Although pancreatic cystic lesions (PCLs) are frequently and incidentally detected, it is a challenge to determine their risk of malignancy.¹
Using an ELISA model, researchers have confirmed the high sensitivity and specificity of the monoclonal antibody Das-1 in detecting pancreatic cystic lesions (PCLs) with a risk for malignancy, according to research published in Gastroenterology.
The investigators sought to validate the sensitivity and specificity of the novel monoclonal antibody Das-1 to identify potential high-risk PCLs, as well as to evaluate the performance of Das-1 compared with the currently available clinical guidelines and clinical features.
Cyst fluid samples were collected from a large, multicenter cohort of patients (n=181) who underwent surgical resection for PCLs between January 2010 and June 2017 at 4 tertiary referral centers. Of this group, 169 patients had sufficient fluid for analysis.
Among the PCLs, 36 were nonmucinous and 133 were mucinous, with 43 mucinous cystic neoplasms (MCNs) and 90 intraductal papillary mucinous neoplasms (IPMNs). Patients with MCNs were younger and more likely to be women.
Forty-nine patients had available preoperative cyst fluid carcinoembryonic antigen. A previously established threshold of 192 ng/mL was used to discriminate potentially mucinous PCLs, with a 50% sensitivity and a 92.3% specificity (95% CI, 0.329-0.671 and 95% CI, 0.640-0.998, respectively).
Cyst fluids from nonmucinous PCLs had “very little reactivity” with Das-1 by sandwich ELISA assay; low-risk IPMN and MCNs also had minimal reactivity (optical density [OD] 0.019±0.032 and 0.019±0.034, respectively). Conversely, both high-risk IPMN and MCN lesions expressed a “significantly higher” amount of reactivity, compared with low-risk neoplasms and nonmucinous PCLs (OD 0.670±0.555). Increasing ODs in low-risk IPMNs, noninvasive high-risk IPMNs, and IPMNs with an invasive component demonstrated a progressive increase in reactivity to Das-1.
Using Youden’s index (≥0.104), the investigators were able to calculate a statistically valid, optimal cutoff. This cutoff was then used to determine sensitivity and specificity for the segregation of high- and low-risk PCLs (88.2% sensitivity and 99% specificity). Only 1 patient in the cohort with a high-risk MCN had an OD value between the 0.120 and 0.104 cutoffs. Only 1 patient with positive Das-1 ELISA had a low-risk lesion, whereas 8 high-risk patients were nonreactive to Das-1.
Das-1 performance was compared with currently available clinical guidelines. Sendai guidelines had an overall sensitivity, specificity, and accuracy of 94.1%, 13.9%, and 46.2% for identification of high-risk lesions. Comparatively, Fukuoka guidelines were significantly more accurate, with sensitivity, specificity, and accuracy of 97.1%, 20.8%, and 51.5%, respectively. American Gastroenterological Association guidelines were significantly more accurate than both the Sendai and Fukuoka guidelines, with a sensitivity, specificity, and accuracy of 50%, 89.1%, and 73.7%. Overall, the performance of Das-1 was significantly more accurate than the Sendai, Fukuoka, or American Gastroenterological Association guidelines (88.2%, 99%, and 94.7%, respectively).
Limitations to the study include the retrospective, prospective nature of the study, as well as the use of surgical specimens from large tertiary care centers, which introduces surgical selection, referral, and treatment access biases.
The investigators concluded, “The inclusion of the Das-1 marker into the analysis of cyst fluid may aid in the preoperative diagnosis and risk stratification of patients with PCLs.”
Das KK, Geng X, Brown JW, et al. Cross validation of the monoclonal antibody Das-1 in identification of high-risk mucinous pancreatic cystic lesions [published online June 5, 2019]. Gastroenterology. doi: 10.1053/j.gastro.2019.05.014