Principles of Surgical Oncology

Principles of Surgical Oncology

Principles of Surgical Oncology

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Biopsy & Diagnosis - The First Cut

  • Goal: Confirm malignancy, grade, type; guide treatment.
  • Key Principles:
    • Plan incision for future surgery; resect biopsy tract.
    • Adequate, representative tissue.
    • Avoid tumor spillage/seeding.
    • Proper handling (e.g., 10% formalin).
  • Types & Utility:
    • FNAC: Cytology; screening (e.g., thyroid, LN).
    • Core Needle (Tru-Cut): Histology; preferred for solid tumors (breast, sarcoma).
    • Incisional: Wedge from large tumor; diagnostic.
    • Excisional: Complete removal of small lesion; diagnostic & therapeutic (e.g., skin melanoma <2cm, small LN).
    • Frozen Section: Intraoperative; rapid diagnosis, margin assessment. Accuracy ~95-98%.

Tru-Cut biopsy is the gold standard for pre-operative diagnosis of most solid tumors, providing tissue architecture. Fine-needle aspiration biopsy

Staging & Imaging - Mapping the Enemy

  • Purpose: Defines disease extent (local, regional, distant); guides therapy; predicts prognosis.
  • TNM System (AJCC/UICC):
    • T: Primary Tumor (size, local extent/invasion)
    • N: Regional Lymph Nodes (involvement, number, site)
    • M: Distant Metastasis (presence/absence)
  • Staging Types:
    • Clinical (cTNM): Pre-treatment (exam, imaging, biopsy).
    • Pathological (pTNM): Post-surgery; most accurate.
    • ypTNM: Post-neoadjuvant therapy.
  • Key Imaging Modalities:
    • CT: Workhorse for chest, abdomen, pelvis; contrast essential.
    • MRI: Superior for soft tissue (e.g., rectal, brain, liver); DWI.
    • PET-CT (FDG): Metabolic activity; detects occult mets, assesses treatment response. PET-CT showing widespread metastases and treatment response
    • USG/EUS: Initial assessment, guided biopsies (e.g., thyroid, pancreas); GI staging.
    • SLNB (Sentinel Lymph Node Biopsy): Nodal staging (e.g., breast, melanoma), avoids extensive dissection if negative.

⭐ Pathological staging (pTNM), derived from surgically resected tissue, remains the strongest prognostic factor for most solid malignancies after curative intent surgery.

Resection & Margins - Clearance Ops

  • Goal: Achieve R0 resection (microscopically clear margins) for cure.
  • Margin Types:
    • R0: No tumor at margin.
    • R1: Microscopic tumor at margin.
    • R2: Macroscopic residual tumor.
  • Clear Margin: No tumor cells at inked edge. Width varies:
    • Sarcoma: 1-2 cm.
    • Basal Cell Carcinoma (BCC): 3-5 mm.
    • Melanoma: Varies by Breslow depth (e.g., 1 cm for ≤1mm depth).
  • "En bloc" Resection: Tumor + surrounding tissue removed as one unit.
  • Intraoperative Assessment: Frozen section guides further excision if margins positive/close.
  • Palliative Resection: Symptom relief, may be R1/R2.
  • Debulking: Reduces tumor burden, not curative.

⭐ R0 resection is the single most important prognostic factor for survival in most solid tumors. R0, R1, R2 Surgical Resection Margins

Multimodal Treatment - Combined Arms

  • Integrates surgery with chemotherapy (CT), radiotherapy (RT), targeted therapy, immunotherapy.
  • Aims: ↑ cure rates, organ preservation, better Quality of Life (QoL).
  • Key Approaches:
    • Neoadjuvant: Therapy before surgery (downstages tumor, assesses treatment response).
    • Adjuvant: Therapy after surgery (targets micrometastases, ↓ recurrence risk).
    • Concurrent: Therapies given together or in close sequence (e.g., chemoradiation).
  • Palliative: Surgery/therapy for symptom relief (pain, obstruction), not curative; improves QoL.
  • Prophylactic: Risk-reducing surgery in high-risk individuals (e.g., BRCA+ mastectomy).

    ⭐ Neoadjuvant therapy can convert unresectable tumors to resectable, improving surgical outcomes and prognosis.

High‑Yield Points - ⚡ Biggest Takeaways

  • R0 resection (microscopically negative margins) is paramount for curative intent in solid tumors.
  • Sentinel Lymph Node Biopsy (SLNB) is standard for staging in melanoma and breast cancer, guiding further treatment.
  • Multimodal therapy (surgery, chemotherapy, radiotherapy) is often required for locally advanced or aggressive cancers.
  • Accurate tumor staging (TNM) and histological grade are critical for prognosis and treatment planning.
  • Achieving adequate negative surgical margins is a primary goal; specific widths vary by tumor type and biology.
  • Palliative surgery focuses on symptom relief (e.g., obstruction, pain) and improving quality of life, not cure.
  • Neoadjuvant therapy aims to downstage tumors, improving resectability and organ preservation chances before surgery.

Practice Questions: Principles of Surgical Oncology

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What is the standard excision margin for thick melanomas (>2 mm Breslow thickness)?

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Flashcards: Principles of Surgical Oncology

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What is the first line treatment of periocular BCC?_____

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What is the first line treatment of periocular BCC?_____

Mohs micrographic surgery or wide surgical excision with frozen section margin control

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