UCSF study finds surprising driver of cancer care’s carbon footprint

The biggest source of emissions in hospitals and clinics providing radiation treatment for cancer are the systems used to operate buildings and equipment, according to a new UCSF study published last week.

The latest study, published in The Lancet Oncology journal, looked specifically at radiotherapy’s contribution . It examined radiotherapy programs for 10 different cancer types at four institutions across the country — including UCSF — and foundthat 74% of greenhouse-gas emissions at radiotherapy facilities came from the buildings’ general energy usage. HVAC systems accounted for the largest share of those emissions.

Treatment machines accounted for just 3% of the total energy usage, said Dr. Katie Lichter, the first author of the study and a UCSF resident in radiation oncology.

Lichter said the researchers expected “the biggest machine in the room was actually responsible for the greatest emissions,” in part because of the lack of prior research.

“The health-care sector is about 10% of our nation’s emissions,” Lichter said “When I began looking into where oncology stands within that, there was essentially no data at all.”

Lichter told The Examiner that she first began thinking about this area when she started her medical training in 2020 at the height of the COVID-19 pandemic and amid wildfire smoke turning San Francisco’s skies orange.

“I really started to see the interconnectedness of the health-care sector and the health of the world and the planet,” she said.

Patients and health-care workers’ transit accounted for about 25% of the examined radiotherapy facilities emissions, according to the study. That came as no surprise to Lichter, who said transit is a high contributor to health-care carbon emissions nationwide.

The team found that a potential way to mitigate the high emissions during treatment would be to provide shorter treatment sessions — with more intense radiation over fewer days — in order to cut down on patient transit as well as the level of energy used for each treatment.

Using this method — known as hypofractionated radiation therapy — for certain cancer-fighting radiation treatments led to a large drop in emissions: 77% for some prostate cancers and 42% for some breast cancers.

“Not only do we know that this treatment is just as safe, it’s just as effective, it’s cheaper, it saves resources, it’s convenient from a patient perspective — but what if we can also understand that there may be environmental benefits to these treatments as well?” Lichter said.

Lichter argued this treatment isn’t more common because of how the American health-care system is structured. Shorter treatments mean smaller insurance payments, she said.

“You’re paid per day of treatment,” she said.

Lichter said she hopes health-care institutions and systems take away from the study that small changes can make a big impact. Reducing single-use items or other such low-hanging fruit is a good place to start with cutting greenhouse-gas emissions, she said.

Lichter added that a larger conversation about more expansive policy changes is essential to make a bigger impact.

“How can we support our institutions?” Lichter said. “How can we support UCSF to not only deliver high value-based care, but to also have a sustainable focus? I think there are opportunities for cities statewide, even nationally, to support our health-care sector doing this.”

UCSF Health has said it aims to be carbon neutral by 2025. It has worked to reduce its carbon footprint for nearly 10 years, having cut its greenhouse-gas emissions by 26% since 2015, according to officials.

Going forward, Lichter said her research will expand to include other forms of cancer therapy, including surgery, to get a fuller picture of the environmental repercussions of cancer treatment as a whole.

Further down the line, she said the same questions would be asked about other kinds of health care and treatments.

“I hope it’s just an impetus for other other fields to also understand their baseline,” said Lichter. “So then we can get a better understanding of further hotspots and opportunities for mitigation all across the health-care sector.”