Oral Cancer

Oral cancer accounts for 2% of all malignancies in the UK. Amongst the ten most common cancers worldwide.

Over 90% of malignant neoplasms of the mouth are squamous cell carcinomas arising from mucosal surface epithelium. The remainder are adenocarcinomas of minor salivary glands and a few are undifferentiated or metastatic.

 

Epidemiology

Approximately 2000 new cases of intraoral and lip carcinoma are registered each year in the UK. M>F at the moment, but this is changing. It is an age related disease, with 98% of patients > 40 years.

 

Aetiology

Main aetiological factor in lip cancer is sunlight exposure. Causative associations have been made with tobacco, alcohol, betel quid, syphilis, candidosis, lichen planus, dysplastic lesions and oral submucous fibrosis.  Causative factors operate over a long period and the process of malignant change is slow.

Possible protective effect from diet rich in fresh fruits and vegetables and Vitamin A.

 

Site

Nearly 30% of all oral cancer affects the lip -  in some ways this can be regarded as a somewhat different disease to intra-oral carcinoma. The horseshoe shaped region, encompassing floor of mouth, lateral border of tongue and lingual sulcus, is where the majority of intra-oral cancer arises. (Unknown why..? pooling of carinogens in saliva)

 

Clinical appearance and Symptoms

Of any of the following persisting for more than 3 weeks:-

  • Sore on lip/mouth that does not heal
  • Lump on lip/mouth/throat, sometimes with abnormal supplying blood vessels
  • Leukoplakia, erythroleukoplakia or erythroplakia on gums, tongue, mouth lining
  • Sore throat that does not go away, or a feeling that something is caught in the throat
  • Difficulty or pain with chewing or swallowing
  • Swelling of the jaw that causes dentures to fit poorly or become uncomfortable
  • Later carcinomas appear as ulcers with prominent rolled edges and induration (firm infiltration beneath mucosa) and become painful if infected or when eating spicy foods
  • Referred otalgia is a common manifestation of pain from oral cancer
  • Cervical lymph node enlargement (especially hardness or fixation)
  • Dysarthria
  • Dysphagia
  • Beware non-healing extraction socket

 

 

Diagnositic tests

Biopsy and histopathological examination, FNA of equivocal lymph nodes, plain radiography (DPT + CXR), computerized tomography (CT), magnetic resonance imaging (MRI), bone scintigraphy and ultrasound.

Staging—TNM classification

Primary Tumour Size

Regional Lymph Node Involvement

Distant Metastasis

T1  <2cm diameter

N0  no nodes

M0  absent

T2  2—4 cm diameter

N1  single node < 3cm

M1  present

T3  >4cm diameter

N2  multiple Ipsilateral nodes of single node 3—6cm

 

T4  massive >4cm, invading beyond mouth (antrum, pterygoid muscles, base of tongue or skin)

N3  bilateral cervical nodes, or ispsilateral node > 6cm

 

 

Survival

 

  • Adversely related to:
  • Delay in treatment
  • Advanced age
  • Male gender
  • Tumour size
  • Posterior location
  • Lack of histological differentiation
  • Lymph node spread

 

 

Histopathology

Characteristically squamous cell carcinoma shows invasion of deep tissues with cellular pleomorphism and hyperchromatism (increased nuclear staining). Spread can occur by local infiltration, lymphatics (cervical nodes) and late spread via blood stream. Bone initially forms a barrier, but is eventually destroyed, usually by superficial erosion.

 

Management

 

  1. Surgery
  2. Radiotherapy
  • used as sole treatment for primary oral cancers without obvious lymph node involvement
  • also for inoperable tumours

 

3. Chemotherapy

 

Prognosis for Intra-oral Carcinoma

Stage I                 T1N0M0                                          85% survival rate at 5 years

Stage II                T2N0M0                                          65% survival rate at 5 years

Stage III T3N0M0; T1/T2/T3N1M0 40% survival rate at 5 years

Stage IV Any T4, N2, N3 or M1 10% survival rate at 5 years