A groundbreaking clinical study from the University of Surrey and Royal Surrey NHS Foundation Trust has found that structured exercise during chemotherapy significantly increases the presence of immune cells inside tumors. Published in the Journal of Sport and Health Science, the trial offers new hope for improving treatment outcomes in patients with esophageal adenocarcinoma.
First human trial to show immune shift
The randomized controlled study involved 22 patients diagnosed with esophageal cancer. Half undertook a 16-week prehabilitation program, which included supervised aerobic and resistance exercise sessions during and after chemotherapy. The other half received standard treatment without exercise.
“To the best of our knowledge, we believe that our study is the first randomized controlled trial in humans to show that prehabilitation—structured exercise during chemotherapy— can change the tumor environment in a meaningful way,” said Nicola Annels, PhD, co-senior author and senior research fellow at the University of Surrey.
After surgery, tumor samples revealed that those who exercised had significantly more CD8+ T cells and natural killer cells, key immune defenders, than those who did not. The tumors also exhibited mature immune hubs known as tertiary lymphoid structures, which are linked to improved treatment responses.
Fitter patients, stronger immune attack
Co-first author Dr. David Bartlett, PhD, Head of Exercise Science Research within the School of Biosciences and Medicine at the University of Surrey, added: “We found that the fitter a person became, the stronger their immune response inside the tumor.” The results build on promising data from animal studies, but are the first to demonstrate a clear immunological benefit in humans.
In response, the researchers have launched the OPTIMUS trial, which will enroll 50 patients scheduled for surgery after neoadjuvant chemotherapy. The trial will compare the original exercise protocol to a higher-intensity variant, seeking to amplify the immune effect.
Early signs of success and patient empowerment
Already, seven patients have completed the OPTIMUS trial, with some showing complete responses where no tumor was detectable at surgery, an outcome seen in only six percent of patients.
Importantly, participants also reported psychological and physical benefits. One patient described the experience: “Cancer and its treatment take away many things which give us normality; our jobs, our health, our appearance, quality time with family, whilst introducing myriad appointments, chemo side effects, stress over incomes, difficult questions and conversations with children and the very obvious chance of early death. As a cancer patient, one has little or no agency over any of these factors. What the OPTIMUS trial gave me was one thing over which I had control.”
Senior author Nima Abbassi-Ghadi, BMBS, BMedSci, PhD, FRCS, Consultant General and Esophago-Gastric Surgeon at the Royal Surrey County Hospital, emphasized: “These are exciting findings which support the importance of preoperative exercise training for patients undergoing cancer surgery at Royal Surrey. The feedback from our patients has been overwhelmingly positive with some patients who would otherwise not have been able to undergo this life saving surgery, improving their fitness to such a degree that they have now had successful procedures.”
As the OPTIMUS trial continues, researchers hope to confirm and extend their findings, potentially reshaping how cancer care incorporates exercise as a formal component of treatment.
