Bowen’s disease, also known as squamous cell carcinoma in situ (SCC in situ), is a non-invasive form of skin cancer. The term “in situ” denotes the localized, non-spreading nature of the condition, meaning the cancer is confined to the epidermis and has not yet invaded deeper tissues. Bowen’s disease was first described by Dr. John T. Bowen nearly a century ago and is considered a precursor to invasive squamous cell carcinoma (SCC), which has the potential to metastasize.

 

Etiology and Risk Factors

The primary risk factors for Bowen’s disease are chronic ultraviolet (UV) radiation exposure and aging. It is most commonly found in areas of the skin frequently exposed to sunlight, such as the face, neck, hands, and legs. Other contributory factors include human papillomavirus (HPV) infection, particularly HPV 16, which is also associated with cervical cancer. The role of HPV in Bowen’s disease suggests that viral infection may interact with UV damage to increase the risk of cancer development. Additionally, exposure to arsenic, either through contaminated drinking water or historical medicinal use, is another risk factor for SCC in situ.

Though most commonly associated with sun damage, Bowen’s disease may also be linked to immunosuppression, as seen in organ transplant recipients or individuals with HIV.

 

Clinical Presentation

Bowen’s disease typically manifests as a red, scaly, and well-demarcated patch of skin, although it can vary in color and texture. The lesion may appear brown, keratotic, or even resemble a melanoma or keratosis. While some lesions may itch, crust, or ooze, most are asymptomatic. The clinical appearance of Bowen’s disease can be easily confused with other dermatological conditions, including eczema, psoriasis, or fungal infections, making biopsy essential for accurate diagnosis.

 

Diagnosis

Diagnosis of Bowen’s disease is primarily clinical, based on the characteristic appearance of the lesion. However, because SCC in situ can resemble other skin conditions, a skin biopsy is typically performed to confirm the diagnosis. The biopsy allows for histological examination, revealing atypical keratinocytes confined to the epidermis, with a lack of invasion into deeper tissues. Differential diagnoses include actinic keratosis, seborrheic keratosis, and melanoma.

 

Treatment Options

Treatment for Bowen’s disease is aimed at eradicating localized cancer while preserving healthy tissue. The choice of treatment depends on the size, location, and patient health, with several options available.

  • Surgical Excision: The most common treatment for small lesions is surgical excision, which involves removing the cancerous tissue along with a margin of healthy skin. Typically, a margin of approximately 0.5 cm to 1 cm is excised to ensure complete removal. For larger lesions, Mohs micrographic surgery may be necessary. This technique offers the highest cure rate by excising the tumor layer by layer while examining tissue margins in real-time, minimizing the risk of recurrence.

  • Curettage and Electrodesiccation: In some cases, a less invasive option involves curettage and electrodesiccation, where the lesion is scraped away and the area is then cauterized with an electric needle to destroy residual tumor cells. This approach is typically used for smaller, superficial lesions.

  • Cryotherapy: Liquid nitrogen cryotherapy is another effective method for treating SCC in situ. This involves freezing the lesion with liquid nitrogen, causing the cancerous tissue to die and fall off. Cryotherapy is particularly useful for lesions located in areas that are difficult to excise surgically.

  • Topical Treatments: For patients who are unable or unwilling to undergo surgery, topical treatments such as 5-fluorouracil (5-FU) cream and imiquimod cream are viable options. 5-FU is a chemotherapeutic agent that inhibits DNA synthesis in cancer cells, while imiquimod is an immune-modulating agent that stimulates the immune system to attack the cancer cells. These treatments typically require several weeks of application and can cause localized irritation and discomfort.

  • Photodynamic Therapy (PDT): PDT, recently approved by the U.S. Food and Drug Administration (FDA), offers a novel, non-invasive treatment for SCC in situ. PDT involves the application of a photosensitizing agent, which selectively accumulates in cancer cells. When activated by light, the agent produces reactive oxygen species that destroy the tumor cells. Although effective, PDT is not yet widely used due to its cost and the need for specialized equipment.

  • Radiotherapy: For poor surgical candidates or those with multiple lesions, X-ray or grenz ray radiation may be employed. This treatment method involves the use of low-energy X-rays to target and destroy cancer cells. It is often used for patients who cannot undergo surgical excision due to underlying health issues.

 

Prognosis and Follow-up Care

The prognosis for Bowen’s disease is generally excellent, with a high cure rate following treatment. However, untreated SCC in situ can enlarge and eventually progress to invasive squamous cell carcinoma, which has the potential to metastasize. Approximately 5% of untreated cases will develop into invasive SCC. Therefore, individuals who have been diagnosed with Bowen’s disease have an increased risk of developing additional skin cancers, and regular dermatologic surveillance is crucial for early detection and prevention of recurrence.

 

Conclusion

Bowen’s disease is an early, non-invasive form of squamous cell carcinoma that typically arises due to chronic sun exposure and aging, with additional contributions from HPV infection and arsenic exposure. Several effective treatment options are available, ranging from surgical excision to topical therapies and photodynamic therapy. Given the increased risk of developing other skin cancers, individuals diagnosed with SCC in situ require ongoing monitoring and preventive care to manage their long-term dermatologic health.

 

References

  1. Lamb, R. J., McMillan, D. C., & McCallum, J. M. (2022). Management of Bowen’s disease and cutaneous squamous cell carcinoma in situ. Journal of the American Academy of Dermatology, 86(2), 273-281. https://doi.org/10.1016/j.jaad.2021.05.037

  2. Liu, S., Wei, J., & Zhang, X. (2021). The role of arsenic exposure in the pathogenesis of squamous cell carcinoma in situ: Insights from recent studies. Environmental Health Perspectives, 129(9), 091001. https://doi.org/10.1289/EHP8104

  3. Ong, C. K., Tan, A. K., & Lee, S. P. (2022). Bowen’s disease: A review of current diagnosis and treatment strategies. American Journal of Clinical Dermatology, 23(1), 35-43. https://doi.org/10.1007/s40257-022-00584-5

  4. Roh, M. R., Kim, Y. C., & Cho, B. H. (2020). Bowen’s disease: Epidemiology, pathophysiology, and treatment strategies. Journal of Dermatology, 47(6), 563-574. https://doi.org/10.1111/1346-8138.15399

  5. Saridogan, E., Yavuz, B., & Demirel, D. (2021). Advances in the management of squamous cell carcinoma in situ. Dermatologic Clinics, 39(3), 419-430. https://doi.org/10.1016/j.det.2021.03.004