Week 13 Cancer Review

Swallowing, Dental, Oral, and Speech Complications Related to Cancer Treatment

Overview

  • Important aspects of oral hygiene and complications associated with cancer treatments such as therapy and radiation.

  • Involvement of cancer-related conditions and their impact on areas including the tongue, speech, and overall oral health.

Complications

  • Tumor cells may spread within lymphatic areas, creating additional challenges.

  • The risks associated with oral and dental complications in cancer patients.

Reference

  • Adapted from slides modified by C. Constantin PhD, RNC, Elsevier.

Cancer Unit Specific Learning Outcomes

  • Understand the key distinctions and classifications related to cancer, including:

    • Differences between benign and malignant tumors.

    • Biology of cancer cells, focusing on:

    • Transformation and differentiation of cells.

    • Definitions of proto-oncogene, oncogene, and tumor suppressor gene.

    • Importance of tumor markers in cancer detection.

    • Grading and Staging of Cancer to predict outcomes and treatment paths.

Understanding Cancer

Definition

  • Cancer is defined as a disease characterized by disordered growth and differentiation of cells, resulting in uncontrolled cell division.

Mechanism

  1. Normal Cell Functioning

    • Cells undergo normal processes of growth, division, and programmed cell death (apoptosis).

  2. Genetic Alterations

    • Cancer occurs when normal genetic regulation is disrupted, leading to uncontrolled proliferation of abnormal cells.

    • Cancerous cells evade their programmed self-destruction, leading to excessive growth.

Biology of Cancer

Key Features of Cancer Cells

  • Altered Expression of Genes

    • Cancer is related to a shift in the expression of genes responsible for regulating cell proliferation and differentiation.

    • Links between environmental exposures and genetic predispositions to cancer.

    • Susceptibility may also be inherited through mutations that predispose individuals to cancer.

Environmental and Lifestyle Factors

  • Important Risk Factors

    1. Increasing Age

    2. Tobacco Use

    • The primary cause of cancer fatalities with a mere 15% survival rate for lung cancer. Also linked to cancer of the pancreas, bladder, kidneys, mouth, and esophagus.

    1. Nutrition

    • High-fat diets related to cancers such as breast and colon; low-fiber intake linked to colorectal cancer.

    • Mixed evidence on the impact of alcohol consumption on cancers including breast and liver.

    1. UV Radiation

    • Connection to skin cancers.

    1. Viral Infections

    2. Environmental Toxins

Tumors

Classification

  • Benign Tumors

    • Typically composed of well-differentiated cells; encapsulated, and generally do not spread aggressively.

  • Malignant Tumors

    • Characterized by rapid growth rates, poor differentiation, and a loss of normal cellular organization (anaplasia). They possess potential for metastasis.

Neoplasm Definition

  • A term describing new growth (tumor), emphasizing that not all neoplasms are cancerous, showcasing the contrast between malignant and benign tumors.

Benign vs. Malignant Tumors Summary

Feature

Benign Tumors

Malignant Tumors

Growth Rate

Slow

Rapid

Encapsulation

Well-defined capsule

Not encapsulated

Invasiveness

Not invasive

Invasive

Differentiation

Well differentiated

Poorly differentiated

Metastasis

Do not metastasize

Can metastasize

Progression of Cancer

Stages of Development

  • Transition from normal cells through stages of dysplasia and anaplasia leading to cancer progression, with the precursor stages being generally reversible:

    • Dysplasia: Abnormal tissue development but not cancerous.

    • Anaplastic Cells: Indicative of cancer with significant loss of normal architecture.

    • Carcinoma in situ: Pre-invasive cancer potentially treatable before full progression.

Historical Context and Definitions

Carcinoma in Situ (CIS)

  • Refers to early-stage cancerous tumors, originating from epithelial cells but have not invaded surrounding tissues, making them more manageable.

Comparison of Features

Benign and Malignant Tumors

Benign example features:

  • Grows slowly, is encapsulated, and has a low mitotic index.

Malignant example features:

  • Grows rapidly, has a high mitotic index indicating rapid cell division, and can metastasize.

Biology of Cancer Cells

Aging and Mutations

  • Cancer predominantly affects older adults due to the accumulation of multiple mutations over time that collectively enable the emergence of cancerous characteristics.

Characteristics of Cancer Cells

  1. Clonal Proliferation: Cells diverging from a parent cell gain advantageous mutations enabling selective growth.

  2. Decreased Growth Factor Dependency: Cancer cells often proliferate without the normal need for external growth signals.

