The elderly are not treated as aggressively for colon cancer as younger people, even though clinical trials show that the treatments are equally successful for them, researchers from Rand Corp. and UCLA reported Tuesday. However, there is not yet enough data available to show whether this reduced level of care affects survival, the researchers reported in the Journal of the American Medical Assn. The less aggressive therapy may be the result of a misguided compassion on the part of oncologists, who do not wish to subject older patients to the side effects associated with the most powerful treatments.
Colon and rectal cancer will strike an estimated 147,000 Americans this year, killing nearly 50,000. The most common treatment is surgical removal of the tumor, followed by chemotherapy with a combination of the drugs fluorouracil and leucovorin or levamisole. In clinical trials, those drugs produced a 24% reduction in deaths and a 32% decrease in recurrence among all age categories compared to surgery alone. Adding the more powerful drug oxaliplatin increases survival, but with an accompanying increase in severe side effects, which may include nerve damage at the extremities, anemia and other problems.
But the clinical trials of the cancer drugs have been conducted primarily in homogeneous groups of mostly younger patients, said Dr. Katherine L. Kahn of Rand and UCLA's Jonsson Comprehensive Cancer Center. The question is how these findings from clinical trials are translated into treatment in the community and, particularly, how they are used on older patients. There are two questions that need to be asked, she said: Can older patients tolerate the therapy and is therapy beneficial? This report answers the first question with a yes.
Kahn and her colleagues studied the medical records of 675 patients with advanced colon cancer who underwent surgery at a cross-section of medical centers across the country from 2003 to 2005. They were monitored for as long as 15 months after their surgery.
Of the 202 patients who were 75 or older, only 101 received chemotherapy, compared with 87% of the 473 younger patients. Among those who did receive chemotherapy, only 14% of those over 75 received oxaliplatin, compared with 44% of younger patients. Among those who received chemotherapy, many did not complete the recommended six months of treatment: 40% of those over 65 had stopped by five months, compared with 25% of younger patients. And about 18% of patients received less than the recommended dosages of the drugs.
"We don't know if there is a problem with underuse" of chemotherapy, Kahn said. "What we do know is the way doctors have decided to use chemotherapy is somewhat different than what is recommended in trials." And, perhaps most important, the older patients subjected to chemotherapy did not suffer any more serious side effects than the younger patients.
Because most colon cancer recurrences happen during years two to five after the surgery, she added, the team will not be able to determine whether the chemotherapy was beneficial for another year and a half.
-- Thomas H. Maugh II