Squamous cell carcinomas arising in this area are usually well differentiated and are frequently associated with areas of leukoplakia. Papillary, verrucous, and exophytic mucosal growths are usually well differentiated with a low incidence of lymph node metastases (i.e., 10% to 20% for T1 and T2 lesions).
Ulcerative, advanced tumors, which are often associated with muscle invasion, have a higher propensity (60%) for lymph node metastases.
Buccal mucosa cancer — Buccal mucosa cancers are often neglected or misdiagnosed as an infection or consequence of trauma, and thus, rarely present as T1 lesions. Three-year disease-free-survival of 75 to 85 percent for stage I and 65 percent for stage II cancers have been reported
Surgery is typically preferred for buccal mucosa cancers, despite high local recurrence rates and technical challenges; postoperative radiation or chemoradiation is often necessary to optimize locoregional control. Exposure of the cancer can be difficult via a transoral approach, which makes it difficult to obtain clear radial margins in an en bloc fashion. Furthermore, the thin distance between the buccal mucosa and the buccal space permits early invasion to deep structures or to anterior cheek skin. When this happens, the surgeon must decide between taking a thin deep margin and risking recurrence or removing skin and reconstructing both inner and outer cheek surfaces. Although a more aggressive surgery, including exenteration of the buccal space and parotidectomy, may improve oncologic results, the disfigurement and morbidity of these procedures are considerable
Regardless of the depth of resection, the buccal mucosal surface must be aggressively reconstructed, and inadequate soft tissue coverage will result in severe, irreversible trismus. Therefore, many head and neck surgeons recommend free tissue transfer reconstruction (eg, radial forearm flap) for all but the smallest buccal cancers. Even with adequate reconstruction, aggressive rehabilitation must be instituted to optimize functional outcomes.
If RT is used, the initial treatment volume includes the primary tumor with at least 2 cm margins, and an intraoral stent may be used to displace the tongue and reduce the dose delivered to the contralateral side.
Primary surgery is effective for small, superficial T1 lesions without involvement of commissure. The procedure removes the malignancy and eradicates any adjacent leukoplakia. For intermediate T2 lesions and lesions involving the commissure, radiation therapy, which produces a high cure rate with good functional and cosmetic results, is preferred. For T3 and T4 tumors with deep muscular invasion, cure rates after radiation therapy are poor. These lesions are usually treated by radical surgery, reconstruction, and postoperative irradiation. Some investigators have recommended preoperative radiation therapy followed by en bloc excision followed by a reconstructive procedure if needed.
The management of verrucous carcinoma of the buccal mucosa is often controversial. The concept of potential malignant transformation after radiation therapy as reported in the literature is debatable. It is true that well-differentiated lesions are difficult to control with homeopathic doses of irradiation and that recurrences may be more aggressive and hard to manage.Some cases of so-called verrucous carcinoma that are diagnosed by small biopsy and undergo malignant changes after radiation therapy may be diagnosed because of sampling errors because the entire specimen was not available for pathologic examination before radiation therapy. A few patients with the diagnosis of verrucous carcinoma have been treated with radiation therapy and have had no evidence of disease for 10 years or more.
Radiation Therapy Management
For T1 and most T2 lesions without nodal involvement, the results of radiation therapy are best when photon or electron-beam therapy is combined with an interstitial implant or intraoral cone therapy. Small mucosal lesions can occasionally be treated with interstitial radiation therapy alone in edentulous patients. For an interstitial implant, the needles must be inserted percutaneously through the cheek along the base of the lesion, rather than intraorally
In moderately advanced lesions, with or without positive nodes, appropriate radiation therapy must include the primary site and the regional lymph nodes. This is best achieved with external-beam radiation therapy through ipsilateral and anterior wedge pair fields for a tumor dose of 55 to 60 Gy in 6 weeks. This is followed by boost irradiation, sparing the mandible, with interstitial implant, intraoral cone, or electron beam for an additional 20 Gy Fortunately, the tissues of the buccal cheek can tolerate high-dose radiation therapy. Elective neck irradiation generally is not indicated for early lesions with well-differentiated histology. Ipsilateral nodal coverage by elective radiation therapy is advised for large tumors with or without positive nodes. Any residual positive nodes are treated by neck dissection. Any tumor extension to the gingiva or retromolar trigone probably precludes the use of an interstitial implant as the major treatment modality because of its insufficient coverage and attendant risk of osteoradionecrosis. External-beam therapy is the main modality used postoperatively.
Carcinoma of the buccal mucosa: treatment
|Radiation Therapy Results
Results for treating carcinoma of the buccal mucosa are sparse. Three series reported that the 5-year disease-free survival rates after radiation therapy ranged from 50% to 66%, depending on the stage of the primary lesion and the existence of nodal metastases. For small and intermediate lesions, surgical salvage for radiation therapy failures has generally been satisfactory. Large, advanced carcinomas are rarely curable by radiation therapy, and 5-year disease-free rates are approximately 25%. Reported treatment results for carcinoma of the buccal mucosa are summarized.
|XRT - Surg Salvage||100%||84%||89%||69%||82.5%|
|25% (1/4)||42% (13/31)||50% (5/10)||0% (0/5)|