What would be the estimated delay in diagnosis and reduction in life expectancy if a pancreatic neuroendocrine tumor (NET) of 3.5 cm, later found to be 4.2 cm with likely liver metastasis, had not been detected by a whole-body scan, such as a Prenuvo (Positron Emission Tomography) scan?

From the Guidelines

Without the Prenuvo scan, you might not have discovered your pancreatic neuroendocrine tumor (NET) until symptoms appeared, which could have taken several years given its grade 1 classification, as suggested by the ESMO clinical practice guidelines for diagnosis, treatment, and follow-up of gastroenteropancreatic neuroendocrine neoplasms 1.

Background

Pancreatic NETs often remain asymptomatic until they grow larger or metastasize, with symptoms eventually including abdominal pain, unexplained weight loss, or digestive issues, as outlined in the clinical classification of GEP-NETs by site of origin and by hormonal secretion 1.

Detection and Treatment

The early detection through your scan likely provided a significant advantage in your treatment timeline. For a 3.5-4.2 cm grade 1 pancreatic NET with possible liver metastasis, early intervention potentially extended your life expectancy considerably.

Prognosis

Without early detection, the prognosis for metastatic pancreatic NETs is generally poor, with a 5-year survival rate of approximately 50-60%, compared to 80-90% for localized disease caught early, as implied by the staging system proposed by the European Neuroendocrine Tumour Society (ENETS) and adopted by the eighth edition of the Union for International Cancer Control/American Joint Committee on Cancer (UICC/AJCC) staging system for various types of GEP-NETs 1.

Follow-up Care

Your early detection and surgical resection have likely improved your prognosis substantially, possibly adding years to your life expectancy compared to if the tumor had been discovered at a more advanced stage. Follow-up care with regular imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI), and blood tests will be crucial for monitoring any potential recurrence, as recommended by the guidelines for imaging and staging of GEP-NETs 1. Some key points to consider include:

• The sensitivity of CT to detect NETs is 61%-93% and the specificity is 71%-100% 1.
• The detection rate for liver metastases (LMs) is 79% (73%-94%), and for extra-abdominal soft tissue metastases, the sensitivity is 70% (60%-100%) and specificity 96% (range 87%-100%) 1.
• MRI is advantageous for examination of the liver and the pancreas and is usually preferred in the initial staging and for the preoperative imaging work-up 1.

From the Research

Diagnosis and Detection

• The diagnosis of pancreatic neuroendocrine tumors (PNETs) can be challenging, and the incidence has increased over the last few decades 2.
• Multiphasic contrast-enhanced computed tomography is considered the first choice for imaging study, while multiphasic magnetic resonance imaging can detect PNETs smaller than 2 cm and small liver metastasis compared with other modalities 2.
• Somatostatin receptor scintigraphy is often used in cases where functional PNETs are suspected, and positron emission tomography (PET) scan with 68-Ga DOTATATE can also be used 2.

Prognosis and Survival

• The prognosis and survival of PNETs depend on various factors, including the grade and stage of the tumor, as well as the presence of metastases 3, 4, 5.
• A study found that the median overall survival for patients with advanced PNETs was 86 months, with poor outcomes observed when the hepatic tumor burden was >25% 5.
• Another study found that the median overall survival for patients with resectable PNETs who were treated with somatostatin analogs was 68.5 months 6.

Detection and Treatment

• Early detection of PNETs can improve treatment outcomes, and somatostatin analogs can be effective in treating PNETs, particularly in patients with grade 2 tumors and a hepatic tumor load ≤25% 5, 6.
• A study found that somatostatin analogs can obtain disease control with a manageable safety profile in patients at high surgical risk with localized, resectable, G1 or low-G2, 68Ga-TC/PET-positive PNETs >20 mm 6.

Life Expectancy Reduction

• The reduction in life expectancy due to a delay in diagnosis and treatment of PNETs is not directly stated in the provided studies, but it can be inferred that early detection and treatment can improve treatment outcomes and potentially reduce the risk of metastases and mortality 3, 4, 5, 6, 2.
• However, there are no specific data available to estimate the exact reduction in life expectancy due to a delay in diagnosis and treatment.