Data from 169 patients with lung cancer diagnosed during the COVID-19 pandemic between February and June 2020 and from 443 patients diagnosed between February and June during 2017–2019 were analyzed (Table 1). The mean age of the entire study population was 69.1 ± 10.7 years, and 69.3% were male. Histologically, 532 (86.9%) patients had NSCLC, while 80 (13.1%) had SCLC. There were no significant differences in age, performance status (ECOG), smoking history, and cancer subtypes between the two groups.
Table 1. Patient characteristics according to diagnoses years.
|
2020
(Feb–Jun)
(n =169)
|
2017–19
(Feb–Jun)
(n = 443)
|
P value
|
Age at diagnosis, mean ± SD
|
69.4 ± 11.1
|
69.0 ± 10.6
|
0.637
|
Sex, Female
|
53 (31.4%)
|
135 (30.5%)
|
0.832
|
Performance, ECOG 0–2, (%)
|
91.7%
|
93.2%
|
0.686
|
Smoking, never smoker, (%)
|
34.4%
|
29.3%
|
0.443
|
Subtype
|
|
|
0.807
|
NSCLC
|
146 (86.4%)
|
386 (87.1%)
|
|
SCLC
|
23 (13.6%)
|
57 (12.9%)
|
|
Stage of NSCLC
|
|
|
0.015*
|
IA–IB
|
31 (21.2%)
|
98 (25.4%)
|
|
IIA–IIB
|
6 (4.1%)
|
47(12.2%)
|
|
IIIA–IIIC
|
28 (19.2%)
|
76 (19.7%)
|
|
IVA–IVB
|
81 (55.5%)
|
165 (42.7%)
|
|
Stage of SCLC
|
|
|
0.042
|
Limited disease
|
11 (47.8%)
|
14 (24.6%)
|
|
Extensive disease
|
12 (52.2%)
|
43 (75.4%)
|
|
*Statistical significance was tested by the linear by linear association. SD: standard deviation, ECOG: Eastern Cooperative Oncology Group, NSCLC: non-small cell lung cancer, SCLC: small cell lung cancer.
Figure 1 shows the trends in the daily number of confirmed COVID-19 cases in South Korea and the number of outpatients who presented to the pulmonology clinic of the study’s hospital. In South Korea, COVID-19 cases spiked from the third week of February. During this period, the number of pulmonology outpatients at the study hospital dropped by 16% from the previous year. The decline in the number of outpatients continued until June (weekly average number of patients: 721 during 2017–2019 vs. 616 in 2020, p<0.001). Figure 2 shows the monthly number of new lung cancer diagnoses by year. There were no significant differences in the overall number of patients with lung cancer before and after the pandemic (2017: N=138, 2018: N=139, 2019: N=166, 2020: N=169, p=0.605). There were no significant differences when the analysis was limited to NSCLC diagnoses only (2017: N=121, 2018 N=123, 2019: N=142, 2020: N=146, p=0.437). Even with a decline in the number of outpatient visits, the number of new lung cancer diagnoses remained constant. There were also no differences in the percentage of histological subtypes by year and month (Figure 3A and B).
During the COVID-19 pandemic, the proportion of stage III or IV cancer was 74.7%, which was significantly higher than that of the previous years (2017: 57.9%, 2018: 66.7%, 2019: 62.7%), while the proportion of stage I or II cancer decreased to 25.3% (p=0.011) (Table 2). The decline in the number of early lung cancer diagnosis was more evident during the early days of the pandemic (Figure 2C). In the SCLC group, the proportion of patients with limited stage (47.8%) increased from that of the previous years, but the difference was not significant (2017: 29.4%, 2018: 25.0%, 2019 20.8%, 2020:47.8%, p=0.239).
Table 2. Lung cancer stage stratified by subtypes and years.
Lung cancer subtype
|
Stage
|
Total
|
P value*
|
NSCLC
|
Stage I–II
|
Stage III–IV
|
|
0.011
|
2017 (Feb–Jun)
|
51 (42.1%)
|
70 (57.9%)
|
121
|
|
2018 (Feb–Jun)
|
41 (33.3%)
|
82 (66.7%)
|
123
|
|
2019 (Feb–Jun)
|
53 (37.3%)
|
89 (62.7%
|
142
|
|
2020 (Feb–Jun)
|
37 (25.3%)
|
109 (74.7%)
|
146
|
|
Total (Feb–Jun)
|
182 (34.2%)
|
350 (65.8%)
|
532
|
|
SCLC
|
Limited disease
|
Extensive disease
|
|
0.239
|
2017 (Feb–Jun)
|
5 (29.4%)
|
12 (70.6%)
|
17
|
|
2018 (Feb–Jun)
|
4 (25%)
|
12 (75%)
|
16
|
|
2019 (Feb–Jun)
|
5 (20.8%)
|
19 (79.2%)
|
24
|
|
2020 (Feb–Jun)
|
11 (47.8%)
|
12 (52.2%)
|
23
|
|
Total (Feb–Jun)
|
25 (31.3%)
|
55 (68.8%)
|
80
|
|
*Statistical significance was tested by the linear by linear association. NSCLC: non-small cell lung cancer, SCLC: small cell lung cancer.
Preventive measures
In South Korea, prompt development and approval of the COVID-19 diagnosis kit enabled quick and wide-ranging screening since the early days of the pandemic. Screening was performed for those with direct contact with COVID-19 patients and those who showed symptoms of acute respiratory infection. Most university affiliated hospitals, including the hospitals in this study, have designated triage outpatient clinics and in-hospital wards as recommended by health authorities.10 From the moment of presenting to the outpatient or emergency departments, patients with respiratory symptoms were seen by healthcare providers wearing personal protective equipment (PPE) in an isolated area. Suspected patients who needed to be hospitalized were admitted to an isolated ward until the test results were obtained. Even patients who yielded negative results were admitted to an isolated respiratory cohort ward. Patients who tested positive were provided continuous quarantined care or referred to national quarantine facilities. Patients admitted for lung cancer diagnosis, administration of anticancer agents, or surgery were admitted to a ward physically separated from the above-listed patients. They were required to undergo SARS-CoV-2 screening, and only those who tested negative were admitted. No hospital-acquired COVID-19 cases occurred in the hospitals.
While bronchoscopy is essential in the process of lung cancer diagnosis and staging, it is a high-risk, aerosol-generating procedure. Recently, bronchology societies published recommendations for the use of bronchoscopy during the pandemic.11 Most guidelines recommend postponing elective bronchoscopy tests, but in the included hospitals, bronchoscopy was promptly performed on lung cancer-suspected patients. Although the guidelines recommend pre-test screening to identify those with fever, respiratory symptoms, and prior contact with COVID-19 patients, given that some COVID-19 patients are asymptomatic, uniform pre-bronchoscopy COVID-19 screening may be required in regions where community transmission of COVID-19 occurred.12 In our study hospitals, patients admitted for lung cancer and outpatients with respiratory symptoms were required to undergo COVID-19 screening before bronchoscopy. None of the newly diagnosed patients with lung cancer in the study period were infected with COVID-19. To prevent the spread of infection within the hospital, only a number of healthcare professionals wearing PPEs performed the bronchoscopy in a well-ventilated negative-pressure room. Aerosol-generating procedures were not performed during the pretreatment or testing processes. After completing the test, surfaces were thoroughly disinfected. Percutaneous needle biopsy was also performed under similar preventive protocols.