Spotlight on colorectal cancer diagnosis

New diagnoses of colorectal cancer in the U.S. dropped in March and April as physicians and patients halted appointments and screenings during the COVID-19 outbreak, Reuters reported on May 27.

Komodo Health, a San Francisco-based health data firm, analyzed 320 million health care billing records and found that new colorectal cancer diagnoses decreased by more than 32% as the number of colonoscopies and biopsies performed fell by nearly 90% from mid-March to mid-April, compared with the same period last year, the report said. Colorectal cancer surgeries were down by 53%.

As medical facilities begin to reopen and reschedule appointments, physicians may want to keep in mind that the incidence of colorectal cancer is increasing in people younger than age 50 years. A clinical practice update and expert review from the American Gastroenterological Association (AGA) focused on colorectal cancer diagnosis and management in this population. The article, which offers six pieces of best practice advice based on evidence summarized from relevant scientific publications, expert opinion statements, and current practice guidelines, was published online on June 7 by Clinical Gastroenterology and Hepatology.

The review recommended diagnostic evaluation of the colon and rectum in all patients, irrespective of age, who present with symptoms that may be consistent with colorectal cancer, such as rectal bleeding, weight loss, change in bowel habits, abdominal pain, and iron deficiency anemia. Clinicians should also discuss the role of fertility preservation prior to cancer-directed therapy, including surgery, pelvic radiation, and chemotherapy, the AGA said. The remaining four pieces of best practice advice related to genetic testing. Clinicians should:

• obtain family history of colorectal and other cancers in first- and second-degree relatives of patients with young adult-onset colorectal cancer and discuss genetic evaluation with germline genetic testing, either in targeted genes based on phenotypic presentation or in multiplex gene panels, regardless of family history;
• counsel patients on the benefit of germline genetic testing and familial cancer panel testing in the presurgical period to determine which surgical options may be available to the patient with young adult-onset colorectal cancer;
• consider utilizing germline and somatic genetic testing results to inform chemotherapeutic strategies; and
• offer hereditary colorectal cancer syndrome-specific screening for colorectal cancer and extra-colonic cancers only to young adult-onset colorectal cancer patients who have a genetically and/or clinically diagnosed hereditary colorectal cancer syndrome.

For patients with sporadic young adult-onset colorectal cancer, extra-colonic screening and colorectal cancer surveillance intervals are the same as for patients with older adult-onset colorectal cancer, the AGA said.

Next, a study looked at how stage and age at colorectal cancer diagnosis affect survival. Researchers analyzed data from 386,870 patients diagnosed from 2010 to 2014 from 19 cancer registries in seven high-income countries with similar health systems (Australia, Canada, Denmark, Ireland, New Zealand, Norway, and the United Kingdom). They estimated one- and five-year net survival from colorectal cancer by stage at diagnosis, age, and country. Results were published June 1 by Gut.

One-year and five-year net survival, respectively, varied between 77.1% and 87.5% and 59.1% and 70.9% for colon cancer and 84.8% and 90.0% and 61.6% and 70.9% for rectal cancer. For both colon and rectal cancers, the median age at diagnosis was slightly higher in New Zealand, Norway, and the U.K. when compared with Australia, Denmark, Ireland, and Canada. Stage at diagnosis also varied by country, with large proportions of localized colon and rectal cancer in Norway and Australia (as well as in the U.K. for colon cancer) and small proportions of metastatic cancer in Australia and Canada (as well as in Ireland for rectal cancer). Age-standardized five-year net survival from colon and rectal cancer tended to be higher in Australia and Canada, intermediate in Denmark and Norway, and lower in Ireland, New Zealand, and the U.K. Survival differences persisted within each stage at diagnosis and were most pronounced for older age at diagnosis and for advanced disease.

Limitations of the study include the fact that differences between countries in data handling and registration practices may have partially biased the survival comparisons, the study authors noted. “Our study suggests that both early detection and optimal treatment are important factors that may explain survival gaps between countries,” they concluded.

Finally, another study focused on patients whose colorectal cancer diagnosis presents as an emergency. Researchers conducted a historical cohort study of 1,861 individuals ages 52 to 74 years with a diagnosis of colorectal cancer from Jan. 1, 2007, to Dec. 31, 2015, who lived in Winnipeg, Manitoba, a province with universal health care and an organized colorectal cancer screening program. The primary outcomes were defined as an intestinal obstruction, perforation, or emergency hospital admission. Results were published May 26 by JAMA Network Open.

Overall, 345 individuals (18.5%) had an intestinal obstruction, perforation, or emergency hospital admission during the study period. The rate of emergency hospital admissions decreased significantly from 2007 (the start of the province-wide screening program) to 2015 (annual change, −7.1%; 95% CI, −11.3% to −2.8%; P=0.01). There were no changes in the rates of obstructions, perforations, or stage IV colorectal cancer diagnoses. Those who were up to date for colorectal cancer screening were significantly less likely to receive a diagnosis of an intestinal obstruction, perforation, or emergency hospital admission compared to those who were not (odds ratio, 0.38; 95% CI, 0.28 to 0.50; P<0.001).

Limitations of the study include its observational design and the possibility of coding errors and misclassification of patients with intestinal obstruction, perforation, or emergency hospital admission, the study authors noted, as they did not conduct a medical record review to evaluate coding accuracy.