Cancer Screening Rates Have Fallen In US

Despite evidence that earlier diagnosis and improved treatment increases survival, rates of people seeking preventive cancer screening have fallen in the US in the last ten years. Failure of leading bodies to agree screening guidelines, plus reductions in workers with insurance cover could be among reasons for the decline, suggest researchers from the University of Miami Miller School of Medicine.
They write about their NIH-funded study in a paper published 27 December in the online open-access journal Frontiers in Cancer Epidemiology.

In the US, although numbers of cancer survivors have gone up as a result of improved diagnosis and treatment, cancer is still one of the most prominent chronic diseases that in 2011 killed more than 570,000 people.

Alongside a fall in rates of advanced cancer diagnoses in the US in the last ten years, has been an increase in the number of cancer survivors returning to work. The researchers suggest, in their background information, that keeping to a cancer screening schedule could be an important factor (as this helps detect secondary tumors early and reduce potentially limiting side effects).

However, their analysis reveals that although cancer survivors tend to show much higher rates of screening adherence, their numbers too have started falling off in the last three years.

Lead author Tainya Clarke, a research associate in the School's Department of Epidemiology and Public Health, says in a statement:

"There is a great need for increased cancer prevention efforts in the US, especially for screening as it is considered one of the most important preventive behaviors and helps decrease the burden of this disease on society in terms of quality of life, the number of lives lost and insurance costs."

"But despite this, our research has shown that adherence rates for cancer screenings have generally declined with severe implications for the health outlook of our society," she adds.

In January 2012, a new report by the Centers for Disease Control and Prevention (CDC) and the National Cancer Institute (NCI) showed that the percentage of people screened for cancer in the US remains below national targets for 2020, with rates lower among Asian and Hispanic Americans than other groups.

The NIH Study Also Looks at Workforce

For this latest study, Clarke and colleagues examined cancer screening adherence rates of the general public and cancer survivors and compared them to government-recommended "Healthy People" screening goals.

They looked at screening rates for colorectal, prostate, breast and cervical cancers. Not only did they compare rates between the general population and cancer survivors, but they also looked at rates among workers.

The data on screening rates came from National Health Interview Surveys conducted between 1997 and 2010 that in total covered nearly 174,400 people aged 18 and over. These annual surveys randomly sample the US population by household, and collect demographic and health information, including cancer history and cancer-related health behaviors such as cancer screening.

The Results

When they analyzed the data, Clarke and colleagues found that the general population did not meet the government's "Healthy People" screening goals for any type of cancer, apart from colorectal cancer (for this cancer, 54% of the general population underwent screening: the government's 2010 goal is 50%).

But among cancer survivors, who have a higher risk for cancer, the pattern was quite different. Their screening rates, for all types of cancer except cervical (this fell to 78% over the last ten years), exceeded the government goals.

However, the researchers also noticed a decline in the number of cancer survivors who went for cancer screening in the last three years.

Disparities Among Workers

The NIH Survey results also enabled the researchers to include data on working adult Americans with and without a history of cancer: including more than 7,500 with a history of cancer (representing 3.8 million working cancer survivors), and over 119,300 workers with no history of cancer (representing more than 100 million).

They found that among survivors, white collar workers on the whole had higher cancer screening rates than blue collar workers.

Clarke says this was a key finding that she hopes will lead to changes in employment policies to eliminate disparities among different groups of the working population of cancer survivors.

She hopes it will also spur researchers to look more closely at factors influencing screening rates so as to design better workplace interventions and encourage more workers in all occupations to take up screening.

She and her colleagues speculate that ongoing disputes over screening guidelines among bodies like the United States Preventive Services Task Force, American Cancer Society and others, plus reductions in rates of workers covered by insurance that have occurred in the past decade, may lie behind the trend.

Rice University Scientists Turn Soy Mash Into Succinic Acid

The humble soybean could become an inexpensive new source of a widely used chemical for plastics, textiles, drugs, solvents and as a food additive.

Succinic acid, traditionally drawn from petroleum, is one focus of research by Rice chemists George Bennett and Ka-Yiu San. In 2004, the Department of Energy named succinic acid one of 12 "platform" chemicals that could be produced from sugars by biological means and turned into high-value materials.

Several years ago, Rice patented a process by Bennett and San for the bio-based production of succinic acid that employed genetically modified E. coli bacteria to convert glucose into succinic acid in a way that would be competitive with petroleum-based production.

The new succinate process developed by Bennett, San and Chandresh Thakker and reported recently in Bioresource Technology promises to make even better use of a cheap and plentiful feedstock, primarily the indigestible parts of the soybean.

"We are trying to find a cheaper, renewable raw material to start with so the end product will be more profitable," said Thakker, a research scientist in the Bennett lab at Rice's BioScience Research Collaborative and lead author of the study. "The challenge has been to make this biomass process cost-competitive with the petrochemical methods people have been using for many years."

Bennett feels they have done that with soybean-derived feedstock as an inexpensive source of the carbon that microorganisms digest to produce the desired chemical via fermentation. "A lot of people use plant oils for cooking - corn or soybean or canola - instead of lard, as they did in the old days," he said. "The oils are among the main products of these seeds. Another product is protein, which is used as a high-quality food.

"What's left over is indigestible fiber and small carbohydrates," said Bennett, Rice's E. Dell Butcher Professor of Biochemistry and Cell Biology. "It's used in small amounts in certain animal feeds, but overall it's a very low-value material."

The Rice researchers are changing that with the help of E. coli bacteria engineered to process soy meal that generally gets discarded. Certain microbes naturally produce succinic acid from such feedstock, but manipulating E. coli's metabolic pathways (by eliminating pathways that produce other chemicals like ethanol, for instance) can make it far more efficient.

Expanding on their success in producing succinic acid from glucose, the new microbes are engineered to metabolize a variety of sugars found in soybean meal. The theoretical ideal is a 1:1 ratio of feedstock (the extracted sugars) to product, which they feel is achievable by industry. In the lab, under less controlled conditions, they still found the process highly efficient. "We're demonstrating a very high yield," Thakker said. "We're achieving in a flask a non-optimized formation of succinate that is close to the theoretical goal."

Bennett said his lab has been looking at soybeans for nearly three years. "We're always interested in low-cost feedstock," he said. "We were able to get a connection with a soybean group that is very interested in technologies to make better and more profitable use of their crop.

"There's a fair amount of oilseed residuals available, including cottonseed carbohydrates, that are not used for any high-value product, and we're in the space of microbial engineering to enable these sorts of materials to be used in a good way," he said.