Clinical characteristics of patients with sporadic colorectal cancer and primary cancers of other organs.

Most cancer patients often neglect the possibility of secondary cancer. Colorectal cancer (CRC) is the third leading cause of cancer death in Taiwan. It is important to be aware of the clinical characteristics of double cancer in CRC patients for early diagnosis and treatment. We retrospectively analyzed 1,031 CRC patients who underwent surgical treatment at the Department of Surgery of Kaohsiung Medical University Hospital between January 1998 and December 2004. Among these patients, CRC was accompanied by cancer of other organs in 17 patients (1.65%), either synchronously or metachronously. Therefore, we describe our experience regarding the location of CRC, the clinical symptoms and signs of these patients, the TNM stage, histology, phase, association with other malignancies, interval between cancers and clinical outcomes. Of the 17 patients in whom CRC was accompanied by primary cancer of other organs, there were four synchronous and 13 metachronous multiple cancer patients. Our patient group comprised six men and 11 women with ages ranging from 47 to 88 years (median age, 66 years). The most common location of CRC was the sigmoid colon. Six gastric cancers (35.2%) and six breast cancers (35.2%) were associated with primary CRC. The remaining six second primary cancers were one lung cancer, one thyroid cancer, one cervical cancer, one ovarian cancer, one skin cancer, and one urinary bladder cancer. Of the 13 metachronous multiple cancer patients, eight patients developed subsequent CRC after primary cancers of other organs, whereas two patients developed a subsequent second primary cancer after CRC. The intervals between the development of metachronous multiple cancers ranged from 2 to 19 years. In this retrospective analysis, breast and gastric cancer patients were at increased risk of developing subsequent secondary CRC. Careful attention should always be paid to the possibility of secondary CRC in treating these cancer patients. Cancer patients with hematochezia or gastrointestinal symptoms/signs should be evaluated for the possibility of second primary CRC during their regular follow-up.