New Canadian Cancer Society funding to help uncover causes of shoulder problems after breast cancer treatment

Dr. Clark Dickerson, a professor in the Department of Kinesiology and Health Sciences, has received $486,233 from the Canadian Cancer Society's 2026 Challenge Grants program to investigate the causes of shoulder problems that can occur following breast cancer treatment.

The three-year project, “Pinpointing the cause of shoulder problems after breast cancer treatment,” will examine whether exposing shoulder muscles to radiation during treatment contributes to pain, weakness and limitations in arm movement experienced by some breast cancer survivors.

“Many people who receive radiotherapy for breast cancer experience lasting physical side effects that can affect their quality of life,” Dickerson said. “Mild discomfort can worsen over time, making everyday activities more difficult and reducing mobility and strength. Despite the prevalence of these challenges, the underlying causes are not fully understood.”

Working with a multidisciplinary team that includes Dr. Ramana Rachakonda, a radiation oncologist at the Waterloo Regional Health Network Cancer Centre (WRHN), Dickerson will compare outcomes among people receiving breast and lymph node radiation with those receiving breast radiation alone. Participants will be followed throughout treatment and for two years afterward to measure mobility, strength and quality of life.

The partnership with WRHN is central to the study’s clinical relevance and potential impact. Rachakonda is working with Dickerson and the research team to connect detailed radiation treatment information with measures of shoulder function, strength and quality of life. This collaboration will help researchers better understand how radiation exposure to shoulder muscles may contribute to long-term side effects.

The study is the first to directly investigate whether radiation exposure to shoulder muscles contributes to these long-term physical limitations. Researchers hope the findings will support earlier identification of patients at risk and lead to improved prevention and rehabilitation strategies.

The research also aims to identify radiation dose tolerances for shoulder structures and improve understanding of when individuals may benefit from referral to rehabilitation specialists or exercise programs. The ultimate goal is to improve long-term recovery, reduce pain and enhance quality of life for people living beyond breast cancer.