MONDAY, July 20, 2009 (HealthDay News) -- More isn't necessarily better when it comes to surgically removing lymph nodes to diagnose late-stage colorectal cancer, new research shows.
In 1990, the World Congress of Gastroenterology recommended that surgeons remove at least 12 lymph nodes during surgery for colorectal cancer, the study authors noted in the July 20 issue of Archives of Surgery. The standard was widely adopted as a measure of quality in surgical practices.
Then in 2004, researchers from three medical centers in the Chicago-Skokie, Ill., area embarked on an initiative to increase the number of lymph nodes removed during surgery.
They later analyzed the medical records of 701 colorectal cancer patients who'd had surgery between 1996 and 2007. The records included surgeries done before and after the initiative began.
The researchers found that the average number of lymph nodes removed increased from 12.8 to 17.3 after the initiative began. About 72 percent of the patients had at least 12 lymph nodes removed, compared with 53 percent before the initiative.
Even so, the proportion of patients diagnosed with stage 3 colorectal cancer did not change significantly. About 37 percent of patients who had surgery before the initiative were diagnosed with late-stage colorectal cancer, compared with 32 percent of earlier cases.
"Our data suggest that mandatory harvest of a minimum of 12 lymph nodes as a quality indicator or performance measure appears unfounded," the researchers wrote.
The status of lymph nodes near the cancer is one of the best means of determining prognosis and chances of survival in colorectal cancer, which is the third most common type of cancer and the third-leading cause of cancer-related death in the United States, according to background information in the study.
"Accurate lymph node staging also is important for determining prognosis and the need for adjuvant chemotherapy," the researchers wrote. "In addition, lymphadenectomy [lymph node removal] may be therapeutic; several studies have shown a positive association between the number of lymph nodes removed and survival for patients with negative and positive lymph nodes."
The U.S. National Cancer Institute has more on colorectal cancer.