The earlier lung cancer is detected, the better the survival rate. In recent years, diagnosis of early-stage non-small cell lung cancer (NSCLC) has increased while late-stage diagnosis has decreased; According to a 2021 study in JAMA Network Open, the percentage of NSCLC that was diagnosed in stages I/II at the year of diagnosis increased from 26.5% in 2006 to 31.2% in 2016.¹ The percentage of NSCLC diagnosed in stages III/IV using those same parameters decreased from 70.8% to 66.1%.
Though these are encouraging statistics, there is room to improve mortality rates. Lung cancer remains the leading cause of cancer-related deaths in the US for both men and women.² With mortality rates still a concern for lung cancer, what do we know about the likelihood of having an earlier or later-stage cancer at diagnosis?
Recently, studies have examined possible links between certain physical and socioeconomic factors that are associated with earlier or later stages of lung cancer at diagnosis. What are the survival rates for lung cancer, and what do we know about shared factors among patients in their stage at diagnosis?
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Lung Cancer Survival Rates By Stage
Lung cancer stages I-IV are categorized based both on how invasive and large the cancer is, as well as whether it is localized to the lung or has spread to lymph nodes or other organs. When determining survival rates, the National Cancer Institute uses the Surveillance, Epidemiology, and End Results (SEER) database. This groups cancers not by stage but by whether they are localized, regional (spread to nearby lymph nodes), or distant (spread to more distant organs in the body).
SEER data for 5-year lung cancer survival rates show how important it is to find and diagnose the condition early. According to the American Cancer Society (ACS), the 5-year survival rate for patients diagnosed with a localized NSCLC from 2011 to 2017 was 64%.³ This was much higher than those with a regional (37%) or distant (8%) NSCLC. Overall, the 5-year survival rate for NSCLC in this timeframe was 26%, suggesting that not enough lung cancers were being caught early.
For small cell lung cancer, a more aggressive form, the 5-year survival rate for patients in the same time period was much lower; 29% for localized, 18% for regional, and 3% for distant.
Factors Associated With Stage at Diagnosis
Though new cases of lung cancer have been decreasing, it is clear more needs to be done to improve survival rates for those who are still being diagnosed. Are there factors associated with stage and survival rates of lung cancer, and what can we learn from them?
Sex
While women are more likely to receive a lung cancer diagnosis, men are seen as more likely to die from it. The ACS estimated that there would be more women diagnosed with lung cancer than men in 2022 (118,830 cases in women vs. 117,910 in men) but that more men would die from the condition than women (68,820 deaths in men vs. 61,360 in women).⁴
A 2022 study in the Journal of Clinical Oncology examined National Cancer Database data of over 1.1 million patients diagnosed with stages 0-I or stage IV NSCLC from 2004 to 2018, and determined that female patients were 70% less likely to be diagnosed with late-stage NSCLC than males.⁵
Knowing this, health care professionals should stress the importance of timely lung cancer screenings to at-risk male patients. Staying up to date with medical screenings and treatments may help diminish risk for men. In 2022, a study in Cancer Control looked at the data of a number of Canadian adults with lung cancer; Among the men in the group, a higher number of lifetime prostate antigen tests correlated with a reduced risk of late-stage lung cancer.⁶
Race
The race of a patient may play a role in how likely they are to get lung cancer and be diagnosed at a later stage. Black men are 12% more likely to develop lung cancer than white men, though Black women are 16% less likely to than white women.⁴ The Journal of Clinical Oncology study, meanwhile, suggested that African American and Native American patients were more likely to present advanced NSCLC at diagnosis, as were Hispanic patients compared to non-Hispanic patients.⁵
Socioeconomic Status
One reason race may play a role in lung cancer staging is that many minorities are socioeconomically disenfranchised, and thus do not have the access to health care they need. Socioeconomics overall played a role in staging according to the researchers, as those living in educated neighborhoods were less likely to present with stage IV NSCLC.⁵ Specifically, patients living in zip codes where 21% of residents or more do not have a high school degree were at a higher risk of advanced disease.
Comorbidities
In 2020, a study in Cancer Causes & Control found that, among its cohort of patients with NSCLC in the US Military Health System, patients with prior comorbidities were actually less likely to be diagnosed with advanced stage NSCLC than patients with no comorbidities.⁷ This could potentially be explained by patients with comorbidities seeing their health care professionals more often than those without comorbidities.
Within the group of patients with existing comorbidities, different comorbidities brought more or less risk. Patients with chronic obstructive pulmonary disease (COPD) were found to be less likely to have a late-stage diagnosis. However, patients whose comorbidities included congestive heart failure, liver cirrhosis, and chronic hepatitis were more likely to be diagnosed at a later stage.
Physical Activity
Physical activity is beneficial to lung health, but the researchers of the aforementioned Cancer Control study suggested that higher levels of physical activity among participants also correlated with increased odds of late-stage diagnosis.⁶ The researchers attributed this to active patients potentially attributing lung cancer symptoms like dyspnea and weight loss to the the amount and intensity of their exercise.
Many of the factors that affect lung cancer staging at diagnosis speak to a greater need for access and timely, frequent care for patients who are at risk of lung cancer. Improving these disparities benefits patients and health care professionals alike.
References
1. Flores R, Patel P, Alpert N, Pyenson B, Taioli E. Association of stage shift and population mortality among patients with non–small cell lung cancer. JAMA Netw Open. 2021;4(12):e2137508. doi:10.1001/jamanetworkopen.2021.37508
2. Yetman D. Lung cancer survival rates: by stage, age, type, and more. Healthline. https://www.healthline.com/health/lung-cancer-stages-survival-rates. Updated February 8, 2022. Accessed November 9, 2022.
3. Lung cancer survival rates | 5-year survival rates for lung cancer. American Cancer Society. https://www.cancer.org/cancer/lung-cancer/detection-diagnosis-staging/survival-rates.html. Updated March 2, 2022. Accessed November 14, 2022.
4. Lung cancer statistics | How common is lung cancer? American Cancer Society. https://www.cancer.org/cancer/lung-cancer/about/key-statistics.html. Updated February 14, 2022. Accessed November 14, 2022.
5. Verplancke K, Taylor A, Gallegos JM, et al. Demographic and socioeconomic factors associated with stage at diagnosis in non–small cell lung cancer: An NCDB analysis. Journal of Clinical Oncology. 2022;40(16_suppl):9132-9132. doi:10.1200/jco.2022.40.16_suppl.9132
6. Aktary ML, Ghebrial M, Wang Q, Shack L, Robson PJ, Kopciuk KA. Health-related and behavioral factors associated with lung cancer stage at diagnosis: observations from Alberta’s tomorrow project. Cancer Control. 2022 Jan-Dec;29:10732748221091678. doi: 10.1177/10732748221091678. PMID: 35392690; PMCID: PMC9016563.
7. Lin J, McGlynn KA, Nations JA, Shriver CD, Zhu K. Comorbidity and stage at diagnosis among lung cancer patients in the US military health system. Cancer Causes Control. 2020 Mar;31(3):255-261. doi: 10.1007/s10552-020-01269-1. Epub 2020 Jan 27. PMID: 31984449; PMCID: PMC8477344.
