CANCER
- Cancer is a formidable disease globally, causing a significant number of deaths, including over a million cases in India annually.
- Research in biology and medicine has intensely focused on understanding the mechanisms behind cancer development, oncogenic transformations, and strategies for treatment and control.
- Normal cell growth and differentiation in our body are highly controlled and regulated.
- In cancer cells, there is a breakdown of these regulatory mechanisms, leading to uncontrolled growth.
- Normal cells exhibit contact inhibition, where contact with other cells inhibits uncontrolled growth.
- Cancer cells lose this property, resulting in continuous cell division and the formation of masses known as tumors.
- Types of Tumors:
Benign Tumors: Confined to their original location, causing minimal damage and not spreading to other body parts.
Malignant Tumors: Comprised of rapidly proliferating neoplastic or tumor cells that invade and damage surrounding tissues.
- Malignant tumors grow rapidly, competing for vital nutrients and starving normal cells in the process.
- The most feared property of malignant tumors is metastasis.
- Cells sloughed from tumors travel through the bloodstream to distant sites, initiating new tumors wherever they lodge in the body.
Causes of Cancer
- Cancer results from the transformation of normal cells into cancerous neoplastic cells.
- This transformation is induced by various agents known as carcinogens.
- Types of Carcinogens:
Physical Agents: Include ionizing radiations like X-rays and gamma rays, as well as non-ionizing radiations like UV rays. Ionizing radiations cause DNA damage, leading to neoplastic transformation.
Chemical Agents: Found in substances like tobacco smoke, chemical carcinogens play a significant role. Tobacco smoke is a major cause of lung cancer due to identified chemical carcinogens.
Biological Agents: Include oncogenic viruses with genes known as viral oncogenes. Viral oncogenes contribute to the oncogenic transformation of cells.
- Normal cells possess genes called cellular (c-onc) oncogenes or proto-oncogenes.
- Activation of these genes under specific conditions can lead to the oncogenic transformation of cells.
Cancer Detection and Diagnosis
- Timely detection is crucial for successful cancer treatment in many cases, underscoring the importance of early intervention.
Diagnostic Methods:
- Biopsy and Histopathological Studies:
Biopsy involves cutting suspected tissue into thin sections, stained, and examined under a microscope (histopathological studies) by a pathologist. Identifies abnormal tissue changes indicative of cancer.
- Blood and Bone Marrow Tests:
Tests check for increased cell counts, crucial in diagnosing leukemias.
Imaging Techniques - Radiography (X-rays), CT, and MRI:
- Radiography uses X-rays to capture images.
- CT (Computed tomography) generates three-dimensional internal organ images using X-rays.
- MRI uses strong magnetic fields and non-ionizing radiations for accurate detection of pathological and physiological changes in living tissues.
- Valuable for detecting internal organ cancers.
Use of Antibodies: Antibodies Against Cancer-Specific Antigens
- Detection of certain cancers involves antibodies targeting cancer-specific antigens.
- This method aids in the identification of specific cancer types.
Molecular Biology Techniques: Gene Detection for Inherited Susceptibility
- Molecular biology techniques detect genes in individuals with inherited susceptibility to certain cancers.
- Identifying predisposing genes is crucial for cancer prevention.
Treatment of Cancer
Surgery:
- Involves the physical removal of the tumor mass through surgical procedures.
Radiation Therapy:
- Delivers lethal irradiation to tumor cells while safeguarding surrounding normal tissues.
- Precise irradiation of tumor cells with minimal impact on adjacent normal tissues.
- Careful targeting ensures effective tumor cell destruction while minimizing collateral damage.
Chemotherapy:
- Chemotherapeutic Drugs: Various drugs, some tailored to specific tumors, aim to eliminate cancerous cells.
- Side Effects: Common side effects include hair loss, anemia, etc.
- Combination Therapy: Often, a combination of surgery, radiotherapy, and chemotherapy is employed for comprehensive cancer treatment.
Immunotherapy:
- Utilizes substances like α-interferon to activate the immune system, aiding in tumor destruction.
- Challenge: Tumor cells can adeptly evade detection and destruction by the immune system.
- Biological Response Modifiers: Substances like α-interferon activate the patient's immune system, enhancing its ability to destroy tumors.
Comprehensive Treatment Approach:
- Tailored Plans: Individualized treatment plans consider the specific characteristics of the cancer and the patient.
- Minimizing Side Effects: Personalized approaches aim to maximize treatment effectiveness while minimizing side effects.