Metastatic Melanoma Overview

Melanoma is a type of skin cancer, which appears like a flat, asymmetrical mole with irregular borders.  It develops in melanocytes  (pigment cells). While some can develop within a mole, most are new skin growths or spots.

Melanoma is the 6th most common cancer in the U.S.A. and is increasing rapidly.

Suspicious Skin Changes

The following skin transformations warrant immediate attention:

  • Color change
  • Bleeding without cause
  • Ulcerations or infection of skin
  • Itching
  • Pain or tenderness
  • Transformation from flat to raised or vice versa

More serious changes include:

  • Swollen lymph nodes, typically in the groin or armpit
  • Colorless lump
  • Weight loss of unknown cause
  • Headaches
  • Chronic cough
  • Seizures

Once a diagnosis of melanoma is made, one must stage the cancer by assessing the spread (metastasis) for treatment options.

Staging of Melanomas

Typical sites of spread start subcutaneously (under the skin) and then to:

  • Lymph nodes
  • Lungs
  • Liver
  • Brain
  • Bone

Distant metastasis involves the:

  • Adrenal glands
  • Heart
  • Gastrointestinal tract
  • Spleen

Stage 0: melanoma in situ or involving the epidermis but not the dermis underneath

Stage 1 - Based on thickness of the tumor with no spread or lymph node involvement.

  • IA: tumor equal or less than 1 mm with no ulceration and no mitosis
  • IB: the same with ulceration or mitosis

Stage II - determined by thickness and ulceration with no node involvement or distant spread

Stage IIA: T2bNOMO or T3aN0M0

Subclasses:

  • T2b: tumor=1-2 mm. thick with ulceration
  • T3a: tumor=2.1-4 mm with no ulceration
  • N0: no lymph node involvement
  • MO: no spread to distant sites

Stage IIB: T3bN0M0 or T4aN0M0

  • T3b: tumor=2.1-4 mm with ulceration
  • T4a: tumor is more than 4 mm thick with no ulceration
  • N0: no lymph node involvement
  • MO: no spread to distant sites

Stage IIC: T4bN0M0

  • T4b: tumor = more than 4 mm thick with ulcerations
  • N0: no lymph node involvement
  • M0 no spread to distant sites

Stage III: described by level of spread to regional lymph nodes.  No distant spread is found. This is classified as intermediate to high risk for local recurrence or distant metastasis despite treatment.

Stage 3 melanomas are divided by four traits:

  • Number of lymph nodes involved in tumor spread
  • Lymph node spread is microscopic (unseen to the naked eye) or macroscopic (felt or seen by the unaided eye)
  • Satellite metastases (areas of tumor growth beyond the primary melanoma)
  • Presence of ulceration (as seen by pathologist microscopically)

Stage IIIA: T1-T4a N1aM0 or T1-T4aN2M0

  • T1-T4a: tumor=less than 1mm to 4 mm thick with no ulceration
  • N1a: micro metastasis to 1 nearby lymph node
  • N2a: micro metastasis found in 2-3 nearby lymph nodes
  • M0: no distant spread

Stage IIIB: T1-T4bN1aM0, T1-T4bN2aM0, T1-T4aN1bM)

  • T1-T4a: no ulceration and size from 1 mm to more than 4 mm thick
  • T1-4b: same size but with ulceration
  • N1b: macro metastasis in 1 nearby lymph node
  • N2b: macro metastasis in 2-3 nearby lymph nodes
  • N2c: presence of satellite metastases
  • M0: no spread to distant sites

Stage IV described by the distant metastases further than regional lymph nodes and serum levels of lactate dehydrogenase (LDH). Typically, the spread is to vital organs, e.g. lungs, brain, bone and abdominal organs and soft tissues.

Characteristics include:

  • Location of distant metastases
  • Number and size of tumors
  • Serum LDH level.  Elevation of lactate dehydrogenase usually occurs when internal organs are involved.

Subclasses:

  • M1a: metastasis to distant skin, subcutaneous layer or distant lymph nodes.  Serum LDH = normal
  • M1b: Metastasis to lungs with normal serum LDH
  • M1c: Spread to vital organs other than lungs and LDH = normal or any spread with a rise in LDH
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