Air pollution, climate change, and health

Air pollution, climate change, and health

News A blood test measuring changes in CA-125 concentrations is highly effective in detecting ovarian cancer, according to results from the UK Collabo...

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A blood test measuring changes in CA-125 concentrations is highly effective in detecting ovarian cancer, according to results from the UK Collaborative Trial of Ovarian Cancer Screening (UKCTOCS). 46 237 women, aged 50 years and older, assigned to the multimodal screening (MMS) group of the trial had blood levels of CA-125 tested every year from 2002–11. An algorithm was then used to estimate every woman’s risk of ovarian cancer, referring them to specialists accordingly. During the course of 296 911 women-years of incidence screening,640(<1%)womenhadsurgery, of which 133 (21%) were diagnosed with primary invasive epithelial ovarian or tubal cancer (iEOC). An additional 22 women with iEOC diagnosed within a year of screening were missed.

MMS sensitivity was 85·8% (95% CI 79·3–90·9) and specificity was 99·8% (99·8–99·8). This compares favourably with use of a CA-125 threshold to establish ovarian cancer risk. In 2011, the PLCO trial classified CA-125 levels of 35 U/mL and above as abnormal. This threshold would have detected 41·3% (95% CI 33·5–49·5) of ovarian cancers in the UKCTOCS trial; reduction of the threshold to 22 U/mL would have detected 66·5% (49·5–58·4). “This is good news—we are moving in the right direction”, said lead author Usha Menon (University College London, London, UK). But she stressed that the key question, to be answered in ongoing analyses, is whether MMS confers any mortality benefit. Three-quarters of women with ovarian cancer present with advanced disease. “Survival is poor in these women [with

advanced ovarian cancer]. What we don’t know is whether by detecting the disease earlier in this group, we can impact on survival”, points out Menon. In UKCTOCS, 41·4% of patients with iEOC were detected at stage I or II. “What is not known, as yet, is whether the advanced-stage cancers diagnosed clinically are a different, more aggressive disease compared to clinically diagnosed early-stage cancers, or the same disease at a more advanced stage”, added Menon. Peter Jones (Southampton University, Southampton, UK) agrees, “The lowering of [cancer] stage at diagnosis is a potentially useful surrogate marker of the effectiveness of early detection, but it really does depend on seeing differences in survival”, he told The Lancet Oncology.

BSIP, LA/Science Photo Library

CA-125 blood test in early detection of ovarian cancer

Published Online May 12, 2015 S1470-2045(15)70237-8 For the PLCO trial see JAMA 2011; 305: 2295–303

Talha Khan Burki

Air pollution, climate change, and health Expanding industries worldwide are increasing the emission of CO2 and air pollutants to an alarming extent, with the resultant poor air quality having serious consequences on the environment, climate, and public health. In a new modelling study, investigators predict the health benefits of changes in carbon and co-pollutant emission standards for power plants in the USA. Their results add to the growing body of evidence showing that reducing carbon emissions from fossil-fuel-fired power plants alone can not only curb climate change, but will also have nearterm health benefits. However, the scale of these health benefits will depend on the design of the policies that enforce these standards into practice. The investigators predict that the greatest health benefits could be achieved with carbon emission policies that are stringent, but flexible, and demand user-side energy efficiency. Vol 16 June 2015

In such a policy scenario, reduced carbon emission will cause ozone and fine particulate matter concentrations to drop and avert a substantial number of premature deaths. The authors predicted that every year up to 3500 premature deaths (95% CI 780–6100) could be avoided by 2020, corresponding to 7·3 premature deaths averted per million ton decrease in CO2 emissions. Governments discussing policies to reduce carbon emission are relying on such modelling studies to make informed decisions. “It is important for scientists to quantify these connections as best we can so that we have a complete picture of the whole climate, pollution, and health system”, lead author Charles Driscoll (Syracuse University, Syracuse, NY, USA) explained to The Lancet Oncology. According to the International Agency for Research on Cancer

(IARC), there is sufficient evidence to link air pollution with risk of cancer. “Climate change is a very complex problem, and one can imagine scenarios that could affect cancer incidence upward or downward, such as changes in the distribution of sunlight, affecting skin cancer incidence, or changes in the ecology of insect vectors, altering patterns of cancer subsequent to malaria infection”, says Dana Loomis (IARC, Lyon, France). Although this study does not specifically address cancer, Loomis welcomes these results, agreeing that clear health benefits can be gained from reductions in air pollution as one of the critical upstream drivers of climate change, and concludes that there is certainly potential for cancer scientists to assess the effects of climate-related changes on cancer.

Published Online May 12, 2015 S1470-2045(15)70238-X For the study by Driscoll and colleagues see Nat Clim Chang 2015; published online May 4. DOI:10.1038/NCLIMATE2598

Josefine Gibson e269