Floor of mouth cancers deserve special attention because of important nearby structures and considerations for reconstruction. It is important to obtain a complete en bloc excision with negative margins while retaining important structures when possible. The floor of mouth contains the sublingual glands, Wharton ducts, and the lingual nerve. Deep floor of mouth cancers may result in communication with subsequent staging neck dissection (see below on the role of neck dissection in early stage cancer). Reconstruction of a floor of mouth defect is recommended. Very small floor of mouth cancers, or those with limited floor of mouth extension, can be left to granulate or closed primarily. A split thickness skin graft (STSG) may be needed for larger lesions without significant depth. Rotational mucosal flaps, or local pedicled flaps such as the submental island flap, may be considered for more significant defects. Finally, free flap reconstruction, usually with a radial forearm free flap, may be considered for deep or extensive floor of mouth cancers, especially where communication with the neck occurs.
When oral cavity cancers extend to the mandible, management of the bony component may be necessary. In appropriate circumstances, a marginal mandibulectomy may be performed. In this case, a rim of the mandible is taken in continuity with the cancer. This is appropriate for cancers that extend close to, but do not invade the mandible. Reconstruction may be performed with local mucosal flaps, STSG, or free tissue transfer. A segmental resection of mandible is advised when there is a deep done invasion. The cancer is removed en bloc with a segment of the mandible leaving a gap in mandibular continuity. Reconstruction with bony free tissue transfer, such as fibula free flap, is generally recommended.
Hard palate/maxilla cancers include those arising from the mucosa of the hard and gingiva of the upper teeth. Primary cancers of the maxillary sinus or nasal cavity are not included in this category. Because the mucosa overlying the bone of the hard palate and maxilla is thin, management of the bone is a critical part of resecting these cancers. When there is suspicion of bone involvement, en bloc resection with the underlying bone is favored to confirm the status of the deep margins. While some surgeons consider removing the soft tissue tumor and burring down the bone, in these cases the deep margin remains unexamined and the deep margin may be at risk. Partial bony excisions can be reconstructed with a split thickness skin graft and subsequent custom denture. Infrastructure maxillectomy, which refers to full-thickness resection of the palatal mucosa and bone creating communication between the mouth and the nose or maxillary sinus, may require either pre-surgical fabrication of an obturator, or flap (pedicled or free) closure.
Buccal mucosa cancers arise from the inner aspect of the cheek. Cancers that invade deeply here have access to the buccal space and therefore can spread deep easily. Deeply invasive buccal cancers tumors can invade through mucosa to include cheek skin, complicating reconstruction. Reconstruction of this area is always needed to minimize scarring and fibrosis that could result in trismus. STSG is preferred for superficial lesions. Mucosal flaps or even free tissue transfer may be needed for deeper cancers.