Cancer is defined as a large group of diseases with multiple causes, manifestations, treatments, and prognoses.
Cancer can originate in any organ system and in any cell that can evade regulatory controls over cell proliferation and differentiation.
Essentially, cancer represents a variety of diseases characterized by uncontrolled cellular growth and replication.
CANCER DEVELOPMENT
Cancer begins with a singular rogue cell that has a defect, leading to continuous division instead of performing programmed cell death (apoptosis).
Normal healthy cells maintain a steady state of division, ensuring the production of healthy cells.
A damaged cell typically is instructed to undergo apoptosis, but if it 'misses the memo,' it continues to replicate, leading to rampant, uncontrolled, and disorganized growth resulting in cancer.
METASTASIS
Definition: Metastasis refers to the spread of cancer cells from the original tumor to other parts of the body.
Mechanism of Spread:
Metastasis can occur via the blood and lymphatic systems.
Cancer cells may avoid detection by the immune system or exploit it for survival and growth.
If cancer remains undetected, it can alter the tumor microenvironment, prompting the body to create new blood vessels to nourish the tumor (angiogenesis).
Common pattern of spread: Cancer generally first spreads to adjacent tissues, then to the nearest lymph nodes, and subsequently may access distant sites through the cardiovascular system.
Example: If lung cancer metastasizes to the brain, it is still referred to as lung cancer with metastasis in the brain.
HOW DOES CANCER DEVELOP?
Cancer is classified as a genetic disease (not necessarily inherited).
Causes of Genetic Changes:
Errors during cellular division.
DNA damage from environmental factors (e.g., chemicals, UV radiation).
Mutations passed down from parents.
Acquired Genetic Mutations:
The primary cause of cancer (sporadic cancer) is due to acquired genetic mutations which are not inherited.
Only 5-10% of cancer types are linked to hereditary conditions.
CANCER BURDEN IN THE US
Over 2 million new cancer cases projected for diagnosis in 2024, with about 611,720 anticipated deaths from cancer.
Most common cancers ranked (2024):
Breast
Prostate
Lung/Bronchus
Colon/Rectum
Melanoma
Bladder
Kidney/Renal
Non-Hodgkin Lymphoma
Endometrial
Pancreatic
Leukemia
Thyroid
Prostate, lung, and colorectal cancers account for 48% of new cancer diagnoses in males, while breast, lung, and colorectal cancers account for 51% in females.
The survival rate for cancer patients is rising and projected to continue increasing.
CANCER DISPARITIES IN THE US
Black/African American populations exhibit higher mortality rates for many cancer types compared to other racial/ethnic groups.
Black women face higher mortality from breast cancer despite lower incidence rates than White women.
Rural Appalachia reports significantly higher incidence rates of colorectal, lung, and cervical cancers compared to urban areas.
Black men have more than double the mortality rate from prostate cancer compared to White men.
Education level correlates with cancer mortality rates: individuals with less education are more likely to die prematurely from colorectal cancer.
Higher incidence rates of cervical cancer are noted in Hispanic/Latino, Black/African American, and American Indian/Alaska Native women, with Black women having the highest mortality rates.
American Indians/Alaska Natives show elevated mortality rates from kidney cancer and have the highest incidence and mortality rates for liver cancer.
Rates of smoking and alcohol consumption, both risk factors for cancer, are higher among lesbian, gay, and bisexual youths than heterosexual youths.
ETIOLOGIES
Cancer can be attributed to multiple sources, classified into categories such as viruses, bacteria, physical agents, chemical agents, and genetics.
VIRUSES AND BACTERIA
Approximately 10-12% of global cancers are linked to viral infections.
Examples of virus-related cancers:
Human Papilloma Virus (HPV) - cervical, oral/pharyngeal, anal, vulvar, vaginal, and penile cancers.
Hepatitis B Virus (HBV) - liver cancer.
Epstein-Barr Virus (EBV) - head and neck cancers, lymphoma, stomach cancer.
Helicobacter pylori - stomach cancer.
PHYSICAL AND CHEMICAL AGENTS
Physical agents contributing to cancer include:
Ultraviolet (UV) rays, ionizing radiation, and diagnostic x-ray exposure.
Tobacco smoke (including secondhand smoke) and use of electronic nicotine delivery systems (ENDS).
