Introduction
The lip is the most common site of origin for squamous cell carcinoma of the oral cavity. Unlike other cancers of the oral cavity, the etiology and clinical outcomes of squamous cell carcinoma more closely resemble squamous cell carcinoma of the skin. Cancer of the lips accounts for 0.6% of all malignancies diagnosed in the United States. The primary risk factor for cancer of the lip is sun exposure. As with other skin malignancies, fair skin complexion increases the risk for lip cancer. A study of Canadian farmers showed that these sun-exposed workers had a threefold increased risk of cancer of the lip compared with people with indoor occupations after controlling for smoking history. Also implicating the powerful role of sun exposure in development of cancer of the lip is the finding that cancer of the lip is 40 times more prevalent on the external than the inner lip.
The risk of cancer of the lip increases with age; the average age at diagnosis is in the sixth decade of life. The lower lip is 12 times more likely to be affected than the upper lip, as it sustains greater exposure to sunlight. Of all cancers of the lip, squamous cell carcinoma represents the vast majority. A large epidemiological analysis revealed that up to 95% of nonmelanoma cancers of the lower lip are squamous cell carcinoma. Basal cell carcinoma, the second most common nonmelanoma cancer of the lip, is more likely to be found on the external upper lip and in females. Other types of cancer occur less commonly on the lip, including malignant melanoma and malignant tumors of minor salivary gland origin, such as adenoid cystic carcinoma and adenocarcinoma.
The role of human papillomavirus in the development of squamous cell carcinoma of the head and neck continues to be clarified, but no evidence has been found to date that implicates this virus as a cause of lip cancer. Immunosuppressed populations are at significantly increased risk for lip cancer. Patients who have undergone kidney transplant have a 30-fold increased risk on account of immunosuppressive antirejection drug regimens. The degree of immunosuppression appears to be important, as patients on higher doses demonstrate a higher risk of skin cancer than patients on low-dose regimens. Patients with HIV infection also have a greater risk for development of lip cancer.
Patients with lip cancers generally present at an early stage, as the location is a cosmetically obvious area. Tumors less than 2 cm in size (T1 stage) account for 75% to 80% of lip cancer diagnoses. The staging guidelines for cancer of the lip follow the guidelines for cancer of the oral cavity. These patients generally do well, and surgical excision is curative. In the current literature, the reported 5-year survival rates in patients with squamous cell cancer of the lip without lymph node metastases are between 85% and 99%. A small number of patients present with more advanced primary cancers, characterized by invasion into deeper structures.
While patients with cancer of the lip without cervical metastasis can expect excellent rates of survival, the prognosis is guarded for patients who have lymph node metastasis; the survival rate for these patients decreases to 25% to 50%. Therefore, identification and management of occult neck metastasis are critical. A number of prognostic factors for lymph node metastasis for squamous cell carcinoma of the lip have previously been reported: tumor size/T-stage, tumor grade, depth of invasion, perineural invasion, extreme mitotic activity, positive surgical margins, commissure involvement, and local recurrence.
Management of the N0 neck is controversial; the recent literature has suggested that “high-risk” patients should receive consideration for management of the regional lymphatic basin. Sentinel lymph node biopsy is a surgical option already widely applied as a tool to assess the at-risk lymph node basin in skin cancer. Its role in treatment of squamous cell carcinoma of the oral cavity is also gaining acceptance. This option is especially attractive in lip cancer, as the primary tumor is readily accessible for injection of radioisotope and small neck incisions minimize interference with reconstructive options for the lip.
A chapter on cancer of the lip is incomplete without addressing reconstructive techniques. Reconstruction of defects of the lip can be complex, especially when resection involves the vermillion border or oral commissure. Reconstructive techniques are used to minimize microstomia, retain oral competence, and optimize the cosmetic result. While reconstruction of the lip can be complex, there are several basic principles to guide the surgeon toward the appropriate technique.
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Defects amounting to one-half of the lip can and should be closed primarily.
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Meticulous reapproximation of the vermillion border should be achieved.
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If greater than one-half of the lip is resected, consideration should be given to advancement flaps or “lip-switch” procedures (described later).
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If resection involves the oral commissure, the Estlander flap can be used.
