Cancer Institute A national cancer institute
designated cancer center

Merkel Cell Carcinoma Staging

After Merkel cell carcinoma has been diagnosed more tests will be done to find out if cancer cells have spread from the place the cancer started to other parts of the body. The process used to find out whether the cancer has spread to other parts of the body is called staging. It is important to know the stage of the disease to plan the best treatment.

The following stages are used for Merkel cell carcinoma:

Stage I

The primary tumor dimension is less than or equal to 2 cm without lymph node involvement.

Stage II

The primary tumor is larger than 2 cm in maximum dimension but there is no lymph node involvement.

Stage III

Regional lymph nodes are affected in Stage III or there is an in-transit metastasis.

Stage IV

The tumor has metastasized to any distant site outside of the regional lymph node distribution and/or internal organ (visceral) involvement.


Recurrent disease means that the cancer has recurred (come back) after it has been treated. It may come back in the same part of the body or in another part of the body.

Stanford Medicine Resources:

Footer Links: