Doctor Cassell finished a urologic oncology fellowship at the University of Florida in 1988. He promptly relocated ninety miles to the South in Lake County where he has specialized in the treatment of urologic cancers for the last 20 years. He's made every effort to provide minimally invasive techniques in his urologic therapies where applicable.

Prior to moving to Florida, Dr. Cassell completed a general surgery / urology residency at the University of Medicine and Dentistry in Newark, New Jersey between 1982 and 1987. Those five years of northern, inner city medicine proved to be instrumental in his decision to move to warmer, more bucolic surroundings. Spending the preceding five years attending medical school at St. Georges University in Grenada, West Indies, didn't exactly hurt either.

In 2004, he authored Better Living Through Urology, a self-help book for patients and nursing and medical students. The year before, Dr. Cassell was awarded a patent from the US Patent and Trademark Office for a device to be used in the anastamosis of the bladder and urethra during radical prostatectomy.