What are the treatment options for existing cancer?

Treatment Options for Existing Cancer

The optimal treatment approach for existing cancer requires a multidisciplinary team consultation to consider options including surgery, radiation therapy, systemic therapy (chemotherapy, targeted therapy, immunotherapy), or a combination of these modalities, tailored to the specific cancer type, stage, and patient factors. 1

Multidisciplinary Approach to Cancer Treatment

Cancer treatment decisions should be made through a multidisciplinary team that includes:

• Medical oncology
• Radiation oncology
• Surgical oncology
• Supportive care specialists

Treatment selection depends on:

1. Cancer type and stage
2. Patient performance status and comorbidities
3. Molecular and biomarker profile
4. Treatment goals (curative vs. palliative)

Treatment Modalities

Surgery

• Primary treatment for localized solid tumors
• Options include:
  • Complete excision with wide margins for primary tumors
  • Metastasectomy for limited metastatic disease
  • Palliative procedures for symptom management 2

Radiation Therapy

• Can be used as:

  • Primary treatment
  • Adjuvant therapy after surgery
  • Neoadjuvant therapy before surgery
  • Palliative treatment for symptom control

• Delivery methods include:

  • External beam radiation therapy (EBRT)
  • Three-dimensional conformal radiation therapy (3D-CRT)
  • Intensity-modulated radiation therapy (IMRT)
  • Stereotactic radiosurgery/radiotherapy 1

• Dosing depends on:

  • Extent of disease (higher doses for clinically apparent disease)
  • Intent of treatment (curative vs. palliative)
  • For palliative treatment, less protracted fractionation may be used (e.g., 30 Gy in 10 fractions) 2

Systemic Therapy

Chemotherapy

• Multiple regimens available based on cancer type:

  • Platinum-based regimens (often with etoposide)
  • Cyclophosphamide combinations (with doxorubicin/epirubicin)
  • Taxanes (paclitaxel, docetaxel)
  • Fluoropyrimidines (5-FU, capecitabine)
  • Anthracyclines, gemcitabine, irinotecan 2

• Response rates vary by cancer type and prior treatment:

  • First-line chemotherapy: up to 70% response rates
  • Second or later lines: 9-20% response rates
  • Median duration of response: 2-9 months 2

Immunotherapy

• Checkpoint inhibitors showing significant activity:

  • PD-1 inhibitors (nivolumab, pembrolizumab)
  • PD-L1 inhibitors (avelumab)
  • CTLA-4 inhibitors (ipilimumab) 2, 3

• FDA-approved indications for nivolumab include:

  • Melanoma
  • Non-small cell lung cancer
  • Renal cell carcinoma
  • Classical Hodgkin lymphoma
  • Squamous cell carcinoma of the head and neck
  • Urothelial carcinoma
  • MSI-H/dMMR colorectal cancer
  • Hepatocellular carcinoma
  • Esophageal cancer 3

Targeted Therapy

• HER2-targeted therapy (trastuzumab) for:

  • HER2-overexpressing breast cancer
  • HER2-overexpressing metastatic gastric or gastroesophageal junction adenocarcinoma 4

• Smoothened inhibitors for advanced basal cell carcinoma:

  • Vismodegib shows objective response rates of 30-33% in metastatic BCC
  • 43-48% response rate in locally advanced BCC 2

Treatment Strategies by Disease Stage

Early Stage Disease

• Surgery ± adjuvant therapy based on risk factors
• Consider neoadjuvant therapy for locally advanced disease

Locally Advanced Disease

• Combined modality approach:
  • Neoadjuvant chemotherapy followed by surgery or radiation
  • Concurrent chemoradiation
  • Surgery followed by adjuvant therapy 1

Metastatic Disease

Three main approaches based on disease extent and patient factors 2:

1. Potentially resectable metastatic disease:

   • Aggressive approach with goal of complete resection
   • Combination chemotherapy ± targeted therapy to maximize tumor shrinkage
   • Consider surgical resection if good response

2. Disseminated but intermediate disease:

   • Cytotoxic doublet with targeted agent
   • Consider maintenance therapy after initial response
   • For RAS wild-type colorectal cancer, anti-EGFR antibodies may provide earlier response than bevacizumab

3. Widespread metastatic disease:

   • Focus on disease control and quality of life
   • Options include:
     • Sequential single agents or less intensive combinations
     • Palliative procedures for symptom management
     • Best supportive care 2

Special Considerations

Clinical Trials

• Clinical trial participation should be considered at all stages of treatment
• Preferred option for patients with distant metastatic disease when available 2

Elderly Patients

• Advanced age alone should not preclude treatment
• Assessment should consider biological rather than chronological age
• Older patients with good performance status can tolerate standard treatments 1

Palliative Care

• Should be integrated early in the course of treatment
• Focus on symptom management and quality of life
• May be the most appropriate option for some patients with advanced disease 2

Common Pitfalls to Avoid

• Undertreatment of elderly patients based solely on chronological age
• Failing to involve a multidisciplinary team in treatment planning
• Not considering quality of life impacts when selecting treatment
• Continuing ineffective treatments without clear benefit
• Delaying palliative interventions when appropriate for symptom management
• Not discussing goals of care and treatment expectations with patients 2, 1

Remember that for patients with advanced disease, the goal of treatment may shift from cure to control, with focus on extending life while maintaining quality of life. Treatment decisions should balance potential benefits against toxicity and impact on patient functioning.