Any malignant tumour hides in itself a danger of metastases or spreading outside its primary focus. Metastases are groups of tumour cells that have “travelled” away from the tumour location to other parts of the body. They can spread along the surfaces of body cavities, through lymphatic vessels or blood vessels — with a blood flow, if the tumour cells have penetrated the blood circulation, — as well as use the way of easiest resistance and spread, for example, through tunnels of the protective coating of nerves. Malignancy of any tumour is determined by its metastatic potential. For example such tumours as basal cell carcinoma or squamous cell cancer almost never develops metastases in other organs, while melanoma is opt to spreading both through lymphatic system (metastases in lymph nodes, also distally), and blood circulation. The last or so-called hematogenous metastases in melanoma patients can develop in lungs, liver, brain, bones and other organs. Besides, there is a link between the biological indicators of the primary cancer (depth, ulceration, mitotic activity or proliferation) and likelihood of metastases. Unfortunately, more delayed diagnosis of a cancer brings to a less positive prognosis. There are also tumours, which, on the moment of setting a diagnosis, have widely spread along the entire body, like in most cases of sarcoma. Melanomas are frequently discovered after they have developed metastases. For example, melanoma cells are found in enlarged lymph nodes and then the quest begins. If no suspicious formations can be detected on the skin, one should assume that the melanoma is located in less available areas or, less commonly, it has managed to disappear.
Since the noncutaneous melanomas usually develop more rapidly and aggressively, they are more difficult to discover. It is therefore more frequent cause of fatal outcome than in case of a cutaneous melanoma.
Contrary to basal cell carcinomas and squamous cell cancers, melanomas do not develop in those areas of body that are most exposed to sun, even though the role of insolation in their development has been proved. Currently it is explained with certain mutations triggered by the ultraviolet (UV) radiation. Intensity and duration of the exposure to UV radiation are also crucial factors that may cause melanoma. In case of melanoma the most dangerous episodes are overtanning, especially during childhood and teenage years, while in case of basal cell carcinomas and squamous cell cancers the most important factor is cumulative radiation that accumulates during the lifetime. That is the reason why basal cell carcinomas and squamous cell skin cancers basically develop in elder people, while noncutaneous melanomas are more common at any age, including teenagers. It is also the most frequently occurring tumour for young people until 30 years of age. Mucosal melanomas, even though more common in the second part of life, can occur also in the early age. Amelanotic melanomas are especially aggressive and they are frequently discovered with delay, because one does not think that such formations can be deadly; they are usually observed for a long time and are not subject to the microscopic testing.
The only officially recognised prophylaxis is avoiding direct sun rays and not attending sun beds. Besides, sunscreens are mandatory when exposed to sun, but the best of all is to wear clothing that covers body and head. Unfortunately there are no other safe methods proven.
One of the most common melanoma, so-called noncutaneous melanomas, develops in eyes (5% of all cases). Usually it is located in one eye and occurrence in both eyes is very seldom. Eye melanomas more often develop in people with light coloured eyes and at later age. Crucial factor is also large amount of dysplastic (atypical) moles on skin, pigment spots in the eyelid area. More frequently eye melanoma develops in people with especially dark iris (melanomatosis of the eye)
Eye melanoma patient most frequently complains about a growing brownish spot in the conjunctiva (eye white), pupil deformation, reduction of visual acuity, flashing spots, fogging, discomfort or irritation of eye. Only when a person has attended an ophtalmologist or, more often, an optometrician to have new glasses prescribed. Sometimes loss of certain areas of vision features black spots appearing at certain angles.
As the melanoma evolves and exerts pressure on eye structures, symptoms that are similar to glaucoma may develop (pain, redness of eyeball, fogging). The darkest pigment spot cannot always been detected by looking in a mirror. Only very careful ophtalmoscopic examination reveals the true picture, because melanoma can hide in the deepest structures of the eye. Therefore regular checks at a physician or an optometrician are essential even if you don’t have any specific complaints.
