Feb 14, 2011

Posted by Sonia Morrison in Uncategorized | 0 Comments

Skin Cancer

Clinical Context

More than 2 million cases of nonmelanoma skin cancer are diagnosed each year, with two thirds being basal cell carcinoma and one third being squamous cell carcinoma. Melanoma is less common than either of these cancers but accounts for 75% of skin cancer deaths. Among US adolescents, 83% report at least 1 sunburn in the previous summer, and only 34% report using sunscreen, with 10% of adolescents and 20% of young adults reporting use of indoor tanning.

This is a report of the USPSTF to update 2003 recommendations on counseling patients to reduce sun exposure to reduce the risk for skin cancer.

Study Highlights

  • The investigators searched for systematic reviews from 2001 to 2008 and used 10 of these reviews to identify evidence.
  • They identified abstracts through MEDLINE and the Cochrane Central Register of Controlled Trials.
  • Randomized controlled trials in primary care settings were included, and cross-sectional trials were excluded.
  • 2 investigators independently rated the quality of studies using specific criteria.
  • Quantitative analysis was not performed because of study heterogeneity.
  • There were no trials meeting criteria for whether behavioral counseling reduced the incidence of skin cancer.
  • However, 11 fair-quality randomized controlled trials examined the effect of counseling interventions on sun-protective behaviors.
  • For adult studies, interventions ranged from self-directed computer programs to stage-based tailored feedback, phone counseling, or written assessments followed by written feedback.
  • Overall, the effect of these interventions on sun-protective behaviors was small and was not clearly clinically meaningful.
  • Among women, appearance-focused behavioral counseling decreased indoor tanning and ultraviolet exposure.
  • The interventions reduced indoor tanning behavior by up to 35%.
  • In young adults (ages 18 to 21 years), computer support decreased midday sun exposure and increased sunscreen use.
  • The interventions were effective at sun avoidance behaviors at up to 24 months.
  • The interventions ranged from a written self-guided booklet to a 30-minute one-on-one peer counseling session.
  • 35 fair-quality studies examined the association between ultraviolet light exposure and the risk for different skin cancers.
  • Increasing intermittent sun exposure during childhood is associated with an increased risk for squamous cell carcinoma, basal cell carcinoma, and melanoma.
  • Regular or early use of indoor tanning may increase the risk for melanoma.
  • 5 fair-quality cohort studies and 7 fair- to good-quality case-control studies examined sun exposure in childhood and the risk for skin cancer.
  • They found that increasing childhood exposure to the sun was associated with an increased risk for squamous cell, basal cell carcinoma, and melanoma.
  • Increasing intermittent sun exposure and total recreational sun exposure were both associated with an increased risk for melanoma (odds ratios, 1.3 – 5.0).
  • Sunbathing behavior in childhood was associated with an increased risk for melanoma (odds ratios, 1.7 – 3.5).
  • Total and chronic sun exposure and occupational sun exposure were strongly associated with melanoma.
  • 5 fair-quality studies examined the association between indoor tanning and the risk for skin cancer.
  • Women who reported regular solarium use (> 1 time per month for 2 – 3 decades) from ages 10 to 39 years had an increased risk for melanoma (risk ratio, 2.37), after adjustment for confounders, including skin phenotype and intermittent sun exposure.
  • Sunscreen use was found to reduce the risk for squamous cell carcinoma (risk ratio, 0.65) but not basal cell carcinoma (risk ratio, 1.02).
  • Sunscreen use had no clear protective effect on melanoma risk.
  • There was no evidence of harms associated with counseling to prevent skin cancer, including vitamin D deficiency.
  • The authors concluded that counseling by primary care clinicians can reduce the risk of sun exposure and increase sun-protective behaviors among women and adolescents. Also, use of sunscreen could reduce the risk for squamous cell carcinoma.
  • They suggested that it was unclear if increasing sun-protective behaviors translated into behavioral change to prevent skin cancer or melanoma and that more studies were needed in the future.

Clinical Implications

  • Counseling to prevent skin cancer is associated with increased sun-protective behaviors among women and adolescents and is not associated with harms.
  • Use of sunscreen reduces the risk for squamous cell carcinoma.

Toxic Free Sunscreen

Further information available on Chae Organic site via http://www.soniamorrison.com


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