific type of colon cancer who opted just for surgery were 93 percent more likely to be alive after five years versus only 75 percent of the people who had chemotherapy were alive after five years. This study confirms the previous research that raised the doubts about efficacy of 5 FU (5- Fluorouracil), a standard chemotherapy for colon cancer. Authors have found that only 15 percent of the colon cancers are known to have deficient DNA mismatch repair (dMMR) because they have lost the ability to repair DNA damage and thus are less aggressive to be treated with strong chemotherapy. In such cases chemotherapy causes more harm than good. It is worth noting that similar study is also published about the efficacy of chemotherapy in breast cancer. After consistent failure to provide a satisfactory cancer cure, more researchers are starting to doubt the use of conventional cancer treatments and are emphasizing the devastating side effects. In addition, much more evidence about the efficacy of nutrients like green tea, vitamin B 6, in combating colorectal cancer is also emerging.

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