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For larger resections (greater than two-thirds), local tissue rearrangement is possible with the Karapandzic flap; however, consideration should be also given to free tissue transfer techniques.
Surgical technique is described as follows for the aforementioned types of lip reconstruction.
Key Operative Learning Points
- 1.
Discuss ablative techniques for removal of cancer of the lip with consideration of optimal reconstruction.
- 2.
Understand the reconstructive ladder and how it may be used in reconstruction of the lip.
- 3.
For full-thickness reconstruction of the lip involving greater than two-thirds of the lip, consideration of the use of free tissue transfer should also be given.
Preoperative Period
History
- 1.
History of present illness
- a.
Approximate date of onset of lesion
- 1)
Many patients present early in the course of the disease; a smaller number of patients may present with deep invasion and ulceration present.
- 1)
- b.
Skin changes elsewhere on the face, neck, or body
- 1)
History of severe sunburns or radiation exposure
- 2)
History of chronic sun exposure (e.g., farmers)
- 1)
- c.
Numbness/hypesthesia of the lip or chin
- a.
- 2.
Past medical history
- a.
Medical illness
- 1)
Medical or immunologic immunosuppression
- 2)
Prior history of other head and neck malignancy
- 1)
- b.
Surgery
- 1)
Previous head or neck surgery
- a)
Primarily focusing on the lower face and neck
- a)
- 2)
History of organ transplant, especially renal transplants indicating immunosuppression
- 3)
Any other surgeries that may indicate a patient may be high risk for operative intervention
- 1)
- c.
Family history
- 1)
Cutaneous malignancies
- 2)
Coagulopathy
- 1)
- d.
Medications
- 1)
Anticoagulation with antiplatelet agents or NSAID use
- 2)
Herbal supplementation
- 3)
Alcohol use
- 4)
Immunosuppressive medications
- 1)
- a.
Physical Examination
- 1.
Palpation and examination of the lip lesion
- a.
Location
- 1)
Involvement of the upper or lower lip
- 2)
Involvement or extension beyond the vermillion border
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Involvement of the oral commissure
- 1)
- b.
Characteristics of the lesion
- 1)
Ulceration
- 2)
Depth of invasion
- a)
Extension into surrounding subcutaneous tissues or muscle
- b)
Perineural involvement of the mental nerve may present as hypesthesia/paresthesia of the chin or lower lip
- a)
- 1)
- c.
Examination of the neck
- 1)
Assess for lymphadenopathy in the neck
- a)
Upper lip with primary lymphatic drainage patterns to levels Ia and Ib
- b)
Lower lip with primary lymphatic drainage patterns to levels Ia, Ib, and jugulodigastric chain
- c)
Cancers involving the upper lip or oral commissure are more likely to have lymphatic spread.
- d)
Most lymphatic metastases to the neck are isolated to levels I–III ( Fig. 27.1 ).
Fig. 27.1
Lymphatic drainage pathways of the lip.
- a)
- 2)
Any previous surgical incisions
- 1)
- a.
Imaging
None—Routine imaging is not recommended for early stage cancers.
Computed tomography (CT) scan is a commonly performed imaging modality for advanced stage cancer not only to assess characteristics of the primary site but also to assess for lymphadenopathy within the neck.
Magnetic resonance imaging (MRI) has similar ability to detect pathologic cervical lymphadenopathy as CT and ultrasound. If there is concern for perineural or bony invasion, MRI is a more sensitive study.
Positron emission tomography CT scan—Ultrasound has been shown to be equally effective in identifying pathologic cervical lymphadenopathy as CT scan and MRI. In some centers, it is the study of choice due to lower cost and lack of radiation exposure.
Indications
- 1.
Biopsy proven malignancy of the upper or lower lip
- 2.
Sentinel lymph node biopsy or elective neck dissection may be considered in patients who have risk factors for regional metastasis.
- 3.
Therapeutic neck dissection is indicated when clinical evidence of regional metastasis is prevent.
Contraindications
- 1.
Distant metastatic disease
- 2.
Prohibitive medical risk
Preoperative Preparation
- 1.
