Malignant melanoma

2020/10/01

The article below is based on a whitepaper by Munich Re Life US that has been adapted for the Canadian market. For further details, please refer to the US study. 

Malignant melanoma is the most serious form of skin cancer. The incidence of melanoma is rising in much of the world, and it is now the seventh most commonly diagnosed cancer in Canada. Given also that it can occur at any age and that it is often found at early stages with a very good prognosis, it is one of the cancers most often encountered in underwriting.

Because of their usually visible location, skin melanomas are often found at early stages without evidence of spread to elsewhere in the body, with 84% remaining localized at the time of diagnosis. The prognosis therefore is generally very good: the net 5-year survival rate for melanoma in Canada, based on results from Canadian Cancer Statistics, is 88%.2 This means that on average, about 88% of people diagnosed with melanoma will survive for at least five years. However, in accordance with the American Joint Committee on Cancer (AJCC) melanoma staging database, survival rates can vary significantly: a 5-year survival rate of 99% for localized skin melanomas, 65% when regional lymph nodes are involved, and just 25% if there are distant metastases.

In addition, even localized melanomas have varying degrees of recurrence risk based on multiple other factors. Some of these are part of the staging criteria, such as the thickness of the lesion and the presence of ulceration. The risk increases with increasing thickness, and though staging guidelines require there to be set cut-off points (1, 2, and 4mm of thickness have been chosen), there is variable risk even within those ranges. This was recognized particularly with thin melanomas: those 1mm or less in thickness. A melanoma thickness of 0.8 to 1.0mm now places one into a higher stage unless a sentinel lymph node biopsy is without evidence of tumor spread. Similarly, the presence of ulceration leads to a prognosis similar to as if the thickness is one level greater.

Using the Surveillance, Epidemiology, and End Results (SEER) database and evidence based research from other sources allows us to identify other factors which affect the prognosis. The mitotic rate of the tumor was already part of the prior (AJCC 7th edition) staging criteria, and although no longer included to keep the staging more simplified, it remains an important prognostic factor for all stages of tumor thickness. In addition, a nodular growth pattern; the presence of lymphovascular invasion; regression of the tumor of greater than 50%; and a tumor location on the scalp, neck, lip, mucosal membrane, or eye, are all independent risk factors for recurrence and increased mortality. Men tend to have worse outcomes than women, and those diagnosed at older ages have higher recurrence rates in the first five years after discovery. It is helpful to take these factors into account for accurate life and disability underwriting risk assessment.

The risk of recurrence, however, does not end at five years. Even for thin melanomas, one may go for many years without any evidence of disease only to present ultimately with a recurrence, and that risk persists for 15 to 20 years or more. This also needs to be factored into the underwriting risk assessment, especially for those with thicker tumors or with other higher risk features.

Recognizing the many risk factors that impact the prognosis, an intuitive expectation is to assume all critical illness coverage is unobtainable. However, as indicated earlier, where risk factors are favourable and the melanoma is found at an early stage (thickness of less than 0.8mm and no ulceration), coverage may be considered once excision is complete and sufficient follow up has been demonstrated in the first two years.

Looking ahead

Major advances in melanoma treatment have already had a major bearing on outcomes and are expected to have an even greater impact over the coming years. Many experts currently speak of metastatic melanoma as likely becoming more of a chronic, treatable disease in the future, rather than an ultimately terminal event. It will be exciting to follow such advances, and you can count on Munich Re to be attuned to these improvements as they develop.
The incidence of melanoma is rising in much of the world, and it is the seventh most commonly diagnosed cancer in Canada.1
Contact the authors
Dr. Tim Meagher
Dr. Tim Meagher
Vice President & Medical Director
Reece Hodgson
Reece Hodgson
Director, Risk Management Unit
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