9 februari 2005: Bron: J Natl Cancer Inst 2005;97:195-209 en J Natl Cancer Inst. 2005 Feb 2;97(3):195-9.

Melanomen die worden verondersteld te zijn veroorzaakt door een teveel aan blootstelling aan de zon blijken minder agressief dan melanomen die niet door een teveel aan zon zijn veroorzaakt, blijkt uit nieuwe Zweedse studie. Vaker blootstelling aan de zon verlaagt het risico op sterven aan melanomen blijkt uit deze studie. Nog opvallender is dat een andere studie bewijst dat meer zon een verkleint risico geeft - ca. 40% minder - op ziekte van Hodgkin. Deskundigen vermoeden dat met name de aanmaak van vitamine D door de blootstelling aan zon hiervoor wel eens verantwoordelijk zou kunnen zijn. De waarschuwing om niet of weinig u zelf aan de zon bloot te stellen zou dus wel eens een verkeerd advies kunnen zijn. Al lijkt 'verbranden' in de zon nog altijd niet erg bevordelijk voor uw gezondheid. Maar verantwoord gebruik maken van de zon lijkt alleen maar goed blijkt ook uit deze studie. Eerst de twee abstracten van de studies en aanvullend een artikel uit Medscape over deze studies.

J Natl Cancer Inst. 2005 Feb 2;97(3):195-9.

Sun exposure and mortality from melanoma.

Berwick M, Armstrong BK, Ben-Porat L, Fine J, Kricker A, Eberle C, Barnhill R. University of New Mexico, Department of Internal Medicine, New Mexico Cancer Research Facility, MSC08 4630, Room 103A, 1 University of New Mexico, Albuquerque, NM 87131, USA. mberwick@salud.unm.edu

BACKGROUND: Melanoma incidence and survival are positively associated, both geographically and temporally. Solar elastosis, a histologic indicator of cutaneous sun damage, has also been positively associated with melanoma survival. Although these observations raise the possibility that sun exposure increases melanoma survival, they could be explained by an association between incidence and early detection of melanoma. We therefore evaluated the association between measures of skin screening and death from cutaneous melanoma.

METHODS: Case subjects (n = 528) from a population-based study of cutaneous melanoma were followed for an average of more than 5 years. Data, including measures of intermittent sun exposure, perceived awareness of the skin, skin self-screening, and physician screening, were collected during in-person interviews and review of histopathology and histologic parameters (i.e., solar elastosis, Breslow thickness, and mitoses) for all of the lesions. Competing risk models were used to compute risk of death (hazard ratios , with 95% confidence intervals ) from melanoma. All statistical tests were two-sided.

RESULTS: Sunburn, high intermittent sun exposure, skin awareness histories, and solar elastosis were statistically significantly inversely associated with death from melanoma. Melanoma thickness, mitoses, ulceration, and anatomic location on the head and neck were statistically significantly positively associated with melanoma death. In a multivariable competing risk analysis, skin awareness (with versus without, HR = 0.5, 95% CI = 0.3 to 0.9, P = .022) and solar elastosis (present versus absent, HR = 0.4, 95% CI = 0.2 to 0.8, P = .009) were strongly and independently associated with melanoma death after adjusting for Breslow thickness, mitotic index, and head and neck location, which were also independently associated with death.

CONCLUSIONS: Sun exposure is associated with increased survival from melanoma.

PMID: 15687362 [PubMed - in process]

J Natl Cancer Inst. 2005 Feb 2;97(3):199-209.

Ultraviolet radiation exposure and risk of malignant lymphomas.

Smedby KE, Hjalgrim H, Melbye M, Torrang A, Rostgaard K, Munksgaard L, Adami J, Hansen M, Porwit-MacDonald A, Jensen BA, Roos G, Pedersen BB, Sundstrom C, Glimelius B, Adami HO. Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Box 281, SE-171 77 Stockholm, Sweden. karin.ekstrom@meb.ki.se

BACKGROUND: The incidence of malignant lymphomas has been increasing rapidly, but the causes of these malignancies remain poorly understood. One hypothesis holds that exposure to ultraviolet (UV) radiation increases lymphoma risk. We tested this hypothesis in a population-based case-control study in Denmark and Sweden.

