Oncology and Neoplasms

Incidence

New cases in a population at a given time

Prevalence

Existing cases in a population at a given time

Primary prevention

Removing risk factors to prevent getting sick in the first place (e.g. immunization)

Secondary prevention

Prevents ongoing disease that are still curable (e.g. pap smear to find cancer cells then remove to cure)

Tertiary prevention

Prevents further damage or reducing complication of disease (e.g. antibiotics)

G1 phase (post-mitotic phase)

DNA synthesis ceases; RNA, protein synthesis, and cell growth occurs

S phase

DNA synthesis occurs, giving rise to two separate sets of chromosomes for each daughter cell

G2 phase (pre-mitotic phase)

DNA synthesis ceases; RNA and protein synthesis continue

M phase

Cell division or mitosis phase

What happens if something goes wrong in a phase?

Cell isn’t allowed to adequately grow or complete the process (if liver cell in g0 moves prematurely, unable to perform functions)

Well-differentiated cells

Neurons, skeletal muscles, and cardiac muscle cannot divide to produce more; permanently specialized (unable to replace)

Progenitor cells (parent)

Skin, hair, blood, and liver cells continue to divide, allowing turnover and tissue repair

Undifferentiated cells

Inactive cells that can be triggered to specialize as needed in cell cycle for growth or repair

Cell prolfieration

Cell divides to replace or add as needed

Cell differentiation

New cells specialize to match structure and function of cells replaced

Neoplasia

Continuous cell growth and differentiation that lacks regulatory controls and increases despite stoppage of stimulus

Factors Leading to Cancer

Family hx, hormones, carcinogens, oncogenic viruses, immunologic mechanisms, long-living stem cells

Angiogenesis

Tumors need and create new blood vessels for oxygen and nutrients

Manifestations of Cancer

Tissue cells and vessels push against one another (ischemia, necrosis, ulcerations), cancer cachexia, paraneoplastic syndromes

Cancer cachexia

High metabolic demand causing weight loss, loss of fat/muscles, anorexia, weakness, anemia

Paraneoplastic Syndromes

Hormones released inappropriately from tumors, causing systemic effects (skin, blood, brain); hypercalcemia (20-30%) from PTH breakdown with metastasis

Biopsy

Take sample of cells, placed under microscope and examined to determine if cancerous or not (e.g. pap smear)

Curative

Remove malignancy entirely

Control

If unable to remove, prolong patient survival and slow down growth of cancer

Palliative

If unable to control, then treat symptoms and provide comforted care

Radiation

High energy can cause ionization and free radicals that stops cell cycle; must be STRONG enough to FULLY kill

Tumors

Masses formed from overgrowth of cells

Cancer origin

Cancer from original site (breast cancer → lung cancer (still breast cancer))

Benign Neoplasms

Slow tumor growth expansively (outwards), but does not invade or spread

Malignant Neoplasms

Tumors grow rapidly and spread widely, has potential to kill regardless of position, compresses blood vessels and outgrows their own blood supply

Staging of Cancer

TNM (tumor, node, metastasis)

In situ (stage 0)

Stage where abnormal cells haven’t spread elsewhere

Localized (stage 1)

Small tumor contained in one place

Regional (stage 2)

Tumor cell grows larger and now near lymph vessels/nodes

Regional (stage 3)

Tumor cell grown deeper into tissues and spread to nearby lymph nodes

Distant (stage 4)

Cancer has spread to other tissues and distant areas

Types of Skin Cancers

Basal cell carcinoma, squamous cell carcinoma, melanoma (most dangerous); ABCDE

What is the highest risk factor of cervical cancer?

Human Papillomavirus (HPV); 91% of cervical cancers attributed

Risk factors for cervical cancer

-Sexual activity at young age

-Hx of chlamydia

-Oral contraceptives

-3 or more full-term pregnancies

-Pregnancy <20 years old

-Born to someone taking DES (diethylstilvbestrol) during pregnancy

Screening for Cervical Cancer

<25yr — don’t need screening due to healthy immune able to clear or undetectable

25-65 — routine screening (HPV every 5 years; pap test every 3 years)

>65 — doesn’t require if past 10 years are negative OR continue 25 years if prior diagnosis

Lung Cancer

-Small cell carcinoma — less common, more aggressive, metastatic upon diagnosis

-Non-small cell carcinoma — most common (adenocarcinomas, squamous cell carcinoma, large cell carcinoma)

-Easy to spread from lungs due to lymphatic vessels connected to lungs

Risk factors for breast cancer

-Early menstruation to late menopause, family hx, physical inactivity, no pregnancies, dense breast tissue

Screening for Breast Cancer

40-44 — optional yearly mammograms

45-54 — recommended yearly mammograms

>55 — mammograms every 2 years or annually

Sign and symptoms of breast cancer

New lump or mass, skin dimpling (Peau d’orange), retraction of nipple, lumps under arms/collar bone

Risk factors for prostate cancer

Older age (less common <40), race/ethnicity (African), family hx

Prostate Specific Antigen (PSA)

Protein from prostate gland can be used to screen issues that indicates prostate cancer

Factors that Affect PSA levels

BPH, ejaculation, riding a bicycle (irritation to prostate), HRT, age, prostatitis

Colorectal Cancer

Aggressive cancer (more than prostate) that starts as polyps and can be cured if removed early

Risk factors for colorectal cancer

-Inactivity (less cardiac output → less circulation through lymph nodes)

-Diets high in red meat, processed meats, fried foods

-Personal hx of IBD (irritation to gut disrupts cells)

-T2DM

Screening for Colon Cancer

Screening starts at age 45

-Colonoscopy is gold standard (q10 years)

-Cologuard q3 years

Pancreatic Cancer

Highest mortality among all cancers; 92% are adenocarcinoma of exocrine tissues

Signs and Symptoms of Pancreatic Cancer

Abdominal or back pain, weight loss and loss of appetite, digestive issues (indigestion, stool changes, jaundice), new-onset diabetes

Risk factors of pancreatic cancer

Lifestyle (alcohol, obesity, smoking), medical (diabetes, inflammation of pancreas), family hx, ethnicities (African-American, Ashkenazi Jews)

What is the most common type of thyroid cancer?

Papillary

Signs and Symptoms of Thyroid Cancer

Difficulty swallowing, hoarseness, sensation of lump in neck, palpable mass in front of neck

Treatments for Thyroid

Thyroidectomy (replace w/ hormones), radioactive iodine treatment (Iodine-131)

How does radioactive iodine treatment work?

Thyroid is a sponge for iodine, and radioactive iodine is mistaken for normal, so it’s absorbed and kills thyroid cells

Multiple Myeloma

Cancer of plasma cells in bone marrow (osteoclasts causing destruction, pathologic fractures, hypercalcemia)

Leukemia

Cancer of blood and bone marrow due to abnormal WBCs (ALL common in children)

Warning Signs and Symptoms of Acute Leukemia

-Fatigue and pallor (anemia)

-Frequent infections (low WBCs)

-Easy bruising, bleeding, or nosebleeds (low platelets)

-Unexplained weight loss

Anticoagulants

Indicated due to cancer causing hypercoagulative state (DVT, PE, MI, stroke risks)