Bowen's disease

Cutaneous squamous-cell carcinoma (cSCC), also known as squamous-cell carcinoma of the skin or squamous-cell skin cancer, is one of the three principal types of skin cancer, alongside basal-cell carcinoma and melanoma. cSCC typically presents as a hard lump with a scaly surface, though it may also present as an ulcer. Onset and development often occurs over several months. Compared to basal cell carcinoma, cSCC is more likely to spread to distant areas. When confined to the epidermis, the outermost layer of the skin, the pre-invasive or in situ form of cSCC is termed Bowen's disease.

The most significant risk factor for cSCC is extensive lifetime exposure to ultraviolet radiation from sunlight. Additional risk factors include prior scars, chronic wounds, actinic keratosis, lighter skin susceptible to sunburn, Bowen's disease, exposure to arsenic, radiation therapy, tobacco smoking, poor immune system function, previous basal cell carcinoma, and HPV infection. The risk associated with UV radiation correlates with cumulative exposure rather than early-life exposure. Tanning beds have emerged as a significant source of UV radiation. Genetic predispositions, such as xeroderma pigmentosum and certain forms of epidermolysis bullosa, also increase susceptibility to cSCC. The condition originates from squamous cells located in the skin's upper layers. Diagnosis typically relies on skin examination, and is confirmed through skin biopsy.

Research, both in vivo and in vitro, indicates a crucial role for the upregulation of FGFR2, part of the fibroblast growth factor receptor immunoglobin family, in cSCC cell progression. Mutations in the TPL2 gene leads to overexpression of FGFR2, which activates the mTORC1 and AKT pathways in primary and metastatic cSCC cell lines. Utilization of a "pan FGFR inhibitor" has shown to reduce cell migration and proliferation in cSCC in vitro studies.

Preventive measures against cSCC include minimizing exposure to ultraviolet radiation and the use of sunscreen. Surgical removal is the typical treatment method, employing simple excision for minor cases or Mohs surgery for more extensive instances. Other options include cryotherapy and radiation therapy. For cases with distant metastasis, chemotherapy or biologic therapy may be employed.

As of 2015, approximately 2.2 million individuals globally were living with cSCC at any given time, constituting about 20% of all skin cancer cases. In the United States, approximately 12% of males and 7% of females are diagnosed with cSCC at some point in their lives. While prognosis remains favorable in the absence of metastasis, upon distant spread the five-year survival rate is markedly reduced to ~34%. In 2015, global deaths attributed to cSCC numbered around 52,000. The average age at diagnosis is approximately 66 years. Following successful treatment of an initial cSCC lesion, there is a substantial risk of developing subsequent lesions. As of 2015, about 2.2 million people worldwide have cSCC at any given time. About 20% of all skin cancer cases consist of cSCC. About 12% of males and 7% of females in the United States develop cSCC at some point in time. While prognosis is usually good, when distant spread occurs five-year survival is ~34%. In 2015, cSCC resulted in approximately 52,000 deaths globally. The mean age at diagnosis is around 66 years. Following the successful treatment of one case of cSCC, a person is at significant risk of developing further cSCC lesions.