Clinics within NETX: Frisco, Frisco West, Allen, McKinney South, McKinney North, Plano East/West, Plano Presbyterian, Garland, Rowlett, Castle Hills Lewisville, Flower Mound, Denton, Denison, Decatur, and Greenville. Texas Oncology Texas Oncology is the largest community-based oncology provider in the country, with 600+ providers at 300+ sites across Texas and southeastern Oklahoma.