Skin, lip, oral, and esophageal cancer (detailed version)

What is cancer?

Cancer refers to a variety of malignant neoplasms that occur throughout the body.

What does the term neoplasm mean?

“New growth,” describing rapid cell growth exceeding normal growth limits.

What is apoptosis?

Programmed cell death, a process that removes aging or damaged cells.

What determines if a neoplasm is benign or malignant?

Whether or not it invades surrounding or distant tissues.

What are carcinomas?

Malignant neoplasms derived from epithelial tissue.

What percentage of oropharyngeal and oral cavity cancers are squamous cell carcinomas?

More than 90%.

Where do squamous cell carcinomas most commonly occur?

On the lateral borders of the tongue.

What areas are included in oral cancers?

Lips, floor of the mouth, buccal mucosa, hard palate, alveolar processes, and oropharynx.

Which additional structures can be affected by oral cancers?

Oropharynx, pharynx, vermillion border, pharyngeal arches, soft palate, palatoglossus, and tonsillar fossae.

How does cancer form?

Cancer forms when normal cells undergo a sequential, multi-step process from normality to metastatic cancer.

What is epithelial dysplasia?

A premalignant condition involving cellular and architectural changes.

What cellular alterations occur in epithelial dysplasia?

Changes in size, shape, and number of nuclei, and increased mitosis.

What architectural changes occur in epithelial dysplasia?

Formation of rete pegs, hyperplasia, and altered maturation.

What cell functions must be disrupted for cancer to occur?

Growth regulation, apoptosis, differentiation, replicative senescence, angiogenesis, DNA repair, tissue remodeling, migration, and immune evasion.

What does growth regulation refer to?

Proliferation beyond the normal number of cells.

What is the role of apoptosis in preventing cancer?

Removes damaged or aging cells through programmed cell death.

What is differentiation?

The degree of alteration of cells from their normal morphology and function.

What is DNA repair?

The process by which a cell monitors and repairs DNA before replication to avoid passing faulty DNA.

What gene mutation is often found in head and neck cancers?

Mutation of p53.

What is tissue remodeling and migration in relation to cancer?

The ability of cancer cells to travel beyond normal tissue borders.

What does immune evasion mean?

The breakdown of the body’s ability to detect and destroy abnormal or cancerous cells.

What is replicative senescence?

The irreversible loss of a cell’s ability to stop dividing after many divisions, resulting in faulty cells.

What is angiogenesis?

The buildup of vascular tissue needed to sustain cancerous growth.

What are the main categories of risk factors for cancer?

Host susceptibility, environmental factors, and exposure.

What are the primary risk factors for oral cancer?

Tobacco use and excessive alcohol intake.

What shift has occurred in oncology focus?

From treatment-oriented to prevention-oriented philosophy.

How does tobacco contribute to cancer development?

Tobacco is the major cause of oral cancer in the U.S. and contributes to about 30% of all cancers.

How many people with oral cancer are smokers?

Eight out of ten.

What fraction of oral cancer patients continue smoking after diagnosis?

One in three.

What is the relationship between cigarette smoking and oral cancer?

Direct causal link to cancers of the oral cavity and pharynx.

How does alcohol increase oral cancer risk?

Alcohol dehydrates cells, increasing vulnerability to carcinogens.

How is oral cancer risk related to alcohol dose?

It is dose-related; risk increases with more than four drinks per day.

What percentage of oral cancer patients drink alcohol?

About 70%.

How much more likely are drinkers to develop oral cancer?

Six times more likely.

How does alcohol enhance the carcinogenic effect of tobacco?

By increasing cell permeability and releasing toxic compounds such as acetaldehyde.

What is the combined risk for heavy drinkers and smokers?

100 times higher than normal.

How do nutritional deficiencies affect cancer risk?

They reduce the body’s ability to prevent cancer.

What virus is a major cause of tonsillar cancer in the U.S.?

Human Papillomavirus (HPV).

How many types of HPV exist?

More than 100.

What is HPV classified as?

The most common sexually transmitted infection.

What cancers is HPV associated with?

Oral cavity and oropharyngeal squamous carcinoma.

Which HPV type is most associated with oropharyngeal cancer?

HPV-16.

Which oral sites are commonly affected by HPV-related cancer?

Tongue and tonsils.

What are risk factors for HPV-related oral cancer?

Early sexual activity, multiple partners, and oral sex.

How does HPV-related oral cancer prognosis compare to others?

It has a better prognosis and is more sensitive to radiation and chemotherapy.

What cancer has oral HPV surpassed in frequency?

Cervical cancer.

At what age does oral cancer risk increase?

After age 45.

What is the median age for oral and pharyngeal cancers?

62 years.

How does aging affect cancer risk?

It weakens immune function and increases biochemical processes that promote carcinogenesis.

Is cancer increasing among younger individuals?

Yes.

What type of radiation exposure is linked to lip cancer?

Actinic (solar) radiation.

What precancerous lesion is caused by UV overexposure?

Actinic cheilitis, usually on the lower lip.

Who is most at risk for lip cancer?

Fair-skinned individuals, particularly men.

Have lip cancer rates increased or decreased?

Decreased.

What other factors increase oral cancer risk?

Low fruit and vegetable intake and presence of leukoplakia, erythroplakia, or erythroleukoplakia lesions.

Which oral lesions carry a greater threat of malignancy?

Erythroplakia and erythroleukoplakia.

Which sites are more likely to develop oral squamous cell carcinoma?

Floor of mouth, tongue, retromolar/soft palate areas.

What is lichen planus?

A chronic inflammatory dermatologic disease.

Is transformation of lichen planus into malignancy common?

Controversial; limited to severe cases.

What management is recommended for lichen planus?

Regular evaluation, follow-up, and biopsy.

How are early-stage oral cancers treated?

With surgery or radiation therapy.

How are late-stage cancers treated?

With a combination of surgery, postoperative radiation, and chemotherapy.

What is photodynamic therapy?

Laser treatment option that allows healing without fibrosis.

Are chemotherapeutic agents effective alone?

Generally not; best used in combination with surgery or radiation.

How are small intraoral lesions treated?

With a single modality.

How are larger lesions treated?

With a combination of modalities.

What types of radiotherapy are used for oral cancers?

External-beam irradiation, brachytherapy, and modulated radiotherapy.

What are common side effects of radiation therapy?

Pain, xerostomia, dysgeusia, cervical caries, epithelial atrophy, alopecia, hyperpigmentation, mucositis, osteoradionecrosis, and telangiectasias.

What is osteoradionecrosis?

Bone death due to radiation exposure; a lifetime risk.

What is telangiectasia?

Clusters of damaged small blood vessels in the skin (spider veins).

Is chemotherapy commonly used alone for oral cancer?

No, it’s typically adjunctive.

How do cytotoxic drugs work?

They disrupt the DNA of cancer cells, preventing reproduction.

What are common side effects of chemotherapy?

Acute mucositis, dysphagia, xerostomia, altered saliva quality, candidiasis, neurotoxicity, and altered sensation.