Photodynamic therapy of pancreatic cancer and elastic scattering spectroscopy of the duodenal mucosa for the detection of pancreaticobiliary malignancy

The diagnosis and treatment of pancreaticobiliary malignancy is of major interest to our group. Building on prior work, we undertook a phase I study of verteporfin photodynamic therapy in patients with locally advanced, unresectable, pancreatic cancer. We also initiated an optical diagnostic study using elastic scattering spectroscopy (ESS) of the normal-appearing periampullary duodenal mucosa in vivo to investigate the hypothesis of a field effect in pancreaticobiliary malignancy. In a phase I dose escalation study, patients were treated with interstitial verteporfin PDT via a single fibre, to determine its general safety profile and the optimum treatment parameters needed to achieve effective and safe necrosis of tumour, With increasing light doses, there was a linear increase in the extent of tumour necrosis around the fibre, without serious adverse events. Follow-on studies using multiple fibres are planned. In 30 patients with benign or malignant pancreaticobiliary disease undergoing clinically-indicated endoscopy, ESS spectra were collected from the normal-appearing duodenum and antrum and a diagnostic algorithm generated by principle component and linear discriminant analysis. Pooled data from duodenal sites distal to the ampulla gave a sensitivity of 86% and a specificity of 72% (82% AUC) for the detection of malignancy, whereas those from the periampullary region had a sensitivity of 77% and a specificity of 61% (72% AUC); antral measurements were not able to discriminate with such accuracy. These early results suggest that ESS of the duodenal mucosa could represent a novel minimally invasive diagnostic test for pancreaticobiliary malignancy.