Proliferation in African Breast Cancer: Biology and Prognostication in Nigerian Breast Cancer Material

Department of Pathology, University of Calabar Teaching Hospital, Nigeria.
Modern Pathology (Impact Factor: 6.19). 08/2002; 15(8):783-9. DOI: 10.1097/01.MP.0000021764.03552.BD
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Three hundred cases of invasive breast carcinoma from the University of Calabar Teaching Hospital, Nigeria were subjected to evaluation of proliferative activity by mitotic counts. The prognostic significance and association with other prognostic factors were evaluated. The mitotic activity was expressed as mitotic activity index (MAI), and standardized mitotic index (SMI). Pearson's correlation and univariate and multivariate Cox's regression were used. The mean follow-up time was 25.9 months. The mean values of SMI and MAI were 42.6 mitotic figures per square millimeter and 30.5 mitotic figures per 10 high-power fields, respectively, and these were much higher than values reported for Europe or other Western countries. The SMI had a positive correlation with tumor size (r = 0.31, P <.0001), histologic grade (r = 0.68, P <.0001), nuclear area (r = 0.45, P <.0001), and negative correlation with fraction of fields with tubular differentiation (FTD; r = -0.56, P = <0.0001). There was no statistically significant difference in the mitotic activity between the postmenopausal and the premenopausal patients. Also, lymph node-positive patients had higher counts than did lymph node-negative patients. Earlier determined grading associated decision thresholds divided the patients into groups of favorable and unfavorable prognosis. However, the statistically optimal thresholds for Nigerian material were different (32 and 92 mitotic figures per square millimeter for SMI). Tumor size of 5 cm, SMI, and MAI were independent prognostic factors. Nigerian breast cancers are high-grade, high-stage, and high-proliferating cancers occurring in a younger population than those of the Western countries. Proliferation is also more active. Evaluation of SMI or MAI can improve the distinction between aggressive and less aggressive variants of breast cancer.

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Available from: Teijo Kuopio, Apr 14, 2014
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    • "In this study we investigated how this is reflected in the pattern of mitotic counts in Libyan breast cancer. The current work on proliferative indices were compared with the proliferative indices in Finnish and Nigerian breast cancer patients which were studied previously by Ikpatt et al., 2002 [6] in Nigerian patients and by Kronqvist et al., 1998 [9] in Finnish patients, by the same method. "
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    ABSTRACT: Background: We evaluated the relation of proliferative indices with clinicopathological features and prognosis in breast cancer (BC) of Libyan female patients. The data were compared with corresponding results in Finland and Nigeria. Patients and methods: Histological samples of breast cancer from 130 patients were retrospectively studied. Mitotic activity index (MAI) and standardized mitotic index (SMI) were estimated. Results: There were statistically significant correlations between the proliferative indices and most clinicopathological features, with the strongest association observed for histological grade (P = 0.01 for SMI and P = 0.003 for MAI). The proliferative differences between Libyan, Nigerian, and Finnish population were prominent. The mean values of SMI and MAI in Libyan BC patients were 32.1 mitotic figures per square millimeter and 27.3 mitotic figures per 10 high-power fields, respectively. This is clearly lower than those in Nigeria but much higher than those in Finland. The differences between countries are seen in whole material and are also present in subgroups. The results indicated that mitotic activities can be reliable prognostic indicators in Libyan BCs, as they were among Finnish and Nigerian females. Univariate and multivariate analyses found at cut-offs of 19 and 44 mitosis/mm(2) of SMI were the most significant prognostic factors. Conclusions: Proliferative indices with careful estimation of the MAI and SMI could be applied as quantitative criteria for Libyan BC to separate the patients into good, moderate, and bad prognosis groups.
    09/2013; 2013:831714. DOI:10.1155/2013/831714
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    • "The lack of association between basal CK+ status and larger tumor size is quite unexpected [51]. This unusual finding might reflect the fact that large size at presentation, due to late disease diagnosis, is one of the main features of BC in Sudanese patients, when compared to BC in patients from Europe and North America [9, 37, 62, 63]. Due to longer survival, this could result in a relative enrichment of less aggressive subtypes among the BCs of larger size [37, 64], a hypothesis that requires to be further investigated in larger and prognostically well-characterized BC series from Sudan. "
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    • "Young age at diagnosis of breast cancer has been reported in many studies from the United States and Europe to be an independent predictor of worse survival (Saghir et al, 2006). Breast cancers in Uganda occur in a younger population than those in the Western countries (Pathak et al, 2000) but are similar to the Nigerian and Zimbabwean situations (Ihekwaba, 1992; Muguti, 1993; Ikpatt et al, 2002). Our results show that 54% of all patients were below 50 years of age, whereas Swanson and Lin (1994) reported age incidence in the United States of less than 23% in the same age bracket. "
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