Clark's level explained

Clark's level is a staging system, which describes the level of anatomical invasion of the melanoma in the skin. It was developed by Wallace H. Clark Jr. at Harvard University and Massachusetts General Hospital in the 1960s.

Levels

Five anatomical levels are recognized, and higher levels have worsening prognostic implications. These levels are:^[1]

• Level 1: Melanoma confined to the epidermis (melanoma in situ)
• Level 2: Invasion into the papillary dermis
  • Level 3: Invasion to the junction of the papillary and reticular dermis Level 4: Invasion into the reticular dermis
• Level 5: Invasion into subcutaneous tissue.

National usage

In the United States, the current staging system adopted by the American Joint Committee on Cancer (AJCC) no longer considers Clark's level, because it is less prognostic and more subjective than other alternatives.^[2]

However, it is a mandatory component for melanoma pathology in Sweden.^[3]

See also

• Staging of melanomas
• Breslow's depth

Sources

• Melanoma Staging Systems. National Cancer Institute. A resource on Clark's levels and Breslow's depth.
• Original article from Breslow. Cancer res, 1969.

Notes and References

1. Web site: NCI Dictionary of Cancer Terms. 2020-02-13. National Cancer Institute.
2. Web site: Breslow Depth and Clark Level. Melanoma Research Alliance. 2020-02-13.
3. Web site: Bilaga 6. Kvalitetsbilaga för patologi (KVAST-bilaga). Regionala Cancercentrum i Samverkan, guidelines by Swedish Society of Pathology. 2020-02-13.