SEER Training Modules
11/27/12 - The NCI is working on updating materials.
Melanoma Staging Schemes
Malignant melanoma is an example of a site where several staging schemes with prognostic significance have been developed based on a different histologic and clinical criteria. Each has been shown to be a valid method of staging disease at this site.
Clark's Level of Invasion
History:
Proposed by WH Clark, et al, in 1969. Showed that the risk of nodal metastases could be directly related to the depth of penetration of the tumor.
Criteria:
Histologic classification based on resection of entire lesion.
Restrictions:
- Does not take nodal involvement into consideration; deals only with primary tumor.
- Uniformity of staging not always reproducible because of variations in the depth of layers of the skin.
- Cannot be applied accurately to melanomas of the palms and soles.
- Histologic difference between growth patterns of superficial spreading and nodular malignant melanomas.
Categories:
Level I: Confined to epidermis (in situ); never metastasizes; 100% cure rate Level II: Invasion into papillary dermis; invasion past basement membrane (localized) Level III: Tumor filling papillary dermis (localized), and compressing the reticular dermis Level IV: Invasion of reticular dermis (localized) Level V: Invasion of subcutaneous tissue (regionalized by direct extension)
Guidelines for Clark's Levels:
- The most difficult differentiation is between Level II and Level III.
- Level I is technically non-existent (in-situ melanoma has other names).
- If there is involvement of lymph nodes or distant metastases, another staging system must be used.
- Examination of entire tumor is important in order to accurately assess the level of invasion.
Breslow's Depth of Invasion
History:
Proposed by A. Breslow in 1970.
Criteria:
Pathologic staging based on measurement of tumor invasion of dermis using the micrometer on the microscope. More reproducible system than Clark's Levels.
Categories:
- Actual measurement of depth of lesion is recorded Example: lesion measures 0.8 mm
- Cases are grouped for study as follows:
- 0.75 mm (comparable to Clark Level II)
- > 0.75 - 1.5 mm (comparable to Clark Level III)
- > 1.5 - 4.0 mm (comparable to Clark Level IV)
- > 4.0 mm (comparable to Clark Level V)
Guidelines for using Breslow's system:
- Record measurement in abstract. If both Clark's and Breslow's stages are given, record both.
- If there is involvement of lymph nodes or distant metastases, another staging system must be used.
- Examination of entire tumor is important in order to accurately assess the level of invasion.
Clinical Staging for Malignant Melanoma
- Used for staging of melanomas which have spread beyond the primary tumor or which do not have adequate tissue for pathological examination.
- Clinical staging includes results of tests and examinations as well as pathological findings.
- Clinical staging parallels Summary Staging
- Stage I Localized—without metastases to distant or regional nodes (allows localized disease up to 5 cm. from initial tumor within primary lymphatic drainage area
- Stage II Regionalized—involvement of regional nodes
- Stage III Disseminated—visceral or lymphatic metastases or multiple cutaneous or subsequent metastases
- Reference to stage in melanoma cannot be assumed to be clinical, Clark's, or Breslow's unless specifically identified as such.
