Basis of oncology. Diagnosis of tumors. Staging and grading of malignant tumors. Screening of malignant tumors.
A tumor is a pathological process of uncontrolled cell and tissue growth, not related to normal renewal or regeneration. The process of transformation from a normal cell to a malignant one involves several key biological alterations:
- Initiation: Genetic damage by carcinogens activates oncogenes or inactivates tumor suppressor genes.
- Promotion: Proliferation of these altered cells.
- Persistence: Irreversible loss of growth control.
- Progression: Formation of a neoplasm with invasive and metastatic potential.
Biological Hallmarks of Cancer
- Self- sufficiency in growth signals
- Insensitivity to anti- growth signals
- Evasion of apoptosis
- Unlimited replication (immortalization)
- Angiogenesis (inducing blood supply)
- Invasion and metastasis
- Genomic instability (newer addition)
Cancer cells grow and proliferate autonomously, escaping normal controls. They include:
- Proliferating cells – targets of chemotherapy.
- Temporarily silent cells (TSCs) – non- dividing but can reactivate.
- Permanently silent cells (PSCs) – non- malignant and non- dividing.
Diagnosis of Tumors
1. Clinical Methods
- History and Physical Examination: General condition, signs of mass, organ function.
- Lab Tests: General labs and tumor markers.
2. Tumor Markers
Used for screening, diagnosis, prognosis, and monitoring response:
Note: These markers may be elevated in benign conditions too.
3. Imaging (Instrumental Methods)
- Ultrasound, CT, MRI, PET, Endoscopy, X- rays
4. Tissue Diagnosis
- Biopsy: Fine needle, core, excisional, or incisional
- Exploratory operations: Laparotomy, thoracotomy, if imaging and biopsy are inconclusive