Those findings are drawn from a new study published today in the journal Archives of Surgery by a University of Michigan Health System surgeon and her colleagues.
The study adds to the long list of racial disparities already known to exist in colorectal cancer incidence, screening and treatment. And it confirms that many patients of any race still aren't receiving appropriate post-surgery radiation therapy.
Cancer of the colon and rectum is the fourth most common form of cancer in the United States, and the second leading cause of cancer death. More than 135,000 Americans are expected to be diagnosed with colorectal cancer this year. Although incidence and mortality rates of colorectal cancer in the United States are declining, the rate of decline for African-Americans is slower than for whites.
The new study finds that African-Americans with rectal cancer were diagnosed at a younger age than whites, and were more likely to have reached an advanced stage of cancer progression before their cancer was caught.
They were also more likely than whites to have a kind of surgery that removes the bowel sphincter, meaning that they would have to wear a waste-collecting colostomy bag for the rest of their lives.
African-Americans were also less likely than whites to get radiation before or after surgery. But in fact, only half of patients received such radiation, no matter what their race -- despite the fact that radiation after surgery has been proven to help survival.
"What we saw is that many people aren't getting optimal care, and that some groups are getting even less optimal care than others," says Arden Morris, M.D., MPH, a colorectal surgeon in the U-M Division of General Surgery and Comprehensive Cancer Center. "We need further studies to understand these differences, and to guide efforts to improve care through broader adherence to treatment guidelines."
Morris began the study while she was a Robert Wood Johnson scholar at the University of Washington, using the Surveillance Epidemiology and End Results (SEER) cancer database.
She and her colleagues examined surgery and radiation treatment patterns for 52,864 rectal cancer patients -- 3,851 of them black -- who were treated between 1988 and 1999. The SEER database includes 11 cancer registries and represents 14 percent of the U.S. population.
The study focused on rectal cancer patients, whose tumors occur in the last 8 to 10 inches of the large intestine. These patients have different treatment options than those whose cancer starts higher up, in the six-foot expanse of the colon.
One major difference is that rectal cancer patients whose cancer has spread to nearby tissue or lymph nodes often have surgery near the sphincter, or muscle, that controls the exit of the bowels. The operation removes the cancerous area and nearby lymph nodes.
Many surgeons, especially those who operate on many rectal cancer patients each year, have learned to operate in this area without removing the sphincter and leaving patients in need of a colostomy bag.
But the study showed that a higher percentage of whites than blacks had this kind of sphincter-sparing surgery, while blacks were 42 percent more likely than whites to have sphincter-ablating procedures called abdominoperineal resection.
Previous studies have shown poorer self-image and quality of life for patients whose surgery leaves them in need of a permanent colostomy, which can inhibit their social and sexual activity.
Another racial gap was seen in the use of adjuvant radiation therapy -- a series of radiation doses aimed at the cancerous area from outside or inside the body. Fifty-six percent of African Americans received no radiation after surgery, compared to 53 percent of whites -- an odds ratio of 30 percent.
"The fact that only half of all patients received radiation, when it has been recommended as the standard of post-surgical care for more than a decade, is quite concerning," says Morris. "We don't know where the system is breaking down but we obviously need to do a better job of diffusing the evidence-based treatment guidelines that have been developed for rectal cancer."
Morris and her colleagues also found that only 7 percent of patients had radiation before their operation, an approach known as neoadjuvant therapy that aims to shrink the tumor and therefore the area affected by surgery. As this treatment plan increases in use, she hopes future analyses can show whether race-based gaps in treatment are narrowing.
Overall, Morris notes that colorectal surgeons might take a page from the playbook of cardiac surgeons, who have implemented effective nationwide strategies for measuring and improving the quality of surgical care. And, she calls for further studies to get to the bottom of why there are such gaps between what is recommended and what is carried out -- for all patients.
"The SEER data do not allow us to see what kind of role economics, geography, hospital system, surgeon experience or referral patterns have on the rates of sphincter-sparing surgery and adjuvant radiation, but further research should help ascertain that," she notes. "In the meantime, it would be easy but wrong to blame these disparities on individual doctors. This is a problem with our medical system. It deserves attention and it can be fixed."
In addition to Morris, the research team includes Nancy Baxter, M.D., Ph.D., of the University of Minnesota, and Kevin Billingsley, M.D., and Laura-Mae Baldwin, M.D., MPH, of the University of Washington. The study was partially supported by the Robert Wood Johnson Foundation.
For more information on colorectal cancer treatment and surgery at the U-M Comprehensive Cancer Center, visit www.cancer.med.umich.edu or call the Cancer AnswerLine at 1-800-865-1125.
Journal
Archives of Surgery