Introduction
Cancer treatment aims to eliminate cancer cells while minimizing damage to normal tissues.
Chemotherapy and radiotherapy are two primary treatments, often used in combination with surgery, targeted therapy, and immunotherapy, depending on the type and stage of cancer.
Chemotherapy
Definition:
Chemotherapy uses anti-cancer drugs to destroy or inhibit the growth of cancer cells.
How Chemotherapy Works:
Targets rapidly dividing cells, including cancer cells.
Interferes with cell division (mitosis) or damages DNA, leading to cell death (apoptosis).
Mechanisms of Action:
Alkylating Agents:
Damage DNA by adding alkyl groups, preventing replication (e.g., cyclophosphamide).
Antimetabolites:
Mimic normal substances in the cell, disrupt metabolism and DNA synthesis (e.g., 5-fluorouracil).
Antitumor Antibiotics:
Bind to DNA and prevent RNA synthesis (e.g., doxorubicin).
Mitotic Inhibitors:
Block cell division by inhibiting microtubule formation (e.g., paclitaxel).
Topoisomerase Inhibitors:
Prevent DNA replication by inhibiting topoisomerase enzymes (e.g., etoposide).
Platinum-based Drugs:
Platinum will decompose around the cancerous cells so they will have a toxic environment. (e.g., Cisplatin)
Modes of Drug Administration:
Intravenous (IV): Most common, delivers drugs directly into the bloodstream.
Oral: Tablets or capsules, convenient for home use.
Intramuscular (IM): Injection into muscles for slower absorption.
Topical: Applied directly to the skin (used for certain skin cancers).
Intrathecal: Delivered into cerebrospinal fluid to treat brain or spinal cord cancers.
Adjuvant and Neoadjuvant Chemotherapy:
Adjuvant Chemotherapy:
Given after surgery or radiotherapy to eliminate residual cancer cells and reduce recurrence risk.
Example: Treating breast cancer post-surgery.
Neoadjuvant Chemotherapy:
Administered before surgery to shrink tumors, making them easier to remove.
Example: Reducing tumor size in advanced head and neck cancers.
Combination Therapy:
Uses multiple drugs or integrates chemotherapy with other treatments like radiotherapy.
Enhances effectiveness and reduces the chance of drug resistance.
Side Effects of Chemotherapy:
Affects rapidly dividing normal cells (e.g., bone marrow, hair follicles).
Hair Loss (Alopecia)
Nausea and Vomiting
Fatigue
Suppressed Immune System (risk of infections)
Anaemia and Bleeding
Neuropathy (nerve damage)
Radiotherapy
Definition:
Uses high-energy radiation (X-rays, gamma rays, or protons) to kill or damage cancer cells.
How Radiotherapy Works:
Damages the DNA in cancer cells, preventing them from dividing and causing them to die.
Affects both cancerous and normal cells, but normal cells can repair themselves more effectively.
Types of Radiotherapy:
External Beam Radiation Therapy (EBRT):
Radiation is delivered from a machine outside the body.
Commonly used for solid tumors.
Internal Radiation Therapy (Brachytherapy):
Radioactive material is placed directly inside or near the tumor.
Used for cancers like prostate or cervical cancer.
Systemic Radiation Therapy:
Radioactive substances are injected or taken orally (e.g., radioactive iodine for thyroid cancer).
Techniques in Radiotherapy:
3D Conformal Radiation Therapy (3D-CRT):
Delivers radiation to match the tumor's shape, reducing damage to healthy tissue.
Intensity-Modulated Radiation Therapy (IMRT):
Adjusts the intensity of radiation beams to target the tumor more precisely.
Stereotactic Radiotherapy (SRT):
High doses of radiation are delivered to small tumors with high precision (e.g., brain tumors).
Side Effects of Radiotherapy:
It Depends on the area treated and the radiation dose.
Skin Reactions: Redness, peeling, or blistering.
Fatigue
Hair Loss (localized to the treatment area)
Dry Mouth or Sore Throat (head and neck cancer)
Digestive Issues (if the abdomen is treated)
Long-term Effects:
Fibrosis, secondary cancers, or organ damage near the treatment site.