METHODS: A total of 3740 patients diagnosed between October 1, 1999, and August 30, 2002, with incident malignant lymphomas, including non-Hodgkin lymphoma, chronic lymphocytic leukemia, and Hodgkin lymphoma, and 3187 population controls provided detailed information on history of UV exposure and skin cancer and information on other possible risk factors for lymphomas. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by logistic regression. Statistical tests were two-sided.

RESULTS: Multivariable-adjusted analyses revealed consistent, statistically significant negative associations between various measures of UV light exposure and risk of non-Hodgkin lymphoma. A high frequency of sun bathing and sunburns at age 20 years and 5-10 years before the interview and sun vacations abroad were associated with 30%-40% reduced risks of non-Hodgkin lymphoma (e.g., for sunbathing four times a week or more at age 20 versus never sunbathing, OR = 0.7, 95% CI = 0.6 to 0.9; for two or more sunburns a year at age 20 versus no sunburns, OR = 0.6, 95% CI = 0.5 to 0.8). These inverse associations increased in strength with increasing levels of exposure (all P(trend)< or =.01). Similar, albeit weaker, associations were observed for Hodgkin lymphoma. There were no clear differences among non-Hodgkin lymphoma subtypes, although associations were stronger for B-cell than for T-cell lymphomas. A history of skin cancer was associated with a doubling in risks of both non-Hodgkin and Hodgkin lymphoma.

CONCLUSIONS: A history of high UV exposure was associated with reduced risk of non-Hodgkin lymphoma. The positive association between skin cancer and malignant lymphomas is, therefore, unlikely to be mediated by UV exposure.

PMID: 15687363 [PubMed - in process] Sunlight-Related Melanomas Inherently Less Aggressive
By Anthony J. Brown, MD

NEW YORK (Reuters Health) Feb 07 - Sun exposure has been linked to increased survival from melanoma and now new research suggests that this is due, at least in part, to sunlight-related tumors being inherently less aggressive than those not tied to sun exposure. The effects of sun exposure on cancer, however, may not be limited to cutaneous malignancies. In another study, also reported in the Journal of the National Cancer Institute for February 2, researchers shows that high UV radiation exposure is associated with a reduced risk of non-Hodgkin lymphoma (NHL).
"Our findings provide the strongest evidence to date that the better prognosis of (sunlight-related) melanomas is not simply due to earlier detection of these types," Dr. Marianne Berwick, lead author of the first study, told Reuters Health.

Dr. Berwick, a researcher from the University of New Mexico in Albuquerque, noted that "further studies are needed to determine how sun exposure might reduce melanoma aggressiveness," but said that the effect could be mediated through vitamin D or involve an enhancement of DNA repair capacity. The findings stem from a study of 528 melanoma patients who were entered in the Connecticut Tumor Registry.

Sunburn, high intermittent sun exposure, self-reported skin awareness, and solar elastosis, a histologic marker of sun damaged-skin, were all linked to increased survival from melanoma. Conversely, melanoma thickness, mitoses, ulceration, and head and neck location were associated with decreased survival.
On multivariate analysis, skin awareness was a strong, independent predictor of increased survival, consistent with the belief that earlier detection leads to better outcomes. However, solar elastosis, which does not relate to detection, was found to be an even stronger predictor of increased survival. Dr. Berwick emphasized that these findings have no bearing on current recommendations that "avoiding sun exposure reduces the risk of melanoma." Moreover, she added that they also do not suggest that exposing melanomas to sunlight, ex post facto, will improve survival.

In the second study, Dr. Karin Elkstrom Smedby, from the Karolinska Institutet in Stockholm, and colleagues investigated UV radiation exposure as a possible cause for increasing rates of malignant lymphoma in recent decades. Instead, the researchers found that high UV radiation exposure, as measured by frequent sunbathing and sunburns, cut the risk of NHL by up to 40% depending on the level of exposure.
The study involved 3740 patients with malignant lymphomas and 3187 population controls. High UV radiation exposure also seemed to protect again Hodgkin's lymphoma but the association was weaker than with NHL. The authors found that a history of skin cancer doubled the risk of both types of lymphoma. Given the other findings, this association is "unlikely to be mediated by UV exposure," they add.
,br> J Natl Cancer Inst 2005;97:195-209.

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