Cancer Treatment

• Major treatment modalities used in the management of cancer:

  • Surgical excision (local)
  • Radiotherapy (local/regional)
  • Chemotherapy (systemic/targeted)
  • Biologic therapy (including immunotherapy and gene therapy)
• Cancer treatment modalities may be:

  • Primary curative intent
  • Palliative (given in a non-curative setting to optimize symptom control, improve quality of life, and sometimes to improve survival)
  • Adjuvant systemic therapy used in patients with the primary tumor removed but who are at high risk of metastatic disease
  • Neoadjuvant treatment given prior to local therapy, e.g., to shrink the tumor before surgery
• Surgery:

  • Oldest form of cancer treatment
  • Used to diagnose, stage, and treat cancer & certain cancer-related symptoms
  • For most patients, surgery is part of a curative plan
  • Surgeon is part of a multidisciplinary care team
  • Types of surgeries depend on the stage and location of the tumor, patient anatomy, and fitness for surgery
• Surgical excision:

  • Goal: to remove cancer and an area of healthy tissue surrounding it (clear margin) to prevent local recurrence
  • Types of surgeries depend on the stage and location of the tumor, patient anatomy, and fitness for surgery
  • Excision of lymph nodes in the area of the tumor at the time of surgery can help determine prognosis and further treatment options
• Oncoplastic reconstructive surgery:

  • DIEP (deep inferior epigastric perforating vessels) flap involves the skin and fat from the lower abdomen with blood supply provided by specific arteries and veins
  • Nipple-Sparing Mastectomy or Nipple Reconstruction and 3D Nipple Tattooing are common procedures
• Axillary vs sentinel node dissection:

  • Axillary dissection can result in arm swelling, pain, and/or limited range of motion
  • Sentinel lymph node dissection is done for diagnostic staging of the axilla, removing only the first draining node
  • Biopsy of a sentinel lymph node can reveal lymphatic metastases, eliminating the need for extensive dissection of the regional lymph-node basin
• Radiation therapy:

  • Uses high-energy rays to kill or slow the growth of cancer cells
  • Can be used as primary treatment or after surgery, or combined with other modalities
  • Different ways to give radiotherapy include external beam radiotherapy, systemic therapy, and brachytherapy
• Basic radiobiology:

  • The aim of radiotherapy is to kill tumor cells and spare normal tissues
  • DNA is the main target, with radiation-induced cell death mechanisms including double-strand DNA breaks
  • Radiation damage time course can lead to radiation pneumonitis and radiation-induced lung disease
• Principles of chemotherapy:

  • Depends on exploitable biochemical differences between tumor and host cells
  • Ideal chemotherapy drugs would be selective for malignant cells and leave host cells unharmed
  • Classical chemotherapy targets the cell cycle/proliferation
• Classes of cytotoxic drugs:

  1. Antimetabolites

  2. Alkylating agents

  3. Cytotoxic antibiotics

  4. Plant alkaloids/microtubule inhibitors
• Multi-modality treatment protocols:

  • Increasingly used for cancer treatment
  • Objectives include improvement in local control, eradication of distant metastases, and acceptable normal tissues tolerance