Spotlight on colorectal cancer survival

One study found that colorectal cancer diagnosed six to 60 months after colonoscopy leads to a shorter life expectancy, while two others found increased risks of mental illness and chronic opioid use among colorectal cancer survivors.

Colorectal cancer (CRC) survivors face many challenges, as evidenced by three recent studies.

The first study found that CRC detected six to 60 months after colonoscopy may lead to a shorter life expectancy. Researchers assessed patients registered in the Taiwan Cancer Registry between 2002 and 2009 who had CRC confirmed within six months after a colonoscopy (detected group; n=22,169) or who received a colonoscopy six to 60 months before diagnosis (postcolonoscopy group; n=1,653). They estimated life expectancy and expected years of life lost by comparing the survival ratio between the two cohorts and an age-, sex-, and calendar year-matched referent group from life tables in a national database. Patients were followed until 2011. Results were published online on March 5 by Digestive Diseases and Sciences.

Overall, the postcolonoscopy group had shorter life expectancies than the detected group (stage 2, 13.6 vs. 16.1 years; stage 3, 8.7 vs. 12.6 years; and stage 4, 2.1 vs. 4.1 years [P<0.001]). Postcolonoscopy patients were older at diagnosis, had a shorter life expectancy, had more proximal cancer locations, and received more endoscopic polypectomy procedures than those in the detected group. While their life expectancy was always lower in comparisons within the same gender and tumor stages 2 to 4 (P<0.001), after adjustments for age distribution or lead-time bias, there was no consistent trend in the difference of expected years of life lost between groups.

Limitations of the study include a lack of access to detailed colonoscopy reports and treatment information. In addition, participants' family history of CRC was not known, the study authors said. “Intensive surveillance for high risk groups with a thorough, high-quality colonoscopy is crucial for the early detection and reduction in [postcolonoscopy] CRC,” they concluded.

In the second study, researchers found an increased risk of mental illness or depression in CRC survivors. They assessed the short- and long-term risk of developing any mental illness among 8,961 CRC survivors diagnosed between 1997 and 2013 and enrolled in the Utah Cancer Registry. They obtained mental health diagnoses from EHRs and statewide facilities data connected to the Utah Population Database. Survivors were matched to 35,897 individuals from a general population cohort. Results were published online on March 5 by the American Journal of Clinical Oncology.

Overall, CRC survivors were at increased risk for any mental health diagnosis at 0 to 2 years (hazard ratio [HR], 3.70; 95% CI, 3.47 to 3.95), between 2 and 5 years (HR, 1.23; 95% CI, 1.09 to 1.38), and greater than 5 years (HR, 1.20; 95% CI, 1.07 to 1.36) after cancer diagnosis. They were also at increased risk of depressive disorders in particular during these time periods. Risk factors included colostomy and Charlson Comorbidity Index of 1 or more. In addition, there was an increased risk of death among CRC survivors diagnosed with any mental health disorder (HR, 2.18; 95% CI, 2.02 to 2.35) and depression (HR, 2.10; 95% CI, 1.92 to 2.28).

Limitations of the study include a lack of patient-recorded outcomes and the potential for surveillance bias due to increased medical care among cancer survivors, the study authors noted. “The need for supportive care among CRC survivors persists throughout all periods of follow-up. Mental health screening should be incorporated into surveillance and survivorship visits,” they wrote.

In the third and final study, researchers used the Surveillance, Epidemiology, and End Results registry linked to Medicare claims to compare chronic opioid use (≥90 consecutive days) among older opioid-naïve survivors of CRC, lung cancer, and breast cancer who were matched with noncancer controls. Among participants with chronic opioid use, they compared rates of high-dose use (average ≥90 morphine mg equivalents daily). Results were published online on Feb. 28 in the Journal of Clinical Oncology.

Overall, there were 46,789 cancer survivors, diagnosed from 2008 to 2013 at age 66 years and older, and 138,136 noncancer controls. The overall percentage of CRC survivors with chronic opioid use was low, ranging from 2.0% in the year after diagnosis to 4.3% six years after diagnosis. In the first year after the index date (survivors' diagnosis date), chronic use among CRC and lung cancer survivors exceeded that among controls (odds ratios, 1.34 [95% CI, 1.22 to 1.47] for CRC and 2.55 [95% CI, 2.34 to 2.77] for lung cancer), while breast cancer survivors were less likely than controls to have chronic opioid use. Differences between survivors and controls declined each year thereafter. CRC survivors with chronic opioid use were more likely than controls to have a high daily dose in the first three years after diagnosis. By three years, they were no more likely to be chronic opioid users than controls.

Limitations of the study include the inability to determine whether chronic opioid use in the cohorts was indicative of appropriate pain management. The authors also noted that they excluded patients enrolled in hospice but did not exclude those with progressive or recurrent disease. “These findings point to the low long-term risk of chronic opioid use in older cancer survivors,” they concluded. “Attention should focus on older survivors with chronic opioid use, who consistently receive higher doses than their noncancer counterparts.”