A very dangerous disease, skin cancer can progress through different stages. Each of them is characterized by its own peculiarities. Diagnosing melanoma at an early stage is crucial, as the earlier the lesion is removed, the higher the chances of recovery. In this article, we will discuss what melanoma stages there are.
Melanoma is a kind of skin cancer, which is diagnosed in 2% cases of skin cancer, so it is a rare one, but 75% of deaths following skin cancer are attributed to melanoma. A very serious disease, it must be treated as soon as possible.
There are four main stages of melanoma, with stage 0 being the starting point.
- Stage 0. At this stage, melanoma is found only within the outer layer, i.e. the epidermis. It is often termed in situ melanoma, which literally means “melanoma in place”. It is there, it has the potential to grow and progress, but at this stage of its development, it is usually easy to cure. It takes a surgeon to remove the lesion. Melanoma at stage 0 is unlikely to spread to other organs.
- Stage 1. There used to be two kinds of stage 1. One of them was assigned when the depth of the melanoma was 2 mm with no microscopy-tested ulceration, no affected lymph nodes, and no metastases; the other one was when the lesion was 1 mm, but there was ulceration. In either case, no lymph nodes or other organs are affected. The kind of treatment usually used in such cases is that of surgical removal. Sometimes lymph node removal is also needed; such a need arises when the lesion is within the range of 1-4 mm, and it’s growing fast. However, starting from January 1, 2018, stage 1 is defined as invasive tumors that are not thicker than 0.8 mm, with no signs of ulceration. Definitions of stages provided below will be adjusted to the recent changes in recommendations issued by AJCC. The reason the previous definition is provided above is that some doctors may still use the old classification.
- Stage 2. The size of a stage 2 melanoma is 0.8-4 mm. It poses a high risk of spreading, and some lesions that are thicker than 4 mm also belong to this category. If microscopic analysis shows ulceration is already in place, it can mean the stage is more advanced than stage 2. Tumor removal is usually accompanied by removal of the affected lymph nodes. Besides, radiation or drug treatment can be used to help prevent relapse.
- Stage 3. At stage 3, ulceration is more important than thickness. The tumor spreads to sentinel lymph nodes, or to the tissue between the lesion and the lymph nodes. If there are metastases, such cases are also assigned to stage 3. The tumor can spread more than 2 cm away from the place of its origin. There are different subtypes of the stage, which are assigned depending on the number of lymph nodes affected, whether the metastases reached the nodes or are still in-transit, how many cancer cells there are, and if they can be seen with the naked eye or they are microscopic.
- Stage 4. Tumors that advanced to stage 4 metastasized to distant tissues, including such organs as the lungs, heart, brain, gastrointestinal tract, bones, and liver. In order to determine how advanced a melanoma is, two factors are used: the first one is the level of LDH, and the second one is how distant the metastases are.
How is the process of staging carried out?
To determine what stage a melanoma is at, a doctor can use the following diagnostic methods:
- Microstaging. The tissue sample is analyzed under a microscope.
- Clinical staging. Examination of lymph nodes.
- Staging after investigation. MRI, PET, and CT scans.