So Neuroendocrine Tumors often present with large volume Liver Metastases and because these are relatively Indolent Tumors the patient often does not know that he has a Neuroendocrine Tumors specially those who have non-functioning Neuroendocrine Tumors. They don't know till such time that there liver is studded with metastases and they have large volume disease from the Neuroendocrine Tumor which effects the liver and often these patients present with some non specific complaints of a dragging sensation of a pain in the liver or sometimes they are incidentally picked up when an ultrasound or a CT Scan is done for some other purpose.
And that leads to the you try and look for what are this tumors and often they find that these are Metastatic Neuroendocrine Tumors and because these patients present with such large volume disease surgery or a very selective kind of a procedure like a Transarterial Chemoembolization or RFA or Microwave Ablation is often not an option.
So, patients of Neuroendocrine Tumors often present first time to a doctors clinic with large volume liver metastases and because these are relatively indolent tumors specially those patients who have non functioning Neuroendocrine Tumors which means that these patients don't secrete the hormones which cause the typical Carcinoid Syndrome of flushing and diarrhea and redness and sweating.
About 80% of patients of Neuroendocrine Tumor don't have functioning tumors and it is this segment of patients who often present first time to the clinic with large volume liver metastases now when a person has got large volume liver metastases which is involving both lobes of the liver the options of a segmental resection or operating on a certain part of the tumor or actually removing the tumor surgically actually is often not an option by the time they reach the clinic even technique such as RFA or microwave ablation which are often techniques which are used in patients hepatocellular carcinoma are not used in patient of neuroendocrine tumor simply because they reach the doctors clinic when the disease has already progressed beyond what can be treated with a Localized Liver Directed Therapy and such patients most of the times are either treated with Transarterial Radioembolisation or with PRRT depending on whether or not their tumor expresses somatostatin receptors positivity or not.
So, one of the techniques which is used in PRRT is to actually administer the PRRT intraarterially directly into the liver and this is done in patients who have got a large volume liver metastases or liver-dominant metastases so that means the most of the metastatic sides are in the liver.
So what happens is that you do an angiography just same way as a Transarterial Radioembolisation or Transarterial Chemoembolization is done and you inject the PRRT medicine directly into the liver and the tumor cells in the liver because they are very vascular because they receive there blood supply from branches of the hepatic artery they absorb the PRRT medicine in the first pass so the first time that the medicine actually reaches the target tumor cells it is absorbed and extracted from the blood stream by these cells as a result we are able to actually deliver a much higher dose of this medicine directly into the liver so this is called intra arterial PRRT and recent studies have shown that it improves the effectiveness of PRRT without increasing the toxicity to a large extent.