Cancer

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.