A fairly common disposition of Neuroendocrine Neoplasms is a primary with associated local/regional secondary’s (e.g. lymph nodes), and often with liver metastases. Technically speaking, the liver is distant. However, many metastatic patients appear to have additional and odd appearances in even more distant places, including (but not limited to) the extremities and the head & neck. Certain things are known about the behaviour of Neuroendocrine Neoplasms (NENs) (a term for Neuroendocrine Tumours and Neuroendocrine Carcinoma) and specialists will be analysing many factors when working out the type of NEN and how it might behave. This is useful in cases of unknown primaries as it can give them clues to the possible location(s). Read more about these issues in my article “Needle in a Haystack“.

How does cancer spread?

In addition to the primary growing into other areas, cancer can form metastases through the blood steam and the lymphatic system, a system of thin tubes (vessels) and lymph nodes that run throughout the body in the same way blood vessels do. The lymph system is an important part of our immune system as it plays a role in fighting bacteria and other infections; and destroying old or abnormal cells, such as cancer cells. The lymphatic system also contains organs, some of which feature regularly in NETs. If cancer cells go into the small lymph vessels close to the primary tumour they can be carried into nearby lymph glands where they stick around. In the lymph glands they may be destroyed (that is actually one of the jobs of the lymph glands) but some may survive and grow to form tumours in one or more lymph nodes.

Why is the liver frequent site for metastases?

According to the University of California Surgery Department, the risk of cancer spreading to the liver depends on the site of the original cancer. For example, cancers of the GI tract often spread to the liver because their blood drains directly through the liver, this might explain the many metastatic cases of NETs (amongst other factors). Liver metastases are sometimes present when the original (primary) cancer is diagnosed, or it may occur months or years after the primary tumour is removed. After the lymph nodes, the liver is the most common site of metastatic spread. Most liver metastases originate from the colon, rectum, pancreas, stomach, esophagus, breast, lung, and some less common sites. Several factors influence the incidence and pattern of liver metastases. These include the patient’s age and sex, the primary site, the histologic type, and the duration of the tumour (important point for NETs). The majority of liver metastases present as multiple tumours. Only 10% of all cases present with a solitary metastatic lesion. Moreover, in more than three-quarters (3/4) of patients with liver metastases, there is involvement of both lobes of the liver.

My own experience

As a metastatic Small Intestine NET case, I had the usual bulky chains of lymph node metastases in or around the mesentery that frequently appear with an abdominal primary. Most of these were removed along with my primary resection. However, I had known since shortly after diagnosis in 2010 that I had ‘hotspots’ in my left ‘axillary’ lymph nodes (armpit) and my left ‘supraclavicular fossa’ (SCF) lymph nodes (clavicle). These were found on Octreoscan but at the time, they were not pathologically enlarged – just showing uptake. Of course I also had multiple liver metastases and subsequent surgery (read more about that here). I had the fairly common issue of desmoplasia but in the less common location of the retroperitoneum. 

In early 2012, 15 months after removal of primary and 10 months after liver resection, one of the axillary lymph nodes became palpable (signs of growth) and this coincided with a small spike in Chromogranin A. A total of 9 lymph nodes were removed very shortly after this surveillance, 5 of which tested positive for NETs (Ki-67 <5%). As part of the same operation, 5 SCF left clavicle nodes were removed but tested negative. On a subsequent Octreoscan, the armpit was clear but the clavicle area still lit up. However, there is no pathological enlargement or pain – so this is just monitored. The SCF nodes also light up on Ga68 PET (and also sub-pectoral nodes, something never mentioned on any previous scan).

I also have a 2-3mm lung ‘nodule’, discovered in 2011 and has been tracked since then. Apparently, lung nodules are a pretty common incidental finding. This is monitored and does not light up on any nuclear scan (Octreotide or Ga68 PET).

My Ga68 PET scan in 2018, added right rib number 11 to my “metastases CV” – read more here.