Use of sunscreen and risk of melanoma and non-melanoma skin cancer: a systematic review and meta-analysis

Background

The use of sunscreen is a key component of public health campaigns for skin cancer prevention, but epidemiological studies have raised doubts on its effectiveness in the general population.

Objectives

This systematic reviewand meta-analysis aimed to assess the association between risk of skin cancer and sunscreen use.

Materials & Methods

We searched PubMed, BIREME and Google Scholar from inception to May 17, 2017, to identify observational studies and controlled trials. We used a random-effects model for conventional and cumulative meta-analyses.

Results

We included 29 studies (25 case-control, two cohort, one cross-sectional, and one controlled trial) involving 313,717 participants (10,670 cases). The overall meta-analysis did not showa significant association between skin cancer and sunscreen use (odds ratio (OR) = 1.08; 95% CI: 0.91-1.28, I² = 89.4%). Neither melanoma (25 studies; 9,813 cases) nor non-melanoma skin cancer (five studies; 857 cases) were associated with sunscreen use, with a pooled OR (95% CI) of 1.10 (0.92-1.33) and 0.99 (0.62-1.57), respectively. The cumulative evidence before the 1980s showed a relatively strong positive association between melanoma and sunscreen use (cumulative OR: 2.35; 95% CI: 1.66-3.33). The strength of the association between risk of skin cancer and sunscreen use has constantly decreased since the early 1980s, and the association was no longer statistically significant from the early 1990s.

Conclusions

While the current evidence suggests no increased risk of skin cancer related to sunscreen use, this systematic review does not confirm the expected protective benefits of sunscreen against skin cancer in the general population.

     

Effectiveness of interventions to support the early detection of skin cancer through skin self-examination: a systematic review and meta-analysis

Skin cancer is increasing in many countries, including in the UK. For example, in the USA in 2017, over 87,000 people had been diagnosed with a dangerous type of skin cancer (melanoma); of these it was expected that nearly 10,000 would die from the condition. We are a U.K based research team that conducted a review of scientific papers from across the world. Our aim was to examine and pool the existing research on whether the different approaches to helping people to examine their own skin, to detect skin cancer early, are effective or not. This review identified all the relevant published articles for available research studies up to April 2018. The identified relevant studies totalled 18 in number, which we then summarised. These approaches included education, such as teaching and reminding people (sometimes using technology, for example, using computers and mobile phones) to examine their skin and quickly report any suspicious changes to their doctor. We found that the various approaches used had a positive effect on peoples’ likelihood and ability to examine their skin, especially in the short-term. More studies targeted people at higher risk of skin cancer, such as those with a previous diagnosis of skin cancer, compared to people at no greater risk. Of the research we looked at, two thirds of the studies were poorly designed. Skin specialists should raise awareness and support people to routinely examine their skin for skin cancer, especially those at high risk.     

Imiquimod for actinic keratosis: systematic review and meta-analysis

Benefit and harm associated with treating actinic keratosis (AK) with the immune response modifier imiquimod was assessed using published randomized-controlled trials. Five randomized double-blind trials lasted 12-16 weeks and treated 1,293 patients. Complete clearance occurred in 50% of patients treated with imiquimod, compared to 5% treated with vehicle, and the number needed to treat (NNT) for one patient to have their keratosis completely cleared after 12-16 weeks was 2.2 (95% confidence interval 2.0-2.5). For partial (>/=75%) clearance the NNT was 1.8 (1.7-2.0). The proportion of patients with any adverse event, any local adverse event, or any treatment-related adverse event was substantially higher with imiquimod than with vehicle, and numbers needed to harm for one additional adverse event with imiquimod over 12-16 weeks ranged from 3.2 to 5.9. Particular local adverse events with imiquimod included erythema (27%), scabbing or crusting (21%), flaking (9%), erosion (6%), edema (4%), and weeping (3%). Imiquimod 5% cream was effective in the treatment of AK, preventing potential development of squamous cell carcinoma. Future investigation might be aimed at elucidating optimal dosing to minimize adverse events without detriment to efficacy, and evaluating long-term recurrence.     

Lasers for scars: a review

Many articles have been published on improving the appearance of scars; however, there are no definitive management protocols. Our objective was to review the literature on laser therapy for various types of scars. There are multiple laser modalities that have been studied with certain features that may be indicated for specific scar types. Suggestions are given for further studies.     

