What are the steps to diagnose and treat suspected cancer?

Steps to Diagnose and Treat Suspected Cancer

The diagnosis of cancer should be established by the least invasive method that provides adequate tissue for diagnosis, while simultaneously confirming the stage of disease whenever possible. 1

Initial Diagnostic Evaluation

History and Physical Examination

• Complete personal and family medical history, including evaluation of:
  • Organ-specific symptoms (bone pain, neurological symptoms)
  • Non-specific symptoms (fatigue, anorexia, weight loss)
  • Risk factors for specific cancers
• Thorough physical examination including:
  • Breast, genitourinary, pelvic, and rectal examinations
  • Examination of lymph nodes
  • Skin examination
  • Attention to past biopsies or removed lesions

Basic Laboratory Tests

• Complete blood count
• Electrolytes and liver function tests
• Renal function tests
• Calcium levels
• Occult blood stool testing

Initial Imaging

• CT scan of the chest, abdomen, and pelvis is recommended for most suspected cancers 1
• For specific presentations:
  • Mammography for breast abnormalities or axillary adenopathy in women
  • Head and neck CT for cervical lymphadenopathy

Tissue Diagnosis Principles

Biopsy Strategy

1. Biopsy the site that would confer the highest stage (metastasis or suspicious lymph node rather than primary lesion) 1
2. Choose the least invasive method with highest yield 1
3. Obtain adequate tissue volume for diagnosis and molecular testing 1

Specific Approaches Based on Presentation

• Central lesions: Bronchoscopy with transbronchial needle aspiration 1
• Peripheral lung nodules: Radial EBUS or navigational bronchoscopy if available; otherwise TTNA 1
• Mediastinal involvement: EBUS-NA, EUS-NA, or mediastinoscopy 1
• Pleural effusion: Ultrasound-guided thoracentesis; if negative, consider pleural biopsy 1
• Solitary metastatic site: Tissue confirmation of the metastatic site if feasible 1
• Multiple distant metastases: Biopsy the most accessible site; if difficult to access, obtain diagnosis of primary lesion 1

Pathological Assessment

Required Elements

• Histological type and grade
• For carcinomas: immunohistochemistry for appropriate markers
  • Adenocarcinoma: PSA in males, estrogen/progesterone receptors in females with axillary metastases 1
  • Poorly differentiated carcinomas: Immunohistochemistry to exclude lymphomas and germ cell tumors 1
• Biomarker analysis as appropriate for the tumor type
• For surgical specimens: tumor size, margins, lymphovascular invasion, lymph node status 1

Staging Evaluation

General Approach

1. Clinical evaluation to provide initial definition of tumor stage 1
2. CT scan of chest with contrast (extended to include liver and adrenal glands if PET unavailable) 1
3. Additional imaging for metastases if abnormal clinical evaluation or suspicious findings on CT 1

Advanced Imaging

• PET imaging recommended for patients being considered for curative-intent treatment to evaluate for metastases (except brain) 1
• Site-specific symptoms warrant directed evaluation with appropriate studies 1
• Tissue sampling of suspicious metastatic sites is recommended to confirm clinical stage prior to treatment 1

Treatment Planning

Multidisciplinary Approach

• A multidisciplinary team approach is recommended for patients requiring multimodality therapy 1
• Team should include representatives from:
  • Pulmonary medicine
  • Thoracic surgery
  • Medical oncology
  • Radiation oncology
  • Palliative care
  • Radiology
  • Pathology

Treatment Selection Based On:

• Tumor extent/location (size, number of lesions, lymph node involvement)
• Tumor biology (pathology, biomarkers, gene expression)
• Patient factors (age, general health status, preferences) 1

Special Considerations

Cancer of Unknown Primary (CUP)

• Represents 3-5% of all malignancies 1
• Requires thorough workup including immunohistochemistry to identify potentially curable tumors
• Treatment should be tailored based on clinicopathologic subsets 1
• Certain subsets (poorly differentiated neuroendocrine carcinomas, peritoneal carcinomatosis in females) have specific treatment approaches with better outcomes

Timeliness of Care

• Delivery of care should be timely and efficient 1
• Interventions to improve timeliness should address local barriers
• Balance timeliness with other dimensions of healthcare quality (safety, effectiveness)

Common Pitfalls to Avoid

1. Inadequate tissue sampling: Ensure sufficient tissue for diagnosis and molecular testing
2. Failure to biopsy the most appropriate site: Target the site that would confer the highest stage
3. Premature exclusion from curative treatment: Always confirm suspected metastatic disease with tissue sampling before excluding patients from potentially curative therapy 1
4. Overdiagnosis: Be aware of potential for overdiagnosis, particularly in lung, prostate, and breast cancer screening 2
5. Misdiagnosis: Can lead to patient mistrust and complications in subsequent care 3

By following this systematic approach to diagnosis and staging, clinicians can efficiently establish the diagnosis of cancer and determine the appropriate treatment strategy while minimizing unnecessary procedures and delays in care.