Clinical Topics & News
Colorectal Carcinoma and Emerging Targeted Therapies
Targeted therapies for specific mutations in colorectal cancer have led to an increase in patient overall survival.
Carcinoembryonic antigen (CEA) is often used as a marker for relapse in colorectal cancer. But in as many as 40% of recurrences, the serum CEA shows unmeasurable elevations. And some patients with resected colorectal cancer (CRC) have transient elevations of CEA levels; the false-positive rate during follow-up has been as high as 16%, say researchers from Kaohsiung Medical University, Taiwan. They propose “a more powerful tool”: a membrane array-based multigene biomarker assay, or biomarker chip, which detects circulating tumor cells in the peripheral blood.
Related: Colorectal Carcinoma and Emerging Targeted Therapies
The researchers conducted a study in 298 patients with CRC to test that alternative. The patients were enrolled after radical curative resection for primary CRC tumor; 82 were stage I, 102 were stage II, and 114 were stage III. Patients were followed for a median of 28.4 months, every 3 months for 3 years, then every 6 months. At each follow-up visit, laboratory studies included serum CEA levels. Elevated CEA levels were defined as 2 consecutive measurements of >5 ng/mL at a 3-month interval.
During the study period, 48 patients (16.1%) had postoperative relapse, and 26 (8.7%) died. Of all 298 patients, 62 (20.8%) had a total biomarker chip score higher than the cutoff value. Of the 48 who relapsed, 42 (87.5%) showed positive biochip results prior to relapse.
The positive biochip results were significantly associated with postoperative relapse. In fact, the biomarker chip was better for predicting relapse than were the postoperative serum CEA levels with higher sensitivity (87.5% vs 60.4%), specificity (92.0% vs 83.2%), positive predictive value (67.7% vs 40.8%), negative predictive value (97.5% vs 91.6%), and accuracy (91.3% vs 79.5%).
Moreover, the biochip predicted relapse “considerably earlier” than did CEA levels (10.7 vs 2.8 months). The researchers note that CRC-related deaths are largely attributable to clinical relapse. The sooner a relapse is diagnosed, the more amenable the tumor may be to resection, increasing the likelihood of long-term survival.
In sum, the biomarker chip would be a more accurate tool for predicting relapse, the researchers say. They also suggest that, in clinical practice, combining the 2 tests could enhance confidence in the diagnosis.
Source:
Chang YT, Huang MY, Huang CW, et al. PLoS One . 2016;11(10):e0163264.
doi: 10.1371/journal.pone.0163264.
