Preventing Female Cancers with Light

A major advantage of photodynamic therapy, or PDT, is its ability to eliminate tumors and other diseased tissues while preserving normal tissues. PDT is technically known as a non-surgical ablative therapy because it destroys (ablates) malignant and pre-malignant growths without causing the damage the surgery incurs on the body itself. Such therapeutic specificity or disease-targeting ability is one of the main reasons PDT has garnered so much attention as a way to treat more delicate areas of the body.

Among the more delicate aspects of the human anatomy is the vulva, a tender part of the female genitalia that has been described as the outer portal of the human womb. This structure protects the vaginal opening and provides pleasure during sexual intercourse. In various branches of art, the vulva has been depicted as the organ that has the power to “give life” while also bestowing sexual pleasure.

A recent study at the Comprehensive Gynecologic Cancer Center of CHA Bundang Medical Center in Gyeonggi-do, Korea, sought to determine whether PDT could be effective in preserving the vulva’s structure and function. The focus was on a group of women with various precancerous conditions affecting the vulva and associated structures.  Over a ten-year period, a total of 15 women received PDT for three different types of premalignant lesions: vulvar intraepithelial neoplasia (VIN), vaginal intraepithelial neoplasia (VAIN), or vulvar Paget’s disease.  

The treatment procedure involved an intravenous injection of the photosensitizer Photogem®, followed by light treatment.   A photosensitizer is an agent that captures and then converts light energy for therapeutic purposes. Two days after the injection, the surface of the vulva was illuminated with red light using a 630-nm laser at a specific light dose.

Three months after the treatment, 80% of the women had shown a complete response, as reported online ahead-of-print in the 14 July 2015 issue of Lasers in Surgery and Medicine. At the one year mark, two cases had shown a recurrence, and 71% of the patients had maintained a complete response.

The treatment was also well tolerated, with only two cases having photosensitivity reactions such as facial swelling and itchy skin. To reduce such discomfort, patients can be pre-medicated with non-steroidal anti-inflammatory drugs or NSAIDs.  But the obvious benefit of PDT is that the treatment experience itself is very mild—certainly light years better than more conventional approaches such as cryotherapy, the localized freezing of the target tissue (see quote below).

The Korean authors concluded that “PDT may be an effective alternative treatment for premalignant lesions of the female lower genital tract to preserve normal anatomy and sexual function without therapeutic impairment.” By treating these precancers, this tissue-preserving, humane treatment was helping to prevent the onset of female cancers later on.

According to a report published last year in the Annals of Dermatology, PDT may also be effective against intraepidermal squamous cell carcinoma (Bowen’s disease) of the vulva. This disease has the potential to progress to an invasive carcinoma and may affect both the skin and the mucous membranes of the genital area. The report focuses on two cases that were successfully treated at Gachon University Gil Medical Center in Incheon, Korea.

“The vulva area is difficult to treat using cryotherapy due to its painful nature and some patients simply do not favor aggressive treatment for cosmetic reasons,” the authors state. “On the other hand, PDT is painless and produces good cosmetic outcomes.” Nevertheless, despite many reports of successful PDT treatment, only a few have addressed the treatment of female genital lesions.

The Gachon University authors offer the following conclusion: “The use of topical PDT for the treatment of Bowen’s disease on the vulva area appears to be a highly effective therapeutic option that produces good cosmetic results. Furthermore, it is a tissue-sparing treatment and non-invasive. Both of our patients were satisfied with their cosmetic results, although the skin lesions partially remained.” They encourage further research to develop the use of PDT to treat Bowen’s disease and other conditions affecting the vulva region.

Sources

Choi MC, Kim MS, Lee GH, Jung SG, Park H, Joo WD, Lee C, Lee JH, Hwang YY, Kim SJ. Photodynamic therapy for premalignant lesions of the vulva and vagina: A long-term follow-up study. Lasers Surg Med. 2015 Jul 14. [Epub ahead of print]

Kang HK, Yun JH, Son YM, Roh JY, Lee JR. Photodynamic Therapy for Bowen’s Disease of the Vulva Area. Ann Dermatol. 2014 Apr;26(2):241-5

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