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Introduction Occult nodal tumour cells should be categorised as micrometastasis (MMs) and isolated tumour cells (ITCs). A recent meta-analysis demonstrated that MMs, but not ITCs, are prognostic for disease recurrence in patients with stage I/II colon cancer. Aims & methods The objective of this retrospective multicenter study was to correlate MMs and ITCs to characteristics of the primary tumour, and to determine their prognostic value in patients with stage I/II colon cancer. Results One hundred ninety two patients were included in the study with a median follow up of 46 month (IQR 33–81 months). MMs were found in eight patients (4.2%), ITCs in 37 (19.3%) and occult tumour cells were absent in 147 patients (76.6%). Between these groups, tumour differentiation and venous or lymphatic invasion was equally distributed. Advanced stage (pT3/pT4) was found in 66.0% of patients without occult tumour cells (97/147), 72.9% of patients with ITCs (27/37), and 100% in patients with MMs (8/8), although this was a non-significant trend. Patients with MMs showed a significantly reduced 3 year-disease free survival compared to patients with ITCs or patients without occult tumour cells (75.0% versus 88.0% and 94.8%, respectively, p = 0.005). When adjusted for T-stage, MMs independently predicted recurrence of cancer (OR 7.6 95% CI 1.5–37.4, p = 0.012). Conclusion In this study, the incidence of MMs and ITCs in patients with stage I/II colon cancer was 4.2% and 19.3%, respectively. MMs were associated with an reduced 3 year disease free survival rate, but ITCs were not. [ABSTRACT FROM AUTHOR]

Abstract: Introduction: Detection of occult tumour cells in lymph nodes of patients with stage I/II colorectal cancer is associated with decreased survival. However, according to recent guidelines, occult tumour cells should be categorised in micrometastases (MMs) and isolated tumour cells (ITCs). This meta-analysis evaluates the prognostic value of MMs and of ITCs, separately. Methods: PubMed, Embase, Biosis and the World Health Organization International Trials Registry Platform were searched for papers published until April 2013. Studies on the prognostic value of MMs and ITCs in lymph nodes of stage I/II colorectal cancer patients were included. Odds ratios (ORs) for the development of disease recurrence were calculated to analyse the predictive value of MMs and ITCs. Results: From five papers, ORs for disease recurrence could be calculated for MMs and ITCs separately. In patients with colorectal cancer, disease recurrence was significantly increased in the presence of MMs in comparison with absent occult tumour cells (OR 5.63; 95%CI 2.4–13.13). This was even more pronounced in patients with colon cancer (OR 7.25 95%CI 1.82–28.97). In contrast, disease recurrence was not increased in the presence of ITCs (OR 1.00 95%CI 0.53–1.88). Conclusion: Patients with stage I/II colorectal cancer and MMs have a worse prognosis than patients without occult tumour cells. However, ITCs do not have a predictive value. The distinction between ITCs and MMs should be made if the detection of occult tumour cells is incorporated in the clinical decision for adjuvant treatment. [Copyright &y& Elsevier]

Absract: Purpose: Most studies on the sentinel node (SN) procedure in patients with colorectal cancer include immunohistochemical analysis of the SN only. To evaluate the real diagnostic accuracy of the SN procedure with immunohistochemical analysis, the presence of occult tumour cells in all histologically negative lymph nodes was compared to the presence of these cells in SNs. Also the reproducibility of diagnosing occult tumour cells (OTC) and the sensitivity of three different antibodies was assessed. Methods: Between November 2006 en July 2007, an ex vivo SN procedure was performed in 58 histologically N0 patients with colorectal cancer. All lymph nodes (n = 908, mean 15.7) were step-sectioned and immunohistochemistry was performed using two antibodies against cytokeratins (Cam5.2, and CK 20) and one antibody against BerEp-4. Results: OTC were identified in 19 of 58 patients, with micrometastases (0.2–2 mm) in 7 and isolated tumour cells (ITC)(<0.2 mm) in 12 patients. The overall agreement in diagnosing OTC between two independent pathologists was 86%. An SN was identified in 53 of 58 patients. All micrometastases were found in SNs. In two patients with negative SNs, ITC''s were demonstrated in non-SNs (sensitivity 88%, and overall accuracy 96%). Conclusion: Additional immunohistochemical analysis of histologically negative lymph nodes demonstrates occult tumour cells in 33% of the patients resulting in an upstaging rate of 12%. Occult tumour cells are predominantly found in the SN, therefore SN mapping has the potential to refine the staging system for patients with colorectal cancer. [Copyright &y& Elsevier]