Gaining Control of Oligometastatic Cancer with Proton Therapy
July 3, 2025
Recent years have brought major advances in the treatment of oligometastatic cancer. In the past, such cancers were treated with palliative care meant to slow the spread of tumors and improve patient comfort. Now targeted radiation – including proton therapy – when used in conjunction with other treatments can enable clinicians to eliminate metastases and stop the progression of cancer.
What has emerged over the past five to 10 years is a paradigm in which patients with limited metastases can be aggressively treated with curative intent. Proton therapy is an avenue to treat these metastatic deposits in a precise and systematic manner.
Proton therapy allows oncologists to deliver a beam of protons directly to a tumor while avoiding damage to surrounding tissues. Proton therapy is a highly effective and safe option for managing oligometastases in the lung, kidney, prostate, colorectal region, and soft tissues from lung, colorectal, prostate, and kidney cancers—among others. Proton therapy treatment can patients to continue their current chemo/immune/hormone therapy regimens by targeting only areas that are not responding. Alternatively, proton therapy may allow for a delay in initiation of chemo/immune/hormone therapy.
Dr. Matthew Ferris
Medical Director, Maryland Proton Treatment Center
Assistant Professor of Radiation Oncology, University of Maryland School of Medicine
The Goal is Global Control
To treat oligometastatic cancers, radiation oncologists, medical oncologists and surgeons draw up a care plan consisting of surgery, chemotherapy and radiation therapy based on a patient’s individual needs. Proton therapy is a form of radiation and yields the same control of oligometastatic spots while limiting potential side effects as there is less collateral dose.
The precision of proton therapy can lead to better overall health outcomes for patients. Proton therapy significantly lowers the risk of developing a secondary cancer compared to traditional photon therapy. Proton therapy also gives a lot less dose to circulating blood in the body compared to normal photon-based radiation; this minimizes dose to the important immune cells circulating in that blood and helps keep them alive and able to fight the cancer. Additionally, proton therapy is less likely to cause lymphopenia than photon therapy.
Higher Quality of Life, Better Outcomes
Any time you’re sparing the secondary tissues, risks are lower. Numerous studies demonstrate the safety and efficacy of stereotactic body radiation therapy (SBRT), which has many similarities to proton therapy, in treating oligometastatic cancers. Proton therapy can be used in place of photon SBRT, and often this has a lot of dose advantages. Several studies show the efficacy of using SBRT to control metastasis of prostate and lung cancers. A long-term study of 99 patients showed significantly higher 5-year survival rates for those who received SBRT compared to those who received standard palliative treatments.
Proton therapy allows patients to get back to their lives sooner. Oncologists are often able to treat multiple metastasis in a single session. By embracing this treatment approach, it’s possible that people can live longer free of the side effects of either the cancer or the cancer treatments.
