Diagnosis and Radiofrequency Ablation of Early Stage Pancreatic Cancer: A Systematic Review

Purpose: The purpose of the study is to systematically review the roles of CA 19-9 combined with positron emission tomography/computed tomography (PET/CT) and radiofrequency ablation as a possible efficacious diagnostic and treatment modalities of early stage pancreatic cancer.

Materials and Methods: MEDLINE and EMBASE were systematically searched up to May 2019 for reports in the English language. We included diagnostic studies with reported accuracy data using 18-fluorodeoxyglucose (18-FDG PET/CT alone, CA 19-9 alone, and 18-FDG PET/CT in combination with CA 19-9). The second part of the study included studies with oncologic outcomes and safety data of patients treated for early stage pancreatic cancer. Case reports and experimental and animal studies were excluded. We extracted and pooled data on sensitivity and specificity for the diagnostic studies while aggregating data on morbidity, mortality, and median overall survival for the therapeutic studies. Heterogeneity analyses were performed.

Results: Eighty-one studies (with a total of 9489 patients) evaluated CA 19-9 as a diagnostic tool, showing 78.9% pooled sensitivity at standard 37 to 40 units/mL but 95.0% at proposed threshold value of 32 units/mL. Eighteen studies (with a total of 410 patients) evaluated 18-FDG PET and/or CT as diagnostic tools, showing a pooled specificity of 84.8%. No study evaluated the use of 18-FDG PET/CT in tandem with CA 19-9 in diagnosis of early stage pancreatic adenocarcinoma. Six studies (362 patients) evaluated radiofrequency ablation, showing 22-month median overall survival from diagnosis and 1.6% 30-day mortality rate. The pooled morbidity was 21% (95% confidence interval, 17%–23%). Although the morbidity data were substantially heterogeneous across studies (I2 = 91.2%), the overall survival data were relatively homogenous across studies (I2 = 20.1%).

Conclusions: Although no study evaluated the use of 18-FDG PET/CT in tandem with CA 19-9 in diagnosis of early stage pancreatic adenocarcinoma, it is proposed that early detection of pancreatic adenocarcinoma be proceeded in two-stage process in which patients with known risk factors are initially screened with sensitive CA 19-9 at 32 units/mL and, if positive, are ruled out with specific 18-FDG PET/CT. If positive for both CA 19-9 and PET/CT, endoscopic ultrasound with biopsy can be considered. After a patient has been diagnosed, radiofrequency ablation can be an efficacious adjunctive treatment modality of early stage pancreatic cancer with a pooled median overall survival time of 22 months compared with 6.8 months for a gemcitabine regimen or 11.1 months for FOLFIRINOX. A randomized clinical trial will be needed.