Neoadjuvant therapy in patients with pancreatic cancer: a disappointing therapeutic approach?

Evaluation of response using FDG-PET/CT and diffusion weighted MRI after radiochemotherapy of pancreatic cancer: a non-randomized, monocentric phase II clinical trial-PaCa-DD-041 (Eudra-CT 2009-011968-11)

Background

Pancreatic cancer is a devastating disease with a 5-year survival rate of 20–25%. As approximately only 20% of patients diagnosed with pancreatic cancer are initially staged as resectable, it is necessary to evaluate new therapeutic approaches. Hence, neoadjuvant (radio)chemotherapy is a promising therapeutic option, especially in patients with a borderline resectable tumor. The aim of this non-randomized, monocentric, prospective, phase II clinical study was to assess the prognostic value of functional imaging techniques, i.e., [¹⁸F]2-fluoro-2-deoxy-d-glucose positron emission tomography/computed tomography (FDG-PET/CT) and diffusion weighted magnetic resonance imaging (DW-MRI), prior to and during neoadjuvant radiochemotherapy.

Methods

Patients with histologically proven resectable, borderline resectable or unresectable non-metastatic pancreatic adenocarcinoma received induction chemotherapy followed by neoadjuvant radiochemotherapy. Patients underwent FDG-PET/CT and DW-MRI including T1- and T2-weighted sequences prior to and after neoadjuvant chemotherapy as well as following induction radiochemotherapy. The primary endpoint was the evaluation of the response as quantified by the standardized uptake value (SUV) measured with FDG-PET. Response to treatment was evaluated by FDG-PET and DW-MRI during and after the neoadjuvant course. Morphologic staging was performed using contrast-enhanced CT and contrast-enhanced MRI to decide inclusion of patients and resectability after neoadjuvant therapy. In those patients undergoing subsequent surgery, imaging findings were correlated with those of the pathologic resection specimen.

Results

A total of 25 patients were enrolled in the study. The response rate measured by FDG-PET was 85% with a statistically significant decrease of the maximal SUV (SUV_max) during therapy (p < 0.001). Using the mean apparent diffusion coefficient (ADC), response was not detectable with DW-MRI. After neoadjuvant treatment 16 patients underwent surgery. In 12 (48%) patients tumor resection could be performed. The median overall survival of all patients was 25 months (range: 7–38 months).

Conclusion

Based on these limited patient numbers, it was possible to show that this trial design is feasible and that the neoadjuvant therapy regime was well tolerated. FDG-PET/CT may be a reliable method to evaluate response to the combined therapy. In contrast, when evaluating the response using mean ADC, DW-MRI did not show conclusive results.

Electronic supplementary material

The online version of this article (10.1007/s00066-020-01654-4) contains supplementary material, which is available to authorized users.

Neoadjuvant therapy prior to surgical resection for previously explored pancreatic cancer patients is associated with improved survival

BACKGROUND

Patients with pancreatic ductal adenocarcinoma (PDAC) are frequently referred to tertiary centers after unsuccessful attempted resections at other institutions. The outcome of these patients who are ultimately resected is not well understood.

METHODS

We performed a retrospective review of patients with PDAC who underwent re-exploration between 1995 and 2013 at a single high volume tertiary care institution. We aimed to evaluate the association of neoadjuvant therapy prior to re-exploration on pathologic findings and clinical outcome in previously explored patients with PDAC.

RESULTS

Between 1995 and 2013, 50 of the 2,062 patients who were surgically explored underwent pancreatic resection following a previous exploration where they were deemed unresectable. The most common reason for unresectability at initial operation was vascular invasion (80%) and a presumed R2 resection. Thirty-seven (74%) patients received neoadjuvant therapy. Neoadjuvant therapy was associated with improved TNM stage (P=0.002), fewer positive lymph nodes (0 vs. 2, P=0.025), and improved median survival (24 vs. 13 months, P=0.044). Compared to R2 resected patients with PDAC who had not previously been explored, re-explored patients had significantly lower pathologic T and N stages (P<0.001) and a longer median survival (19 vs. 10 months, P<0.001).

CONCLUSIONS

Patients with PDAC deemed unresectable may warrant re-exploration. Treatment with neoadjuvant therapy between operations is associated with improved pathological stage and survival. In this highly selected group of patients, successful resection is associated with improved survival compared to R2 resections.