Bullous pemphigoid and diabetes mellitus: a systematic review and meta-analysis

We aimed to systematically review and meta-analyze the association between diabetes mellitus (DM) and bullous pemphigoid (BP). Bullous pemphigoid (BP) is a prevalent autoimmune subepidermal blistering disease. Comorbid health conditions like neurological diseases and malignancies have been associated with BP. Growing evidence suggests that type 2 diabetes mellitus (T2DM) may increase the risk of developing BP. This review aims to synthesize this evidence. A systematic literature review was performed using Medline, PubMed, and Scopus in March 2022. Studies exploring the association between BP and DM were included. Data were extracted, and quality was assessed using the Newcastle–Ottawa scale. Meta-analysis was conducted to identify the odds ratio (OR) and 95% confidence intervals (CI) of the association. Seventeen studies were included, most being case–control studies from Europe and Asia. The pooled OR was 2.06 (95% CI: 1.61–2.62), suggesting a significant association between DM and BP. However, strong heterogeneity (I² = 88%) was observed. Evidence consolidates a significant relationship between DM and BP, potentially due to alterations in the immune system and skin properties caused by diabetes. Strengths of this review include a comprehensive search, rigorous methodology, large sample size, and heterogeneity evaluation. However, varying study quality, potential publication bias, and unaccounted confounding factors present limitations. There is a potential link between T2DM and an increased risk of BP. Further studies are required to understand this association and the underlying mechanisms.     

Management of unwanted hair in females

The development of lasers as a treatment for unwanted hair has led to an increased interest in this field. Laser hair removal is frequently commercially led and there are few controlled studies to demonstrate efficacy. It is important to be aware of all treatment modalities for hair removal so that patients can be counselled adequately. This review covers all methods of hair removal from physical through hormonal to laser treatment and allows the reader to understand the pros and cons of each form of therapy.     

Patient education in chronic skin diseases: a systematic review

The negative impact of skin disease on quality of life (QoL) has been described in many studies. Patient education as an adjunct to treatment, with the aim of improving QoL and reducing disease severity, is a relatively new technique in dermatology. The objective of this article is to analyse and summarise evidence concerning the effects of patient education on QoL and disease severity in patients with chronic skin diseases. All source material was identified through searches in MEDLINE and Embase. The CONSORT statement was used to assess the quality of reported randomised controlled studies. Ten of 254 studies met the inclusion criteria. In five of them, statistically significant improvements in QoL were reported. The severity of skin disease significantly improved in three studies. In conclusion, patient education appears to be effective in improving QoL and in reducing the perceived severity of skin disease.     

Lasers for facial rejuvenation: a review

BACKGROUND: Different types of laser are used for resurfacing and collagen remodeling in cutaneous laser surgery. METHODS: A systematic review was performed of the different types of laser currently employed for skin rejuvenation. These systems are either ablative [high-energy pulsed or scanned carbon dioxide (CO2) laser emitting at a wavelength of 10,600 nm, single- or variable-pulse or dual ablative/coagulative mode erbium:yttrium aluminum garnet (Er:YAG) laser emitting at a wavelength of 2940 nm, or systems combining both 10,600 nm and 2940 nm wavelengths] or nonablative [Q-switched neodymium:yttrium aluminum garnet (Nd:YAG) laser emitting at a wavelength of 1064 nm, Nd:YAG laser emitting at a wavelength of 1320 nm, or diode laser emitting at a wavelength of 1450 nm]. Different protocols, patient selection, treatment techniques, and complications are discussed for each system. RESULTS: New-generation CO2 resurfacing lasers have been successful in the treatment of photodamaged skin and scarring, with a postoperative morbidity dependent on the depth of thermal damage. Because of its minimal penetration, the pulsed Er:YAG laser, usually used in the treatment of more superficial rhytides, produces less postoperative morbidity. Novel ablative systems have been developed and a further understanding of laser-tissue interaction has led to the design of nonablative systems for the treatment of rhytides, scarring, and photodamaged skin, the efficacy and profile of which remain to be evaluated in the long term. CONCLUSIONS: There are several effective techniques for scar revision and the treatment of aged skin, but all have their drawbacks due to a lack of precise depth control and unwanted damage to the lower layers of the dermis. The Er:YAG laser is the treatment of choice for fine lines and superficial scars, whereas the CO2 laser is better for deeper rhytides and scars. In the future, a combination of lasers may be used for facial rejuvenation.