Changes in Newly Identified Cancer Among US Patients From Before COVID-19 Through the First Full Year of the Pandemic

We previously reported a substantial decline in new cancer diagnosed early in the COVID-19 pandemic in the United States. During the period from March 1 to April 18, 2020, weekly cases fell 46.4% (from 4310 to 2310) for 6 cancers combined, with significant declines for each type.¹ This was expected, given recommendations to conserve health care resources to address the initial set of patients with COVID-19. Medical practices have since reopened, but patient concerns remain. This study updates the analysis through March 2021.

This cross-sectional study included patients across the United States who received testing at Quest Diagnostics for any cause from January 2018 through March 2021, and whose ordering physicians assigned International Statistical Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM) diagnosis codes associated with any of 8 cancer types: breast (female patients only), colorectal, lung, pancreatic, cervical, gastric, esophageal, or prostate. Each patient was counted once, at the first instance of each ICD-10-CM code, starting January 2018; a cancer diagnosis during 2019 to 2021 was considered new if the patient had no prior ICD-10-CM entries for the same cancer since January 2018. Monthly trends were evaluated for 4 periods: prepandemic (January 2019 to February 2020) and pandemic periods: 1 (March to May 2020), 2 (June to October 2020), and 3 (November 2020 to March 2021). This study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline for cross-sectional studies.² This study was considered exempt by the Western Institutional Review Board, in accordance with 45 CFR §160 and §164, because no study participant provided specimens or information not already existing as part of health care operations.

Monthly numbers of newly diagnosed patients (Wilcoxon rank sum test), mean ages (2-sided t test), and sex distributions (χ² test) were compared between prepandemic and each of 3 periods of the pandemic. Results were considered statistically significant at P < .05. Analyses were performed using SAS Studio 3.6, version 9.4 (SAS Institute).

This study included 799 496 patients (45% women); mean (SD) patient age was 67.9 (12.0) years. A total of 453 712 (56.7%) patients were included in the prepandemic period, 68 246 (8.5%) in pandemic period 1, 146 518 (18.3%) in period 2, and 131 020 (16.4%) in period 3. Sex distribution remained consistent between prepandemic and each of 3 pandemic periods for all cancers except colorectal cancer in the first pandemic period. Mean patient age varied only slightly across periods; however, because of large sample sizes, differences reached statistical significance for most cancer types (Table).

Prepandemic, the mean monthly number of patients with newly identified cancer was highest for prostate (13 214), followed by breast (9583), colorectal (4101), lung (3015), pancreatic (1177), cervical (493), gastric (415), and esophageal (409) cancer. During the first pandemic period, the mean monthly number of new diagnoses fell 29.8% (from 32 407 to 22 748) for the 8 cancers combined. Declines were significant for all cancer types, ranging from 21.2% for pancreatic (from 1177 to 927; P = .03) to 36.1% for breast (from 9583 to 6122; P = .01). During the second pandemic period, the mean monthly number of patients newly diagnosed with cancer was 29 304 (9.6% decrease) for 8 cancers combined, statistically the same level as in prepandemic for all cancers except prostate. During the third pandemic period, mean monthly patient numbers (26 204; 19.1% decrease) remained significantly lower compared with the prepandemic period for all cancers; however, the magnitude of declines was lower than during the first period (Figure).

Our results indicate a significant decline in newly identified patients with 8 common types of cancer in the first and third pandemic periods (winter months) but not in the second period (summer months). A potential limitation of this study is our lack of an access to some baseline characteristics of the patients (eg, race/ethnicity and access to care) to examine their possible associations with delayed cancer care. Because the number of newly identified patients with cancer in the third pandemic period did not exceed the prepandemic value, as would be expected if patients with delayed care returned for care, many cancers may remain undiagnosed. The impact of delayed diagnosis may vary with the type of cancer and the extent of delay but could lead to presentation at more advanced stages, with potentially poorer clinical outcomes.³ Our findings call for planning to address the consequences of delayed diagnoses, including strengthened clinical telehealth offerings supporting patient-clinician interactions.

Accepted for Publication: July 13, 2021.

Published: August 31, 2021. doi:10.1001/jamanetworkopen.2021.25681

Open Access: This is an open access article distributed under the terms of the CC-BY-NC-ND License. © 2021 Kaufman HW et al. JAMA Network Open.

Corresponding Author: Harvey W. Kaufman, MD, Quest Diagnostics, 500 Plaza Dr, Secaucus, NJ 07094 (harvey.w.kaufman@questdiagnostics.com).

Author Contributions: Dr Kaufman and Ms Chen had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: All authors.

Acquisition, analysis, or interpretation of data: Kaufman, Chen, Niles.

Drafting of the manuscript: Kaufman, Chen.

Critical revision of the manuscript for important intellectual content: All authors.

Statistical analysis: Chen, Niles.

Administrative, technical, or material support: Kaufman, Fesko.

Supervision: Kaufman.

Conflict of Interest Disclosures: Drs Kaufman and Fesko and Ms Chen reported owning stock in Quest Diagnostics outside the submitted work. No other disclosures were reported.

Additional Contributions: We appreciate the superb editorial support from Jeff Radcliff (Quest Diagnostics). He was not compensated beyond his usual salary.