Cancer Patients and COVID-19 Outcomes by Locale

It’s well known that people with cancer are more vulnerable to the ravages of COVID-19 than the general population. What has not been known is whether the severity of COVID-19 in cancer patients has anything to do with where in the US they reside. A new study delved into COVID-19 outcomes in cancer patients nationwide and found no significant differences in mortality associated with geographic location.

A team of scientists at cancer centers throughout the country looked at data on 4749 cancer patients, with a median age of 66, who were treated at 83 cancer centers in the northeast, midwest, south, and west between March and November 2020. Based on patient residence data, the subjects were divided into 9 separate US census divisions. The primary outcome was 30-day all-cause mortality, with a secondary composite outcome including mechanical ventilation and ICU admission.

The results revealed no significant differences in outcomes among subjects in all 9 census divisions. However, patients treated at centers situated in locales with fewer than 250,000 people fared better than those treated at centers in locales with at least 1 million people (adjusted odds ratio, 0.31; 95% confidence interval, 0.11-0.84). Also, patients treated between September and November had significantly lower mortality rates than those treated during the first wave of the pandemic, from March to May (aOR, 0.32, 95% CI, 0.17-0.58).

The study results were not exactly what the researchers expected. “[W]e hypothesized that major clinical outcomes of COVID-19 would vary across the US, given fluctuating case rates, resource burdens, and rationing of care that was happening in some places.” Jessica Hawley, MD, assistant professor in the division of oncology, University of Washington/Fred Hutchinson Cancer Research Center in Seattle, and an author of the study, told Contagion. “[T]he observation that mortality and composite outcome rates did not significantly differ by region in time-adjusted models was somewhat surprising. But this should be reassuring for patients with cancer treated across the US.” The fact that mortality rates improved as the pandemic went on also is a good sign for patients, Hawley noted, adding, “We are getting better at taking care of them.”

Patients in less dense metropolitan areas manifested less severe symptoms initially than patients in more populated areas. Nearly 4 out of 5 (79.1%) exhibited “mild COVID-19 severity,” according to Hawley, compared with roughly half in centers in busier locations. It’s possible that particular environmental or social variables such as pollution exposure were factors in this disparity, but the current study did not allow for this kind of comparison.

While the study did not reveal regional differences in outcomes for COVID-19-positive cancer patients, it did show differences between individual cancer centers, something that Hawley hopes will be further studied to see if specific processes or actions affected outcomes at each center. She cited the example of the use of a large convention center in New York City as a subacute facility during the peak of the initial pandemic surge, which helped hospitals handle their case overloads. “Additionally, many health care volunteers from across the nation came to New York City to volunteer and assist in the short term, filling a void for the much-needed extra personnel,” she said. “Perhaps the availability of these types of external supports and ‘pop-off valves’ for the healthcare system permitted outcome stabilization in some regions.”

One limitation of the study is that it used data from patients mainly at large academic medical centers, which is not where most cancer patients are treated. Also, Hawley noted, patients who transfer into these centers for care tend to be sicker and have worse outcomes than those treated at community health care facilities.

The study took place before COVID-19 vaccines were available to the general public; cancer patients who get vaccinated have additional protection against the virus.