A test that identifies circulating tumor cells present in the bloodstream accurately detected early-stage colorectal cancer, according to results of a study scheduled for presentation at the Gastrointestinal Cancers Symposium.
“Our study is important because there is still some reticence among patients to use stool-based tests or have an invasive exam like colonoscopy to detect colorectal cancer,” Wen-Sy Tsai, MD, assistant professor at Linkou Chang Gung Memorial Hospital in Taipei, Taiwan, said in a press release. “Our results may point to a solution for people who are reluctant to get an initial screening colonoscopy or are not compliant in returning stool-based test kits that they get from their doctors.”
Tsai and colleagues enrolled 620 people aged 20 years or older who were scheduled for routine colonoscopies or had colorectal cancer; 438 participants had either adenomatous polyps or early- to late-stage colorectal cancers. All participants had their blood tested for circulating tumor cells using the CellMax biomimetic platform (CMx, CellMax Life).
Results showed a specificity value of 97.3% (95% CI, 93.7-98.8).
“We believe our high specificity results are important because a high number of false-positive results would discourage many people who are considering getting screened for colorectal cancer from doing so,” Tsai said in the release.
Sensitivity was 76.6% (95% CI, 67.9-83.5) for detection of circulating tumor cells in precancerous lesions and 86.9% (95% CI, 82.8-90.1) for stage I to stage IV cancers.
The test showed high accuracy — 84% for precancerous samples and 88% for cancerous samples — with rates that appeared superior to those of fecal occult blood testing.
The test could potentially cost less than $100, making it an affordable option, according to the release.
Colonoscopy should still be the “gold-standard” diagnostic test and is needed for tumor or polyp sample removal if a circulating tumor test is positive, according to study author Ashish Nimgaonkar, MD, assistant professor of medicine at Johns Hopkins University.
“Screening for colorectal cancer can be life-saving, but Americans still lag behind federal government screening goals because current screening options can be inconvenient and uncomfortable for patients,” Nancy Baxter, MD, FRCSC, FACS, PhD, chief of the general surgery department at St. Michael’s Hospital in Toronto, professor of surgery at University of Toronto, and an ASCO expert who was not involved in the study, said in the release. “Though this research needs more investigation, a simple, accurate blood test could help increase screening rates, which could ultimately improve detection of colorectal cancers at earlier stages when treatment is most likely to be curative.” – by Cassie Homer
Tsai, et al. Abstract 556. Presented at: Gastrointestinal Cancers Symposium; Jan. 18-20, 2018; San Francisco.
Disclosures: Tsai reports no relevant financial disclosures. Nimgaonkar reports a consultant/advisory role with CellMax Life. Please see the full study for all other authors’ relevant financial disclosures.