Domain 2.16Anatomy and Physiology

Environmental Injuries And Cancer

Last updated June 16, 2026

Overview

Welcome to the study guide for Environmental Injuries and Cancer. While these two topics may seem different, they both involve the body's reaction to external stressors—whether that be extreme temperatures affecting homeostasis or carcinogens (cancer-causing agents) damaging DNA.

Why is this critical for your role?

  • Screening & Prevention: As a Medical Assistant (MA), you are the front line for cancer screening. You will prepare patients for Pap smears, assist with skin biopsies, and instruct patients on how to prepare for colonoscopies.
  • Recognizing Emergencies: You must be able to instantly recognize the difference between heat exhaustion (urgent) and heat stroke (life-threatening emergency).
  • Patient Education: You will frequently educate patients on sun safety, self-exams, and the importance of routine preventive testing.

This guide covers the pathophysiology of major cancers and environmental emergencies, focusing on the signs, symptoms, and diagnostic tools you will encounter on the exam and in the clinic.

1. Foundations of Oncology

Oncology is the study of tumors (neoplasms) and cancer. When cellular biology goes wrong, it often results in abnormal growth. To understand specific cancers, you must first understand the terminology.

Neoplasms (Tumors)

A neoplasm is a "new growth" of abnormal tissue. Not all tumors are cancer.

  • Benign: Non-cancerous. Grows slowly, is encapsulated, and does not spread.
  • Malignant: Cancerous. Grows rapidly, invades tissue, and can spread.
Feature Benign Malignant (Cancer)
Growth Rate Slow Rapid
Encapsulation Usually encapsulated (contained) Non-encapsulated (invasive)
Spread Does NOT spread to other parts of the body. Metastasizes (spreads) to distant organs via blood or lymph.
Recurrence Rare after removal Common
Suffix Often ends in -oma (e.g., Lipoma = fatty tumor). Carcinoma or Sarcoma.

Exam Tip: Be careful! While "-oma" usually means tumor, some malignant cancers end in "-oma" too (e.g., Melanoma, Lymphoma). Context is key.

Cancer Classifications (Naming based on Cell Type)

Cancers are named based on the type of tissue where they originate.

Term Tissue Origin Memory Aid
Carcinoma Epithelial Tissue (Skin, organ linings). Carcinoma Covers the organs. (Most common type, e.g., Melanoma, Lung cancer).
Sarcoma Connective Tissue (Bone, muscle, fat, cartilage). Sarcoma = Structural tissue.
Leukemia Blood-forming tissues (Bone marrow). Leukocytes = White blood cells.
Lymphoma Immune system (Lymph nodes). Affects the Lymphatic system.

Key Terminology

  • Metastasis: The spread of cancer cells from the primary site (origin) to a distant secondary site (e.g., breast cancer spreading to the lungs) via the blood or lymph system.
  • Biopsy: The removal of a sample of tissue/cells for microscopic examination. This is the definitive method for diagnosing cancer.
  • Carcinogen: A substance capable of causing cancer (e.g., Cigarette smoke, UV radiation, Asbestos).

2. Common Cancers

You must be familiar with the following specific types of cancer, their risk factors, and how they are detected.

A. Skin Cancer

Skin cancer is the most common cancer in the United States. It primarily affects the epidermis (the outer layer of the skin).

  • Basal Cell Carcinoma: The most common and least dangerous type. Looks like a pearly or waxy bump.
  • Squamous Cell Carcinoma: Arises from squamous cells. Looks like a red nodule or scaly lesion.
  • Melanoma: The most dangerous form of skin cancer. It arises from melanocytes (pigment-producing cells) and can metastasize quickly.

The ABCDE Rule for Melanoma MAs often screen patients during intake. If you see a mole with these features, bring it to the provider's attention immediately.

Letter Feature Warning Sign
A Asymmetry One half of the mole does not match the other half.
B Border The edges are irregular, ragged, notched, or blurred.
C Color The color is not the same all over (shades of brown, black, blue, white, or red).
D Diameter The spot is larger than 6 mm (about the size of a pencil eraser).
E Evolving The mole is changing in size, shape, or color.

