Seasonal variations of symptoms and occurrence of human bladder carcinomas

A longitudinal study of transitional cell carcinomas of the urinary bladder has been performed in a region of Western Norway. Hematuria and infection were the first symptoms of neoplasia of the urinary bladder, showing marked and reproducible seasonal variations. Most of the tumours showed the first symptom at the end of the year. They also had a higher histological grade (WHO) than those occurring at other times of the year. This indicates that environmental factors dependent on the season may be of importance for the manifestation of malignant growth of the urinary bladder.