This study confirms that mitoses 2 is a powerful predictor of metastasis in LCTs

This study confirms that mitoses 2 is a powerful predictor of metastasis in LCTs. higher than for TCs (0. 95% versus 0. 72%, CIAM, P= 0. 299). Similarly, although not statistically significant, the TMCB mean Ki-67 index for metastatic group (MG) was higher than for nonmetastatic group (NMG) (1. 01% versus 0. 71% by CIAM, P= 0. 281). However when Ki-67 index data was categorized at various levels, there is suggestion of a useful cutoff (0. 50%) to predict metastasis (P= 0. 106, CIAM). A significantly higher proportion of patients with mitosis 2 and Ki-67 index 0. 50% had metastasis (P= 0. 033) compared to other patients. Similarly patients with tumor size 3 cm and Ki-67 0. 50% had a greater percentage of metastases than others (P= 0. 039). Although there was a strong correlation between two (MCM versus CIAM) counting methods (r= 0. 929, P= 0. 001), overall the calculated Ki-67 index was slightly higher by MCM (range 0 to 6. 4, mean 1 . 5) compared to CIAM (range 0 to 2 . 9, mean 0. 75). Conclusion. This study confirms that TMCB mitoses 2 is a powerful predictor of metastasis in LCTs. Although this is a small sample size, there is suggestion that analysis of Ki-67 TMCB index along with mitoses and tumor size may be a useful adjunct for predicting metastasis in LCTs. == 1 . Introduction == Carcinoid is a relatively uncommon neuroendocrine tumor of the lung. These tumors are classified as typical carcinoids (TC) and atypical carcinoids (AC) using Travis criteria who defined TC as a tumor with <2 mitoses/10 HPF and no necrosis, whereas the presence of spotty necrosis or 210 mitoses/10 HPF are diagnostic of AC [1, 2]. Traditional staging and histologic grading have been used to predict the biologic behavior of LCTs. Recently there is much interest to evaluate proliferation markers particularly Ki-67 in neuroendocrine tumors arising from various sites in an attempt to identify high risk subsets that may behave more aggressively. At a 2009 European Neuroendocrine Society Consensus Conference, an international group of experts proposed a grading system (G1G3) utilizing a combination of Ki-67 and mitoses to stratify patients with GI neuroendocrine tumours [3]. However , there is only limited information in the literature on LCTs correlating mitotic rate, Ki-67 index, and clinical outcome. In this study our objectives are (1) to evaluate the usefulness of Ki-67 index as well as traditional parameters such as mitoses and tumor size for predicting metastasis in LCTs and (2) to develop a systematic counting method for Ki-67 estimation in LCTs and compare the Manual Conventional Method (MCM) and the Computer Assisted Image Analysis Method (CIAM) for calculating Ki-67 index. We hypothesis that in LCTs in addition to mitoses, Ki-67 index might be an important parameter for identifying high risk subsets of patients for whom multimodal therapy may be considered for management. == 2 . Materials and Methods == == 2 . 1 . Histologic Analysis == We conducted a computerized search of the pathology records at London Health Sciences Centre (LHSC) and St . Joseph's Health Centre (SJHC) in London, Ontario, Canada, over a 25-year period (19822007). Forty-eight consecutive patients who had a histologic diagnosis of LCTs in resected specimens were selected for this study. All cases were reclassified into TC and AC using the criteria by Travis et al. [1]. Slides were reviewed and mitoses were counted using a Zeiss microscope at Mmp15 40x objective in three sets of 10 HPF (6 mm2of viable tumor), and the average mitotic determine per 10 HPF (2 mm2) was calculated as suggested by Travis et al. [1]. Patient demographics and tumor characteristics as well as metastatic and survival data were evaluated by chart review. Two representative sections of tumor were stained for Ki-67 (Vector laboratories; antibody to Ki-67 antigen, clone MM1, Burlingame, CA, USA) by ABC method (heat-induced epitope retrieval with citrate buffer, prediluted (1: 200), completed manually at LHSC immunohistochemistry lab). Ki-67 counting was performed using both Computer Assisted Image Analysis Method (CIAM) and a Manual Conventional Method (MCM). The Ki-67 labeling index was calculated as the ratio of number of stained cells to total number of cells expressed as a percentage. Both mitotic count and Ki-67 counting were performed in a blind fashion without knowledge of clinical data. == 2 . 2 . Ki-67 Counting by Computer-Assisted Image Analysis Method == For quantitative evaluation.