Chlorophyll fluorescence as a selection tool for cold tolerance of photosynthesis in maize (Zea mays L.)

The possibility of using quenching analysis of chlorophyll a fluorescence as a selection tool for improving the cold tolerance of maize was investigated in six genotypes differing greatly in the ability to develop a competent photosynthetic apparatus at low temperature. Upon gradual cooling, measurements of the quantum yield of electron transport (ΦPSII) indicated that leaves of tolerant genotypes, that developed at suboptimal temperature (15 °C), maintained higher rates of electron transport than leaves of sensitive genotypes. This difference was largely due to the ability of the tolerant plants to keep higher efficiency of excitation energy capture by open photosystem II reaction centres (F′v/F′m). The absence of genotypic differences in leaves that developed at optimal temperature indicates that the trait is not expressed constitutively, but relies on adaptation mechanisms. Furthermore, the genotypic difference was not expressed under increasing illumination at 15 °C and 25 °C suggesting that the trait is also low-temperature-specific and is not expressed solely in response to increasing excess light energy. Applying the method to flint and dent breeding population led to a substantial increase (up to 31%) in the photosynthetic capacity of hybrids between selected F3 inbreeding families grown at suboptimal temperature, demonstrating that the method is an efficient selection tool for improving the cold tolerance of maize through breedin

Breast cancer screening programme in Switzerland 2010-2015

This fourth national monitoring report for Swiss Cancer Screening shows the results of organised mammogra-phy screening in Switzerland for the years 2010-2015, subdivided into two triennial periods, 2010-2012 and 2013-2015, respectively. The number of regional programmes increased from 7 in 2010 to 10 in 2015, currently covering the geograph-ical area of 12 cantons. In 2015, 56.5 percent of the 50-69 years old women in Switzerland lived in an area covered by a breast cancer screening programme, nearly a doubling of coverage since 2010. The results in this monitoring report are based on available data from 7 programmes (VD, VS, GE, FR, BEJUNE, SG-GR, TG) in the period 2010-2012 and from 8 programmes (with BE) in the period 2013-2015. The coverage by invitation rate increased from 91% in 2010-2012 to 98% in 2013-2015. Almost 290,000 from the 680,000 eligible women in 2013-2015 attended for screening, resulting in a participation rate of 42.5%. The participa-tion decreased by more than 4% compared to 2010-2012, mainly due to the low participation in the large new programme of Canton of Bern. Similar decreases between the two triennial periods were found in the first round participation (32.9% vs. 38.3%) and in the reattendance of the women who participated in the previous round (81.7% vs. 85.6%). Without Bern, the overall participation rate was stable around 47% and the first round participation around 38-39%. Participation rates are likely slightly underestimated, as some participa-tion records could not be extracted from the new information system MC-SIS. Prevalent screening in 2013-2015 led to a recall rate (73.0 per 1000 women screened) slightly higher than recommended by the European Guidelines but substantially lower than in 2010-2012 (86.9 per 1000). The main consequence of the reduced recall rate is a substantially lower false-positive rate (67 vs. 80 per 1000). There is a concomitant but less pronounced decrease in breast cancer detection (6.1 vs. 6.9 per 1000) given the slightly increased positive predictive value of the screening examination (8.4% vs. 8.0%). Although the classi-fications of tumour characteristics are partly incomplete, most tumour distribution proportions are in accord-ance with the European Guidelines

Impact of mammographic screening and advanced cancer definition on the percentage of advanced-stage cancers in a steady-state breast screening programme in the Netherlands

Background: To estimate the percentages of advanced-stage breast cancers (BCs) detected during the course of a steady-state screening programme when using different definitions of advanced BC. Methods: Data of women aged 49–74 years, diagnosed with BC in 2006–2015, were selected from the Netherlands Cancer Registry and linked to the screening registry. BCs were classified as screen-detected, interval or non-screened. Three definitions of advanced BC were used for comparison: TNM stage (III–IV), NM stage (N+ and/or M+) and T size (invasive tumour ≥15 mm). Analyses were performed assuming a 10% overdiagnosis rate. In sensitivity analyses, this assumption varied from 0 to 30%. Results: We included 46,734 screen-detected, 17,362 interval and 24,189 non-screened BCs. By TNM stage, 4.9% of screen-detected BCs were advanced, compared with 19.4% and 22.8% of interval and non-screened BCs, respectively (p < 0.001). Applying the other definitions led to higher percentages of advanced BC being detected. Depending on the definition interval, non-screened BCs had a 2–5-times risk of being advanced. Conclusion: Irrespective of the definition, screen-detected BCs were less frequently in the advanced stage. These findings provide evidence of a stage shift to early detection and support the potential of mammographic screening to reduce treatment-related burdens and the mortality associated with BC

