Detection of metastatic disease with sentinel lymph node dissection in colorectal carcinoma patients

Background In curative colorectal cancer surgery, radical lymph node dissection is essential for staging and decision-making for adjuvant treatment. Purpose The aims of the study were to analyse to what extent sentinel lymph node dissection (SLND) in colorectal cancer could upstage N0 patients and how lymphatic mapping could demonstrate micrometastatic disease. Patients and methods In a prospective study, patients were selected by CT scanning, avoiding bulky disease and distant metastasis. When standard staining (HE) was negative, micrometastases were searched for by immunohistochemistry (cytokeratin 11, CEA and Ca19-9 antibodies). Micrometastatic lymph nodes were classified N+(i). Results Detection of sentinel lymph nodes was successful in 48 out of 52 colorectal cancer patients. Among the 44 M0 patients, 22 were N0 (i−) and 22 were N+ (13 with standard HE procedure, three were N+ (macrometastasis) with the SN as the only positive node and six patients had 1–4 micrometastatic SN (N+(i)). An overall potential upstaging of 9/44 could be considered after SLND. With a mean follow-up of 48 months survival, analysis showed that disease-specific survival of the group of six N+(i) patients was intermediate between the group of 22 N0 (i−) patients and the group of 16 N+ patients. Conclusion SLND may improve the detection of metastasis in conventionally bivalved nodes. Further studies could assess if micrometastatic disease detected in SN could be integrated into the risk factors for stage II patients in order to consider adjuvant chemotherapy.