What is the management approach for cancer of the floor of the mouth?

Management of Floor of Mouth Cancer

Surgery is the preferred primary treatment option for floor of mouth cancer, with radiotherapy as an alternative when surgery would result in poor functional outcomes. 1 The management approach depends on tumor stage, patient factors, and the need to preserve critical functions like mastication, deglutition, and speech.

Diagnostic Workup

• Essential evaluations:

  • Biopsy for histological confirmation
  • Complete head and neck examination
  • Contrast-enhanced CT and/or MRI of primary tumor and neck
  • Chest imaging to rule out metastases or second primaries
  • Dental/prosthodontic evaluation with jaw imaging
  • PET-CT for stage III-IV disease 2, 1

• Additional assessments:

  • Nutrition, speech, and swallowing evaluation
  • Examination under anesthesia with endoscopy if indicated
  • Orthopantomography to detect dental defects requiring correction before treatment 2

Treatment Algorithm by Stage

Early Stage Disease (T1-T2, N0)

1. Primary treatment options:

   • Surgical excision (preferred) 2, 1
   • Selective neck dissection guided by tumor thickness
     • For tumors with depth of invasion <5mm and cT1N0: active surveillance is valid 1
     • For tumors with depth of invasion <10mm: sentinel lymph node biopsy is an option 1
   • Radiotherapy as alternative if surgery would cause poor functional outcomes 2, 1

2. Adjuvant therapy considerations:

   • If negative margins and no adverse features: observation
   • If positive margins: re-excision or postoperative chemoradiotherapy (preferred, category 1) 2
   • If extracapsular spread: postoperative chemoradiotherapy (preferred, category 1) 2
   • For other risk features (perineural invasion, vascular embolism): consider postoperative radiotherapy 2

Advanced Stage Disease (T3-T4, N+)

1. Primary treatment options:

   • Surgery with appropriate reconstruction 2, 1
   • Bilateral neck dissection for advanced disease 2
   • Combined modality approach with radiation and chemotherapy for unresectable cases 1

2. Adjuvant therapy:

   • Postoperative radiotherapy (58-63 Gy) for high-risk features 1
   • Postoperative chemoradiotherapy (66 Gy with cisplatin) for positive margins and extranodal extension 1
   • Adjuvant therapy should start within 6-7 weeks after surgery 1

Special Considerations

• Margin status is critical: When negative margins (≥5 mm) are achieved, local recurrence rate is only 13%, regardless of T stage 3
• High rate of occult metastases: Even T1 lesions have a 21% rate of occult metastatic disease, warranting elective treatment of regional lymphatics 3
• Reconstruction techniques: Microvascular reconstruction techniques have improved functional outcomes after surgical management 2
• Radiation techniques: IMRT is preferred to minimize xerostomia and protect salivary function 2

Follow-up and Surveillance

• Regular clinical examinations to monitor for recurrence and second primaries
• Most recurrences occur within the first 2 years after treatment 1
• Assessment of thyroid function (TSH every 6-12 months) after neck irradiation 2, 1
• Imaging studies as clinically indicated 1

Treatment Outcomes

• Five-year disease-specific survival by stage: Stage I (95%), Stage II (86%), Stage III (82%), and Stage IV (52%) 3
• Local control with surgery alone can reach 81%, with regional control at 71% 3
• Adjuvant radiotherapy significantly improves regional control in stage IV disease 3

The management of floor of mouth cancer requires a multidisciplinary approach involving surgical oncologists, radiation oncologists, medical oncologists, dentists, speech pathologists, and nutritionists to optimize both oncologic and functional outcomes.