Pain and pain generation in pancreatic diseases

Neurotransmitter substance P mediates pancreatic cancer perineural invasion via NK-1R in cancer cells

Pancreatic cancer significantly affects the quality of life due to the severe abdominal pain. However, the underlying mechanism is not clear. This study aimed to determine the relationship between Substance P (SP) and pancreatic cancer perineural invasion (PNI) as well as the mechanism of SP mediating pancreatic cancer PNI, which causes pain in patients with pancreatic cancer. Human pancreatic cancer cells and newborn dorsal root ganglions (DRG) were used to determine the expression of SP or NK-1R in pancreatic cancer cells and DRGs cells by QT-PCR and Western blotting. The effects of SP on pancreatic cancer cell proliferation and invasion were analyzed using MTT assay and Transwell Matrigel invasion assay, respectively. Alterations in the neurotropism of pancreatic cancer cells were assessed by coculture system, which mimics the interaction of tumor/neuron in vivo. SP is not only widely distributed in the neurite outgrowth from newborn DRGs but also expressed in MIA PaCa-2 and BxPC-3 cells. NK-1R is found to be overexpressed in the pancreatic cancer cell lines examined. SP induces cancer cell proliferation and invasion as well as the expression of matrix metalloproteinase (MMP)-2 in pancreatic cancer cells, and NK-1R antagonists inhibit these effects. Furthermore, SP promotes neurite outgrowth and the migration of pancreatic cancer cell cluster to the DRGs, which is blocked by NK-1R antagonists in the coculture model. Our results suggest that SP plays an important role in the development of pancreatic cancer metastasis and PNI, and blocking the SP/NK-1R signaling system is a novel strategy for the treatment of pancreatic cancer.

Efficacy of endoscopic ultrasound-guided celiac plexus block and celiac plexus neurolysis for managing abdominal pain associated with chronic pancreatitis and pancreatic cancer

BACKGROUND/GOALS

Endoscopic ultrasound (EUS)-guided celiac plexus block (CPB) and celiac plexus neurolysis (CPN) have become important interventions in the management of pain due to chronic pancreatitis and pancreatic cancer. However, only a few well-structured studies have been performed to evaluate their efficacy. Given limited data, their use remains controversial. Herein, we evaluate the efficacy of EUS-guided CPB and CPN in alleviating chronic abdominal pain due to chronic pancreatitis and pancreatic cancer respectively.

STUDY METHODS

Using Medline, Pubmed, and Embase databases from January 1966 through December 2007, a thorough search of the English literature for studies evaluating the efficacy of EUS-guided CPB and CPN for the management of chronic abdominal pain due to chronic pancreatitis and pancreatic cancer was conducted, along with a hand search of reference lists. Studies that involved less than 10 patients were excluded. Data on pain relief was extracted, pooled, and analyzed.

RESULTS

A total of 9 studies were included in the final analysis. For chronic pancreatitis, 6 relevant studies were identified, comprising a total of 221 patients. EUS-guided CPB was effective in alleviating abdominal pain in 51.46% of patients. For pancreatic cancer, 5 relevant studies were identified with a total of 119 patients. EUS-guided CPN was effective in alleviating abdominal pain in 72.54% of patients.

CONCLUSIONS

EUS-guided CPB was 51.46% effective in managing chronic abdominal pain in patients with chronic pancreatitis, but warrants improvement in patient selection and refinement of technique, whereas EUS-guided CPN was 72.54% effective in managing pain due to pancreatic cancer and is a reasonable option for patients with tolerance to narcotic analgesics.

Factors affecting outcome after Frey procedure for chronic pancreatitis

BACKGROUND

Debilitating abdominal pain remains the most common presentation of chronic pancreatitis and the treatment remains challenging.

OBJECTIVE

This prospective study analyzed the outcome of Frey's procedure in patients with inflammatory head mass.

METHODS

For the period between 2002 and 2007, 77 patients with chronic pancreatitis underwent Frey procedure for intractable abdominal pain. The mean follow-up was 14 months. For the purpose of analysis of the outcome, patients were grouped as poor pain control (19%) and good pain control groups (81%) based on the pain scores during follow-up.

RESULTS

There was no 30-day mortality. The logistic regression analysis showed that decreased volume percentage (48%) of head mass resected (p=0.003) and small diameter of the pancreatic duct (p=0.05) were associated with poor pain outcome. Subgroup analysis revealed that patients with small duct disease were associated with increased operative time (p=0.001), poor pain scores (p=0.001), and increased weight loss (p=0.003) during follow-up.

CONCLUSIONS

Frey procedure can be performed with zero mortality and low morbidity in a high-volume center. It provides good pain relief in majority of the patients. Volume of the head mass cored affects pain outcome. Correlation between poor results in terms of pain relief and weight loss following Frey's procedure, and small duct disease supports the view that duct diameter is an important predictor of pain relief.