Hydroxyurea (HU) is one of the mainstay agents used to treat myeloproliferative disorders as well as sickle cell anemia. There has been lately increasing reports of secondary skin malignancies in patients receiving Hydroxyurea therapy but the literature consists essentially of case reports. Current incidence of melanoma skin cancer in the general population in the United States is 15 per 100 000 person, and of non melanoma skin cancer is 230 per 100 000 lightly pigmented individuals and 3.4 per 100 000 darkly pigmented individuals.
We reviewed 292 charts of patients treated with HU in our institution. 237 patients carried a diagnosis of myeloproliferative disorder, 14 patients were treated for sickle cell anemia and 41 patients were being treated with HU for HIV as part of a regimen to decrease viral load. Charts were reviewed looking for development of skin malignancies.
Among the patients with sickle cell anemia, the incidence of skin cancer was nil. Among the patients with HIV there were 2 cases of non melanoma skin cancer. Among patients with myeloproliferative disorders, there were 16 cases of skin cancer. The pathology was non-melanoma skin cancer. Subgroup analysis based on skin phenotype revealed that the incidence was higher than the general population in both dark and light-skinned individuals: the rate was 0.9434 per 100 among the dark skinned individuals, statistically significant when compared to the established rate of 0.0034 per 100 dark-skinned individual in the general population. Similarly among light-skinned individuals, the calculated rate was 12.0968 per 100-person, which is statistically significant compared to the rates in light-skinned individuals in the general population of 0.2300 per 100 person with a p-value of 0.001.
Our study showed a significantly higher incidence of non-melanoma skin cancer among patients treated with HU. While HU is well known to have cutaneous side effects in terms of hyperpigmentation, skin ulcers, scaling or skin atrophy, its implication in skin cancers had only been in the form of case reports. Our study thus highlights a true risk of skin malignancies with HU. It is worth noting though that there were only non-melanoma skin cancers, which are non-aggressive, localized and treatable. Thus this heightened incidence of skin cancer does not appear to bear a mortality or morbidity burden on patients treated with HU.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.