Background: Patients with primary colorectal cancers have a higher risk of development of second tumours synchronously or metachronously. This special group of patients raise a particular interest in their characteristics and outcome.
Methods: The records of 1009 patients with colorectal cancer were scrutinized. A group with multiple cancers was identified. Perioperative investigations, patterns of follow-up, pathological variables and outcome were noted.
Results: There were 22 patients with metachronous tumours and 39 with synchronous tumours following 'curative' operations in 20 and 28 respectively. There was no difference in Dukes classification between the two groups: Polyps were associated with metachronous lesions in ten of 22 patients and synchronous lesions in 17 of 39 patients. Five-year survival was 75 per cent for patients with metachronous tumours and only 18 per cent for those with synchronous tumours.
Conclusion: In this study patients with metachronous tumours seemed to do very well while those with synchronous lesions did very badly. There were no identifiable demographic or clinical characteristics to account for this. There is a need to study this group of patients and identify factors like tumour biology or host resistance which prevent spread of tumour.