  3. Immortalization: Presence of telomerase contributes to unlimited cell division.

  4. Anchorage Independence: Ability to grow without attachment to a surface, traditionally required for normal cell growth.

Hallmarks of Cancer Cells

Six Key Characteristics

  1. Self-sufficiency in growth signals: Tumors can produce their own growth signals (autocrine stimulation).

  2. Resistance to anti-growth signals: Cancer cells ignore signals that typically halt cell proliferation.

  3. Evading apoptosis: Cancer cells develop mechanisms to circumvent programmed cell death.

  4. Limitless replicative potential: Cancer cells can divide indefinitely.

  5. Sustained angiogenesis: Formation of new blood vessels to support tumor growth.

  6. Tissue invasion and metastasis: Cancer cells invade surrounding tissues and may spread to distant parts of the body.

Tumor Markers

Definition and Importance

  • Tumor markers are biological substances produced by cancer cells or in response to cancerous conditions. They include hormones, proteins, enzymes, and genetic material.

Examples of Tumor Markers

Tumor Marker

Cancer Type

Alpha fetoprotein

Hepatic, germ cell

Carcinoembryonic antigen (CEA)

Gastrointestinal, pancreas, lung, breast

Prostate-specific antigen (PSA)

Prostate

Catecholamines

Pheochromocytoma (adrenal medulla)

Urinary Bence Jones protein

Multiple myeloma

Homovanillic acid

Neuroblastoma

Cancer's Seven Warning Signs

General Warning Signs

  1. Change in bowel or bladder habits.

  2. A sore that does not heal.

  3. Unusual bleeding or discharge.

  4. Thickening or lump in breast or elsewhere.

  5. Indigestion or difficulty swallowing.

  6. Obvious changes in warts or moles.

  7. Nagging cough or hoarseness.

Warning Signs Specific to Children

  1. Continued, unexplained weight loss.

  2. Headaches with vomiting in the morning.

  3. Increased swelling or persistent pain in bones or joints.

  4. Lump or mass in abdomen, neck, or elsewhere.

  5. Development of a whitish appearance in the pupil of the eye.

  6. Recurrent fevers not caused by infections.

  7. Excessive bleeding or bruising.

  8. Noticeable paleness or prolonged tiredness.

Diagnosis of Cancer

Diagnostic Features

  • Varied signs and symptoms related to the tumor’s characteristics.

  • Tumor markers may provide preliminary indications.

  • Physical examinations may reveal pressure symptoms, obstruction, and persistent sores.

Biopsy Importance

  • A biopsy is critical for obtaining tissue samples for histological examinations, facilitating the analysis of genetic alterations.

Grading and Staging of Cancer

Purpose

  • Grading and staging are essential for predicting tumor behavior and determining suitable treatment options.

Grading

  • Refers to the histological characterization of tumors based on the extent of anaplasia.

    • Grade 1: Well-differentiated with minimal deviation from normal.

    • Grade 2: Moderately well-differentiated with observable structural changes.

    • Grade 3: Poorly differentiated with significant structural changes.

    • Grade 4: Very anaplastic with minimal resemblance to normal cells.

Staging

  • Staging describes the tumor location, spread, and involvement of lymph nodes and other organs. It incorporates factors such as tumor size and metastasis presence.

Staging Classification Using TNM System

  • T: Primary tumor characteristics.

  • N: Node involvement (lymph nodes).

  • M: Distant metastasis presence.

Clinical Staging Breakdown

  • Stage 0: Cancer in situ (no invasion).

  • Stage I: Localized tumor growth.

  • Stage II: Limited local spread.

  • Stage III: Extensive regional spread.

  • Stage IV: Present distant metastasis.

Staging Criteria and Their Importance

Detailed Staging Factors

  1. Tumor Size and Local Extent: Size marked as T (e.g., T1 for <2 cm).

  2. Local Lymph Node Involvement: Assessed as N (e.g., N0 indicating no involvement).

  3. Distant Metastasis: Evaluated as M (e.g., M0 indicating no metastasis).

References

  1. Lewis, R. (2015). Human Genetics: Concepts and Applications (11th ed.). New York, NY: McGraw-Hill Education.

  2. McCance, K.L., Huether, S.E., Brashers, V.L., & Rote, N.S. (2010). Pathophysiology: The Biological Basis for Disease in Adults and Children (6th ed.). Maryland Heights, MO: Mosby Elsevier.