Clinical Implications of FDG-PET in Pancreatic Ductal Adenocarcinoma Patients Treated with Neoadjuvant Therapy

A striking elevation of CA19-9 after preoperative therapy negates prognostic benefit from radical surgery in resectable and borderline resectable pancreatic cancer

BACKGROUND

Identifying patients who can be spared nonbeneficial surgery is crucial, as pancreatic cancer surgery is highly invasive, with substantial negative effects on quality of life. The study objective was to investigate a useful indicator of patients who do not gain prognostic benefit from radical surgery after neoadjuvant therapy for resectable and borderline resectable pancreatic cancer.

METHOD

We compared factors among 609 patients with resectable or borderline resectable pancreatic cancer receiving neoadjuvant therapy during 2005-2019. Patients were divided into a poor-prognosis group (no surgery or postresection recurrence within a year) and a good-prognosis group (no recurrence or recurrence >1 year after resection).

RESULTS

Patients who experience a recurrence within a year of resection (poor-prognosis group) did no better than patients who received neoadjuvant therapy and progressed but never made it to surgery. The value of carbohydrate antigen 19-9 after neoadjuvant therapy was the most significant indicator to predict the poor prognosis group and the elevation of carbohydrate antigen 19-9 (>200 U/mL) identified only poor prognosis group with high specificity of 96.6%. The overall survival of patients with more than 200 of carbohydrate antigen 19-9 after neoadjuvant therapy was significantly very poor and their 2-year survival rate was only 41.4%.

CONCLUSION

A striking elevation of carbohydrate antigen 19-9 after neoadjuvant therapy for resectable or borderline resectable pancreatic cancer is a good indicator of poor prognosis. Patients with carbohydrate antigen 19-9 >200 U/mL after neoadjuvant therapy should not undergo radical surgery.

Metabolic tumor burden as a prognostic indicator after neoadjuvant chemotherapy in pancreatic cancer

BACKGROUND

There is no standardized assessment for evaluating response although neoadjuvant chemotherapy (NAT) is widely accepted for borderline resectable or locally advanced pancreatic cancer (BRPC or LAPC). This study was aimed to evaluate NAT response using positron emission tomography (PET) with 2-deoxy-2-[fluorine-18]fluoro-D-glucose ( 18 F-FDG-PET/CT) parameters alongside carbohydrate antigen (CA) 19-9 levels.

METHODS

Patients who underwent surgery after NAT for BRPC and LAPC between 2017 and 2021 were identified. The study assessed the prognostic value of PET-derived parameters after NAT, determining cutoff values using the K-adaptive partitioning method. It created four groups based on the elevation or normalization of PET parameters and CA19-9 levels, comparing survival between these groups.

RESULTS

Of 200 eligible patients, FOLFIRINOX and gemcitabine-based NAT was administered in 166 and 34 patients, respectively (mean NAT cycles, 8.3). In a multivariate analysis, metabolic tumor volume (MTV) demonstrated the most robust performance in assessing response [hazard ratio (HR) 3.11, 95% confidence interval (CI) 1.73-5.58, P <0.001] based on cutoff value of 2.4. Patients with decreased MTV had significantly better survival than those with elevated MTV among individuals with CA19-9 levels less than 37 IU/l (median survival; 35.5 vs. 20.9 months, P <0.001) and CA19-9 levels at least 37 IU/l (median survival; 34.3 vs. 17.8 months, P =0.03). In patients suspected to be Lewis antigen negative, the predictive performance of MTV was found to be limited ( P =0.84).

CONCLUSION

Elevated MTV is an influential prognostic factor for worse survival, regardless of post-NAT CA19-9 levels. These results could be helpful in identifying patients with a poor prognosis despite normalization of CA19-9 levels after NAT.

Quarter-Century PET/Computed Tomography Transformation of Oncology: Hepatobiliary and Pancreatic Cancer

[18F] Fluorodeoxyglucose (18F-FDG) PET/CT can improve the staging accuracy and clinical management of patients with hepatobiliary and pancreatic cancers, by detection of unsuspected metastases. 18F-FDG PET/CT metabolic parameters are valuable in predicting treatment response and survival. Metabolic response on 18F-FDG PET/CT can predict preoperative pathologic response to neoadjuvant therapy in patients with pancreatic cancer and determine prognosis. Several novel non-FDG tracers, such as 68Ga prostate-specific membrane antigen (PSMA) and 68Ga-fibroblast activation protein inhibitor (FAPI) PET/CT, show promise for imaging hepatobiliary and pancreatic cancers with potential for radioligand therapy.

Currently Debated Topics on Surgical Treatment of Pancreatic Ductal Adenocarcinoma: A Narrative Review on Surgical Treatment of Borderline Resectable, Locally Advanced, and Synchronous or Metachronous Oligometastatic Tumor

BACKGROUND

Previously considered inoperable patients (borderline resectable, locally advanced, synchronous oligometastatic or metachronous pancreatic adenocarcinoma (PDAC)) are starting to become resectable thanks to advances in chemo/radiotherapy and the reduction in operative mortality.

METHODS

This narrative review presents a chosen literature selection, giving a picture of the current state of treatment of these patients.

RESULTS

Neoadjuvant therapy (NAT) is generally recognized as the treatment of choice before surgery. However, despite the increased efficacy, the best pathological response is still limited to 10.9-27.9% of patients. There are still limited data on the selection of possible NAT responders and how to diagnose non-responders early. Multidetector computed tomography has high sensitivity and low specificity in evaluating resectability after NAT, limiting the resection rate of resectable patients. Ca 19-9 and Positron emission tomography are giving promising results. The prediction of early recurrence after a radical resection of synchronous or metachronous metastatic PDAC, thus identifying patients with poor prognosis and saving them from a resection of little benefit, is still ongoing, although some promising data are available.

CONCLUSION

In conclusion, high-level evidence demonstrating the benefit of the surgical treatment of such patients is still lacking and should not be performed outside of high-volume centers with interdisciplinary teams of surgeons and oncologists.