Surgical Margins if Oral Cavity Squamous Cell Carcinoma

The ultimate aim of surgical resection is:
- Adequate clearance of the tumor
Inadequate clearance of the tumor results in:
- Increased local recurrence and decreased long-term prognosis
Indications for postoperative radiotherapy (PORT) include:
- Positive or close margins:
  - However despite PORT:
    - Local recurrence rates do not approach those in which adequate clearance is achieved at the primary operation
Increasing resection margins in the region of the head and neck:
- Potentially results in increased functional and cosmetic deficit
Resection margins of up to 2 cm have been advocated:
- However such margins result in significant functional deficit following the resection of even the smallest of tumors
Three-dimensional, 1 cm resection margins:
- Have been demonstrated as acceptable when dealing with oral and oropharyngeal tumor:
  - Adopting 1 cm surgical margins:
    - Account is taken of the shrinkage that occurs post-resection:
      - So ensuring greater than 5 mm pathological margins
  - It should be remembered that the use of 5 mm as a cut-off point for ‘clear’ margins is arbitrary and purely represents a margin that is considered acceptable
  - It is vitally important to continually reassess margins visually and by palpation during tumor resection
  - If approaching the resection of a tumor with curative intent:
    - Then reconstructive considerations should not influence the tumor resection
Comparison of published data regarding the incidence of positive margins and their influence on survival or local recurrence is complicated by the variable definition of a positive margin:
- The definition of a positive margin ranges from:
  - Invasive tumor at the margin, tumor within 1 mm and tumor within 5 mm
- The UK Royal College of Pathologists have issued guidelines:
  - Suggesting clear margins if the histological clearance is 45 mm
  - Close margins if 1 mm to 5 mm
  - Positive margins if less than 1mm
The incidence of positive margins for tumors of the oral cavity:
- Has been demonstrated as being higher than other head and neck sites:
  - Potentially due to its complex anatomy and three-dimensional shape
- Large tumors, perineural spread, vascular permeation, a noncohesive invasive front or cervical metastasis:
  - Are all associated with a greater risk of failing to achieve clear margins:
    - These features suggest that close or involved margins:
      - Potentially reflect a more aggressive tumor
The incidence of close or involved margins following tumor resection may be greater than 60% depending on tumor site and size:
- Invariably, it is the deep margin that is close or positive:
  - However close deep margins do not necessarily require adjunctive treatment:
    - The use of ultrasonography to aid in determining deep margin resection has been described
Frozen sections are not routinely used by many surgeons:
- Reasons cited being potential cost
- Inability to reliably prevent positive final margins
- Poor relocation of biopsy site should the result be positive
Ninety-nine percent of American head and neck surgeons:
- Routinely use frozen section intraoperatively:
  - However overreliance on frozen section may result in undertreatment of tumors
When conducting a bony resection:
- A 1 cm margin should be achieved:
  - It has been demonstrated that it is unusual for extension of tumor in bone to exceed the overlying soft tissue extension