The incidence of primary pancreatic carcinoid tumors in the United States is increasing rapidly, new research shows.
"A diagnosis of primary pancreatic carcinoid tumor no longer appears to be so uncommon and the increase in the number of tumors diagnosed in recent years has been rapid," said lead author Dr. Gyulnara Kasumova of Beth Israel Deaconess Medical Center in Boston.
"The rate of increase in new diagnoses is somewhat surprising, but it can be justified in the context of advanced biochemical staining techniques and increased use of imaging," she told Reuters Health by email. "The more favorable prognosis of carcinoid tumors relative to other pancreatic neuroendocrine tumors (PNETs), which persists in patients who undergo surgery, was unexpected, but it further highlights that this is in fact a distinct tumor subtype."
For their study, online December 12 in the Journal of the American College of Surgeons, Dr. Kasumova and her colleagues analyzed data from the National Cancer Data Base (NCDB) spanning 2004 to 2013.
Among more than 10,700 patients, 12.7% had been diagnosed with carcinoid tumors, 84.7% with nonfunctional PNETs and 2.6% with functional PNETs.
The number of functional PNETs remained steady over time, but the rates of non-functional and carcinoid tumors rose sharply. In 2004, only 36 (5.7%) carcinoid tumors were diagnosed, while in 2013 that number was 497 (27.7%).
Overall survival was significantly better for carcinoid than functional and non-functional tumors, with five-year survival rates of 63.1%, 58.3%, and 52.6%, respectively.
Among the resected patients, overall survival for carcinoid tumors (89.2%) improved significantly more than for functional and non-functional tumors (76.6%, and 78.7%, respectively).
On multivariate analysis of the resected cohort, mortality was significantly higher for patients with functional (hazard ratio, 1.81) and non-functional PNETs (HR, 1.40) compared with those with carcinoid tumors.
Senior author Dr. Jennifer F. Tseng, also at Beth Israel, told Reuters Health by email, "Providing an accurate diagnosis and prognosis to patients may affect treatment planning decisions, and proper tumor identification may also impact future clinical trial designs. The biggest question remaining will be how these new insights will change outcomes of cancer care for patients with pancreatic neuroendocrine tumors."
"These tumors are highly curable, so I want to emphasize that 'pancreas' and 'tumor' come in many different flavors, and these types are very far from a death sentence," she said. "Clinicians and patients should have hope, seek out experts, and find the best treatment for their particular types of tumors."
Dr. Renuka Iyer, section chief for Gastrointestinal Oncology at Roswell Park Cancer Institute in Buffalo, New York, told Reuters Health by email, "Epigenetic research is needed, and this work may prompt collaborations to investigate results of studies like this one."
But she cautioned, "The authors do not know the stage in over 30% of the cases, and in the absence of providing information on the stage of the patients who had resection, this is difficult to interpret."
"In this disease, a symptomatic primary tumor is removed even in the face of metastatic disease, and this is done more often in carcinoids than pancreatic neuroendocrine tumors, given the morbidity of pancreatic surgery," Dr. Iyer explained. "Appendiceal carcinoids are far less likely to have nodal involvement, and this could have greatly impacted the findings if these were included."
"It is known that 20% of patients have second primary tumors, which was noted, but those patients were not included. They may have unique genetic signatures and are also worthy of further study," she said.
"Two drugs were approved in 2011 to treat pancreatic neuroendocrine tumors, and one drug was approved in 2016 to treat carcinoids. In 2017, approval to use peptide radioreceptor therapy is anticipated for carcinoids, and all these new data may influence outcomes moving forward," Dr. Iyer added.
The study was presented in September, 2016, at the Annual Meeting of the New England Surgical Society in Boston.
J Am Coll Surg 2016.