B. Lung Cancer

  • Definition: Malignant tumor arising from the lungs and bronchi (Carcinoma).
  • Risk Factors: Cigarette smoking is the #1 risk factor (linked to 80-90% of lung cancer deaths). Exposure to asbestos and radon gas are environmental risks.
  • Key Symptoms:
    • Chronic cough that worsens.
    • Hemoptysis: Coughing up blood.
    • Dyspnea (shortness of breath) and wheezing.
  • Diagnostics: Chest X-ray, CT Scan, Bronchoscopy (visual exam of airways).

C. Breast Cancer

  • Definition: Malignant tumor that develops in the cells of the breast (usually ducts or lobules).
  • Risk Factors: Family history (genetics like BRCA1/BRCA2 genes), advanced age, hormone replacement therapy.
  • Key Symptoms:
    • Lump or mass in the breast or underarm (axilla).
    • Changes in breast shape or skin texture (dimpling).
    • Nipple discharge or retraction.
  • Screening & Diagnostics:
    • Mammogram: An X-ray of the breast. The American Cancer Society recommends annual screening for women starting at age 45 (varies by guidelines).
    • Breast Self-Exam (BSE): Patients should perform this monthly to check for changes.

D. Cervical Cancer

  • Definition: Cancer of the cervix (the lower part of the uterus that connects to the vagina).
  • Primary Cause: Almost all cases are caused by the Human Papillomavirus (HPV), a sexually transmitted infection.
  • Key Symptoms: Often asymptomatic in early stages. Later: abnormal vaginal bleeding (between periods or after menopause), pelvic pain.
  • Screening & Prevention:
    • Pap Test (Pap Smear): Screening procedure to detect precancerous cells on the cervix.
    • HPV Vaccine: Prevents infection against the high-risk strains of HPV that cause cancer.

E. Prostate Cancer

  • Definition: Cancer of the prostate gland (a walnut-sized gland in men that produces seminal fluid).
  • Risk Factors: Age (most common in men over 65), family history, race (African American men are at higher risk).
  • Key Symptoms:
    • Difficulty starting urination (hesitancy).
    • Weak urine flow or frequent urination at night (Nocturia).
    • Note: These symptoms mimic Benign Prostatic Hyperplasia (BPH).
  • Diagnostics:
    • PSA (Prostate-Specific Antigen): A blood test. Elevated levels suggest prostate issues but are not specific to cancer.
    • DRE (Digital Rectal Exam): The provider palpates the prostate through the rectum to check for lumps.

F. Colorectal Cancer

  • Definition: Cancer of the colon or rectum (large intestine). Most begin as small clumps of cells called polyps.
  • Risk Factors: Age > 50, diet high in red/processed meats, family history, chronic inflammatory bowel disease (Crohn's/Ulcerative Colitis).
  • Key Symptoms: Change in bowel habits (diarrhea/constipation), blood in the stool, abdominal pain, unexplained weight loss.
  • Screening & Diagnostics:
    • Colonoscopy: Visual exam of the entire colon using a scope. This is the "Gold Standard" because polyps can be found and removed during the exam.
    • Fecal Occult Blood Test (FOBT): A test to detect hidden (occult) blood in the stool.

3. Blood and Lymphatic Cancers

These cancers affect the blood, bone marrow, and lymphatic system.

A. Leukemia

  • Definition: Cancer of the body's blood-forming tissues, including the bone marrow and lymphatic system. It usually involves the White Blood Cells (Leukocytes).
  • Pathophysiology: The bone marrow produces excessive, abnormal white blood cells that don't function properly. These crowd out healthy red blood cells and platelets.
  • Types: Can be Acute (fast-growing) or Chronic (slow-growing).
    • Acute Lymphoblastic Leukemia (ALL) is the most common cancer in children.
  • Key Signs & Symptoms:
    • Fatigue (due to anemia).
    • Frequent infections (due to poor WBC function).
    • Easy bruising or bleeding (due to low platelets).
    • Bone pain.

