Relationship between naevi and BCC

This article, although quite obvious really, has just been published. The interesting thing is how naevi on the back were not associated with increased risk.

regards

Ian

http://www.southernsun.com.au

 

J Eur Acad Dermatol Venereol. 2012 Sep;26(9):1092-6. doi: 10.1111/j.1468-3083.2011.04213.x. Epub 2011 Aug 16.

Melanocytic naevi and basal cell carcinoma: is there an association?

Source

Cancer and Population Studies Unit, Queensland Institute of Medical Research School of Life Sciences and Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia.

Abstract

BACKGROUND:

Melanoma and basal cell carcinoma (BCC) affect similar body sites and share a complex relationship with sun exposure.

OBJECTIVE:

To establish the existence and magnitude of association between melanocytic naevi, the strongest predictors of melanoma, and BCC to give possible insights into shared pathways of solar ultraviolet tumourigenesis.

METHODS:

In a community-based longitudinal Australian study, detailed information was collected about sun sensitivity, and dermatologists assessed skin colour and counted naevi on the forearms (1986) and back (1992). The BCC frequency and sites were prospectively monitored until 2007. Multivariate logistic regression was used to assess the association of naevi on the forearms or on the back with the development of BCC, adjusting for other risk factors.

RESULTS:

Of 1621 study participants in 1992, 1339 (average age 49) had complete follow-up and 401 (30%) of these had 1202 histologically confirmed BCCs until 2007. After adjustment for age, gender, skin colour, naevi on the back and sun exposure, overall BCC risk increased significantly in those with forearm naevi (odds ratio: 1.5; 95% confidence intervals: 1.1-1.9). Risk of BCC specifically on the back was doubled in those with many (11 or more) forearm naevi compared with no forearm naevi (odds ratio: 2.4; 95% confidence interval: 1.1-4.8). Naevi on the back were not associated with subsequent basal cell carcinoma.

CONCLUSIONS:

High naevus prevalence on the arms is associated with future BCC development.

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  1. #1 by hein2cv on October 21, 2012 - 10:05 pm

    Hmm, yes, sharing the same body sites. Not so sure about that. We find more BCCs than melanomas at most sites, and there seems to be a correlation between their development and blistering, intense – not so much chronic – solar exposure. However, on legs, I see very few BCCs [excepting thigh, and even there…], but these appendages account for a goodly proportion of melanomas. BTW, am in NZ for a few days so will not be able to participate in any discussion this may give rise to. Back tomorrow night late.

  2. #2 by stewart precians on October 22, 2012 - 12:31 am

    yes, a bit hard to work out why only forearm naevi increased BCC risk, especially on back. More studies probably needed.

  3. #3 by Tom Crawford on October 22, 2012 - 5:34 am

    There is so much discussion about UV exposure and melanomas now the “correlation” between BCC and MM I am not so sure about this , there are places in the world Finland for example where I was informed they have 600 confirmed cases of MM a year.One might expect their solar exposure is low , then there is the incidence of soles of feet melanoma and genital melanoma.
    Although the empirical evidence may suggest sun exposure is important, it surely is not the only factor , if it was then why does not the rate of MM approximate BCC.It may be of value to consider the potential inducers of these types of mm.
    By the way does any one know the ratio of basal cells to melanocytes in the epidermis?

    • #4 by Dr Ian Katz on October 22, 2012 - 6:46 am

      There is obviously a huge genetic component as well – two people in Australia with the same sun-exposure and one may get skin cancer and the other may not.
      About 1:4 to 1:10 melanocytes to basal keratinocytes
      regards
      Ian

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