Oral Cavity Squamous Cell Carcinoma

Oral cavity carcinoma (ICD-10-GM C06.9: Mouth, unspecified) is a malignant neoplasm of the oral cavity. Most tumors of the oral cavity (about 95%) are squamous cell carcinomas (PEC; oral cavity squamous cell carcinoma, OSCC). Oral cavity carcinomas are mostly found in the floor of the mouth and the lateral border of the tongue. The upper jaw is the least commonly affected. Sex Ratio: This tumor is about three times more common in men than in women. Frequency peak: The mean age of onset is in the sixth decade of life. The disease is most common in men between 55 and 65 and in women between 50 and 75. The incidence (frequency of new cases) is approximately 10,000 cases per year (in Germany). Course and prognosis: The earlier the disease is detected and treated, the better the chances of recovery.

Symptoms – complaints

Suspicious is any change in the oral mucosa with excess tissue and/or tissue defect, as well as a change in color or hardening of the mucosa. There are two main types of oral cavity carcinoma – endophytic and exophytic. Approximately 99% of all PEC of the oral cavity grow endophytically, i.e. invasively into the tissue.Classically, an ulcer (boil) is visible, surrounded by a raised rim and a red zone of inflammation. Necrosis (tissue destruction) often occurs in the center of the tumor, because the tumor grows so rapidly that the blood supply in the center is not guaranteed.Only about one percent of tumors grow exophytically, that is, the tumor mass sits on top of the tissue.A special form is verrucous (wart-shaped) squamous cell carcinoma of the oral cavity. Other possible symptoms include bleeding, fetor ex ore (bad breath), mechanical disturbance, numbness, or loss of adjacent teeth.General symptoms include decreased performance, fatigue, loss of appetite, and weight loss.

Pathogenesis (disease development) – etiology (causes)

The main risk factors for developing oral squamous cell carcinoma include nicotine and alcohol. A smoker has a 3-6-fold increased risk compared with a nonsmoker. If alcohol is also consumed, the risk increases by another 2.6% compared to the smoker who does not drink. The main reason for this is the fact that alcohol makes the oral mucosa more permeable to the carcinogens of tobacco. Another risk factor is chewing betel nut.Other important risk factors are:

  • Poor oral hygiene
  • A weakened immune system
  • Chronic mechanical trauma
  • Viral infections
  • UV and radioactive radiation

Deficiencies of iron, folic acid, or cobalamin are considered likely risk factors, as this leads to decreased protection against carcinogenic noxious agents through atrophy of the oral mucosa (oral mucosa). Furthermore, human papillomavirus (HPV), more than two-thirds of type 16, was detected in more than 50% of squamous cell carcinomas in a study (Cruz et al. 1996). Similarly, Epstein-Barr viruses (EBV) were detected in more than half of the tissue samples examined. Leukoplakias (are skin lesions consisting of a whitish, limited change in the mucous membranes that can transform into a malignant tumor) or ulcers (ulcers) infected with Candida albicans (fungal infection) show a higher risk of malignant transformation (malignant degeneration) than uninfected lesions. Periodontitis is considered an independent risk factor. Studies of the oral cavity microbiome revealed increased bacterial classes associated with periodontitis in samples from cancer patients.

Consequential diseases

If oral cavity PEC is treated with radiatio (radiation therapy), radiation-related sequelae may occur. These include:

  • Radioxerostomia – radiation treatment-induced dry mouth.
  • Radiation caries
  • Radiogenic mucositis – oral mucositis caused by radiation treatment.
  • Infected osteoradionecrosis – radiation treatment-related bone loss with infection of the same.

Furthermore, patients with oral squamous cell carcinoma (OSCC) have an increased risk (+ 85%) of developing second primary cancer (SPC) over a prolonged period of time. Prognostic factors

  • If treatment of squamous cell carcinoma of the oral cavity is given later than 6 weeks after diagnosis, this worsened the chances of survival by 18%.

Diagnostics

  • If PEC is suspected, a biopsy (tissue sample) is first taken and examined histologically (fine tissue). If the suspicion of carcinoma is confirmed, further investigations follow. This includes first the search for metastases (daughter tumors).
  • Immunological rapid test to detect antibodies against HPV 16 in whole blood (in vitro diagnostics with Prevo-Check: see below Prevo-Check rapid test); the test should not be performed in persons whose vaccination was less than 6 years ago. In such cases, a positive result is to be expected, even if there is no HPV16 infection.
  • A chest x-ray (chest radiograph) and skeletal scintigraphy help detect metastases in major organs such as the lungs and in the bones.
  • To determine if cervical lymph nodes are affected and need to be removed, sonography (ultrasound examination) of the lymph node stations is performed. However, this does not detect micrometastases.
  • A computed tomography (CT) gives accurate information about the location and size of the tumor.
  • Recently, optical coherence tomography (OCT) has been primarily used for more advanced diagnosis of oral cavity carcinoma, allowing imaging of tissue structures in situ with micrometer resolution, thus allowing assessment of invasiveness.

Therapy

  • Based on the examinations performed, a treatment plan is made. This almost always includes surgical removal of the tumor. If it is not certain whether micrometastases are present, only the sentinel lymph node (guardian lymph node) can be removed and examined initially. Only if the sentinel lymph node is affected, a neck dissection is then performed. A neck dissection (neck preparation) is a radical operation with removal of all lymph nodes of the neck.
  • In advanced stages, chemotherapy in combination with radiation therapy sometimes follows the surgery.
  • Regular checks are essential to monitor the success of therapy and to detect any recurrence (recurrence of the tumor) at an early stage.

Despite the comprehensive therapy measures, the 5-year survival rate is only about 50%. Therefore, it is important to act preventively, avoid nicotine and alcohol and practice adequate oral hygiene. Regular check-ups with the dentist help to detect any changes in the oral mucosa at an early stage and thus to be able to initiate therapy in good time.