Table 2. Tumor Characteristics.
| Characteristic | No. (%) (N = 51) |
|---|---|
| Location of aggressive SCCa | |
| Scalp | 6 (12) |
| Face | 34 (67) |
| Neck | 1 (2) |
| Trunk | 2 (4) |
| Arm or hand | 6 (12) |
| Genitalia | 2 (4) |
| Histologic classification of SCC | |
| Well differentiated | 10 (20) |
| Moderately differentiated | 15 (29) |
| Poorly differentiated | 21 (41) |
| Spindle cell morphologic characteristics | 2 (4) |
| Desmoplastic | 3 (6) |
| Primary tumor, median (range), mm | |
| Diameter of SCC | 18.0 (4-64) |
| Total No. (No. missing) | 50 (1) |
| Depth of invasion | 6.2 (1-20) |
| Total No. (missing) | 48 (3) |
| Tumor-free margins on histologic examination | 2.0 (0-15) |
| Total No. (No. missing) | 38 (13) |
| Clark level of invasionb | |
| Level I | 1 (2) |
| Level II | 1 (2) |
| Level III | 0 |
| Level IV | 14 (28) |
| Level V | 33 (65) |
| Missing data | 2 (4) |
| Perineural invasion | |
| Absent | 30 (59) |
| Present | 20 (39) |
| Missing data | 1 (2) |
| Local recurrence | |
| Absent | 21 (41) |
| Present | 23 (45) |
| Missing data | 7 (14) |
| Metastasis sitec | |
| No metastasis | 6 (12) |
| Lymph nodes | 30 (59) |
| Parotid gland | 10 (20) |
| Liver | 2 (4) |
| Lung | 6 (12) |
| Brain | 4 (8) |
| Bone | 7 (14) |
| Skin | 11 (22) |
| Muscle | 1 (2) |
| Intraorbital | 1 (2) |
Abbreviation: SCC, squamous cell carcinoma.
a
An aggressive SCC was defined by regional metastasis (lymph nodes or parotid gland); distant metastasis including liver, lung, brain, or bone; or a local, therapy-resistant progression of primary SCC.
b
Clark level I is confined to the epidermis, level II penetrates the papillary dermis, level III fills the papillary dermis, level IV extends into reticular dermis, and level V invades subcutis.
c
Metastasis location was counted for every patient; some had multiple organ metastasis.