Dr. Matthew McMillan

Dr. Matthew McMillan, MD, is a radiation oncologist at Memorial Sloan Kettering Cancer Center (MSK), where he specializes in the treatment of lung cancer, gastrointestinal cancers, metastatic disease, and bladder cancer. He sees patients at MSK Commack on Long Island and at the New York Proton Center in New York City. Dr. McMillan earned his medical degree from the University of Michigan, where he received a national research fellowship from Alpha Omega Alpha and graduated with Distinction in Research. He completed his radiation oncology residency at MSK, where he also served as Chief Resident before joining the faculty. His clinical focus is on matching each patient with the safest, most effective radiation therapy plan, whether that involves proton therapy, stereotactic body radiation therapy (SBRT), or other advanced techniques. He applies particular expertise to ultra-central lung tumors, which are situated close to critical structures in the chest and carry a heightened risk of radiation-related side effects, often incorporating proton therapy to better protect surrounding healthy tissue.

A significant part of Dr. McMillan's work involves advancing the safety and effectiveness of radiation therapy through research. He co-leads an international consortium of more than 30 centers focused on improving SBRT for ultra-central lung tumors, and he helps design clinical trials that combine radiation with immunotherapy. His research includes analyzing blood and tumor samples to understand how treatment reshapes the immune system, with a particular interest in immune checkpoint blockade, a form of immunotherapy that removes inhibitory signals on immune cells and helps them recognize and destroy tumors. He works closely with medical oncology colleagues to refine how radiation and immunotherapy can be integrated in both clinical practice and trial settings, with the goal of personalizing treatment so patients receive the greatest benefit with the fewest side effects.

In his day-to-day practice, Dr. McMillan places a strong emphasis on clear communication and coordinated care. He takes time to address patients' concerns about how radiation may affect their breathing or digestion, what side effects to expect, and how to minimize them, explaining options in plain language. He collaborates closely with surgeons, medical oncologists, and other specialists to ensure each patient receives a treatment plan tailored to their individual goals. Outside of medicine, he enjoys spending time at the park with his family and watching sports with friends and family.