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Prognosis and survival for melanoma
People with melanoma may have questions about their prognosis and survival. Prognosis and survival depend on many factors. Only a doctor familiar with a person’s medical history, type of cancer, stage, characteristics of the cancer, treatments chosen and response to treatment can put all of this information together with survival statistics to arrive at a prognosis.
A prognosis is the doctor’s best estimate of how cancer will affect a person, and how it will respond to treatment. A prognostic factor is an aspect of the cancer or a characteristic of the person that the doctor will consider when making a prognosis. A predictive factor influences how a cancer will respond to a certain treatment. Prognostic and predictive factors are often discussed together and they both play a part in deciding on a treatment plan and a prognosis.
The following are prognostic and predictive factors for melanoma.
People with early stage melanomas have a good prognosis. Prognosis becomes poorer with increasing stage.
Depth of invasion or thickness
The thicker the tumour, the poorer the prognosis. A thin melanoma (less than 1 mm thick) has a lower risk of spreading to nearby lymph nodes or distant sites. A thicker melanoma (thicker than 4 mm) has a greater risk of recurrence.
The presence or absence of ulceration of the primary melanoma is an important prognostic factor. A melanoma is said to be ulcerated if the layer of skin covering the melanoma is not clearly seen. If there is bleeding or ulceration at the primary site, the prognosis is poorer. Ulceration increases the risk of metastasis and the risk of the melanoma coming back after treatment.
Lymph node involvement
If the cancer has spread to any lymph nodes, the prognosis is poorer. The greater the number of lymph nodes involved, the poorer the prognosis. People with cancer in a single regional lymph node have a more favourable outcome than people with 2 or more involved regional lymph nodes.
If the involved lymph nodes can be felt (are palpable) the prognosis is poorer than when there is only microscopic evidence of lymph node involvement.
Melanoma involving the extremities (arms and legs) has a better prognosis than melanoma involving the trunk, head or neck.
Men have a poorer prognosis than women. This may be because men more commonly develop melanomas that involve the trunk, head or neck, while women more commonly develop melanomas that involve the extremities.
People who are diagnosed at a younger age often have a greater risk of metastases.
Melanomas that have no radial growth phase and only a vertical growth phase, such as nodular melanomas, have a poorer prognosis because they are usually diagnosed at a later stage.
Mitotic rate is how fast the cancer cells are growing and dividing. In T1 melanomas, an increased mitotic rate generally means an increased risk of metastases.
In stage IV melanoma, prognosis is worse with each number of metastatic sites and with metastasis to organs. High serum lactate dehydrogenase (LDH)serum lactate dehydrogenase (LDH)An enzyme that is involved in energy production in cells. levels and low performance statusperformance statusThe measure of how well a person is able to perform ordinary tasks and carry out daily activities. are also associated with a less favourable outcome in people with stage IV melanoma.