Cancer is relatively uncommon in younger age group and the risk increases with increasing age.
Tumors, which occur in children, are Wilms' tumor of the kidney and Nerve tissue cancer. Cancers of the lung, gastric system and prostate gland become more common with increasing age. Cancer of the breast can occur at any age, but generally occurs after the age of 30 years. Certain cancers are more common in men because of their habits. Many cancers predominantly occur in one sex for no apparent reason.