A study published in the Journal of the American Medical Association examined time-to-colonoscopy in 70,124 Kaiser Permanente members in California.
Douglas A. Corley, MD, PhD, a Kaiser Permanente gastroenterologist and research scientist in Northern California, and colleagues reviewed positive fecal immunochemical testing data for members between 50 and 75-years-old.
Approximately 40 percent of patients had follow-up colonoscopies within one month, 64 percent within two months and 74 percent within three months.
Here's what they found.
1. There was no significant differences in colorectal cancer risk after colonoscopies two, three, four, six, seven or nine months later.
2. By 10 months to 12 months however, colorectal cancer risk increased by approximately 50 percent, and advanced cancers risk almost doubled.
3. Waiting longer than 12 months increased the risks to more than double for any type of cancer and more than tripled the risk for advanced cancer.
4. Less than 3 percent of patients with positive fecal immunochemical testing data were diagnosed with colorectal cancer and less than 1 percent of those patients developed advanced cancers.
Researchers concluded that patients should schedule a colonoscopy within a few months after a positive fecal immunochemical test.