A federally funded study published in JAMA Oncology found that people diagnosed with cancer in the first years of the COVID-19 pandemic had worse short-term survival than people diagnosed in the years just before it. Researchers said the results align with concerns that pandemic disruptions to screening, diagnosis and treatment could affect lives, and they analyzed whether the pattern held across multiple types of cancer and stages of disease.

The study focused on patients whose first diagnosis of a malignant cancer came in 2020 and 2021, using national cancer registry data. The researchers compared their one-year survival outcomes with historical survival patterns for patients diagnosed between 2015 and 2019. They said the analysis looked across a range of cancers and whether patients were diagnosed at late or early stages.

Todd Burus, of the University of Kentucky, led the study. Burus said the researchers were not able to definitively show what drove the worse survival, but he said “But disruptions to the health care system were probably a key contributor.” In the study framing, the researchers worked to filter out deaths mainly attributed to the coronavirus so they could assess whether factors other than COVID-19 infections were also playing a role.

The study reflects the broader disruption of health care during the pandemic, including delays to cancer screening such as colonoscopies, mammograms and lung scans. Burus noted that cancer prevention, diagnosis and treatment measures did not simply disappear during the pandemic, explaining that “We didn’t forget how to do those things.” He said, however, that disruptions could have changed access and changed how quickly people received treatment.

The researchers reported that one-year survival was lower for both early- and late-stage diagnoses for all cancer sites combined. They said the differences were especially large for colorectal, prostate and pancreatic cancers.

In the study’s survival estimates, researchers found that more than 96% of people with early-stage cancer diagnoses in 2020 and 2021 survived more than a year, while more than 74% of people with late-stage diagnoses survived more than a year. The study estimated those rates were slightly lower than what would have been expected based on the 2015 to 2019 trends, which the researchers said resulted in about 17,400 more deaths than expected within one year.

Recinda Sherman, a researcher from the North American Association of Central Cancer Registries, praised the study as an effort to document the pandemic’s impact in more specific terms. She said, “As this study is the first to document pandemic-related, cause-specific survival, I think it is important,” adding, “The more we understand about the impact of COVID-19, the better we will be able to prepare for the next one.”

Hyuna Sung of the American Cancer Society said the findings point to a key question about how durable any survival decline might be. She said, “Transient declines in survival that quickly recover may have little impact on long-term mortality trends,” and she said additional research will determine whether any effect lasts beyond the short term.