What are the options for radiation therapy and tumor mapping in prostate cancer treatment?

Radiation Therapy and Tumor Mapping Options for Prostate Cancer

For prostate cancer treatment, multiple radiation therapy options exist including intensity-modulated radiotherapy (IMRT), stereotactic body radiotherapy (SBRT), and brachytherapy, with the choice depending on risk stratification and specific patient factors. 1

Radiation Therapy Options

External Beam Radiation Therapy (EBRT)

• Intensity-Modulated Radiotherapy (IMRT): Highly conformal treatment using multiple radiation beams/arcs 1

  • Recommended dose escalation (≥76-78 Gy) for improved biochemical progression-free survival 1
  • Should utilize target localization and image-guidance procedures to optimize therapeutic ratio 1

• Stereotactic Body Radiotherapy (SBRT): Delivers higher doses per fraction in fewer treatments 1

  • Appropriate for select patients with localized disease
  • Requires advanced planning and image guidance

• Volumetric Modulated Arc Therapy (VMAT): Variation of IMRT with potentially faster delivery 1

Brachytherapy

• Low-Dose Rate (LDR) Brachytherapy: Permanent seed implantation

  • May be offered as monotherapy for low-risk localized prostate cancer 1
  • May be combined with EBRT for intermediate-risk disease 1

• High-Dose Rate (HDR) Brachytherapy: Temporary implantation

  • Can be used alone or as boost with EBRT 1
  • Allows for precise dose delivery

Risk-Based Radiation Recommendations

Low-Risk Disease

• Single modality EBRT or brachytherapy recommended 1
• ADT should NOT be added except to reduce prostate size for brachytherapy 1
• Active surveillance is preferred over immediate treatment 2

Intermediate-Risk Disease

• EBRT or brachytherapy alone or in combination 1
• For unfavorable intermediate-risk, consider adding ADT to radiation 1

High-Risk Disease

• EBRT with 24-36 months of ADT 1
• EBRT combined with brachytherapy plus ADT 1
• Strong recommendation (Grade A evidence) for long-term ADT with radiation 1

Tumor Mapping and Imaging

Pre-Treatment Imaging

• MRI Fusion Imaging: Integrates MRI data with CT simulation for improved target delineation 1
• CT Simulation: Standard for treatment planning 1
• Cross-sectional imaging (CT or MRI) and bone scan recommended for unfavorable intermediate-risk and high-risk patients 1
• Avoid unnecessary imaging (abdomino-pelvic CT, bone scans) for very low or low-risk patients 1

Treatment Guidance Technologies

• Fiducial Markers: Implanted for improved target localization 1
• Image-Guided Radiation Therapy (IGRT): Uses cone-beam CT for daily positioning 1
• Rectal Spacers: Reduce radiation dose to rectum, decreasing toxicity 1

Optimization Techniques

• Simulation procedures:

  • Bladder/rectum filling instructions
  • Patient immobilization
  • Fiducial marker placement
  • Rectal spacer use 1

• Planning procedures:

  • Highly conformal radiation planning
  • Normal tissue dose constraints
  • Target volume delineation 1

Treatment Side Effects

• Patients should be informed that ADT with radiation increases likelihood and severity of sexual dysfunction 1
• Brachytherapy has similar effects as EBRT regarding erectile dysfunction and proctitis but can exacerbate urinary obstructive symptoms 1
• Modern techniques aim to reduce toxicity while maintaining efficacy 1

Important Considerations

• Dose escalation has consistently demonstrated improved biochemical progression-free survival 1
• The therapeutic ratio between tumor control and normal tissue injury is critical 1
• Advanced technologies have improved cancer outcomes with equal or improved toxicity profiles 1

By utilizing these radiation therapy options and tumor mapping techniques, clinicians can optimize treatment outcomes while minimizing side effects for patients with prostate cancer.