ABSTRACT
BACKGROUND: In 2000, an Italian non-governmental organisation (NGO) began a 9-year project to establish a surgical pathology laboratory at the Bugando Medical Centre (BMC) in Mwanza, Tanzania, a country with a low Human Development Index (HDI), and as of 2009, the laboratory was operating autonomously. The present survey aims to evaluate the reproducibility of histological and cytological diagnoses assigned in the laboratory's early years of autonomous activity. We selected a random sample of 196 histological and cytological diagnoses issued in 2010-2011 at the BMC surgical pathology laboratory. The corresponding samples were sent to Italy for review by Italian senior pathologists, who were blinded to the local results. Samples were classified into four diagnostic categories: malignant, benign, inflammatory, and suspicious. The two-observer kappa-statistic for categorised (qualitative) data was then calculated to measure diagnostic concordance between the local Tanzanian pathologists and Italian senior pathologists. The k-Cohen was calculated for concordance in the overall study sample. Concordance and discordance rates were also stratified by subset: general adult, paediatric/adolescent, and lymphoproliferative histopathological diagnoses; fluid and fine needle aspiration (FNA) cytological diagnoses; and PAP tests. Discordance was also categorised by the corresponding hypothetical clinical implications: high, intermediate, and not significant. RESULTS: Overall concordance was 85.2% (167 of 196 diagnoses), with a k-Cohen of 0.7691 (P = 0.0000). Very high concordance was observed in the subsets of adult general pathological diagnoses (90%) and paediatric/adolescent pathological diagnoses (91.18%). Concordance in the subset of PAP tests was 75%, and for fluid/FNA cytological diagnoses it was 56.52%. Concordance among 12 histological subtypes of lymphoma was 75.86%, with substantial discordance observed in the diagnosis of Burkitt lymphoma (five cases diagnosed by Italian pathologists versus 2 by local pathologists). The overall proportion of discordance with high hypothetical clinical implications was 6.1% (12 diagnoses). CONCLUSION: This blind review of diagnoses assigned in Tanzania, a country with low HDI, and in Italy, a country with a very high HDI, seemed to be a sensitive and effective method to identify areas of potential error and may represent a reference point for future, more detailed quality control processes or audits of surgical pathology services located in limited-resource regions.
ABSTRACT
Background: It has been shown that colorectal carcinoma is increasing in incidence in African countries. This could be due to change in life style. Molecular patho- genesis of colorectal cancer commonly involves mutation in p53 gene which leads to expression of p53 protein in tumor cells. Expression of p53 protein has been associated with poor clinical outcome and reduced survival in patients. Objective: This was a retrospective laboratory based study carried out in the Department of Pathology Makerere University; Kampala; Uganda. The aim of the study was to evaluate the expression of p53 protein in colorectal carcinoma in Ugandan patients; specifically its association with histological types; degree of differentiation; sites of the tumor and demographic characteristics of the patients. Methods: Immuno- histochemistry was carried out on 109 patient's paraffin embedded tissue blocks of colorectal carcinoma diagnosed in the Pathology Department; Faculty of Medicine Makerere University Kampala during the period 1995 to 2005. The indirect immunoperoxidase method using monoclonal antibody p53 DO-7 and Envision + Dual link system-HRP to detect p53 expression was used. Haematoxylin and eosin stain was used for evaluation of histological types and degree of differentiation of the tumors. Topography of the tumors and demographic data were obtained from accompanying histological request forms. Results: Out of 109 patient's tissue blocks that were studied; 61 cases (56) expressed p53 protein in the nucleus of malignant cells. Right sided colonic tumors were commoner (53.2) than left sided colonic tumors (46.8). p53 protein was expressed more in left sided colonic tumors with a significant difference (p0.05); it was also expressed more in well differentiated tumors and non mucinous adenocarcinomas but with no significant difference (p0.05). p53 expression was not affected by age or sex. Conclusion: Frequency of p53 protein expression in Ugandan patients did not differ from that reported in the other parts of the world. It was expressed more in the left sided colonic tumors and this could support the hypothesis that right and left colonic tumors could have different pathogenesis and probably also responsible for difference in prognosis in these two topographic sites