Overdiagnosis and overtreatment of breast cancer: Microsimulation modelling estimates based on observed screen and clinical data

There is a delicate balance between the favourable and unfavourable side-effects of screening in general. Overdiagnosis, the detection of breast cancers by screening that would otherwise never have been clinically diagnosed but are now consequently treated, is such an unfavourable side effect. To correctly model the natural history of breast cancer, one has to estimate mean durations of the different pre-clinical phases, transition probabilities to clinical cancer stages, and sensitivity of the applied test based on observed screen and clinical data. The Dutch data clearly show an increase in screen-detected cases in the 50 to 74 year old age group since the introduction of screening, and a decline in incidence around age 80 years. We had estimated that 3% of total incidence would otherwise not have been diagnosed clinically. This magnitude is no reason not to offer screening for women aged 50 to 74 years. The increases in ductal carcinoma in situ (DCIS) are primarily due to mammography screening, but DCIS still remains a relatively small proportion of the total breast cancer problem

Increased risk of second malignancies after in situ breast carcinoma in a population-based registry

Among 1276 primary breast carcinoma in situ (BCIS) patients diagnosed in 1972–2002 in the Southern Netherlands, 11% developed a second cancer. Breast carcinoma in situ patients exhibited a two-fold increased risk of second cancer (standardised incidence ratios (SIR): 2.1, 95% confidence interval (CI): 1.7–2.5). The risk was highest for a second breast cancer (SIR: 3.4, 95% CI: 2.6–4.3; AER: 66 patients per 10 000 per year) followed by skin cancer (SIR: 1.7, 95% CI: 1.1–2.6; AER: 17 patients per 10 000 per year). The increased risk of second breast cancer was similar for the ipsilateral (SIR: 1.9, 95% CI: 1.3–2.7) and contralateral (SIR: 2.0, 95% CI: 1.4–2.8) breast. Risk of second cancer was independent of age at diagnosis, type of initial therapy, histologic type of BCIS and period of diagnosis. Standardised incidence ratios of second cancer after BCIS (SIR: 2.3, 95% CI: 1.8–2.8) resembled that after invasive breast cancer (SIR: 2.2, 95% CI: 2.1–2.4). Surveillance should be directed towards second (ipsi- and contra-lateral) breast cancer

Rising incidence of breast cancer among female cancer survivors: implications for surveillance

The number of female cancer survivors has been rising rapidly. We assessed the occurrence of breast cancer in these survivors over time. We computed incidence of primary breast cancer in two cohorts of female cancer survivors with a first diagnosis of cancer at ages 30+ in the periods 1975–1979 and 1990–1994. Cohorts were followed for 10 years through a population-based cancer registry. Over a period of 15 years, the incidence rate of breast cancer among female cancer survivors increased by 30% (age-standardised rate ratio (RR-adj): 1.30; 95% CI: 1.03–1.68). The increase was significant for non-breast cancer survivors (RR-adj: 1.41, 95% CI: 1.04–2.75). During the study period, the rate of second breast cancer stage II tripled (RR-adj: 3.10, 95% CI: 1.73–5.78). Non-breast cancer survivors had a significantly (P value=0.005) more unfavourable stage distribution (62% stage II and III) than breast cancer survivors (32% stage II and III). A marked rise in breast cancer incidence among female cancer survivors was observed. Research to optimise follow-up strategies for these women to detect breast cancer at an early stage is warranted

Overdiagnosis and overtreatment of breast cancer: Overdiagnosis and overtreatment in service screening

Screening mammography has been shown to be effective for reducing breast cancer mortality. According to screening theory, the first expected consequence of mammography screening is the detection of the disease at earlier stages and this diagnostic anticipation changes the population incidence curve, with an observed increase in incidence rates at earlier ages. It is unreasonable to expect that the age-specific incidence will ever return to pre-screening levels or to anticipate a significant reduction of incidence at older ages immediately after the first screening round. The interpretation of incidence trends, especially in the short term, is difficult. Methodology for quantification of overdiagnosis and statistical modelling based on service screening data is not well developed and few population-based studies are available. The overtreatment issue is discussed in terms of appropriateness of effective treatment considering the question of chemotherapy in very early stages and the use of breast conserving surgery