Which patients with locally advanced pancreatic cancer should we be selecting for chemoradiotherapy?


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Sophie Otter1,Ria Kalaitzaki2,Irene Chong2,Diana Tait2
1Royal Surrey County Hospital,2Royal Marsden Hospital

Abstract

Background

Pancreatic cancer is often diagnosed late with locally advanced or metastatic disease. Patients with locally advanced pancreatic cancer (LAPC) have a median survival of 6-11 months. There is some controversy over the role of chemoradiotherapy versus chemotherapy alone in the management of these patients. The aim of this study was to identify patients who derive the most benefit from chemoradiotherapy and therefore develop selection criteria.

Method

Patients with LAPC who were treated with radiotherapy at a dose of 45Gy or greater at the Royal Marsden Hospital between January 2004 – October 2014 were identified. Their Electronic Patient Record was reviewed to collect data regarding demographics, staging investigations, radiotherapy and chemotherapy details, response to treatment (on imaging and by serum CA19-9 levels) and outcome. Survival outcomes were analysed by Kaplan-Meier plots.

Results

138 patients were identified. 97% received chemotherapy prior to radiotherapy and 85% received concurrent chemoradiotherapy. Patients who had a response on imaging (PET-CT or CT) after chemotherapy (before starting radiotherapy) had a median OS of 17.4 months compared to 10.3 months in non-responders (HR 0.55, 95% CI 0.35-0.87, p=0.01). At 3 months post-radiotherapy, responders on CT had a median OS of 56 months compared to 10.7 months (HR 0.28, p=0.003). Decrease in CA19-9 prior to radiotherapy was not significantly correlated with PFS or OS. At 3 months post-radiotherapy, OS was 19.1 months in CA19-9 responders compared to 10.5 months in non-responders (p<0.001).

 

Conclusion

Patients who responded to chemotherapy on imaging prior to radiotherapy had a significantly better PFS and OS than non-responders and therefore appeared to derive the greatest benefit from chemoradiotherapy. This could therefore be used in the selection of patients for chemoradiotherapy. A decrease in CA19-9 levels prior to radiotherapy did not correlate with improved survival and therefore is less useful for patient selection for chemoradiotherapy.