Prostate cancer survival is dependent on season of diagnosis

• Published in: The Prostate 2007-09, Vol.67 (12), p.1362-1370
• Main Authors: Lagunova, Zoya, Porojnicu, Alina Carmen, Dahlback, Arne, Berg, Jens Petter, Beer, Tomasz M., Moan, Johan
• Format: Article
• Language: English
• Subjects: Aged; Animals; Biological and medical sciences; Calcifediol - blood; Carcinoma, Squamous Cell - blood; Carcinoma, Squamous Cell - epidemiology; Carcinoma, Squamous Cell - pathology; Diet; Fishes; Gynecology. Andrology. Obstetrics; Humans; Incidence; latitude dependency; Male; Male genital diseases; Medical sciences; Middle Aged; Nephrology. Urinary tract diseases; Norway - epidemiology; prognosis; prostate cancer; Prostatic Neoplasms - blood; Prostatic Neoplasms - epidemiology; Prostatic Neoplasms - pathology; seasonal variation; Seasons; Sunlight; Survival Analysis; Tumors; Tumors of the urinary system; Urinary tract. Prostate gland; vitamin D
• ISSN: 0270-4137; 1097-0045
• DOI: 10.1002/pros.20577

BACKGROUND We have earlier found that the prognosis for several cancers is dependent on season of diagnosis. More recently, both prostate cancer incidence and mortality have been shown to increase with increasing latitude, which probably relates to photosynthesis of vitamin D. METHODS The 3 year survival of prostate cancer patients has been analyzed with the Cox regression method for two age groups at different latitudes in Norway. RESULTS Patients diagnosed during the summer and autumn had the best prognosis (Ralative risk (RR) death 0.8; 95% CI 0.75–0.85). Similar results were observed in three regions of the country that differ with respect to annual fluences of solar UV radiation, incidence rates of squamous cell carcinoma (SCC) and intake of fish. Furthermore, similar relationship between the season and survival was seen among patients ≤65 years and >65 years old, although the younger group had a slightly larger advantage of summer and autumn diagnosis. CONCLUSIONS The seasonal effect on prognosis may be related to the seasonal variations of calcidiol (the marker of vitamin D status). The lack of latitude effect and the similarity of prognosis for different age groups may be related to higher consumption of vitamin D in food in the north region and to increase of such consumption with age. Prostate 67: 1362–1370, 2007. © 2007 Wiley‐Liss, Inc.