American Cancer Society’s CEO is stepping down. But she plans to stay in Philadelphia to advance cancer research.

Karen E. Knudsen, a prominent Philadelphia cancer research leader, is stepping down from her role as chief executive of the American Cancer Society after three years to pursue new avenues to advance treatment options and support services.

Knudsen’s prior work includes serving as executive vice president of oncology services for Jefferson Health and director of the Sidney Kimmel Comprehensive Cancer Center. She joined the American Cancer Society as its first female CEO in 2021.

Knudsen plans to stay in Philadelphia and wants to focus on projects that bring together seemingly unlikely partners to speed up efforts to treat cancer and improve life for families living with cancer, she told The Inquirer.

She pointed to her success growing the American Cancer Society’s investment arm, which supports clinical trials that have been unable to secure other private-sector funding or public grants, and creating a new cancer-screening partnership with a private company as examples of the types of partnerships she’d like to help forge in Philadelphia.

“We have to be willing to think differently and take bold, innovative steps,” she said.

Knudsen declined to share specifics on her future employment, noting she will stay on with the American Cancer Society as an executive strategic adviser through early 2025.

The cancer organization plans to appoint an interim CEO by the end of the year and launch a national search for a new, permanent chief executive.

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The national nonprofit society, headquartered in Atlanta, is a leader in cancer advocacy and policy, a top grant-maker for cancer research, and has hundreds of local offices, including a hub in Philadelphia, that provide support services to families.

Under her leadership, the nonprofit grew revenue by 30% over three and a half years, expanded its cancer research program, and established new patient support programs. Knudsen brought on the ACS’s first chief diversity officer. And in May, the organization hired longtime retail executive Rob Muller as its Philadelphia-based first chief business transformation officer.

Knudsen played a leading role in growing the organization’s investment arm, BrightEdge, which supports cancer research projects that have potential to dramatically change patient care in the near-term.

“The American Cancer Society was in search of a visionary leader, and that is exactly what we found in Dr. Knudsen,” Board Chair Brian Marlow said in a statement. “She and her team have transformed ACS into an even more impactful, successful charitable organization.”

She also helped launch joint business ventures: a partnership with Color Health, a California cancer-detection company, to increase cancer screening, and ACS LION, a training and certification program for patient navigators.