Familial clustering of cancer in two tertiary care hospitals in Nairobi, Kenya.

To describe the occurrence of cancers in families of individuals diagnosed cancer.Cross-sectional descriptive study.Outpatient cancer clinics at Kenyatta National Hospital (KNH) and Radiotherapy Clinic at Nairobi Hospital.Patients with a tissue histological or cytological diagnosis of cancer.A reported family history of cancer.A total number of 485 cancer patients were recruited, 382, from KNH and 103 from Nairobi Hospital. These index cases had 45 different types of cancer, with the most common being breast and uterine-cervical malignancies. Prevalence of family history of cancer was found to be 18.8% and was highest among 1st degree relatives. Documentary evidence was seen in 48.4% and history of cancer corroborated by medical personnel in an additional 11%. In 18.7% of cases more than one relative was interviewed to confirm the family history of cancer. Educational levels of the index cases correlated with knowledge of family history of cancer, with those of higher educational level having been more informed about their families' medical history. There was a prevalence of familial cancers of 30% at Nairobi Hospital patients and 15.7% at KNH patients.We found the prevalence of family history of cancer in our population to be 18.8% and was highest among 1st degree relatives. This has implications for targeted screening and therefore early diagnosis which is beneficial.