Older patients were 28% more likely than younger ones to be hospitalized for treatment of complications following a surveillance colonoscopy, study data shows.
Follow-up colonoscopies for people over age 74 who have a history of colon cancer or certain pre-cancerous polyps should be carefully considered, because the risk of hospitalization for a post-procedure adverse event may outweigh the benefits, researchers say.
An Hong Tran, MD, Kaiser geriatric fellow, found a higher risk of adverse events requiring hospitalization in seniors over age 74 — and relatively few cancers — compared with similar patients who underwent the procedure between ages 50 and 74.
"The surprising thing about our study was the differences between risks and benefits of surveillance colonoscopy (a term for a follow-up colonoscopy done several years after a prior finding of polyps or colorectal cancer) between the elderly patients and younger patients," Tran says.
Screenings Raise Risk as Well as Awareness
Tran used data from a study of 28,000 people who underwent a colonoscopy at Kaiser Permanente Los Angeles Medical Center between 2001 and 2010. The paper was published Monday in JAMA Internal Medicine online.
Of the nearly 5,000 patients over age 74 who underwent surveillance colonoscopies, only five cancers were detected, but 527 patients required a post-procedure hospitalization within 30 days.
By comparison, in the younger group of 23,000 patients between the ages of 50 and 74, there were 368 colorectal cancers detected, but only 184 patients required post-procedure hospitalization.
Tran emphasizes that it's unclear how many hospitalizations in either group may have been related to an adverse event stemming from the colonoscopy itself, such as gastrointestinal tract hemorrhage, cardiac arrhythmia, or perforation, because data for 24% of patients is missing.
Tolerance Wanes with Age
But it was clear that the older the patient, the higher the risk of a hospitalization related to the procedure itself. Patients in the older group were 28% more likely than those in the younger group to have to go back to the hospital within 30 days.
One factor in the equation is that patients with more comorbidities seemed to have a higher risk of requiring hospitalization after a surveillance colonoscopy. Why that is so is unclear.
"Our theory is that their ability to tolerate this procedure is less as they get older," Tran says.
A flaw in the dataset was that it did not include patients who had a complication after surveillance colonoscopy that prompted a trip to an emergency department, where it was successfully treated without the necessity for an inpatient admission. It might be that just as many patients or even more required ED care, but that older patients were more severely affected by the adverse event and required hospitalization for it.
Tran says her study is important because as people age and receive recommendations from their physicians to undergo colon cancer screening, many will have polyps excised or be diagnosed with cancer, and will be advised to undergo subsequent colonoscopy surveillance.
It's important for providers to discuss with those patients the risk of harm and the low chance of cancer recurring in the colon, which could affect lifespan.
"Our hope is that with this data, we can shed some light into the risk and benefits of this procedure, so physicians can have more informed discussions with their patients," Tran says.
Few Cancers Detected
"How do we explain this trend," which seems counterintuitive, Tran asks rhetorically. "It may be that what we're seeing is that we're doing something right, which is having good colorectal cancer screening."
Tran says that it's important for other researchers to try to replicate this data in other healthcare settings besides Kaiser Permanente, which is well-known for its aggressive colonoscopy screening and surveillance program. Hers is one of only a few that look beyond initial colonoscopy screening to the larger question of repeat colonoscopies after a polyp finding or diagnosis of cancer.
"We haven't really talked too much about the population of people who already had a history of polyps or colon cancer," she says.
Tran's research finding on surveillance colonoscopy dovetails with the 2008 guideline on screening colonoscopy from the U.S. Preventive Services Task Force, which recommends against the procedure for adults after age 75, however cautions that "there may be considerations that support colorectal cancer screening in an individual patient."