For years, lung cancer has remained the second most common form of cancer among both men and women (second to prostate cancer in men and breast cancer in women). However, it is by far the leading cause of cancer death among both men and women. A recent study conducted at the National Cancer Institute has revealed that lung cancer rates in the United States have continued to drop in recent years, and researchers believe it may coincide with a decline in smoking estimates.
Lead researcher Denise Riedel Lewis and her colleagues used the Surveillance, Epidemiology, and End Results (SEER) program to gather data surrounding overall lung cancer cases between 1977 and 2010. The research team also examined individual types of lung cancer such as squamous cell, small cell, adenocarcinoma, large cell, other, and unspecified carcinoma diagnoses. Ethnic groups included white and black people between 1971 and 2010 as well as non-white Hispanic people, Asian/Pacific Islanders, and white Hispanics between 1992 and 2010.
The overall lung cancer rates among black and white men and women dropped significantly over the past 20 years compared to all other ethnic groups. Rates of squamous and small cell carcinomas have also experienced a steep drop in the past two decades, but more so with men rather than women. Although adenocarcinoma rates also started to decline after 1990, by 2005 those numbers began to creep back up, especially in women.
"The good news is that lung cancer rates are declining,” Riedel Lewis told Healthday News. “However, it's not as clear for certain subtypes, and we are not exactly sure of the reasons behind these increases."
While the research team could not comment on the cause for an overall decline in lung cancer diagnoses with certainty, they speculate that it may be related to a decline in smoking rates. The recent increase in adenocarcinomas was most likely due to smokers switching to low-tar, low-nicotine, or “light” cigarettes, which tend to make people inhale deeper. Breathing smoke deeper causes it to reach the outer areas of the lungs where adenocarcinomas develop.
“Smoking cessation [stopping smoking] represents the single most important step that smokers can take to enhance the length and quality of their lives,” said the U.S. Surgeon general.
According to the American Cancer Society, at least 80 percent of lung cancer deaths are the result of cigarette smoke and that’s not just for the people who do the smoking. Non-smokers who live with smokers increase their risk of developing lung cancer by between 20 and 30 percent.
Source: Devesa S, Travis W, Caporaso N, Check D, Riedel Lewis D. US lung cancer trends by histologic type. Cancer. 2014.