GNS300 CHAPTER 17 ONCOLOGY

Overview of Radiation Therapy

Goals of Radiation Therapy

• Cure, Control, and Palliation: The primary goals of radiation therapy include:

  • Cure: Striving to completely eliminate cancer from the patient’s body.

  • Control: Aiming to manage cancer progression, especially in metastatic cases.

  • Palliation: Focusing on alleviating symptoms to improve the quality of life for patients with advanced cancer.

• Combination Treatments: Radiation therapy is frequently combined with other modalities such as:

  • Surgery: Pre- or post-operative radiation can assist in controlling or shrinking tumors.

  • Biological Therapy: These therapies enhance the immune response or block cancer growth in conjunction with radiation.

  • Chemotherapy: Administered alongside radiation to attack cancer cells in various ways, increasing overall effectiveness.

Mechanism of Radiation Therapy

• Definition: Radiation therapy utilizes ionizing radiation to induce ionization and excitation in cells when the radiation is absorbed by tissues, leading to cellular damage.

• Types of Ionizing Radiation:

  • Electromagnetic Rays: This includes X-rays and gamma rays, which penetrate deeply and can target tumors effectively.

  • Particulate Radiation: Comprising electrons, protons, neutrons, and both beta and alpha particles, these particles can offer specific targeting benefits.

• Cell Damage: High-energy radiation primarily damages the DNA of cells, disrupting their ability to divide and function properly. Cancer cells are generally more sensitive to these effects than healthy cells, which allows radiation to selectively target harmful cells while sparing normal ones where possible.

• Recovery of Normal Cells: Unlike cancer cells, normal cells often have repair mechanisms that enable them to recover from damage, provided that the radiation doses fall within a manageable range, ensuring that healthy tissues can recuperate.

Use in Palliative Care

• Tumour Reduction: Low doses of radiation are effective in reducing tumor size, leading to symptomatic relief with minimal adverse effects.

• Symptomatic Relief: Radiation therapy can effectively relieve pain by reducing tumor mass that exerts pressure on critical structures, including nerves and organs such as the spinal cord, thus alleviating debilitating symptoms.

Combination with Surgery

• Indications for Combined Treatment:

  • Organ Preservation: Particularly in scenarios such as breast conservation therapy where the goal is to eliminate cancer while retaining as much healthy tissue as possible.

  • High Risk of Local Recurrence: In patients with a significant chance of tumor return if solely treated with surgery, combining radiotherapy is often essential.

  • Making Inoperable Cancers Operable: Radiation can shrink tumors effectively to the point where surgical intervention becomes feasible.

• Preoperative Benefits: Prior to surgery, radiation can assist in increasing the safety and efficacy of cancer removal by enhancing surgical margins and reducing tumor burden, ultimately leading to better surgical outcomes.

Overview of Radiation Therapy

Goals of Radiation Therapy

• Cure, Control, and Palliation: The primary goals of radiation therapy include:

  • Cure: Striving to completely eliminate cancer from the patient’s body.

  • Control: Aiming to manage cancer progression, especially in metastatic cases.

  • Palliation: Focusing on alleviating symptoms to improve the quality of life for patients with advanced cancer.

• Combination Treatments: Radiation therapy is frequently combined with other modalities such as:

  • Surgery: Pre- or post-operative radiation can assist in controlling or shrinking tumors.

  • Biological Therapy: These therapies enhance the immune response or block cancer growth in conjunction with radiation.

  • Chemotherapy: Administered alongside radiation to attack cancer cells in various ways, increasing overall effectiveness.

Mechanism of Radiation Therapy

• Definition: Radiation therapy utilizes ionizing radiation to induce ionization and excitation in cells when the radiation is absorbed by tissues, leading to cellular damage.

• Types of Ionizing Radiation:

  • Electromagnetic Rays: This includes X-rays and gamma rays, which penetrate deeply and can target tumors effectively.

  • Particulate Radiation: Comprising electrons, protons, neutrons, and both beta and alpha particles, these particles can offer specific targeting benefits.

• Cell Damage: High-energy radiation primarily damages the DNA of cells, disrupting their ability to divide and function properly. Cancer cells are generally more sensitive to these effects than healthy cells, which allows radiation to selectively target harmful cells while sparing normal ones where possible.

• Recovery of Normal Cells: Unlike cancer cells, normal cells often have repair mechanisms that enable them to recover from damage, provided that the radiation doses fall within a manageable range, ensuring that healthy tissues can recuperate.

Use in Palliative Care

• Tumour Reduction: Low doses of radiation are effective in reducing tumor size, leading to symptomatic relief with minimal adverse effects.

• Symptomatic Relief: Radiation therapy can effectively relieve pain by reducing tumor mass that exerts pressure on critical structures, including nerves and organs such as the spinal cord, thus alleviating debilitating symptoms.

Combination with Surgery

• Indications for Combined Treatment:

  • Organ Preservation: Particularly in scenarios such as breast conservation therapy where the goal is to eliminate cancer while retaining as much healthy tissue as possible.

  • High Risk of Local Recurrence: In patients with a significant chance of tumor return if solely treated with surgery, combining radiotherapy is often essential.

  • Making Inoperable Cancers Operable: Radiation can shrink tumors effectively to the point where surgical intervention becomes feasible.

• Preoperative Benefits: Prior to surgery, radiation can assist in increasing the safety and efficacy of cancer removal by enhancing surgical margins and reducing tumor burden, ultimately leading to better surgical outcomes.