Oncology: Study of Cancer

When Normal Cells go “Rogue” Cancer is a disease by unrestrained and excessive multiplication of body cells Or in simpler terms Cancer is normal cells that have begun to divide at a rapid and non organized rate

Rogue cell division

Put another way Cancer is a group of disease in which cells are: aggressive (grow and divide without respect for normal cellular limits) invasive (invade and destroy adjacent tissues) sometimes metastatic (spread to other location in the body Nearly all cancers are caused by abnormalities in the genetic material of the transformed cell

Cancer cells compared to Normal

Breast Cancer cells

Probability of Developing or Dying from cancer Increase with age 43% of new cancer cases and 60% of deaths will occur among those who are at least 70 years of age 40% of women and 45% of men will develop cancer in their life time 1 in 4 Canadians will die of cancer 62% of those diagnosed will survive for 5 years (depends on the type of cancer)

Definitions: sorry there are a few Anaplasia: Loss of differentiation of cells Return to a more primitive cell type Lack of orderly arrangement Tumors Masses or growths that arise from normal tissue Neoplasm New growth, benign or malignant tumors

Sorry still on Definitions Remissions Lessening of Symptoms of a disease Carcinogens: agents that cause cancer Chemicals, drugs, radiation, viruses Mutations Change in the DNA of a cell May be caused by exposure to a carcinogen or spontaneously

And two more Differentiation Prognosis Specialization of cells Expected outcome of disease Mortality Morbidity

Now we can move into our discussion on Cancer

Defining a Tumor Malignant Benign Tending to become worse and results in death Benign Non cancerous still can cause death depending on location ie in the brain, heart, kidney

Defining a Tumor Encapsulated (Good) Infiltrative (Bad) Surrounded by a capsule Infiltrative (Bad) Extending beyond normal tissue boundaries

Invasive (Very Bad) Having the ability to enter and destroy surrounding tissue

Metastases (Worst) Spread of malignant tumor to a secondary site

Causes of Cancer: not well understood Environmental Heredity: Retinoblastoma Viruses: HPV, HIV Spontaneous

Retinoblastoma

Environmental Chemicals & Drugs Radiation Hydrocarbons (Smoke) Insecticides Industrial cleaners Insulations Hormones Steroids Mercury Radiation UVA,UVB Skin cancer X-rays Damage to cell DNA Nuclear fusion Chernobyl in the Ukraine Hiroshima Result: Leukemia

Viruses HIV AIDs Human Papilloma Virus Epstein-Barr virus Kaposi Sarcoma Human Papilloma Virus Four strains 6,11,16,18 that cause cervical cancer Epstein-Barr virus Causes Burkitt’s lymphoma

Classification of Cancers Types of tumors Malignant Benign Types of Cancers Carcinomas Sarcomas Mixed-tissue tumors

Benign Grows slowly Encapsulated Differentiated cells Fibrous capsule Differentiated cells Resemble normal mature tissue Do not metastasis Do not form secondary tumors

Malignant: usually grows rapidly Infiltrative & Invasive May be initially encapsulated Anaplasia Resemble primitive or embryonic cells Not capable of mature cellular function Lack orderly arrangement Metastasis Travel through bloodstream or lymphatic system Create secondary tumors

Carcinomas vs Sarcomas Carcinomas: Solid tumors Sarcomas Epithelial tissue Lining of external & internal body surfaces Skin Glands Digestive, urinary Reproductive 50% of tumors in women are carcinomas Supportive & connective tissue Bone Adipose Muscle Cartilage Bone marrow Lymphatic/immune Rare form of cancer Is increasing

Mixed Tissue Tumors Can contain both epithelial and supportive and connective tissue Kidney Ovaries Testes

Factors to determine Prognosis Location of tumor Microscopic appearance Grading Degree of differentiation Extent of spread Metastases Number of secondary tumors Location of secondary tumors

Microscopic Grading: Four grades Grade I well differentiated closely resembles original tissue cells Grade II less differentiated still can determine parent cells

Grading:III-IV Grade III Grade IV Even less differentiated Grade IV Anaplasia Difficult to determine tumor tissue site of origin Example is used in Papanicolaou tests (Pap smears)

Degree of Spread Staging 0-5 Stage I very early cells localized to few cell layers Stage 2 spread to deeper cell layers ? Infiltrate to surrounding tissue

Stage 3-4 Stage 3 Stage 4 infiltrated surrounding tissue contained in the primary cancer site Stage 4 invasive to near by sites

Stage 5-recurrences Stage 5 Recurrent In Canada stage 5 metastases to other organs of the body via the bloodstream or lymphatic system Recurrent cancer cells have reappeared after treatment In Canada stage 5

Lymphatic Involvement Spread to lymph nodes is indicated by the number of nodes involved N1 infiltrate one lymph node N3 infiltrate three lymph nodes

Metastases M1: one site of metastasis M2: two sites of metastasis M3: three sites of metastasis Mx: more than four sites

Tumor size can also by staged T1 small tumor present T2 larger tumor T3 progressive increase in tumor size Tx tumor so invasive unable to determine size

Cancer Coding Grade 3 Stage 4 N3 Tx M3 What does this mean? What is the prognosis? Grade I Stage 2 N0 TI M0

Treatment Surgery Radiation Chemotherapy Biological Therapy

Surgery Encapsulated with limited infiltration and limited metastases Example: stomach, breast, uterus, prostrate Sometimes done to decrease the size of the tumor for palliative reasons Example: decrease pain from tumor pressing on nerve

Radiation Therapy Maximal dose of ionizing radiation to the tumor cells Minimal dose to the surrounding cells Targeted at non-differentiated cells What is the difficulty? Where would this be difficult to do? Solution can be pellets. Say what?

Chemotherapy Drugs target rapidly dividing cells (non differentiated) Block replication to decrease growth Given by Intravenous (IV) and oral route Often used with other treatments Used in T1-4N1-4M1-3 Carcinomas, Sarcomas & Mixed-Tissue Tumors Which body system has cells that normal divide rapidly? (hint SE of chemo)

Biological Agents Using immune cells to target and fight tumor cells Researchers are focusing on NKC and T-cells Hormones: Estrogen is used to treat prostate cancer Creating vaccinations ie Gardasil to boost the immune response Utilizing the MHC on phage cells to create antibodies against cancer cells