B. Lymphoma

  • Definition: Cancer of the lymphatic system (part of the immune system).
  • Key Symptom: Painless swelling of lymph nodes (lymphadenopathy) in the neck, armpits, or groin.
  • Two Main Types:
    1. Hodgkin's Lymphoma: Marked by the presence of a specific cell type called Reed-Sternberg cells. Generally has a high cure rate.
    2. Non-Hodgkin's Lymphoma: More common; includes a diverse group of blood cancers.

4. Environmental Injuries: Thermal Emergencies

The body maintains a core temperature of approx. 98.6°F (37°C) through homeostasis. When environmental conditions overwhelm the body's regulatory mechanisms, injury occurs.

A. Hyperthermia (Heat Illness)

Hyperthermia is an elevated body temperature. It progresses in severity from cramps to exhaustion to stroke.

Condition Signs & Symptoms MA Response / Treatment
Heat Exhaustion Heavy sweating (diaphoresis), pale/cool skin, nausea, dizziness, rapid pulse. Move to cool area, encourage fluids, loosen clothing.
Heat Stroke Hot, RED, DRY skin (no sweating), high fever (>103°F), confusion, unconsciousness, bounding pulse. Medical Emergency (Call 911). The cooling mechanism has failed. Cool rapidly (ice packs to axilla/groin) while waiting for EMS.

Exam Tip: The key difference is the skin. Wet/Sweaty = Exhaustion. Dry = Stroke (Emergency).

B. Hypothermia

Hypothermia is a core body temperature below 95°F (35°C).

  • Causes: Exposure to cold weather, immersion in cold water, or prolonged exposure to cool temperatures in elderly/infants.
  • Signs & Symptoms:
    • Mild: Uncontrollable shivering, numbness, pale/cyanotic (blue) skin.
    • Severe: Shivering STOPS, confusion, slurred speech, slow breathing/pulse, loss of consciousness.
  • MA Response:
    • Remove wet clothing immediately.
    • Warm the patient gradually (blankets, warm fluids if conscious). Rapid warming can cause heart arrhythmias.

C. Burns (Review)

Recall the burn classifications:

  • 1st Degree: Redness, pain (Epidermis only).
  • 2nd Degree: Blisters, severe pain (Epidermis + Dermis).
  • 3rd Degree: Charred/white, painless due to nerve damage (Full thickness).

5. Summary of Screening Guidelines

As an MA, you will help track patient compliance with these screenings.

Cancer Type Screening Tool General Guideline (varies by patient risk)
Breast Mammogram Annually starting age 45-50.
Cervical Pap Smear + HPV Test Every 3-5 years for women ages 21-65.
Colorectal Colonoscopy Every 10 years starting at age 45.
Prostate PSA Blood Test Discussion with provider starting age 50.
Skin Visual Exam Annual check; self-exam monthly (ABCDE).

6. Final Key Takeaways

  • ABCDE Rule: Memorize this for Melanoma detection (Asymmetry, Border, Color, Diameter, Evolving).
  • Heat Stroke vs. Exhaustion: Heat Stroke is defined by dry, hot skin and is a life-threatening emergency.
  • HPV Link: Human Papillomavirus is the primary cause of Cervical Cancer.
  • Terminology:
    • Carcinoma: Epithelial tissue (Remember: Carcinoma Covers).
    • Sarcoma: Connective tissue (Remember: Sarcoma = Structural).
  • Metastasis: The spread of cancer to a new location.
  • Carcinogen: Any substance capable of causing cancer.
  • Leukemia: Cancer of the White Blood Cells/Bone Marrow (causes fatigue and bruising).
  • Lymphoma: Cancer of the lymph nodes (causes painless swelling).
  • Screening Tools: PSA (Prostate), Mammogram (Breast), Colonoscopy (Colon), Pap (Cervix).
  • Biopsy: The only definitive way to confirm a cancer diagnosis.