Colorectal cancer (CRC) is the third most common malignancy in the world and its rank has changed from the 9th to the 5th among 10 prevalent cancers in Iran. The prevalence of gastrointestinal and non- gastrointestinal malignancies increases significantly in the first-degree relatives of patients with colorectal cancer. We intend to determine the prevalence of all types of cancers among the first-degree and the second-degree relatives of patients diagnosed with colorectal cancer at Shariati hospital-TUMS 2011

In this descriptive study all patients diagnosed with colorectal cancer who were registered in the Cancer Registry System affiliated to Tehran University from 1990 to 2011 were enrolled. They were called (at least three times); We ask about all types of cancer in their first-degree and second-degree relatives.

Of all 210 patients with colorectal cancer in the registry a total of 102 questionnaires were completed. The response rate was 48.6%. Of these patients, 54 were males (52.9%), mean age was 66.9±12.1 years. A total of 49 patients (48%) have a positive family history of all types cancers (median:2 IQR 1-7). In twenty-nine patients 28.4%, one of their first-degree relatives (FDR) was diagnosed with the malignance. Eighty-eight of first degree relatives (FDRs) and second degree relatives (SDRs) of our patients were diagnosed with malignancy (78 FDRs and 10 SDRs) that of them 48 patients had solid tumors (39 patients had CRC).

Although CRC is the most common cancer in FDRs of patient were diagnosed with CRC, a family history of CRC is related to an increase of all types of malignancy.