Diagnostic Performance of a Tumor Marker Gene Test to Personalize Serum CA19-9 Reference Ranges

Aspects and outcomes of surveillance for individuals at high-risk of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer-related deaths and is associated with a poor prognosis. The majority of these cancers are detected at a late stage, contributing to the bad prognosis. This underscores the need for novel, enhanced early detection strategies to improve the outcomes. While population-based screening is not recommended due to the relatively low incidence of PDAC, surveillance is recommended for individuals at high risk for PDAC due to their increased incidence of the disease. However, the outcomes of pancreatic cancer surveillance in high-risk individuals are not sorted out yet. In this review, we will address the identification of individuals at high risk for PDAC, discuss the objectives and targets of surveillance, outline how surveillance programs are organized, summarize the outcomes of high-risk individuals undergoing pancreatic cancer surveillance, and conclude with a future perspective on pancreatic cancer surveillance and novel developments.

Using Tumor Marker Gene Variants to Improve the Diagnostic Accuracy of DUPAN-2 and Carbohydrate Antigen 19-9 for Pancreatic Cancer

PURPOSE

Circulating carbohydrate antigen 19-9 (CA19-9) levels reflect FUT3 and FUT2 fucosyltransferase activity. Measuring the related glycan, DUPAN-2, can be useful in individuals unable to synthesize CA19-9. We hypothesized that similar to CA19-9, FUT functional groups determined by variants in FUT3 and FUT2 influence DUPAN-2 levels, and having tumor marker reference ranges for each functional group would improve diagnostic performance.

MATERIALS AND METHODS

Using a training/validation study design, FUT2/FUT3 genotypes were determined in 938 individuals from Johns Hopkins Hospital: 607 Cancer of the Pancreas Screening (CAPS) study subjects with unremarkable pancreata and 331 with pancreatic ductal adenocarcinoma (PDAC). Serum DUPAN-2 and CA19-9 levels were measured by immunoassay.

RESULTS

In controls, three functional FUT groups were identified with significant differences in DUPAN-2 levels: FUT3-intact, FUT3-null/FUT2-intact, and FUT3-null/FUT2-null. DUPAN-2 training set diagnostic cutoffs for each FUT group yielded higher diagnostic sensitivity in the validation set for patients with stage I/II PDAC than uniform cutoffs (60.4% [95% CI, 50.2 to 70.0] v 39.8% [30.0 to 49.8]), at approximately 99% (96.7 to 99.6) specificity. Combining FUT/CA19-9 and FUT/DUPAN-2 tests yielded 78.4% (72.3 to 83.7) sensitivity for stage I/II PDAC, at 97.7% (95.3 to 99.1) specificity in the combined sets, with higher AUC (stage I/II: 0.960 v 0.935 for CA19-9 + DUPAN-2 without the FUT test; P < .001); for stage I PDAC, sensitivity was 62.0% (49.1 to 73.2; AUC, 0.919 v 0.883; P = .03). CA19-9 levels in FUT3-null/FUT2-null PDAC subjects were higher than in FUT3-null/FUT2-intact subjects (median/IQR; 24.9/57.4 v <1/2.3 U/mL; P = .0044). In a simulated CAPS cohort, AUC precision recall (AUCPR) scores were 0.51 for CA19-9 alone, 0.64 for FUT/CA19-9, 0.73 for CA19-9/DUPAN-2, and 0.84 for FUT/CA19-9/DUPAN-2.

CONCLUSION

Using a tumor marker gene test to individualize CA19-9 and DUPAN-2 reference ranges achieves high diagnostic performance for stage I/II pancreatic cancer.

Using a CA19-9 Tumor Marker Gene Test to Assess Outcome After Pancreatic Cancer Surgery

BACKGROUND

Cancer antigen 19-9 (CA19-9) is widely used as a marker of pancreatic cancer tumor burden and response to therapy. Synthesis of CA19-9 and its circulating levels are determined by variants encoding the fucosyltransferases, FUT2 and FUT3. Individuals can be grouped into one of four functional FUT groups (FUT3-null, FUT-low, FUT-intermediate, FUT-high), each with its own CA19-9 reference range based on its predicted capacity to produce CA19-9. The authors hypothesized that a FUT variant-based CA19-9 tumor marker gene test could improve the prognostic performance of CA19-9.

METHODS

Preoperative and pre-treatment CA19-9 levels were measured, and FUT variants were determined in 449 patients who underwent surgery for pancreatic ductal adenocarcinoma (PDAC) at Johns Hopkins Hospital between 2010 and 2020, including 270 patients who underwent neoadjuvant therapy. Factors associated with recurrence-free and overall survival were determined in Cox proportional hazards models.

RESULTS

Higher preoperative CA19-9 levels were associated with recurrence and mortality for patients in the higher-FUT groups (FUT-intermediate, FUT-high for mortality, with adjustment for other prognostic factors; hazard ratio [HR], 1.34 and 1.58, respectively; P < 0.001), but not for those in the lower-FUT groups (FUT3-null, FUT-low). As a tumor marker, CA19-9 levels of 100 U/ml or lower after neoadjuvant therapy and normalization of CA19-9 based on FUT group were more sensitive but less specific predictors of evidence for a major pathologic response to therapy (little/no residual tumor) and of early recurrence (within 6 months).

CONCLUSION

Among patients undergoing pancreatic cancer resection, a CA19-9 tumor marker gene test modestly improved the prognostic performance of CA19-9.