EOD Primary Tumor
**Note 1:** If there is a discrepancy between the Clark level and the pathological description of extent (invasion into the layers of the dermis), use the higher (more extensive) code.
**Note 2:** Code the greatest extent of invasion from any procedure performed on the lesion, whether it is described as a biopsy or an excision. For example, if a punch biopsy with involvement of Clark level IV is followed by a re-excision with residual tumor involving Clark level II, code 300 (Clark level IV).
**Note 3:** Satellite lesions/nodules or in-transit metastases are coded in EOD Regional Nodes.
**Note 4:** If a Breslow’s depth is given in the pathology report and there is **no other indication of involvement**, the following guidelines may be used (***Note:** If a physician documents a different Clark's Level then provided by these guidelines, go with the physician's Clark Level*)
* Code 000: Level I (In situ)
* Code 100: Level II (< 0.75 mm Breslow’s Depth)
* Code 200: Level III (0.76 mm to 1.50 mm Breslow’s Depth)
* Code 300: Level IV (> 1.50 mm Breslow’s Depth)
**Note 5:** In addition to EOD Primary Tumor, the following data items are also collected to determine the extent of the primary tumor:
- *Breslow's Thickness* [NAACCR Data Item #3817] and
- *Ulceration* [NAACCR Data Item #3936]
(1) Fritz AG, Ries LAG (eds). **SEER Extent of Disease 1988: Codes and Coding Instructions (3rd Edition, 1998)**, National Cancer Institute, NIH Pub. No. 98-2313, Bethesda, MD, 1998
(2) Young JL Jr, Roffers SD, Ries LAG, Fritz AG, Hurlbut AA (eds.). **SEER Summary Staging Manual-2000: Codes and Coding Instructions**, National Cancer Institute, NIH Pub. No. 01-4969, Bethesda, MD, 2001.
(3) Collaborative Stage Work Group of the American Joint Committee on Cancer. **Collaborative Stage Data Collection System User Documentation and Coding Instructions, version 02.05**. American Joint Committee on Cancer (Chicago, IL)
(4) Gress, D.M., Edge, S.B., Gershenwald, J.E., et al. **Principles of Cancer Staging**. In: Amin, M.B., Edge, S.B., Greene, F.L., et al. (Eds.) AJCC Cancer Staging Manual. 8th Ed. New York: Springer; 2017
(5) Gershenwald, J.E., Scolyer, R.A., et al. **Melanoma of the Skin**. In: Amin, M.B., Edge, S.B., Greene, F.L., et al. (Eds.) AJCC Cancer Staging Manual. 8th Ed. New York: Springer; 2017