Columbia's Department of Radiation Oncology has treated 500 patients with adaptive radiation therapy-a milestone that reflects the department's leadership in bringing the latest advances in radiation therapy to cancer patients at NewYork-Presbyterian/Columbia University Irving Medical Center.
Adaptive radiation therapy, which uses AI to almost instantly fine-tune a patient's treatment plan each day, solves a long-standing issue in radiation oncology: the difficulty of adapting treatment to anatomical changes that can occur during weeks of therapy.
"Patients' bodies do not stay the same during radiation: they lose weight, they gain weight, tumors get smaller, tumors get larger, or nearby organs shift position," says David Horowitz, associate professor of radiation oncology and director of adaptive radiation at Columbia University Vagelos College of Physicians and Surgeons and a radiation oncologist at NewYork-Presbyterian/Columbia."Fine-tuning the plan before each session lets us deliver the maximal radiation dose to the tumor while reducing the risk of irradiating nearby healthy tissues."
With conventional radiotherapy, patients receive radiation doses designed at the beginning of their treatment course, regardless of any changes in anatomy that occur during the weeks of treatment. "We didn't have the technological capability or computing power to recalculate the treatment plan quickly enough to account for these changes without causing a delay in treatment," says Tony Wang, professor of radiation oncology at Columbia University Vagelos College of Physicians and Surgeons and co-director of the Center for Radiosurgery at NewYork-Presbyterian/Columbia University Irving Medical Center.
Now, with the help of AI, patients can have their treatment plan reassessed and optimized before every session.
"Fine-tuning the plan before each session lets us deliver the maximal radiation dose to the tumor while reducing the risk of irradiating nearby healthy tissues," says Michael Price, vice chair for physics and director of enterprise technical strategy and innovation and associate professor of radiation oncology at Columbia University Vagelos College of Physicians and Surgeons.
"The potential benefits to the patient-better cancer control and fewer side effects-are substantial."
A paradigm shift in radiation treatment planning
In conventional radiation therapy, planning is a complex process that can take up to two weeks to prepare and test before the patient receives the first dose.
Adaptive radiation uses sophisticated three-dimensional CT imaging to identify changes in the patient's anatomy-including in the tumor and nearby structures-since the patient was last treated. A machine learning module automatically recalculates the plan based on the patient's changed anatomy, and the radiation therapy team reviews and approves each recalculated treatment plan before it is implemented. The entire process adds only a few minutes to each treatment.
"Being able to give the right treatment to the right patient at exactly the right time, that's a paradigm shift in radiation oncology," Horowitz says. "It takes a real investment of time and effort from our medical physicists, and it's made us very successful."
Potential benefits for some cancers
At Columbia, the adaptive radiotherapy system is used to treat patients with gastrointestinal, bladder, cervical, and rectal cancers, which are located near organs that frequently change in volume.
"It's really eye-opening when you see where the bowel is on a day-to-day basis and realize just how much radiation it would have received without adaptive therapy," says Horowitz.
"We've treated a few patients here with adaptive radiation who I don't think could have been safely treated at all with conventional radiation therapy. It would have required exposing healthy tissues to unacceptable doses."
Over time, radiation oncologists at NewYork-Presbyterian and Columbia have expanded to tumors in the lung, and complex head and neck cancers. "Irradiating large head and neck cancers poses a risk to nearby structures such as the optic nerve or brainstem," says Wang. "With the adaptive system, we can deliver very focused radiation doses to the tumor while reducing the risk to nearby structures."
Studies have shown that adaptive radiation reduces side effects and lowers radiation exposure of healthy tissues, though the treatment's effects on tumor progression and survival are still being evaluated in large multicenter studies.
"At Columbia, we're seeing very good side effect profiles compared to conventional approaches, patients are happy with it, and physicians have adopted it into their workflows," says Horowitz. "While we await data on cancer progression and survival, all signs point to adaptive radiation becoming a powerful and standard tool in our fight against cancer."
