Background: Undetected micrometastases represent the single most important cause of treatment failure in patients undergoing putatively curative resection for colorectal cancer because current staging techniques are unable to identify patients with minimal residual disease.
Methods: A highly sensitive reverse transcription-polymerase chain reaction technique has been used to amplify tissue-specific messenger RNA from lymph nodes classified as tumour-free using both conventional histopathology and immunohistochemistry.
Results: Four of 15 patients were restaged after genetic diagnosis of lymph node micrometastases, while in a further two additional positive nodes were detected.
Conclusion: Sensitive genetic techniques that detect minimal residual disease merit further study, particularly as there is evidence that patients may benefit from adjuvant chemotherapy.