Cancers of the oral cavity are often treated with surgery for several reasons:

1. **Local Control:** Surgery allows for the removal of the tumor, providing local control of the cancer. This is particularly important in the oral cavity, where tumors can be accessible for surgical intervention.

2. **Diagnostic and Staging:** Surgery is often used for the biopsy of suspicious lesions to confirm the diagnosis and determine the stage of cancer. Staging is crucial for deciding the most appropriate treatment strategy, and surgery helps in obtaining tissue samples for accurate staging.

3. **Accessibility:** The oral cavity is a relatively accessible area for surgical procedures. Surgeons can often reach and remove tumors with relative precision, especially in the early stages of the disease.

4. **Preservation of Function:** Depending on the size and location of the tumor, surgeons aim to remove the cancer while preserving as much normal tissue and function as possible. This is especially important in the oral cavity, where functions like speech, swallowing, and mastication are critical.

5. **Adjunct to Other Therapies:** Surgery is often used in conjunction with other treatments like radiation therapy or chemotherapy. For instance, surgery may be employed to remove the bulk of the tumor, and then additional therapies may be used to target remaining cancer cells or reduce the risk of recurrence.

6. **Lymph Node Dissection:** Cancers in the oral cavity can spread to nearby lymph nodes. Surgical procedures may include the removal of affected lymph nodes to prevent the spread of cancer.

7. **Reconstruction:** After tumor removal, reconstructive surgery may be necessary to restore the appearance and function of the affected area. This can involve procedures such as skin grafts, flap reconstruction, or other techniques.

It's important to note that the choice of treatment for oral cavity cancer depends on various factors, including the type and stage of cancer, the patient's overall health, and individual preferences. In some cases, a combination of surgery, radiation therapy, and chemotherapy may be recommended for the most effective treatment outcome.