Prognostic indicators are still not that well understood for OM although there are several predictive factors discussed in medical literature. Several clinical, pathological, and genetic prognostic factors have been identified as being associated with a higher risk of developing metastatic OM include:

• Large tumor size
• Ciliary body involvement
• Presence of orange pigment overlying the tumor
• Age at diagnosis

Pathological findings such as epithelioid (versus spindle) morphology is also associated with higher risk of metastasis.

Unlike melanomas of the skin, a tumor staging system is not widely used by ocular oncologists.

OM rarely spreads through the lymph system, instead it is more likely to spread hemotogenously, or through the blood. This is one of the reasons you are likely to see metasteses ("mets") appear in the liver first.

The genetic makeup of the tumor is also becoming a much more useful prognostic indicator. Recent molecular genetic research has shed light on chromosomal alterations, gene expression patterns and the relationship between these patterns and overall prognosis. The most widely used predictor of metastatic disease is the detection of monosomy 3. A monosomy is any form of aneuploidy (chromosomal abnormality) with the presence of only one chromosome (instead of the typical two in humans) from a pair.

The majority (66% according to the Sandinha paper linked below) of tumors with the monosomy 3 abnormality have a poor prognosis (i.e. result in metastatic disease) versus less than 5% of tumors without chromosome 3 deletion. Put another way, most of the patients missing one of their chromosome 3 pairs exhibited metastatic disease.

Read more: "Monosomy 3 Predicts Death but Not Time until Death in Choroidal Melanoma"

Gains on chromosomes 6 and 8 can help refine the predictive value of monosomy 3 – gain of 6p indicating a better prognosis and gain of 8q indicating a worse prognosis. This information can help predict risk of developing metastatic disease and can be obtained from a fine needle biopsy at the time of treatment of the primary eye tumor.

It appears that the loss of chromosome 3 is related to a new genetic finding – BAP1 (BRCA associated protein 1). If BAP1 is mutated or inactivated in a tumor (often found in tumors with a higher risk of metastasis) and the 2ndcopy is deleted (e.g. when there is loss of one copy of chromosome 3), then this confers a higher risk of metastasis.

This is a newly defined mutation and research is ongoing to understand the relationship between this finding and treatments for OM. Interestingly, this mutation has also been identified in a cancer called mesothelioma. Researchers in both fields are coming together to learn more about this mutation.

Using a different laboratory technique, gene expression patterns of the tumor biopsy can also be used to predict prognosis. Specifically, about half of ocular melanomas are shown to be “class 1” tumors. These tumors exhibit a distinct gene expression pattern, rarely undergo loss of chromosome 3, and have a very low risk of metastasis. In contrast, the other half of ocular melanomas fall into the “class 2” category which exhibit a different gene expression pattern, usually have lost one copy of chromosome 3, and are at a very high risk of metastasis.

Please talk to your ophthalmologist or oncologist as early in your treatment process as possible about having the genetic makeup of your tumor tested!

It cannot be stressed enough that you see an experienced medical oncologist and then follow up with them regularly. Hopefully, good follow-up for you will be like good insurance - you won't ever really need it, but it is there just in case.

Unfortunately, there are no approved guidelines for specific follow-up, but it would likely be comprised of blood work and scans at some sort of regular interval such as every six to nine months (likely guided by some of the factors outlined above, if known).

Some patients have reported having an ultrasound or MRI of the liver 1-2x/year for at least the first 1-5 years following plaque treatment (the liver is the first site of metastasis in 80%-90% of OM patients) with blood work and then possibly 1x/year thereafter. And again, make sure it is a trusted oncologist following these scans and not just your ophthalmologist.

Additionally, there are studies being conducted at various institutions around the country offering adjuvant treatment to people with high risk factors and without metastatic disease.

As with any education and treatment regimen, you are your own best advocate. You need to talk to as many doctors as possible and find a good medical oncologist who you trust and who is knowledgeable about OM. Ask them how many cases they see per year if you’re unsure.