Overdiagnosis and overtreatment of breast cancer: Estimates of overdiagnosis from two trials of mammographic screening for breast cancer

Randomised controlled trials have shown that the policy of mammographic screening confers a substantial and significant reduction in breast cancer mortality. This has often been accompanied, however, by an increase in breast cancer incidence, particularly during the early years of a screening programme, which has led to concerns about overdiagnosis, that is to say, the diagnosis of disease that, if left undetected and therefore untreated, would not become symptomatic. We used incidence data from two randomised controlled trials of mammographic screening, the Swedish Two-county Trial and the Gothenburg Trial, to establish the timing and magnitude of any excess incidence of invasive disease and ductal carcinoma in situ (DCIS) in the study groups, to ascertain whether the excess incidence of DCIS reported early in a screening trial is balanced by a later deficit in invasive disease and provide explicit estimates of the rate of 'real' and non-progressive 'overdiagnosed' tumours from the study groups of the trials. We used a multistate model for overdiagnosis and used Markov Chain Monte Carlo methods to estimate the parameters. After taking into account the effect of lead time, we estimated that less than 5% of cases diagnosed at prevalence screen and less than 1% of cases diagnosed at incidence screens are being overdiagnosed. Overall, we estimate overdiagnosis to be around 1% of all cases diagnosed in screened populations. These estimates are, however, subject to considerable uncertainty. Our results suggest that overdiagnosis in mammography screening is a minor phenomenon, but further studies with very large numbers are required for more precise estimation

Nutrient and anti-nutritional constituents of Penisetum purpureum and four indigenous tree legume of South-Western Nigeria: A potential ruminant feed

A study was carried out to investigate the nutrient composition as well as anti-nutritional constituents of some tree plants (Ficus sur, Bridelia macarrantii, Gmelina arborea and Albizia saman) and forage grass (Penisetum purpureum) in south- western Nigeria. Results indicated significant (P<0.05) variability in values of percentage crude protein (9.71 - 23.67%) where Penisetum purpureum recorded the least value and highest value observed in Ficus sur. Dry matter (DM), Crude fiber (CF), Organic matter (OM) and Ash contents varied significantly (p<0.05) from (23.52-46.23%, 8.45 - 30.22%, 64.01 - 96.95% and 2.66 – 8.44%) respectively. Albizia saman recorded significantly (p<0.05) higher ADF value (35.39%) with intermediate value (4.14%) of NDF. Penisetum purpureum had most ADL value (17.19%) while the least value was recorded in Gmelina arborea. Hemicellulose value ranged between (4.45 - 22.23%) with least value recorded by Ficus sur and highest by Penisetum purpureum plants. The concentrations of anti-nutritional factor was generally low, tannin content significantly (p<0.05) ranged from (0.75 - 3.56%) in Ficus sur and Albizia saman respectively. Penisetum purpureum had the least phytate (0.94 %) while Bridelia macarrantii recorded the most phytate value (2.65%). Saponin, Alkaloid and Oxalate level ranged from (0.10 - 1.51%, 0.36 - 1.58% and 0.34- 1.41%) respectively. The results show that the investigated plants seem to have good nutrient composition as well as low level of anti-nutritional factors and therefore can best be incorporated into ruminant feeding systems.Key words: Nutrient composition; Anti-nutritional constituents; tree plants; forage gras

Performance characteristics, plasma lipids and copper residue in organs and tissues of cockerel chickens fed dietary organic and inorganic copper

A 112-day study was conducted to determine the effect of dietary organic (Copper proteinate) and inorganic (Copper sulphate) Cu source on growth performance, plasma lipids and copper residue in organs and tissues of cockerel chickens. 240 day-old commercial Black-Harco cockerel chicks were randomly distributed to 6 dietary treatments of 40 birds each. Each treatment group was randomly allocated to 4 replicates of 10 birds each. The diets were formulated to contain a basal diet (containing 30.62 and 29.71 mg/kg Cu for starter and finisher phases respectively) supplemented with organic Cu (Cu proteinate; Cu-P) or inorganic Cu (Cu sulphate; CuSO4 ) fed at 3 dietary levels (50, 100 and 150 mg/kg). The birds were fed chicks mash and grower mash at 1-56 days and 57-112 days respectively in a deep litter pen at floor space of 0.06 m2/bird. Cu-P supplementation resulted in significantly higher (P<0.05) final live weight (FLW) and total weight gain (TWG) compared to CuSO4 at starter phase. Better feed conversion ratio was noticed in birds fed Cu-P supplemented diets compared to CuSO4 at 150mg/kg Cu concentration at both starter and finisher phases. Birds fed 150 mg/kg Cu recorded the highest (P<0.05) feed intake value at starter phase. There was significantly higher (P<0.05) accumulation of Cu in the blood, heart, lung, liver and thigh of birds fed Cu-P than those fed CuSO4 . The liver Cu concentration increased as dietary Cu concentration increased. Cu-P supplementation resulted in significant reduction (P<0.05) in plasma cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL) and triglyceride in comparison to CuSO4 . The blood cholesterol, LDL and triglyceride decreased with increased copper concentration. Organic form of copper promotes growth, more bioavailable and more effective in reducing cholesterol than copper sulphate.Keywords: Cockerels chickens, copper residue, and performance characteristic