Adequate assessment of lymphadenopathy and surgical planning regarding whether and how to address the at-risk lymphatic basin
- 2.
Appropriate patient counseling regarding risk of microstomia and oral competence
Operative Period
Anesthesia
General: Preferred method for patient comfort and protection of the airway if there is active bleeding
Monitored anesthesia care (MAC)
Local anesthesia
Positioning
Supine: In addition to supine positioning, proper neck extension and shoulder roll placement are important if sentinel lymph node biopsy or neck dissection is to be performed in conjunction with excision of the primary.
Perioperative Antibiotic Prophylaxis
First-generation cephalosporin: We prefer cefazolin, 1 mg if under 75 kg, 2 mg if greater than 75 kg.
Second-generation cephalosporin
Clindamycin if allergic to penicillins
Monitoring
If neck dissection is performed in conjunction, avoid long-acting paralytic agents until all pertinent cranial nerves are identified.
Instruments and Equipment to Have Available
- 1.
Basic head and neck surgery set
- 2.
Plastic surgery set
- 3.
If sentinel lymph node biopsy is performed, gamma probe would be necessary, and injectable dye such as isosulfan blue is optional.
Key Anatomic Landmarks
- 1.
Superior and inferior labial arteries lie deep to the vermillion border of the upper and lower lip.
- a.
This is especially important when resection is performed. These vessels should be manually compressed to minimize hemorrhage as the incision is carried through the lip.
- a.
- 2.
Vermillion border—The junction between the squamous mucosa of the upper/lower lip and the stratified squamous epithelium of the epidermis. This border is especially important in reconstruction for optimal cosmesis.
- 3.
Wet-dry line—The junction between the keratinized squamous mucosa of the body of the lip and the nonkeratinized labial mucosa
Prerequisite Skills
- 1.
General skin and soft tissue dissection
- 2.
Sentinel lymph node excision techniques (if performed)
- 3.
Selective or therapeutic neck dissection (if performed)
Operative Risks
- 1.
Intraoperative bleeding
- 2.
Postoperative infection
- 3.
Microstomia
- 4.
Loss of oral competence, which may lead to drooling
- 5.
Hypesthesia or paresthesia of the lower face, depending on the extent of resection
- 6.
Poor cosmetic outcome
Surgical Technique
Ablative Surgery
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Lip resection
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Degree of lip resection is dependent upon the pathologic basis of disease.
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Squamous cell carcinoma is the predominant malignancy of the upper and lower lip. Unlike other sites in the oral cavity, margins of less than 1 cm are routinely planned. Many surgeons rely on frozen section analysis for intraoperative margin assessment. The lip is a cosmetically sensitive area, but the malignancy must be removed with adequate surgical margins.
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Basal cell carcinoma is the second most common malignancy of the lip; 3-mm margins are usually sufficient for this type of malignancy.
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Melanoma may occur, though rarely, on the lip. The management of melanoma is dependent on tumor thickness and other pathologic characteristics, similar to other subsites of the head and neck.
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When planning resection, it is important to consider options for reconstruction, which are discussed at length later. Design will focus on the shape of resection, whether it be wedge shaped or rectangular.
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First the incision is inked with a marking pen taking into consideration adequate margins of resection. The vermillion border is then scratched with the back of a #15 blade scalpel for later reapproximation.
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Incisions are made through the skin and subcutaneous soft tissue with a #11 or #15 blade scalpel.
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Once the skin incisions are made, the upper or lower lip is manually grasped lateral to the incision to tamponade bleeding. Bovie or 3-0 silk ties can be used for hemostasis.
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Frozen sections may be sent either from the specimen itself or from selected margins taken from the patient.
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Lymphadenectomy
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Degree of cervical lymphadenectomy will be dependent on presence of pathologic lymphadenopathy as well as the characteristics of the primary lesion.
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Usually a selective neck dissection of levels 1 to 3 will be adequate, but this is dependent on site of lymphatic metastases. The lower lip has bilateral lymphatic drainage pattern, and cancers of the lip involving the midline occur commonly.
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Lip Reconstruction
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Defects less than half of the lip
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If the resection is less than half of the lower or upper lip, this defect can be reapproximated primarily ( Fig. 27.2A to C ).
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