In the United States, the chances of developing lung cancer over a lifetime are about 1 in 14 for men and around 1 in 17 for women. The chances are much higher for people who smoke and lower for people who do not.
While the prognosis, or outlook, for patients diagnosed with lung cancer is usually poor, if the disease is diagnosed in the early stages, there is a higher chance of a cure.
More than 430,000 people in the U.S. alive today have been diagnosed with lung cancer at some point in their lives.
There are two main types of lung cancer. Approximately 80-85 percent of lung cancers are non-small cell lung cancer (NSCLC), and around 10-15 percent are small cell lung cancer. These types are treated very differently.
Optimum timing of adjuvant chemotherapy not clear
The new study - from Yale University in New Haven, CT - concerns NSCLC, of which there are two subtypes that each arise from a different type of lung cell. However, they are usually grouped together because the approaches to their treatment and prognosis are often similar.
Fast facts about lung cancer
- In the U.S., lung cancer is the second most common cancer in both men and women (not counting skin cancer)
- The disease mainly occurs in older people
- The average age at diagnosis is about 70.
In their paper, the Yale researchers note the standard recommendation is that chemotherapy should be administered for NSCLC patients whose cancer has spread to the lymph nodes, whose tumors are 4 centimeters or larger, or where there is extensive invasion into surrounding tissue.
However, while there is general consensus regarding such use of chemotherapy - called adjuvant chemotherapy because it is additional to the main treatment - the optimum timing is not clear.
Many doctors say that the optimum window for giving adjuvant chemotherapy to NSCLC patients is 6-9 weeks following surgery.
However, there are cases where patients need to recover from complications following surgery, and they may not be able to tolerate chemotherapy so soon.
For their study, Daniel J. Boffa, associate professor of surgery at Yale School of Medicine, and colleagues analyzed data on patients in the National Cancer Database in order to examine the relationship between timing of chemotherapy after surgery and 5-year survival.
The National Cancer Database is a hospital-based tumor registry, capable of capturing over 70 percent of U.S. incident lung cancer cases.
Chemotherapy after traditional window may still benefit
The analysis included 12,473 NSCLC patients who met the standard recommendation for adjuvant treatment and received chemotherapy between 18 and 127 days after surgery during 2004-2012.
Results showed that 5-year survival for patients whose chemotherapy started 7-18 weeks following surgery differed little from patients whose chemotherapy started closer to the 6-9-week window that is generally followed.
The analysis also found that surgery followed by delayed chemotherapy was associated with a lower risk of death compared with surgery only.
Researchers conclude that while they did not look at the underlying causes, the results suggest that delaying chemotherapy outside the traditional postoperative window may still offer benefit to NSCLC patients.
Although the findings have yet to be confirmed with further study, Prof. Boffa notes:
"Clinicians should still consider chemotherapy in appropriately selected patients who are healthy enough to tolerate it, up to 4 months after NSCLC surgical resection."
Association of delayed adjuvant chemotherapy with survival after lung cancer surgery, Michelle C. Salazar et al., JAMA Oncology, doi:10.1001/jamaoncol.2016.5829, published online 5 January 2017.
Yale University news release, accessed 9 January 2017.
The JAMA Network news release, accessed 9 January 2017.
Additional source: American Cancer Society, Key statistics for lung cancer, accessed 9 January 2017.
Additional source: World Health Organization, Cancer fact sheet, accessed 9 January 2017.