Newly Diagnosed With Oral (Mouth) Cancer: First Steps

This matters. The throat behind it is a different disease.

NCI defines the oral cavity as running from the skin-vermilion junction of the front lips back to where the hard palate meets the soft palate. Below, it ends at the line of circumvallate papillae on the tongue. Inside are eight subsites:

• Lip.
• Front two thirds of the tongue.
• Buccal mucosa, the lining of the cheek.
• Floor of mouth.
• Lower gingiva, the gum ridge of the lower jaw.
• Retromolar trigone, the small triangle behind the last lower molar.
• Upper gingiva.
• Hard palate.

Your subsite drives the operation, the reconstruction, and the outlook. Find it named on your report.

Three precancerous lesions occur here. They are leukoplakia, erythroplakia, and mixed erythroleukoplakia.

Leukoplakia is the most common. The World Health Organization defines it as a white patch or plaque that cannot be classified as any other disease. It is a diagnosis of exclusion. Candidiasis, lichen planus, and leukoedema must be ruled out first.

Erythroplakia, the red patch, is less common. NCI notes it is far more likely to carry dysplasia or carcinoma. If your lesion is red rather than white, take the biopsy advice seriously.

AJCC 8th edition staging here uses tumor size and depth of invasion together. Depth of invasion, written DOI, is measured down from the level of the normal surface. NCI is explicit: DOI is not tumor thickness.

• T1: tumor 2 cm or less, with DOI of 5 mm or less.
• T2: tumor 2 cm or less with DOI over 5 mm; or tumor over 2 cm and up to 4 cm with DOI of 10 mm or less.
• T3: tumor over 2 cm and up to 4 cm with DOI over 10 mm; or tumor over 4 cm with DOI of 10 mm or less.
• T4a: tumor over 4 cm with DOI over 10 mm, or invasion of nearby structures such as the cortical bone of the jaw, the maxillary sinus, or facial skin.
• T4b: invasion of the masticator space, pterygoid plates, or skull base, or encasement of the internal carotid artery.

One number is worth memorizing. NCI states that a positive surgical margin, or a tumor depth over 5 mm, significantly raises the risk of local recurrence. Risk of hidden nodal spread rises with depth too.

One caveat for gum tumors. Surface erosion of bone or a tooth socket alone does not make a tumor T4.

Extranodal extension means cancer has grown out through the capsule of a lymph node into surrounding tissue. NCI calls it a significant adverse prognostic factor, and the 8th edition built it into the N categories. It is written ENE(+) or ENE(-).

Pathological node categories:

• N1: one node on the same side, 3 cm or smaller, ENE(-).
• N2a: one node on the same side, 3 cm or smaller, ENE(+); or one node over 3 cm up to 6 cm, ENE(-).
• N2b: several nodes on the same side, none over 6 cm, ENE(-).
• N2c: nodes on both sides or the opposite side, none over 6 cm, ENE(-).
• N3a: a node larger than 6 cm, ENE(-).
• N3b: one node on the same side over 3 cm with ENE(+); or multiple nodes with any ENE(+); or a single opposite-side node of any size with ENE(+).

Drainage is not random. First station nodes are the buccinator, jugulodigastric, submandibular, and submental. Midline tumors often drain to both sides. That is why a neck dissection may be done on both sides.

MRI beats CT here. NCI notes it is better at finding head and neck tumors, and at telling nodes from blood vessels.

For stage I and stage II, NCI says these cancers are highly curable by surgery or by radiation therapy. The choice is dictated by the expected functional and cosmetic result, and by whether a surgeon or radiation oncologist with the right expertise is available.

For stage III and stage IV, most patients are candidates for a combination of surgery and radiation therapy. There is an exception. For small T3 lesions with no regional nodes and no distant spread, or with no node larger than 2 cm, radiation alone or surgery alone may be appropriate.

Control rates vary by subsite. NCI reports cure rates of 90 to 100 percent for early lip cancers. Small cancers of the retromolar trigone, hard palate, and upper gingiva reach survival as high as 100 percent. Small cancers of the anterior tongue, floor of mouth, and buccal mucosa reach local control as high as 90 percent.

Hard palate surgery often removes underlying bone, creating an opening into the sinus. NCI notes that a dental prosthesis can fill and cover that defect, restoring swallowing and speech.

See a dentist first. NCI states plainly that dental status evaluation should be performed prior to therapy to prevent late sequelae. Teeth that need extraction should come out before radiation, not after, because healing in irradiated jawbone is poor.

Stop smoking before radiation starts. NCI reports that people who smoke during radiation appear to have lower response rates and shorter survival.

If your plan includes fluorouracil or capecitabine, raise this.

The DPYD gene makes an enzyme that breaks these drugs down. NCI estimates 1 to 2 percent of the population carries germline variants that reduce that enzyme's function. Patients with the DPYD*2A variant who receive these drugs may have severe, life-threatening, sometimes fatal toxicity.

Depending on genotype, avoiding the drug or cutting the dose by 50 percent may be advised. Testing costs less than $200. Insurance coverage varies, because there is no national guideline. It may delay therapy by about 2 weeks. NCI notes that is not advisable in urgent cases.

People with head and neck cancer face a raised chance of a second primary tumor in the upper aerodigestive tract. In one study, daily moderate-dose isotretinoin for 1 year cut the number of second tumors. No survival benefit was shown. Long-term surveillance is the practical answer, not a supplement.

SEER groups oral cavity with pharynx, so these cover both. The survival and stage figures track people diagnosed from 2016 through 2022:

• An estimated 60,480 new cases and 13,150 deaths in 2026, or 2.9 percent of all new cancer cases. Those two totals are American Cancer Society projections, which SEER republishes.
• Median age at diagnosis: 65. Overall 5-year relative survival: 69.9 percent.
• Localized: 26 percent of cases, 88.7 percent survival.
• Regional: 55 percent of cases, 69.7 percent.
• Distant: 12 percent of cases, 36.0 percent.

• Call 911 or go to an emergency department if breathing turns hard or noisy, you cannot swallow your own saliva, or bleeding in the mouth keeps going despite ten minutes of firm pressure. Swelling of the floor of the mouth or the neck that is spreading by the hour belongs here as well.
• Call your cancer team at once if your temperature hits 100.4°F (38°C) or higher at any point during chemotherapy or chemoradiation, even with nothing else wrong. CDC puts a fever on chemotherapy in the emergency category, and antibiotics are meant to start within the hour. Call day or night. If that line does not get you through fast, go to an emergency department and say you are having chemotherapy.
• Call your care team the same day if your temperature hits 100.4°F (38°C) or higher with facial swelling, a surgical wound in the mouth opens, or your voice changes abruptly, and you are not having chemotherapy.
• Call your care team within a day or two if your jaw opens less far than it did a week ago, or mouth pain has grown enough that you are no longer eating or drinking properly.

• Which subsite is the tumor in, and what is my depth of invasion in millimeters?
• Were the margins clear, and by how much?
• Does my pathology report say ENE positive or negative?
• Will I need a neck dissection, and on one side or both?
• Have I been seen by a dentist, a speech and swallowing therapist, and a dietitian yet?
• If fluorouracil or capecitabine is planned, will you test my DPYD status?

https://www.cancer.gov/types/head-and-neck/hp/adult/lip-mouth-treatment-pdq

https://seer.cancer.gov/statfacts/html/oralcav.html

https://www.cdc.gov/cancer-preventing-infections/patients/fever.html