Abstract

Background

Some groups of people have a greater risk of developing common non‐melanoma skin cancers (NMSC).

Objectives

To evaluate interventions for preventing NMSC in people at high risk of developing NMSC.

Search methods

We searched the Cochrane Skin Group Specialised Register (March 2007), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2007, MEDLINE (from 2003 to March 2007), EMBASE (from 2005 to March 2007), the metaRegister of Controlled Trials (February 2007). References from trials and reviews were also searched. Pharmaceutical companies were contacted for unpublished trials.

Selection criteria

Randomised controlled trials of adults and children at high risk of developing NMSC.

Data collection and analysis

Two review authors independently selected studies and assessed their methodological quality.

Main results

We identified 10 trials (7,229 participants) that assessed a variety of interventions.

One trial found T4N5 liposome lotion significantly reduced the rate of appearance of new BCCs in people with xeroderma pigmentosum.

One of three trials of renal transplant recipients showed a significantly reduced risk of new NMSCs when acitretin was compared to placebo (relative risk (RR) 0.22 95% confidence interval (CI) 0.06 to 0.90) and no significant difference in risk of adverse events in two trials (RR 1.80, 95% CI 0.70 to 4.61).

In three trials conducted in people with a history of NMSC, the evidence was inconclusive for the development of BCCs for retinol or isoretinoin. However the risk of a new SCC in one trial (HR 1.79, 95% CI 1.16 to 2.76) and adverse events in another trial (RR 1.76, 95% CI 1.57 to 1.97) were significantly increased in the isotretinoin group compared with placebo.

In one trial selenium showed a reduced risk of other types of cancer compared with placebo (RR 0.65, 95% CI 0.50 to 0.85) but also a significantly elevated risk of a new NMSC (HR 1.17, 95% CI 1.02 to 1.34). The evidence for one trial of beta‐carotene was inconclusive; and there was a trend towards fewer new NMSC in a trial of a reduced fat diet (RR 0.16, 95% CI 0.02 to 1.31), p = 0.09.

Authors' conclusions

Some preventative treatments may benefit people at high risk of developing NMSC, but the ability to draw firm conclusions is limited by small numbers of trials, often with one trial per intervention or with inconsistent results between studies.

Author(s)

Fiona J Bath‐Hextall, Jo Leonardi‐Bee, Neal Somchand, Angela C Webster, Jim Dellit, William Perkins

Abstract

Plain language summary

Interventions for preventing of non‐melanoma skin cancers in high‐risk groups

Non‐melanoma skin cancer is still the most common cancer in the UK, the United States and Australia. People at increased risk of getting non‐melanoma skin cancer include those with lowered immunity, a history of non‐melanoma skin cancer, rare inherited genetic skin disorders, trauma to the skin, exposure to arsenic, albinism or having had psoralen and ultraviolet A treatment. Very few studies have been conducted in people at increased risk of NMSC.

For people with Xeroderma pigmentosum (a rare inherited genetic skin disorder) topical application of T4N5 liposome lotion is beneficial in reducing the rate of appearance of new basal cell carcinomas, however it may increase the risk of a new squamous cell carcinoma. Acitretin in renal transplant recipients may be of some benefit, however, high doses of acitretin are associated with an increased number of adverse events. Retinol or a reduced fat diet may be worth trying for people with a history of non‐melanoma skin cancer. Further prevention studies for people at increased risk of non‐melanoma skin cancer are needed.

Author(s)

Fiona J Bath‐Hextall, Jo Leonardi‐Bee, Neal Somchand, Angela C Webster, Jim Dellit, William Perkins

Reviewer's Conclusions

Authors' conclusions 

Implications for practice 

It should be borne in mind that reduction in sun exposure through seeking shade, clothing protection and wearing sunscreens are all of key importance in the prevention of non melanoma skin cancer. Sun avoidance and protection are not part of the scope of this review as they have been considered elsewhere.

Xeroderma pigmentosum is a rare inherited genetic skin disorder. The frequency of all forms of skin cancer is higher in these people than in the general population. Topical application of T4N5 appears to significantly reduce the rate of appearance of new BCCs and possibly the risk of new BCCs. However these results should not be taken in isolation since this is based on one small study.

Renal transplant recipients are at a significantly increased risk of developing skin cancer compared to immunocompetent individuals. The number of solid organ transplants continue to rise and survival time continues to improve; however with increased survival times comes an increased risk of developing skin cancer.

One study (Bouwes Bavinck 1995) found significantly fewer participants in the acitretin group developed NMSCs within six months, however this is based on one small study. It is possible that altering the immunosuppresive regimens may have an important effect in reducing NMSC risk and this aspect will be considered in the next update of this review.

People with a history of NMSC are at increased risk of developing further NMSC. There is insufficient evidence to support the use of retinol however only two small studies have been done. Isotretinoin increases the risk of developing a new SCC. No difference in the effectiveness of beta carotene, selenium or a reduced fat diet have been seen in this review, however data are from single studies.

Implications for research 

There is an urgent need for more research since the incidence of NMSC is increasing year on year and the number of transplant recipients is also on the increase. Prevention of skin cancers in these groups should be a priority, not only from the patient perspective, but also in terms of financial savings for the Health Services. Further randomised controlled studies of the interventions identified in this review should be done. Further research in people with Xeroderma pigmentosum is needed since this disorder of the skin has a huge impact on the quality of life of these often very young people whose life expectancy may be shortened by over 30 yrs.

Additionally, this systematic review identified no randomised controlled trials for the prevention of non melanoma skin cancer for people with albinism; people with trauma or burns; people with basal cell naevus syndrome; people exposed to arsenic; people with RDEB; or those treated using PUVA. All of these groups of people are at a high risk of NMSC and therefore high quality trials of prevention treatment should be implemented.

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