Downstaging of Pancreatic Adenocarcinoma With Either Neoadjuvant Chemotherapy or Chemoradiotherapy Improves Survival

The benefit of adjuvant chemotherapy following pancreaticoduodenectomy for pancreatic adenocarcinoma depends on response to neoadjuvant therapy

BACKGROUND

The benefit of adjuvant therapy (AT) remains unclear in pancreatic ductal adenocarcinoma (PDAC) after neoadjuvant therapy (NAT) and surgical resection.

METHODS

The 2019 National Cancer Database was queried for patients with non-metastatic PDAC who received NAT followed by pancreaticoduodenectomy. Only patients with data regarding receipt of AT were included. Patients were classified if they had nodal down-staging specifically, or any downstaging (Tumor, Nodal, or overall). Propensity score matching (PSM) adjusted for pretreatment covariate imbalance between groups. The weighted Kaplan-Meier method and log-rank test were used to estimate the cumulative survival.

RESULTS

After exclusion criteria and PSM, a total of 2784 patients remained; 1689 (60.7%) received AT and 1095 (39.3%) did not receive AT. Among all, those with additional AT had a significantly improved overall survival (OS) (p < 0.001). Upon evaluation of patients without downstaging after NAT, those who received AT had improved OS (no nodal downstaging or any downstaging; p = 0.002; p = 0.001). When evaluating patients with downstaging after NAT, those receiving AT did not have improved OS (nodal downstaging or any downstaging: p = 0.352; p = 0.99).

CONCLUSION

Response to NAT appears to correlate with the benefit of AT following pancreaticoduodenectomy; patients who have a favorable response to NAT may not benefit from AT.

Pathologic Tumor Regression is Associated With Improved Survival in Pancreatic Cancer

OBJECTIVES

The advent of effective chemotherapy regimens has increased the use of neoadjuvant multiagent chemotherapy in pancreatic cancer. However, the effect of tumor downstaging with neoadjuvant treatment on survival is unclear.

METHODS

Retrospective study included all resected patients with pancreatic adenocarcinoma who underwent neoadjuvant chemotherapy with FOLFIRINOX or gemcitabine/Abraxane. Downstaging was quantified using (1) difference between presenting AJCC clinical and final pathologic stage and (2) College of American Pathologists (CAP) Tumor Regression Grading Schema.

RESULTS

Eighty-seven patients met inclusion criteria. FOLFIRINOX was the most common regimen, 63.2% vs 21.8%. Change in regimen occurred in 15% of patients. Downstaging based on a difference in AJCC stage group occurred in only 4.6%. In contrast, 45.2% were classified as downstaged by the CAP Tumor Regression of 0-2. Downstaging was similar for FOLFIRINOX gemcitabine/Abraxane (64.7 vs 53.6, P = .12) using the CAP criteria. On univariate analysis, treatment regimen (gemcitabine/Abraxane vs FOLFIRINOX, median survival 27 vs 29 mo; HR 1.57, P = .2) had similar survival. Downstaging by the AJCC stage was not associated with improved survival (HR 1.51, P = .4). However, there was a survival benefit for those downstaged by the CAP Tumor Regression Grading Schema, the median survival of 41 mo vs 25 mo; HR 3.05, P = .009. Improved survival 3.32 (1.35-8.16), P = .009) was maintained on multivariate analysis.

CONCLUSION

Survival is significantly improved in those downstaged, as assessed by the CAP Tumor Regression Schema. Downstaging is an important prognostic variable that can help with joint decision making for clinicians and patients.

Innovative Imaging Techniques Used to Evaluate Borderline-Resectable Pancreatic Adenocarcinoma

A diagnosis of pancreatic cancer carries a 5-y survival rate of less than 10%. Furthermore, the detection of pancreatic cancer occurs most often in later stages of the disease due to its location in the retroperitoneum and lack of symptoms (in most cases) until tumors become more advanced. Once diagnosed, cross-sectional imaging techniques are heavily utilized to determine the tumor stage and the potential for surgical resection. However, a major determinant of resectability is the extent of local vascular involvement of the mesenteric vessels and critical tributaries; current imaging techniques have limited capacity to accurately determine vascular involvement. Surrounding inflammation and fibrosis can be difficult to discriminate from viable tumor, making determination of the degree of vascular involvement unreliable. New innovations in fluorescence and optoacoustic imaging techniques may overcome these limitations and make determination of resectability more accurate. These imaging modalities are able to more clearly discern between viable tumor tissue and non-neoplastic inflammation or desmoplasia, allowing clinicians to more reliably characterize vascular involvement and develop individualized treatment plans for patients. This review will discuss the current imaging techniques used to diagnose pancreatic cancer, the barriers that current techniques raise to accurate staging, and novel fluorescence and optoacoustic imaging techniques that may provide more accurate clinical staging of pancreatic cancer.