Most commonly melanoma develops in the iris (prefrontal or posterior), retina or sclera. It is less common in the conjunctiva (mucous membrane embracing the eyeball).
In such cases usually no biopsy is required, because a physician can rather precisely establish the nature of the suspicious formation by means of ophtalmoscopy and ultrasonics. In order to evaluate melanoma spread it commonly requires computed tomography or magnetic resonance imaging examination. Positron emission tomography (so-called PET/CT) will reveal the most precise spread elsewhere in the body, because the eye melanoma can develop metastases in lungs, liver, bones and also brain.
The basic treatment method is surgery (laser surgery or removal of entire eye). An alternative option is stereotactic radiation. Unfortunately there are no other safe methods tested. In Latvia we have some post-operation or post-radiation experience with prescribing oncolytic virotherapy medications. Usually patients address us when they already have metastases, when nothing else can be offered to them or very expensive drugs are offered (without recovery guarantee) that they cannot afford (several thousand for a monthly course of treatment, and continuing to administer drugs until the next relapse or death of a patient). Approximately 20 patients a year have the eye melanoma detected.
Oncologist Dace Baltiņa claims that almost half of the cases the mucosal melanoma develops on head and neck — nasal channels, sinuses, mouth, throat. Less than one fourth of mucosal melanomas develop in colon and anus. Women are more prone to genital melanomas — most commonly they develop in the vagina orifice, vagina, uterus, cervix. The less frequent are urinary tract melanomas. Melanomas are especially rare in different gastrointestinal organs.
Mucosal melanomas are usually aggressive and hard to discover, because they often have no symptoms for a long time. The most typical complaint is bleeding and melanoma is found when examining the patient due to a suspicion of another kind of tumour in particular area. More often melanomas are found in mouth, throat, anal area, in women — in vagina, cervix, perinaeum and more seldom in gastric organs, meninges and elsewhere. Actually melanoma can develop in any tissue where melanocytes are present.
I recently encountered a case of 27 years old woman who had cervical epithelioid spindle cell melanoma. It is not typical in such age, because mucosal melanoma is more often found in elder patients, having reached 60 years of age. The woman had bleeding and she went to a gynaecologist who took a biopsy sample. It was established that the woman has a melanoma instead of a typical cervical cancer. The woman had a surgery — ovaries were kept, yet the uterus was removed completely. One year later a relapse was established in the vaginal wall, which was proven morphologically when a repeated, and unfortunately non-radical, surgery was conducted. It’s been two years already since she has been administering oncolytic virotherapy medications and luckily has no relapses so far.
Usual therapy tactics is a surgery until the healthy tissues. Actually the surgery is the basic therapy in case of melanoma regardless of its location, a golden standard. Since melanoma is almost insensitive to radiation, this method is mainly used to restrict metastases and symptoms. Due to rare occurrence there are no other evidence-based therapies available. Mucosal melanomas are so seldom occurring that also world literature does not offer sufficient number of cases to compare various therapies.
Unfortunately melanoma belongs to the group of tumours that poorly react also to chemotherapy. Efforts have been made to treat melanoma with hormonal drugs nevertheless it did not result in convincing effect. There are no globally recognized preventive therapies for melanoma after a radical surgery, even though the risk of metastases exist, especially in case of ulcerating melanomas (version B, it is proved in the microscopic examination). American and European guidelines offer these patients merely an observation or participation in a clinical trial, although it is quite clear that melanoma cannot be treated once it has gone metastatic. Latvian patients can have oncolytic virotherapy medications after the surgery as they credibly delay or even prevent development of metastases. But, if the metastases have already developed, no available remedies that we are aware of in this world can help convincingly. The amount of money does not matter. The expensive innovative remedies that are often bought from donations, because their costs are huge, can extend life, but not fully heal, and it is important to understand it. Therefore it is crucial to discover melanoma at its earliest stages when one can hope for a radical surgery and that the ill cells have not spread elsewhere.