Biomedical Engineering Reference
In-Depth Information
the pigment producing cells of the oral mucosa. Oral cancer accounts for approximately 2% of all
malignant tumors in the United States and Europe, approximately 30-40% in the Indian subconti-
nent and more than 90% are squamous cell carcinomas, originating in the tissues that line the mouth
and lips
[15]
. Oral cancer most commonly involves the tongue. It may also occur on the floor of the
mouth, cheek lining, gingiva (gums), lips, or palate (roof of the mouth). Squamous cell carcinoma is
a malignant tumor of squamous epithelium (epithelium that shows squamous cell differentiation) lin-
ing the oral mucosa. These are malignant and tend to spread rapidly. The main causes of oral cancer
are excessive intake of alcohol and tobacco use. Exposure to sunlight is a causative factor for cancer
of the lips, similar to skin cancer. Human papilloma virus, called HPV, is also one of the risk factors
for cause of oral cancer. Immunosuppressed patients (HIV patients, renal transplant patients) have the
highest risk factor for developing oral cancer.
Oral cancerous lesions are most often seen as a painless ulcer, although may present as a swelling,
an area of leukoplakia (white patch or plaque), erythroplakia (well demarcated red velvety patch of
oral mucosa), erythroleukoplakia (speckled leukoplakia), as malignant change of long-standing benign
tumors or rarely in cyst linings or nonhealing extraction socket. Malignancy should be suspected if
any of the above lesions persists for more than 3 weeks. Pain is usually a late feature when the lesion
becomes ulcerated or superinfected. Ulcerated lesions are firm with raised edges, with an indurated,
inflamed, granular base and are fixed to the surrounding tissues. In the later stages, it involves tongue
problems, difficulty in swallowing, pain, and paresthesia (numbness of the affected area).
19.5
TNM CLASSIFICATION OF TUMORS
The TNM staging system for all solid tumors was devised by Pierre Denoix between 1943 and 1952,
using the size and extension of the primary tumor, its lymphatic involvement, and the presence of
metastases to classify the progression of cancer.
T describes the size of the tumor and whether it has invaded nearby tissue
N describes regional cervical lymph nodes that are involved
M describes distant metastasis (spread of cancer from one body part to another) (
Table 19.1
).
19.6
MANAGEMENT OF ORAL CANCER
Suggested management plan (which may vary between operating surgeons) involves:
if
T1-N0: Surgery or radiotherapy.
if
Tumor close to bone having radiotherapy: Safest to remove associated bone to prevent osteoradi-
onecrosis (a condition of nonvital bone in the site of radiation).
if
T2-N0: Selective neck dissection.
if
T2, T3: Prophylactic radiotherapy or prophylactic selective neck dissection.
Surgical excision (removal) of the tumor is usually recommended if the tumor is small enough,
and if surgery is likely to result in a functionally satisfactory result. Radiation therapy with or without
chemotherapy is often used in conjunction with surgery, or as the definitive radical treatment, espe-
cially if the tumor is inoperable. Surgeries for oral cancers include:
