In June this year, the International Agency for Research on Cancer (IARC) reclassified diesel emissions from group 2A (probably carcinogenic to humans) to group 1 (carcinogenic to humans). This puts diesel emissions in the same category as other group 1 carcinogens such as arsenic, asbestos, benzene, ethanol, and formaldehyde. Diesel emissions are associated with an increased risk of lung cancer and possibly an increased risk of bladder cancer although the evidence for this is limited.

These findings may be of concern to some, particularly those who drive diesel vehicles or who are exposed to signficant amounts of diesel emissions in the workplace. Diesel based cars are increasingly in popularity around the world. In Europe for example, about half of new cars sold have diesel engines. In the USA, around 3% of new cars sold are diesel based however this figure is expected to double to 6% by 2015.

We normally think of lung cancer as an affliction of elderly smokers however this isn’t always the case. The following article provides a brief overview of the prevalence, causes, and survival statistics for lung cancer in younger people.

Prevalence

Lung cancer before the age of 50 is relatively rare in the United States however more than 12,000 cases still occur annually, a rate of 4.2 per 100,000 individuals per year. A smoker has around a 1% chance of developing lung cancer before the age of 50 while a non-smoker’s chances are less than 1 in 1,000.

Several recent studies have looked at trends in the mortality differences between smokers and non-smokers. The studies have all produced remarkably similar conclusions – the excess mortality associated with cigarette smoking continues to increase resulting in a growing life expectancy difference between non-smokers and smokers. This is damning for the cigarette industry who have long claimed that increased usage of filtered cigarettes and low tar or “mild” formulations has resulted in a safer product. This simply doesn’t appear to be the case, and if anything, cigarette smokers are at a higher risk of dying from lung cancer, heart disease, and other smoking related illnesses than ever before.

HIV infected individuals are 70% more likely to develop lung cancer, even after adjustment for major lung cancer risk factors such as smoking, according to the results of a study published online in the journal AIDS last month.

Several studies had already found increased rates of lung cancer amongst HIV infected individuals however it had been thought much of the increase was the result of higher smoking rates rather than the disease itself. The prevalence of smoking in HIV infected individuals is around 65% in the USA – more than twice the national average.

Over the last year or so there has been a number of well publicized studies linking aspirin with a reduction in the risk of developing various forms of cancer. Many people will be wondering if the decreased risk of cancer is sufficient to justify taking a low dose aspirin daily. While doctors normally recommend a low dose aspirin regime to prevent myocardial infarction in patients with pre-existing cardiovascular disease, most shy away from recommending low dose aspirin to apparently healthy individuals.

Over the years, many scientific studies have looked at whether marijuana smokers are at an increased risk of developing cancer. Interestingly, despite the fact marijuana smoke shares many of the same carcinogens as cigarette smoke, no study has found a significantly increased risk of cancer as a result of smoking marijuana.

Many smokers want to know their probability of dying from lung cancer in a given time frame, however calculating precise risks can be difficult because there are a variety of factors that influence lung cancer probabilities.

The most important factors influencing lung cancer risk are age, number of years of smoking, average number of cigarettes smoked per day, number of years since smoking ceased (if the individual is a former smoker), and a history of asbestos exposure (working in a high risk occupation for at least 5 years).

Did you know that your chances of beating cancer depend on the season you are diagnosed in? It may seem bizarre but a large number of studies have found that individuals who are diagnosed with cancer in the summer have a better cancer prognosis than those diagnosed in the winter, apparently due to increased production of vitamin D by the body over the summer months.

A 2004 study, published in the journal Cancer Causes and Control, looked at the effect of sunlight on the prognosis of colon, breast, and prostate cancer in Norway. The researchers found that the case-fatality rate was higher in winter than in other seasons for all three forms of cancer.

Carrots are an extremely popular vegetable in the United States and are second only to potatoes in terms of consumption with an average of 12 pounds of carrots consumed per person per year. Carrots are well known for their ability to improve night vision however what is less known is that carrots and other foods rich in carotene may actually protect against lung cancer in both smokers and non-smokers.

One study, published in the journal Cancer Research in 1993, used data on 41,837 women from the Iowa Women’s Health Study to determine the effects of fruit and vegetable consumption on the risk of lung cancer.

Currently Hungary has the dubious honour of having the highest age standardised rate (ASR) of lung cancer in the world for men and the highest rate overall. At more than 50 cases per 100,000 people per year, Hungary’s lung cancer rate is more than twice the global average. The United States has the highest rate of lung cancer among women and the second highest rate overall. The following table shows the fifteen countries with the highest rates of lung cancer in the world (excludes countries with less than 1 million people).

Fish oil supplementation has been shown to improve the response rate to chemotherapy and prevent weight loss in the treatment of the most common form of lung cancer according to the results of a study published in the journal Cancer in February.

The study, conducted by Canadian researchers at the University of Alberta, followed 46 patients who were receiving treatment for non small cell lung cancer. All patients underwent a common chemotherapy regime (carboplatin combined with vinorelbine or gemcitabine). A fish oil supplement containing 2.5g of EPA and DHA was given daily to 15 of the patients while the remaining 31 received the chemotherapy treatment only.

A study, published this month in the journal Cancer Epidemiology, Biomarkers, And Prevention, has suggested that smokers may be able to reduce their risk of developing lung cancer by as much as 60% by consuming at least one glass of red wine each day.

The study was conducted by scientists at Kaiser Permanente in Oakland, California, and involved the study of 84,170 men aged between 45 and 69.

Many smokers want to know exactly how much higher their risk of dying from various forms of cancer is compared to non-smokers. Unfortunately the answer is a lot higher, more than 10 times higher for cancers such as lung, larynx, and mouth cancers.

Interestingly some forms of cancer that one wouldn’t normally associate with smoking such as pancreatic cancer, cervical cancer, and acute myeloid leukemia are also more likely in smokers.

A scientific study has shown that three popular vitamins, vitamin C, vitamin E, and folic acid (vitamin B9) do not reduce lung cancer risk. Furthermore, researchers found a small but significant increase in lung cancer risk amongst smokers taking vitamin E supplements.

The research, which is reported in the March 2008 issue of the American Journal of Respiratory and Critical Care Medicine, followed 77,126 American men and women from the state of Washington aged between 50 and 76.