COLON CANCER Study revises benefits of chemo
The update of a study says the benefits of chemo disappear after 10 years.
Chemotherapy after colon-cancer surgery has become standard in the past decade for most people with tumors that are considered curable.
This approach has evolved based on a number of trials that have shown patients who get the additional treatments have a 33 percent better survival chance after five years than people who get surgery alone.
But in an update of one of the earliest and most influential trials that helped set today's standards, researchers reported Wednesday that the benefit from getting the chemotherapy disappeared after 10 years.
After 10 years, 133 of 375 patients who were treated with surgery alone died from recurrence of colon cancer, compared with 129 out of 349 patients who got chemotherapy after surgery, nor was there any difference in overall survival between the two groups.
According to the American Cancer Society, this year nearly 150,000 Americans will be diagnosed with colorectal cancer, and more than 56,000 will die from the disease, which is the second-leading cause of cancer death in the country, behind lung cancer.
Doctors grade the risk of colon cancer depending on whether a tumor has perforated the muscle wall of the colon or reached the lymph nodes beyond.
If those conditions are reached, chemo after surgery is usually recommended.
Beyond five-year mark
Dr. Roy Smith and colleagues at the National Surgical Adjuvant Breast and Bowel Project, based in Pittsburgh, write in The Journal of the National Cancer Institute that although the chemo in the study -- carried out between 1977 and 1983 -- helped patients survive more than five years, "the benefit is of limited duration."
Generally, colon-cancer patients who survive five years without a recurrence are considered cured, since most relapses happen within two or three years of surgery, so few studies have followed patients as long as Smith's group did.
Smith also pointed out, however, that the three-drug combination of chemo used in the experiment is no longer used today, replaced by other drugs that showed more effectiveness in later tests, and thus "it is possible that the newer chemotherapy regimens would be better than surgery alone" in preventing cancer relapses beyond five years.
Controversy about which patients can most benefit from additional chemo after surgery has grown in recent years, particularly for patients with tumors that have not yet reached their lymph nodes.
Though some studies show a 30 percent five-year survival advantage from chemo, others as recently as 2001 show no significant survival differences.
Dr. Jean Grem, of the University of Nebraska Medical Center in Omaha, commenting on the findings in an editorial, argued that researchers need to focus more on a shorter survival span than even five years for colon-cancer patients getting new chemotherapy combinations.