NURS 336 unit 3

cancers

cancers, in general

-Involves uncontrolled growth of cells

-Higher incidence in men over age 55 (mostly prostate / breast)

-Second-leading cause of death in the US

-Many people can survive cancer tho

-screening is ESSENTIAL

immune cells’ roles in fighting cancer

• Cytotoxic T cells: Kill tumor cells & produce cytokines

• Natural killer cells and activated macrophages lyse tumor cells

• B cells produce antibodies that bind to tumor cells

roles of the immune system in fighting cancer

goal: to reject or destroy cancer cells

• Some cancer cells have changes on their surface antigens called Tumor-Associated Antigens (TAAs) → the immune system recognizes these as cancerous thru Immunologic Surveillance

• Thru Immunologic Escape, cancer cells evade our immune system (suppressor T cells, blocking antibodies bind TAAs, preventing recognition)

genetic link to cancers

2 types of normal genes that can be affected by mutations:

• Protooncogene – Fxn: regulates normal cellular processes. Mutations can alter them to function as oncogenes (these can change a normal cell to a malignant one)

• Tumor-suppression genes – Fxn: regulates cell growth & cell cycle. Mutations can make them inactive.

  • Ex- BRCA-1, BRCA-2, APC gene

classifications of tumors: benign vs malignant

-Benign – well-differentiated (early cancer, restricted to one area)

-Malignant – can invade and metastasize in other areas of the body (vascularized & grow quickly)

histologic classifications of cancer

Appearance of the cells and the degree of differentiation

• Grade 1 – differs slightly from normal cells and are well differentiated

• Grade 2 – more abnormal and moderately differentiated

• Grade 3 – More abnormal and poorly differentiated

• Grade 4 – Immature and primitive and undifferentiated; cell of origin is difficult to determine

• Grade 5 – cannot be assessed

clinical staging of cancers

Determines the extent of the disease process of the cancer

• Stage 0 – cancer in situ (localized and shows no tendency to invade or metastasize)

• Stage I – tumor growth limited to the tissue of origin

• Stage II – limited local spread

• Stage III – extensive local and regional spread

• Stage IV – metastasis (invasion of other tissues)

oncofetal antigens & tumor markers

Malignancy signs, found in both cancer cells & fetal cells. Occurs as a result of the cells un-differentiating into stem cells

• Ex: CEA (colon cancer), AFP (liver cancer), CA-125 (ovarian cancer), CA19-9 (pancreatic and gallbladder cancer), PSA (prostate cancer), CA 15-3 & CA 27-29 (breast cancer)

Tumor markers: kRAS (colon), HER-2 (breast)

Early warning signs of Cancer (CAUTION)

C- change in bowel / bladder

A- a lesion that won’t heal

U- unusual bleeding / discharge

T- thickening or lump you can feel

I – indigestion or difficulty swallowing

O- obvious changes in a mole

N- nagging cough or persistent hoarseness

diagnoses of cancer

BIOPSY is key

Cytology studies, Chest x-ray, CBC, chemistry profile, Liver function studies, Endoscopic examinations, PET scan, Tumor / genetic markers, Molecular receptor status (ex- estrogen and progesterone), Bone Marrow examination

TNM classification system

determines the extent of the cancer disease process

T - Tumor size

• T 0 – no evidence of primary tumor

• Tis – Carcinoma in situ (all histologic features of cancer except invasion)

• T 1-4 – Ascending degrees of increases in tumor size

N - Degree of regional spread to the lymph nodes

• N 0 – No evidence of disease in lymph nodes

• N 1-4 – Ascending degrees of nodal involvement

• N x – Regional lymph nodes unable to be assessed clinically

M- Metastasis

• M 0 – No evidence of distant metastases

• M 1-4 – Ascending degrees of metastasis, including distant nodes

rTNM

• Restaging done after extensive Tx

stages of cancer

1. Initiation (stage I) → mutations in cellular genes

2. Promotion (stage II) → reversible proliferation of the altered cells (lowering dietary fat, obesity, cigarette smoking, alcohol consumption, and stress)

   1. A complete carcinogen –> initiator and promotor (smoking)

   2. Latent period (1-40 yrs) comprises both the initiation and promotion stages (period where there are cancer cells present, but no mass). For the disease to become clinically evident, the cell must reach a palpable 1cm mass

3. Progression (Stage III) → Increased growth rate, invasiveness, & metastasis of the tumor

   1. Metastasis is the spread of the cancer from the primary site to a distant site

chemical carcinogens

Certain chemicals over a period of time have a greater incidence of cancer

• ex- benzene, arsenic, formaldehyde, and certain drugs

• increase risk of leukemia

Tx for radiation exposure

• Take potassium iodide to decrease risk of thyroid cancer

• Don’t use any moisturizer -> it retains the radiation

• The younger the person, the higher their risk of getting radiation cancer

• Wash the body, Burn their clothes

• After a radiation bomb, stay inside for 14 days (stock up on food & water)

viral carcinogens

Certain viruses, termed oncogenic, induce malignant transformation in the cells they infect.

• Burkitt’s lymphoma – from EBV (mono can increase risk of this)

• Kaposi’s sarcoma – from AIDS

• Hepatocellular carcinoma – from hepatitis B virus

• Cervical, anal, head/ neck cancer - from Human papillomavirus

radiation carcinogen

• Exposure to radiation damages the cells

• Higher incidence of cancer in occupations like radiologists, radiation chemists, aircrews, and uranium miners. 

• Leukemia & lymphoma -> After the Atomic Bomb in Hiroshima/Nagasaki

• Thyroid cancer -> from receiving head and neck radiation

• Skin cancer -> UV radiation from tanning beds

biology of cancer: proliferation & differentiation

proliferation: the body’s cells are programmed to divide every so many days, depending on if they are healthy. In cancer, the cell will divide regardless whether or not it’s healthy → so if it’s mutated, this mutation will carry on. Cells that multiply with these problems create a pyramid effect

• healthy cells also have contact inhibition-bladder cells remain in the bladder, etc. This doesn’t happen with cancer cells

differentiation: in a biopsy of a healthy cell, it clearly looks like the type of cell that it is. But in cancer, it has mutated so much that its original type of cell is unrecognizable (it has un-differentiated, possibly into a stem cell)

• well-differentiated cell = good sign

• un-differentiated/ de-differentiated cell = a bad sign, the cancer has spread & they can’t tell the original site

cancer Tx in the cell cycle

chemo Txs target cells in a specific stage of their cell cycle. This is why chemo tx often includes multiple drugs, to target cancer cells in multiple stages