Changing paradigm in pancreatic cancer: from adjuvant to neoadjuvant chemoradiation

First report on the feasibility of a permanently implantable uni-directional planar low dose rate brachytherapy sheet for patients with resectable or borderline resectable pancreatic cancer

BACKGROUND

Margin negative resection in pancreatic cancer remains the only curative option but is challenging, especially with the retroperitoneal margin. Intraoperative radiation therapy (IORT) can improve rates of local control but requires specially designed facilities and equipment. This retrospective review describes initial results of a novel implantable mesh of uni-directional low dose rate (LDR) Pd-103 sources (sheet) used to deliver a focal margin-directed high-dose boost in patients with concern for close or positive margins.

METHODS

Eleven consecutive patients from a single institution with resectable or borderline resectable pancreatic cancer with concern for positive margins were selected for sheet placement and retrospectively reviewed. Procedural outcomes, including the time to implant the device and complications, and clinical outcomes, including survival and patterns of failure, are reported. A dosimetric comparison of the LDR sheet with hypothetical stereotactic body radiotherapy (SBRT) boost is reported.

RESULTS

One patient had a resectable disease, and 10 patients had a borderline resectable disease and underwent neoadjuvant treatment. Sheet placement added 15 min to procedural time with no procedural or sheet-related complications. At a median follow up of 13 months, 64% (n = 7) of patients are alive and 55% (n = 6) are disease-free. Compared to a hypothetical SBRT boost, the LDR sheet delivered a negligible dose to kidneys, liver, and spinal cord with a 50% reduction in max dose to the small bowel.

CONCLUSION

This is the first report of the use of an implantable uni-directional LDR brachytherapy sheet in patients with resected pancreatic cancer with concern for margin clearance, with no associated toxicity and favorable clinical outcomes.

Preoperative CT in patients with surgically resectable pancreatic adenocarcinoma: does the time interval between CT and surgery affect survival?

PURPOSE

The preoperative imaging-to-surgery time interval (ISI) influences the risk of unexpected progression (UP) found at surgery for pancreatic adenocarcinoma. We aimed to assess whether ISI influences disease recurrence and/or survival.

METHODS AND MATERIALS

A single-institution, ethics board-approved retrospective analysis of all patients who underwent attempted resection of pancreatic (PDAC) or periampullary adenocarcinoma (AmpAC) between 1st January 2010 and 31st December 2015 was performed. All patients underwent preoperative abdominal computed tomography (CT). Exclusion criteria were borderline resectable disease and neoadjuvant chemo/radiotherapy. Patients were followed up until 30th June 2016. The population was divided into ISI ≥/<25 days. Kaplan-Meier and Cox regression survival analyses were performed.

RESULTS

239 patients underwent surgical exploration. UP was found in 29 (12.1%) and these patients had longer ISI (median 46 vs. 29 days, p < 0.05). When intention-to-treat analysis was performed, there was no difference in overall survival (OS) between patients with ISI ≥/<25. In those who underwent resection, ISI did not influence disease-free survival (DFS) or OS for PDAC (n = 174). For AmpAC (n = 36), ISI ≥ 25 days was associated with longer OS (p < 0.05) but did not influence DFS. Longer ISI was independently associated with improved OS on regression analysis for AmpAC.

CONCLUSION

Performing surgery for resectable pancreatic adenocarcinoma within 25 days of abdominal CT reduces the chance of UP but does not confer a survival benefit. For those who undergo resection of AmpAC, a longer ISI was associated with longer OS. This probably represents a more biologically indolent disease in this cohort.