Head and neck cancer natural history

Prognosis
Although early-stage head and neck cancers (especially laryngeal and oral cavity) have high cure rates, up to 50% of head and neck cancer patients present with advanced disease. Cure rates decrease in locally advanced cases, whose probability of cure is inversely related to tumor size and even more so to the extent of regional node involvement.

Consensus panels in America (American Joint Committee on Cancer AJCC and Europe) have established staging systems for head and neck squamous cancers. These staging systems attempt to standardize clinical trial criteria for research studies, and attempt to define prognostic categories of disease. Squamous cell cancers of the head and neck are staged according to the TNM classification system, where T is the size and configuration of the tumor, N is the presence or absence of lymph node metastases, and M is the presence or absence of distant metastases. The T, N, and M characteristics are combined to produce a “stage” of the cancer, from I to IVB.

Residual deficits
Even after successful definitive therapy, head and neck cancer patients face tremendous impacts on quality of life. Despite marked advances in reconstructive surgery and rehabilitation, intensity-modulated radiotherapy (IMRT) and conservation approaches to certain malignancies, some patients continue to have significant functional deficits.

Problem of second primaries
Survival advantages provided by new treatment modalities have been undermined by the significant percentage of patients cured of head and neck squamous cell carcinoma (HNSCC) who subsequently develop second primary tumors. The incidence of second primary tumors ranges in studies from 9.1% to 23% at 20 years. Second primary tumors are the major threat to long-term survival after successful therapy of early-stage HNSCC. Their high incidence results from the same carcinogenic exposure responsible for the initial primary process, called field cancerization.

Throat cancer has numerous negative effects on the body systems.

Digestive system
As it can impair a person’s ability to swallow and eat, throat cancer affects the digestive system. The difficulty in swallowing can lead to a person to choke on their food in the early stages of digestion and interfere with the food’s smooth travels down into the esophagus and beyond.

The treatments for throat cancer can also be harmful to the digestive system as well as other body systems. Radiation therapy can lead to nausea and vomiting, which can deprive a body of vital fluids (although these may be obtained through intravenous fluids if necessary). Frequent vomiting can lead to an electrolyte imbalance which has serious consequences for the proper functioning of the heart. Frequent vomiting can also upset the balance of stomach acids which has a negative impact on the digestive system, especially the lining of the stomach and esophagus.

Respiratory system
In the cases of some throat cancers, the air passages in the mouth and behind the nose may become blocked from lumps or the swelling from the open sores. If the throat cancer is near the bottom of the throat it has a high likelihood of spreading to the lungs and interfering with the person’s ability to breathe; this is even more likely if the patient is a smoker, because they are highly susceptible to lung cancer. If the respiratory system is unable to bring oxygen into the body, the oxygen deprivation will cause the body's cells to wither and die, causing one to become weaker and sicker.

Others
Like any cancer, metastasization affects many areas of the body, as the cancer spreads from cell to cell and organ to organ. For example, if it spreads to the bone marrow, it will prevent the body from producing enough red blood cells and affects the proper functioning of the white blood cells and the body's immune system; spreading to the circulatory system will prevent oxygen from being transported to all the cells of the body; and throat cancer can throw the nervous system into chaos, making it unable to properly regulate and control the body.