Synchronous and metachronous adenocarcinomas of the large intestine

The synchronous and consecutive (metachronous) development of two or more primary adenocarcinomas accounts for 3 to 5% of cases of colorectal cancer. Aim of this study is to review our experience in the management of patients with synchronous and metachronous lesions, and reach conclusions regarding their optimal diagnosis, treatment and follow-up.

Between 1987 and 2004, 12 patients (seven men and five women, mean age 67.5 years, range 47-83 years) with synchronous (three patients) and metachronous (nine patients) lesions were treated, comprising 4.3% of all patients submitted to surgery for colorectal cancer. The diagnosis lag for metachronous lesions ranged from 1.5 to 14 years. All three patients with synchronous cancers had two lesions.

Staging colonoscopy and abdominal CT was conducted in 10 patients while the remaining two underwent only abdominal CT due to their critical condition at presentation. Surgery had curative intent in 10 patients and palliative in two. The mean postoperative hospital stay was 21 days (10-49 days). The postoperative mortality was zero. Patients survival after curative procedures was 80% for the first year, 60% for the third and 50% for the fifth year. After palliative surgery, survival was 50% for the first year, and zero for the third.

Patients with colorectal cancer must be followed up regularly after surgery. Follow up aims at early diagnosis and treatment of metachronous lesions that can appear many years after diagnosis of the primary lesion. Preoperative colonoscopy is an invaluable diagnostic (biopsy) and staging (exclusion of synchronous lesions, localization of the primary) modality, dictating the surgical approach. Additionally, it contributes to cancer prevention allowing the discovery and removal of small polyps before their transformation.