If you were to undertake a critical review of all the available research you would come to the conclusion that sunscreen, as part of a SunSmart regime, does reduce the risk of Melanoma and other skin cancers*.

(*Kernagahn is responding to author Ian Wishart concerns about the lack of evidence that sunscreen prevents melanoma.)

The most robust and current research conducted in Australia and published in the Journal of Clinical Oncology in 2011 does just that and a Norwegian study published in 2016 (see details of both studies below).

The Cancer Society would point out that observational epidemiological studies can be confounded because the people who use the most sunscreen have the fairest skin types (and hence at highest phenotypic risk of melanoma) also spend most time outdoors (and hence at highest environmental risk of melanoma).  The society also points out that the only research design that can control such confounding is a randomised controlled trial – which the Australian study was – and that study found that people randomised to use sunscreen on a daily basis had half the melanoma incidence of those who were randomised to applying sunscreen at their own discretion.

But, sunscreen alone is not the solution to preventing skin cancer, the more you minimise the UVA/UBA (sun exposure) the more you minimise the risk of skin cancer, which is why when the UV is high you need to also wear a shirt, hat, sun glasses, and going under shade as they all contribute to reducing your skin cancer risk.

Skin cancer is largely preventable. Over 90% of all skin cancer cases are attributed to excess sun exposure. We encourage all New Zealanders to be SunSmart and to Slip, Slop, Slap and Wrap (not just Slop).

Sunscreen alone is not the solution to preventing skin cancer, as the more you minimise the UV (sun exposure) the more you minimise the risk of skin cancer, so wearing a shirt, hat, sun glasses, and going under shade all contribute to reducing your risk.  When you follow the instructions on the sunscreen label, SPF30 filters 96.7% of UV radiation.  SPF50+ filters 98% of UV radiation.

How to be SunSmart:

  • Slip on a long-sleeved, collared shirt and seek shade, like under a tree.
  • Slop on sunscreen that is at least SPF30+, UVA/UVB broad-spectrum and water resistant
  • Slap on a broad-brimmed hat that shades your face, head, neck and ears
  • Wrap on close fitting sunglasses
  • Don’t use sunbeds

When to be SunSmart:

  • When the ultraviolet index (UVI) is 3 or above
  • From September to April, especially between 10am and 4 pm
  • At the beach, as reflections from water and sand can increase UV
  • At high altitudes, especially near snow, which strongly reflects UV

Mike Kernaghan is chief executive of the Cancer Society of New Zealand

AUSTRALIAN TRIAL

The Australian randomised control trial involved 1621 residents of a Queensland township who for four years in the 1990s were randomly assigned to either daily OR discretionary sunscreen application to head and arms (in combination with 30 mg beta carotene or placebo supplements) until 1996 and were observed until 2006.  Ten years after the trial ceased 11 new melanomas had been identified in the daily sunscreen group and 22 in the discretionary sunscreen use group. The study concluded that melanoma may be preventable by regular sunscreen use in adults.

Green A, Williams G et al (2011) Reduced Melanoma After Regular Sunscreen Use: Randomized Trial Follow-Up, Journal of Clinical Oncology  29 (3)

NORWEGIAN STUDY

The study examined data from the Norwegian Women and Cancer Study involving 143,844 women aged 40 to 75 years at start of study of whom 722 had had cases of melanoma. The study looked at the association between never using sunscreen, using sunscreen with a sun protection factor (SPF) of less than 15 and using a sunscreen with an SPF equal or greater to 15.  It found that sunscreen users reported significantly more sunburns and sunbathing vacations and were more likely to use indoor tanning devices.  It also found that using a sunscreen of SPF 15 or greater was associated “with significantly decreased melanoma risk” compared with using a sunscreen of less than SPF 15. It also concluded that if all women aged 40 to 75 used an SPF 15 or greater sunscreen they could potentially reduce their melanoma incidence by 18 per cent.

Ghiasvand 4, Weiderpass E, Green A et al (2016) Sunscreen Use and Subsequent Melanoma Risk: A Population-Based Cohort Study. Journal of Clinical Oncology 34 (33)

 

1 COMMENT

  1. Sunscreen is expensive lollywater produced by the sponsors of cancer charities and pushed on an unsuspecting public…it protects you from sunburn but there is still no good direct evidence after 40 years of studies that it actually protects users from melanoma. You guys should be ashamed of yourselves in my opinion:

    European Journal of Dermatology

    March 2018, Volume 28, Issue 2, pp 186–201 | Cite as
    Use of sunscreen and risk of melanoma and non-melanoma skin cancer: a systematic review and meta-analysis

    Authors
    Authors and affiliations

    Elizabet saes da SilvaRoberto TavaresFelipe da silva PaulitschLinjie ZhangEmail author

    Elizabet saes da Silva
    1
    Roberto Tavares
    2
    Felipe da silva Paulitsch
    3
    Linjie Zhang
    4Email author

    1.Physiotherapy and Dermatology Clinic, Postgraduate Program in Public Health, Faculty of MedicineFederal University of Rio GrandeRio GrandeBrazil
    2.Faculty of MedicineFederal University of Rio GrandeRio GrandeBrazil
    3.Postgraduate Program in Public Health, Faculty of MedicineFederal University of Rio GrandeRio GrandeBrazil
    4.Postgraduate Program in Public Health and Postgraduate Program in Health Sciences, Faculty of MedicineFederal University of Rio GrandeRio GrandeBrazil

    Clinical Report
    First Online: 29 May 2018

    71 Shares 112 Downloads

    Abstract
    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.

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