Statistical evaluation according to age, sex and tumour localization of patients with cancer referred to Department of Radiation Oncology Cerrahpaşa School of Medicine: 1978-1987. In this study, 13408 cases with histologically confirmed cancer who were treated from 1978 to 1987 at Department of Radiation Oncology Cerrahpaşa School of Medicine were statistically evaluated according to age, sex and tumour localization. The percents of most common first ten cancer types were as follows 16.4% breast, 16% lung, 8.3% larynx, 6.3% cervix uteri., 6.1% skin, 5.2% central nervous system, 4.2% corpus uteri, 3% soft tissue, 2.9% bladder, and 2.7% lymphoma. 54.1% of the cases or 7259 were male and 45.9% or 6149 were female. The percents of first five cancer types in men were as follows 27% lung, 14.6% larynx, 7.5% skin, 6.2% central nervous system, 4.7% bladder and in women were as follows 35% breast, 13.8% cervix uteri, 9.2% corpus uteri, 4.7% ovary and 4.5% skin. Cases have been very predominantly diagnosed at the 40 to 59 years age range, though very occasional patients have been at the 10 to 19 years age range.