Photon irradiation using a water bath technique for treatment of confluent carcinoma in situ of the hand, digits, and nail bed: A case report

Background: Confluent squamous cell carcinoma in situ, or Bowen's disease, involving the hand, digit, and nail bed is rare and represents a significant therapeutic challenge. Surgical excision is recommended as first-line treatment but in cases of extensive disease can lead to unacceptable functional morbidity or cosmetic outcomes. Radiation therapy has been shown to be equally efficacious to surgery in the treatment of carcinoma in situ but its use has historically been limited due to concerns regarding toxicity. In this case report we present a novel therapeutic technique that may enable radiotherapy to be employed as a definitive treatment option in these challenging cases. Case presentation: A 75-year-old white man with a previous history of carcinoma in situ of his right hand previously treated with 5-fluorouracil presented with recurrent biopsy-proven confluent squamous cell carcinoma in situ of multiple surfaces of his right hand and digits with involvement of nail beds. To avoid extensive resection and possible amputation he was offered definitive external beam radiation therapy utilizing a water bath as a tissue-equivalent bolus material. This protocol enabled improved dose homogeneity to the target volume while minimizing acute toxicity. He experienced complete clinical resolution of the disease with only minimal acute edema and hyperpigmentation. Twenty months following treatment completion he remains disease-free with normal function and excellent cosmesis. Conclusions: Therapeutic radiation utilizing water as a tissue-equivalent bolus in this complicated case enabled definitive treatment of disease without compromising functional or cosmetic outcomes. Radiotherapy may therefore be an alternative and under-utilized approach to surgical excision in difficult-to-treat cases of carcinoma in situ.