It is with deep sadness that we announce the tragic loss of Tomás Lyons, MD, medical oncologist in MSK's Breast Cancer Service and the Evelyn H. Lauder Breast Center, who passed away unexpectedly on September 29. During his career at MSK, he made his mark by collaborating with multidisciplinary teams and being actively involved in clinical trials in order to provide the best possible treatments for our patients with breast cancer, as well as providing compassionate care and clear communication to his patients and their loved ones.

"Tomás was an amazing man, full of kindness and humor. His patients loved him. His colleagues loved him. I just cannot convey how deeply he will be missed," noted Mark Robson, MD, Chief of the Breast Medicine Service.

In 2007, Dr. Lyons completed his bachelor of medicine, surgery, and obstetrics (MB, BCh, BAO) degree at the University College Cork in Ireland, where he received a merit scholarship upon entry for receiving a maximum score in his college entrance exams.

In 2010, he received his Member of the Royal College of Physicians of Ireland (MRCPI) from the Royal College of Physicians of Ireland and completed internship and residency in internal medicine at Cork University Hospital in 2008 and 2010, respectively. Dr. Lyons completed his residency and fellowship in medical oncology at Cork University Hospital in 2016, with hospital rotations at Beaumont Hospital, Mater Misericordiae Hospital, and St. Vincent's University Hospital in Dublin.

He joined MSK in 2016 to complete his advanced medical oncology fellowship, in which he conducted research on weight control and cancer. In 2016, he also received the Ainsworth Scholarship from the University of Cork to support his post-graduate fellowship in the United States.

Dr. Lyons was a recipient of many awards throughout his career, including the 2014 and 2016 Oncology Research Award from the Irish Society of Medical Oncology, which he received for his research on long-term anthracycline cardiotoxicity in breast cancer survivors and on a screening test for BRAF mutant melanoma, respectively.

We extend our heartfelt condolences to Dr. Lyons's family, friends, and colleagues.