Table 4. Comparison of demographic and clinical characteristics of patients who had malignant transformation of their PK and those who did not among the histologically confirmed cases (includes definitive, probable, and possible cases of malignant transformation).
BCC, basal cell carcinoma; CI, confidence interval; DSAP, disseminated superficial actinic porokeratosis; MIS, melanoma in situ; NS, not specified; OR, odds ratio; PK, porokeratosis; PM, porokeratosis of Mibelli; SCC, squamous cell carcinoma; SCCIS, squamous cell carcinoma in situ; UV, ultraviolet
* Statistically significant (p < 0.05)
| Malignant transformation | Unadjusted | Adjusted | ||||||||
| Yes (N) | No (N) | OR | 95% CI | P-Value | OR | 95% CI | P-Value | |||
| Demographic information | ||||||||||
| Gender | Female | 12 | 39 | 2.718 | 0.938-7.874 | 0.0730 | -- | -- | -- | |
| Male | 6 | 53 | ||||||||
| Race | African American | 1 | 2 | 2.647 | 0.227-30.853 | 0.4181 | -- | -- | -- | |
| Caucasian | 17 | 90 | ||||||||
| PK characteristics | ||||||||||
| PK type | PM | 4 | 63 | 0.153 | 0.046-0.517 | 0.0016* | 0.101 | 0.025-0.406 | 0.0012* | |
| DSAP | 12 | 29 | ||||||||
| Linear PK | 2 | 0 | -- | -- | -- | -- | -- | -- | ||
| Treatment | No | 12 | 65 | 0.831 | 0.283-2.441 | 0.7813 | -- | -- | -- | |
| Yes | 6 | 27 | ||||||||
| PK location | ||||||||||
| Head/Neck | Involved | 0 | 4 | -- | -- | -- | -- | -- | -- | |
| Uninvolved | 18 | 88 | ||||||||
| Upper extremity | Involved | 11 | 40 | 2.043 | 0.727-5.742 | 0.2021 | -- | -- | -- | |
| Uninvolved | 7 | 52 | ||||||||
| Lower extremity | Involved | 16 | 73 | 2.082 | 0.440-9.852 | 0.5156 | -- | -- | -- | |
| Uninvolved | 2 | 19 | ||||||||
| Trunk | Involved | 2 | 11 | 0.921 | 0.186-4.555 | 1.00 | -- | -- | -- | |
| Uninvolved | 16 | 81 | ||||||||
| Skin cancer history | ||||||||||
| Previous SCC/SCCIS | Yes | 8 | 62 | 0.387 | 0.139-1.081 | 0.1057 | -- | -- | -- | |
| No | 10 | 30 | ||||||||
| Previous BCC | Yes | 7 | 72 | 0.177 | 0.061-0.515 | 0.0015* | 0.541 | 0.146-2.000 | 0.3568 | |
| No | 11 | 20 | ||||||||
| Previous melanoma/MIS | Yes | 3 | 54 | 0.141 | 0.038-0.520 | 0.0015* | 0.379 | 0.060-2.400 | 0.3029 | |
| No | 15 | 38 | ||||||||
| Previous other skin cancer | Yes | 0 | 46 | - | - | - | -- | -- | -- | |
| No | 18 | 46 | ||||||||
| Subsequent SCC/SCCIS | Yes | 11 | 63 | 0.723 | 0.255-2.056 | 0.5879 | -- | -- | -- | |
| No | 7 | 29 | ||||||||
| Subsequent BCC | Yes | 11 | 66 | 0.619 | 0.217-1.770 | 0.4049 | -- | -- | -- | |
| No | 7 | 26 | ||||||||
| Subsequent melanoma/MIS | Yes | 1 | 48 | 0.054 | 0.007-0.422 | 0.0002* | 0.857 | 0.036-20.671 | 0.9242 | |
| No | 17 | 44 | ||||||||
| Subsequent other skin cancer | Yes | 1 | 46 | 0.059 | 0.008-0.461 | 0.0004* | 0.057 | 0.002-1.372 | 0.0745 | |
| No | 17 | 46 | ||||||||
| Exposure history | ||||||||||
| Immune suppression | No | 12 | 64 | 0.875 | 0.298-2.566 | 0.7869 | -- | -- | -- | |
| Yes | 6 | 28 | ||||||||
| UV therapy | No | 17 | 91 | 0.187 | 0.011-3.133 | 0.3018 | -- | -- | -- | |
| Yes | 1 | 1 | ||||||||
| Radiation therapy | No | 13 | 81 | 0.353 | 0.105-1.182 | 0.135 | -- | -- | -- | |
| Yes | 5 | 11 | ||||||||