Staging systems are used to describe the severity of cancer based on the size, extent of invasion, and spread to different body parts. It helps to determine treatment strategy and disease prognosis. TNM is the most commonly used system for staging oral cavity cancers. “T” stands for “Tumor Size”, “N” for “Lymph Nodes”, and “M” for “Metastasis”. Numbers and/or letters after T (is, 1, 2, 3, 4a, and 4b), N (0, 1, 2, and 3), and M (0 and 1) provide more details about each of these factors. Once T, N, and M categories are determined through different diagnostic techniques, this information is combined to assign an overall stage (from 0 to IV) to the disease.
Apart from the stage of disease, the selection of treatment usually depends upon the location of disease, patient’s preference, performance status of the patient, along with other factors. Following are the preferred treatment approaches for different stages of oral cavity cancer, but the final decision is taken after clinical assessment of the patient by an oncologist.
|Stage||TNM Score||Stage Description
|0||Tis N0 M0||Carcinoma in situ or cancerous lesion is present only in the superficial layer of the oral cavity.||For Stage 0 cancers, surgical resection of the involved site is considered as the standard treatment. The patient should be followed-up closely after treatment for any sign of recurrence.|
|I||T1 N0 M0||The primary tumor is </=2 cm in size and the depth of invasion (DOI) is </=5 mm. No spread to nearby lymph nodes or distant body parts.||For Stage I and II cancers, Surgical resection of the involved site and/or radiotherapy is considered as the preferred treatment approach. Chemotherapy along with radiation therapy may be employed after the primary treatment to kill any remaining cancer cells.|
|II||T2 N0 M0||The primary tumor is </=2 cm in size with the DOI between 5 mm and 10 mm or primary tumor is >2 cm but </=4 cm with the DOI </=10 mm. No spread to nearby lymph nodes or distant body parts.|
|III||T1-2 N1 M0
|The primary tumor is </=4 cm in size with the DOI </=10 mm. The disease has spread to a single ipsilateral lymph node measuring </=3 cm without extranodal involvement. No spread to distant body parts.||For Stage III to IVA cancers, a combination of surgery and radiotherapy is usually employed as the first-line treatment. Surgery usually involves the removal of the primary tumor along with affected lymph nodes. Chemotherapy along with radiation therapy may be employed after the primary treatment to kill any remaining cancer cells.|
|T3 N0-1 M0||The primary tumor is >4 cm in size with the DOI between 10 mm and 20 mm. No spread to nearby lymph nodes or distant body parts.|
|IVA||T1-3 N2 M0||The primary tumor is </=4 cm in size with the DOI </=20 mm. The disease has spread to a single ipsilateral lymph node measuring either </=3 cm with extranodal involvement or >3 cm but <6 cm without extranodal involvement; or to multiple ipsilateral or bilateral/contralateral lymph nodes, all measuring <6 cm without extranodal involvement. No spread to distant body parts.|
|T4a N0-2 M0||The primary tumor invades adjacent structures and/or DOI > 20 mm. The disease might have spread to single, multiple, or bilateral/contralateral lymph nodes, all measuring <6 cm without extranodal involvement. No spread to distant body parts.|
|IVB||Any T N3 M0||The primary tumor of any size and DOI that might have invaded the adjacent structures. The disease has spread to lymph nodes measuring >6 cm or with significant extranodal involvement. No spread to distant body parts.||For Stage IVB to IVC cancers, chemotherapy with or without targeted therapy is usually employed as the first-line treatment. Radiation therapy may be employed as palliative treatment.|
|T4b Any N M0||The primary tumor of any size that has invaded a vital structure, such as masticator space, pterygoid plates, skull base and/or surrounds the carotid artery. The disease might or might not have spread to lymph nodes. No spread to distant body parts.|
|IVC||Any T Any N M1||The primary tumor of any size and DOI that might have invaded the adjacent structures. The disease might or might not have spread to lymph nodes. The disease has spread to a distant body part, such as the lungs.|
Palliative Treatment: It helps in improving the overall quality of life by providing relief from the symptoms and by reducing the suffering caused by HNC and its treatment. It is generally given as supportive care for advanced staged HNCs, along with other treatments. It may include but not limited to: using drugs or other interventions to reduce pain, bleeding, and other symptoms; surgical interventions like gastrostomy or tracheostomy to support nutrition or respiration; support and counselling for speech, swallowing, and oral hygiene-related problems; and radiation therapy to palliate pain, bleeding, obstructive problems, etc.
It is very important to assess the benefits of each treatment option versus the possible risks and side effects before making a treatment decision. Sometimes, patient’s choice and health condition are also important to make a treatment choice. Following are ultimate goals for staging and treatment of oral cavity cancer:
- Prolongation of life.
- Reduction of symptoms.
- Improvement of overall quality of life.
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