Such exposures lead to DNA damage, increasing cancer risk by 20-30%.
GENETICS
Genetic factors account for 5-10% of cancers.
Notable hereditary conditions related to cancer include:
Hereditary breast and ovarian cancer syndrome (BRCA1 and BRCA2 mutations).
Multiple endocrine neoplasia syndromes (MEN1 and MEN2).
DIET
Recommendations for diet in relation to cancer prevention include:
Consume at least five servings of fruits and vegetables daily.
Include whole grains in the diet.
Limit sugar intake, especially from sugary drinks.
Minimize consumption of processed foods and red meat.
Limit alcohol intake:
No more than 2 drinks/day for males;
No more than 1 drink/day for females.
Emphasize balance without completely eliminating any foods but focus on fresh foods.
EXERCISE
Engage in 150-300 minutes of moderate-intensity physical activity weekly to maintain health and reduce cancer risk.
SUN SAFETY
Recommended sun safety practices include:
Reduce exposure to the sun between 11 AM - 4 PM.
Apply sunscreen with SPF 30 or higher 30 minutes prior to sun exposure and reapply every 90-120 minutes.
Wear UV protective clothing and a hat.
Avoid tanning beds due to a 20% increased risk of melanoma, which doubles if use begins before age 35.
SCREENING RECOMMENDATIONS
Recommendations for average-risk individuals include:
Colorectal Cancer:
Stool-based screening or visual examination (colonoscopy) beginning at age 45.
Cervical Cancer:
HPV testing every 5 years for women aged 25-65.
Lung Cancer:
Annual low-dose CT scan for people aged 50-80 who smoke or have smoked.
Breast Cancer:
Annual mammography starting at age 40; ultrasound preferred for those with dense breast tissue.
Prostate Cancer:
Informed decision-making regarding testing starting at age 50.
Skin Cancer:
Annual skin check recommended.
DIAGNOSIS AND STAGING
Diagnostic imaging is employed to confirm cancer presence.
Specific tests are designed to identify the cancer type and stage based on tumor size, local invasion, lymph node involvement, and distant metastasis (TNM classification).
Primary Tumor (T):
TX: Cannot be assessed,
T0: No evidence of primary tumor,
Tis: Carcinoma in situ,
T1, T2, T3, T4: Increasing size of tumor.
Regional Lymph Nodes (N):
NX: Unable to assess,
N0: No affected lymph nodes,
N1, N2, N3: Increasing number of nodes involved.
Distant Metastasis (M):
MX: Not assessed,
M0: No distant metastasis,
M1: Distant metastasis present.
ANATOMIC STAGE/PROGNOSTIC GROUPS
Staging guide based on TNM classification for breast cancer:
Stage 0: Tis N0 M0 (DCIS)
Stage I: T1 N0 M0 or T1 N1mi
Stage II: T0 N1 M0 or T1b > 0.5-1 cm
Stage III: T2 N2 M0 or T3 N0 M0
Stage IV: Any T Any N M1 (systemic metastasis)
PHYSICAL EXAM COMPONENTS
A comprehensive head-to-toe physical exam is performed, including:
Performance status evaluation using the ECOG scale (0-5).
Laboratory draws, typically including CBC with differential, BMP, and LFTs.
Imaging studies for cancer detection and treatment response assessment.
CANCER MANAGEMENT
Treatment goals may be curative, control, or palliative:
Curative: Complete eradication of disease.
Control: Relieving symptoms and controlling disease progression.
Palliative: Taking measures to improve quality of life without expecting a cure.
RADIATION TREATMENT
Approximately 60% of cancer patients receive radiation therapy at some point.
It may be used before (neoadjuvant) or after (adjuvant) surgery.
The objective is to damage cancerous cells, particularly DNA.
Dosing considerations:
Sensitivity of the target.
Nearby critical structures.
Types of radiation treatment:
External beam radiation therapy (EBRT) provided in daily fractions.
Internal radiation or brachytherapy involves placing radioactive sources inside or near the tumor.
NURSING MANAGEMENT IN RADIATION
Watch for fatigue, the most common side effect.
Provide skin care by assessing for redness and instructing care using lukewarm water and avoiding harsh products.
Provide antiemetics or analgesics as needed and advise patients on proper clothing to avoid skin irritation.