Oncology is the medical specialty that studies of benign and malignant tumors, but with special attention to the malignant, ie cancer.

The term derives from the Greek Oncology onkos (mass or tumor) and the suffix-ou-logos (study). The professional in this field are oncologists.

Pediatric oncologists, who specialize in the care of children with any type of cancer.

Orthopedic oncologists: are devoted to the study, diagnosis and treatment of patients with bone and joint tumors mainly, and surgical reconstruction using megaprótesis (post-tumor resection) or massive bone transplants.

Plastic Surgeons Oncology: Oncology perform plastic surgery, a branch of restorative or reconstructive surgery after local excision of cancer.