Photoprotection: Fundamental in Organ Transplant Patients

We read with interest the article by Soltani-Arabshahi and Tristani-Firouzi published in the Facial Plastic Surgery Journal in October 2013, on chemoprevention of nonmelanoma skin cancer (NMSC) in solid organ transplant patients (OTR). We commend them for their extensive review of the literature and thoughtful discussion on chemopreventive modalities from retinoids and nonsteroidal anti-inflammatory agents to photodynamic therapy and nutritional factors. As the population of long-term surviving OTRs increases, so does the need to prevent ultraviolet (UV)-induced NMSC, the leading form of cancer in this population. The least invasive preventive approach of sun avoidance via sunscreen use often gets missed in the management algorithm. In a November 2009 publication in the British Journal of Dermatology, Ulrich et al assessed the preventive effects of sunscreen use in chronically immunocompromised OTRs and found a marked difference in favor of the intent-to-treat sunscreen group. Regular use of sunscreens, as part of a consequent UV-protection strategy, significantly prevented the development of further actinic keratosis, invasive squamous cell carcinoma and, to a lesser degree, basal cell carcinoma in OTRs. [Fig. 1] outlines the light blocking spectrum of common sunscreen ingredients. In a November 2008 review in the Clinics in Dermatology Journal, González et al described the best option for photoprotection to include a physical blocker such as zinc oxide, with antioxidants (vitamin E, vitamin C, astaxanthin, and flavonoids) and stimulators of repairing mechanisms (dihydroxyacetone and DNA repair enzymes) to get the broadest and most effective coverage.

Fig. 1 Wavelength spectrum coverage of common sunscreen ingredients.

Soltani-Arabshahi and Tristani-Firouzi reported that “given the increasing number of patients on immunosuppressive therapies who are at high risk of developing numerous and/or aggressive NMSC, the need for a safe and effective prevention strategy is rising.” We wholeheartedly agree and corroborate that further studies need to be performed to address chemoprevention options for areas with field cancerization. That said, due diligence should also be performed to encourage patients' utilization of the least invasive, easily attainable, and cost-effective options such as broad spectrum sunscreens and ultraviolet protection factor clothing before progression to systemic chemoprevention treatments. Finally, sun-protective antioxidants (such as B-carotene supplementation and polypodium leucotomos extract) may have a role that has yet to be explored in this population. We present an evidence-based summary of the chemopreventive and noninvasive treatment options for NMSC treatment among OTRs ([Table 1]).

Table 1 Modality for prevention of NMSC in solid organ transplant patients

Treatment	Level of support
Photoprotection	Effective
PDT	Effective
Imiquimod	Effective
Diclofenac sodium, topical	Potential prevention
Celecoxib	Modest potential prevention
Oral retinoids	Effective for SCC
DFMO	Potential in BCC, no impact on SCC
Caffeine	Consumption inversely associated with BCC, no impact on SCC
5-FU	Not studied in large randomized controlled trials
Ingenol mebutate	Not studied in immunosuppressed
Perillyl alcohol	Not supported
Topical retinoids	Not supported
Vitamin D	Not supported
B-carotene	Not supported

Abbreviations: 5-FU, 5-fluorouracil; BCC, basal cell carcinoma; DFMO, difluoromethylornithine; NMSC, nonmelanoma skin cancer; PDT, photodynamic therapy; SCC, squamous cell carcinoma.