A combination of six serum markers to detect colorectal cancer (CRC) was found to be comparable to the performance of fecal immunochemical testing, finds a study in Clinical Cancer Research.

The early detection of CRC significantly improves the prognosis of patients and is a key factor for reducing mortality. The current practice of CRC screening is based around fecal occult blood testing (FOBT) or fecal immunochemical testing (FIT), with patients who test positive referred to a specialist for colonoscopy. But the difficulty of such approaches is that patient compliance with stool based assays tends to be low.

“Serum based minimally invasive markers would be highly attractive for CRC screening as they could easily be integrated in any health check up without the need for additional stool sampling,” write the authors, Norbert Wild and colleagues from the Department of New Technologies at Roche Diagnostics GmbH (Penzberg, Germany). But unfortunately none of the numerous biomarkers under evaluation has been considered to have sufficient sensitivity and specificity for widespread usage.

In the current study, funded by Roche Diagnostics GmbH, Wild and colleagues tested 22 biomarkers in 1,027 blood samples taken from 301 CRC patients, 143 patients with adenoma, 266 controls, 141 disease controls and 176 patients with other cancers.

The investigators  identified a combination of six markers that detect CRC in serum with high sensitivity, with the established tumour marker CEA giving the highest sensitivity ( 43.9%) followed by the novel marker seprase (42.4%), CYFRA 21-1 (35.5%), OPN(30.2%),  Ferritin (23.9%) and anti-p53 (20.0% ). While considered to be insufficient as diagnostic markers on their own, the markers showed additive value in combination, producing 69.6% sensitivity at 95% specificity and 58.7% at 98% specificity.

In an additional part of the study involving 75 samples from CRC patients and 234 controls, the sensitivity was found to be 82.4% for the six marker combination versus 81.8% for the FIT test at 95% specificity and 68.9% for the marker combination versus 72.7 % for the FIT test at 98% specificity.

“The performance of the marker combination is comparable with FIT and might improve the acceptance of CRC screening in the general population,” conclude the authors, adding that they are currently validating the algorithm in a multicentre screening study.

Reference

N Wild, H Andres, W Rollinger, et al. A combination of serum markers for early detection of colorectal cancer. Clinical Cancer Research 2010; 16: 6111-6121.