TNM Definitions
AJCC Stage Groupings

Basal cell carcinoma rarely metastasizes, and thus a metastatic work-up is usually not necessary.[1] Regional lymph nodes should be routinely examined in all cases of squamous cell carcinoma, especially for high-risk tumors appearing on the lips, ears, perianal and perigenital regions, or high-risk areas of the hand.[2] In addition, regional lymph nodes should be examined in cases of squamous cell carcinoma arising in sites of chronic ulceration or inflammation, burn scars, or sites of previous radiation therapy treatment.

The American Joint Committee on Cancer (AJCC) has designated staging by TNM classification.[3] The TNM classification is used to stage both basal cell carcinoma and squamous cell carcinoma.

Primary tumor (T)

• TX: Primary tumor cannot be assessed
• T0: No evidence of primary tumor
• Tis: Carcinoma in situ
• T1: Tumor not larger than 2 cm in greatest dimension
• T2: Tumor larger than 2 cm but not larger than 5 cm in greatest dimension
• T3: Tumor larger than 5 cm in greatest dimension
• T4: Tumor invades deep extradermal structures (e.g., cartilage, skeletal muscle, or bone)

   [Note: In the case of multiple simultaneous tumors, the tumor with the highest T category will be classified, and the number of separate tumors will be indicated in parentheses, e.g., T2 (5).]

Regional lymph nodes (N)

• NX: Regional lymph nodes cannot be assessed
• N0: No regional lymph node metastasis
• N1: Regional lymph node metastasis

Distant metastasis (M)

• MX: Distant metastasis cannot be assessed
• M0: No distant metastasis
• M1: Distant metastasis

Stage 0

• Tis, N0, M0

Stage I

• T1, N0, M0

Stage II

• T2, N0, M0
• T3, N0, M0

Stage III

• T4, N0, M0
• Any T, N1, M0

Stage IV

• Any T, any N, M1

Basal cell carcinoma

Basal cell carcinoma is at least three times more common than squamous cell carcinoma in nonimmunocompromised patients. It usually occurs on sun-exposed areas of skin, and the nose is the most frequent site. Although there are many different clinical presentations for basal cell carcinoma, the most characteristic type is the asymptomatic nodular or nodular ulcerative lesion that is elevated from the surrounding skin and has a pearly quality and contains telangiectatic vessels. Basal cell carcinoma has a tendency to be locally destructive. High-risk areas for tumor recurrence include the central face (e.g., periorbital region, eyelids, nasolabial fold, or nose-cheek angle), postauricular region, pinna, ear canal, forehead, and scalp.[4] A specific subtype of basal cell carcinoma is the morpheaform type. This subtype typically appears as a scar-like, firm plaque. Because of indistinct clinical tumor margins, the morpheaform type is difficult to treat adequately with traditional treatments.[1]

Squamous cell carcinoma

Squamous cell tumors also tend to occur on sun-exposed portions of the skin such as the ears, lower lip, and dorsa of the hand. However, squamous cell carcinomas that arise in areas of non–sun-exposed skin or that originate de novo on areas of sun-exposed skin are prognostically worse since they have a greater tendency to metastasize. Chronic sun damage, sites of prior burns, arsenic exposure, chronic cutaneous inflammation as seen in long standing skin ulcers, and sites of previous x-ray therapy are predisposed to the development of squamous cell carcinoma.[1]

Actinic keratosis

Actinic keratoses are potential precursors of squamous cell carcinoma. These typical red scaly patches usually arise on areas of chronically sun-exposed skin, and are likely to be found on the face and dorsal aspects of the hand. Although the vast majority of actinic keratoses do not become squamous cell carcinomas, as many as 5% of actinic keratoses will evolve into this locally invasive carcinoma. Due to this premalignant potential, the destruction of actinic keratoses is advocated.[1]

References

1. Wagner RF, Casciato DA: Skin cancers. In: Casciato DA, Lowitz BB, eds.: Manual of Clinical Oncology. 4th ed. Philadelphia, Pa: Lippincott, Williams, and Wilkins, 2000, pp 336-373. 
   
   
2. Rayner CR: The results of treatment of two hundred and seventy-three carcinomas of the hand. Hand 13 (2): 183-6, 1981.  [PUBMED Abstract]
   
   
3. Carcinoma of the skin (excluding eyelid, vulva, and penis). In: American Joint Committee on Cancer.: AJCC Cancer Staging Manual. 6th ed. New York, NY: Springer, 2002, pp 203-208. 
   
   
4. Dubin N, Kopf AW: Multivariate risk score for recurrence of cutaneous basal cell carcinomas. Arch Dermatol 119 (5): 373-7, 1983.  [PUBMED Abstract]
   
   

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