Women Face Increased Global Mortality in Lung Cancer, Declines in Breast Cancer by 2030

Although the year 2030 seems a long way off, cancer mortality rates across the globe will still be an unfortunate reality; however, one cancer type in women may be on the decline.

In a recent study, published in Cancer Research, researchers found that lung cancer mortality rates among women are projected to increase by 43 percent from 2015 to 2030. However, on a positive note, the same study projected that breast cancer mortality rates will decrease by 9 percent in that time frame.

“We are in (a positive direction) in the reduction of the impact of breast cancer mortality worldwide; however, we have a lot of work to do in the reduction of the impact of lung cancer mortality among women worldwide.” Jose M. Martínez-Sánchez, Ph.D., MPH, BSc, associate professor and director of the Department of Public Health, Epidemiology and Biostatistics at Universitat Internacional de Catalunya in Barcelona, said in an interview with CURE.

“In other words, if we do not work to reduce the impact of lung cancer among women, we will know in the future that women who overcome a breast cancer (may end up dying from) lung cancer,” he added.

Previous studies have projected these mortality rates for lung and breast cancers among women, but only in a single country or continent. So, Martínez-Sánchez and colleagues estimated trends in mortality caused by these cancers on a global scale by analyzing data from the World Health Organization (WHO) Mortality Database from 2008 to 2014.

Of the 52 countries included in the study analysis, 29 were located in Europe; 14 in the Americas; seven in Asia; and two from Oceania.

Lung Cancer

In lung cancer, the global mortality rate among women is projected to increase from 11.2 women per 100,000 in 2015 to 16 women per 100,000 by 2030 — for which the highest rates would occur in Europe and Oceania and the lowest in America and Asia. Although projected for the highest rates, Oceania is predicted to see a slight decrease in lung cancer mortality during this time – a fall from 17.8 women per 100,000 to 17.6 by 2030.

Martínez-Sánchez attributed high rates of lung cancer mortality in women to the tobacco epidemic and a shift that has been seen in social smoking trends between genders.

“Smoking behavior among women was socially not accepted in the middle of the last century,” he added. “For this reason, the habit of smoking was always more common among men; however, in the last few decades smoking among women has increased. Moreover, there is a 30- to 40-year delay between the habit of smoking and developing lung cancer.”

However, trends varied by country in regards to the tobacco epidemic and women.

“The tobacco epidemic is a descriptive model that categorizes the countries in four different stages according to tobacco consumption (percentage of current and former smokers) and the mortality attributable to smoking among gender,” Martínez-Sánchez explained. “Following this model, the countries around the world are not in the same stages of the tobacco epidemic. For this reason, we observed diverse patterns of trend due to this model.”

To address the increased amount of lung cancer-associated mortality, Martínez-Sánchez suggested that countries implement smoking cessation programs in to annual screenings for women or to offer recommendations and guidelines for lung cancer screening — similar to what the US Preventive Services Task Force (USPSTF) has done in recent years.

“This research is particularly important because it provides evidence for health professionals and policymakers to (determine) global strategies to reduce the impact of lung cancer among women in the future,” he added.

Breast Cancer

In breast cancer, the global mortality rate among women is projected to decrease from 16.1 women per 100,000 in 2015 to 14.7 women per 100,000 in 2030 — for which the highest rates would occur in Europe, with a decreasing trend overall, and the lowest rates in Asia, with an increasing trend overall during this time frame.

“Breast cancer has been the first cause of death from cancer among women. However, the mortality rates of breast cancer have been decreased in the last years,” Martínez-Sánchez noted.

In particular, he attributed this to improved treatment options and screening programs in developed countries.

“Since the 1980s, there have been continuous advancements in treatment, such as the use of adjuvant therapy to reduce the risk of breast cancer recurrence, new chemotherapy drugs to slow cancer growth, and the introduction of sentinel lymph node biopsy to assess breast cancer spread,” Martínez-Sánchez explained.

“Currently, clinicians approach this disease with a rapidly evolving multidisciplinary treatment. Secondly, breast cancer screening is the second key factor to explain the decrease in developed countries where the participation rates in this screening program are very high,” he added.

However, lifestyle factors may also be reflective upon why mortality rates differ among continents. For example, obesity and alcohol intake are related to an increase in estrogen hormone levels, which can be associated with an increased risk for breast cancer, Martínez-Sánchez said.

Implications

Overall, high-income countries showed the highest projected age-standardized mortality rates for both lung and breast cancer in 2030 compared with middle-income countries. However, high-income countries appeared to be more likely to have decreasing breast cancer mortality rates.

Lastly, the researchers found that developed countries will be the first to witness lung cancer mortality rates surpass those from breast cancer.

“The main implication of our findings is that we still have time to reduce the impact of lung cancer mortality among women — empowering and helping them to stop smoking,” Martínez-Sánchez said.

Therefore, as a next step, Martínez-Sánchez and colleagues would like to evaluate and compare the potential benefits of the implementation of primary (smoking cessation) and secondary (screening) preventions for women worldwide.

“Undoubtedly, these strategies will reduce the health, social and economic impact of lung cancer among women in the future,” he said.