Lymph node negative colorectal cancers with isolated tumor deposits should be classified and treated as stage III.

Background: The prognostic role of pericolic or perirectal isolated tumor deposits (ITDs) in node-negative colorectal cancer (CRC) patients is unclear. Rules to define ITDs as regional lymph node metastases changed in subsequent editions of the TNM staging without substantial evidence. Aim of this study was to investigate the correlation between ITDs and disease recurrence in stage II and III CRC patients.
Materials and Methods: The medical files of 870 CRC patients were reviewed. Number, size, shape, and location pattern of all ITDs in node-negative patients were examined in relation to involvement of vascular structures and nerves. The correlation between ITDs and the development of recurrent disease was investigated.
Results: Disease recurrence was observed in 50.0% of stage II patients with ITDs (13 of 26), compared with 24.4% of stage II patients without ITDs (66 of 270) (P < .01). Disease-free survival of ITD-positive stage II patients was comparable with that of stage III patients. Also within stage III, more recurrences were observed in ITD-positive patients compared with ITD-negative patients (65.1 vs. 39.1%, respectively). No correlation was found between size of ITDs and disease recurrence. More recurrences were seen in patients with irregularly shaped ITDs compared with patients with 1 or more smooth ITDs present.
Conclusions: Because of the high risk of disease recurrence, all node-negative stage II patients with ITDs, regardless of size and shape, should be classified as stage III, for whom adjuvant chemotherapy should be considered.