Surgery is the primary treatment for about 25% of those diagnosed with cancer - and the best candidates have localized tumors that can be readily removed. If a patient's cancer has metastasized it is usually inoperable.
Malignant Tumor Surgery Removal -- Some Examples
Location of Tumor
All are very prevalent cancers (50,000+ diagnosis/year), and all are marked by solid state tumors that often can be detected early (before the cancer has spread) making the tumors viable candidates for surgical removal.
Surgical treatment of cancer has improved mainly because the equipment used is more "high tech" (for example, microsurgery and robots). But the largest sources of R&D funds remains Big Pharma and Biotech -- who are only interested in advances involving anti-cancer drugs.