Older Americans who visit their doctors regularly are less likely to develop or die from colon and rectal cancers, according to a new study.
Researchers credit screening that catches precancerous growths and early cancers for the differences seen in rates of both cancers and deaths among people on Medicare.
"The main takeaway here is that we need to improve access to primary care and encourage elderly people to use primary care," Dr. Jeanne Ferrante, the study's lead author from the Robert Wood Johnson Medical School in Somerset, New Jersey, said.
Colorectal cancers are the second leading cause of cancer-related deaths in the U.S., according to the Centers for Disease Control and Prevention (CDC).
Screening rates for colon cancer have increased over the past few years, but the CDC says about 22 million people are not up-to-date with the tests.
A primary care doctor's recommendation is one of the best ways to persuade people to get screened for colon and rectal cancer, Ferrante's team writes in the Annals of Internal Medicine.
To see whether regularly visiting the doctor translated into a cancer risk difference, the researchers looked at data from a national registry on cases of colon and rectal cancer between 1994 and 2005. They also used Medicare records to track doctor visits over about two years.
They compared a total of 205,804 people between the ages of 67 and 85 years old who were diagnosed with colorectal cancer to similar adults who were cancer free.
Overall, the people who went to their primary care doctors five to 10 times during a period of 27 months or less were about 6 percent less likely to be diagnosed with colon and rectal cancers, compared to people who only went to the doctor once or not at all.
People with the most primary care visits were about 22 percent less likely to die from colon and rectal cancers, compared to those with the fewest visits.
People with five to 10 recorded doctors' visits were also 21 percent less likely to die of any cause compared to those who saw a doctor least often.
Ferrante said the more often people went to their primary care doctors the more likely they were to get screenings and therefore not get colorectal cancer.
The government-backed U.S. Preventive Services Task Force (USPSTF) recommends that people between ages 50 and 75 get screened by colonoscopy every 10 years, or more frequently with other methods.
During a colonoscopy, a doctor uses a long flexible tube equipped with a tiny video camera to see the interior of the colon and remove pre-cancerous growths if they're found.
Alternatively, the USPSTF says people in that age group can have a high-sensitivity fecal occult blood test every year, or a sigmoidoscopy - which is similar to a colonoscopy - every five years in addition to fecal occult blood testing every three years.
"It makes sense that if you aren't seen much by a primary care provider you don't have someone bringing up disease prevention opportunities," said Dr. Barbara Turner, who co-authored an editorial accompanying the new study.
More than a quarter of people included in the study had no recorded primary care visit or just one over a 27-month period.
"We found, despite having universal Medicare insurance, 25 percent of these beneficiaries do not go to see primary care doctors… and these people were more likely to develop colorectal cancer," Ferrante said.
She and her colleagues caution, however, that they cannot say primary care doctors' visits caused fewer cases of cancer.
For example, they could not account for all other possible explanations, including that healthier people tend to go to the doctor more.
"Anytime you do research with large databases you can't say something causes something else, you have to say it's associated with it," Turner, director of the Research to Advance Community Health Center at the University of Texas Health Science Center at San Antonio, said.
But Turner said there is a growing body of evidence to support the results of the new study.
"We need to push people to understand the value of receiving regular primary care," she said.