Cancer“If you say you can or you can't you are right either way” ― Henry Ford

Definition

It is a malignant neoplasm

Neoplasms are diseases that involve unregulated cell growth.

In cancer, cells divide and grow uncontrollably, forming malignant tumors.

A malignancy (from the latin male “badly” + -gnus “born”) is the tendency of tumors to become progressively worse.

Cancers as a group account for approximately 13% of all deaths each year with the most common being: lung cancer (1.4 million deaths), stomach cancer (740,000 deaths), liver cancer (700,000 deaths), colorectal cancer (610,000 deaths), and breast cancer (460,000 deaths)

Signs and Symptoms

In the beginning it usually produces no symptoms.

Signs and symptoms only appear as the mass continues to grow or ulcerates.

The symptoms that result depend on the type and location of the cancer.

It is not uncommon for people diagnosed with cancer to have been treated for other diseases to which it was assumed their symptoms were due

Local symptoms

Depends on cancer type.

Lung cancer causes coughing, esophageal cancer, difficulty in swallowing.

Changes in bowel habits can be a sign of colorectal cancer.

Masses on the body can, at times, be easily felt.

Ulcerations can cause blood in the urine, stool or appear as a sore that does not heal.

Systemic Symptoms

These symptoms are due to distant effects of the cancer.

Unintentional weight loss.

Fever.

Excessively tired.

Changes to the skin.

Nervous system disorders.

This is a slide showing the abnormal blood of a person with Leukemia. Note the large number of immature, non-functional white blood cells.

Metastasis

Metastasis is when cancer cells break off of a tumor, travel in the blood stream, land somewhere in the body and began to grow another tumor.

Symptoms of this can include enlarged lymph nodes, enlarged liver and speen, facture of effected bones and neurological symptoms.

Most cancer deaths are due to cancer that has metastasized.

Causes

Cancers are primarily an environmental disease.

90-95% of the cases attributed to environmental factors are due to genetics.

Tobacco (25-30%), diet and obesity (30-35%), infections (15-20%), radiation (up to 10%), stress, lack of physical activity and pollutants.

Chemicals

Cancer is caused by DNA mutations that affect cell growth.

Mutagens are substances that cause DNA mutations.

Mutagens that cause cancer are called carcinogens.

Tobacco smoke contains over 50 known carcinogens.

Some carcinogens are not mutagens. Alcohol is an example of that.

Diet and Exercise

Diet, physical inactivity, and obesity are related to 30-35% of cancer deaths.

Physical inactivity has negative affects on the immune and endocrine system.

Diets low in vegetables and high in salt are linked to certain cancers.

Infection

18% of all cancers are related to infectious disease.

Viruses are the main culprits with bacteria and parasites playing a lesser role.

Oncovirus – cancer causing virus.

Example human papillomavirus – causes cervical cancer.

Woman are strongly encouraged to get vaccinated against HPV

Radiation

Up to 10% of invasive cancers are related to radiation exposure.

This includes UV light and radon gas.

This can take up to 40 years to develop.

Children and adolescents are twice as likely to develop radiation induced luekemia.

Prolonged exposure to UV radiation from the sun can lead to melanoma.

Hormones

Some cause cancer to grow.

High Estrogen and progesterone levels linked to breast cancer.

High levels of testosterone linked to prostate cancer.

Hormone replacement therapy has increased # of cancers for that group.

Growth hormone may increase incidence of certain cancers.

Pathiophysiology

Cancer is fundamentally a disease of tissue growth regulation failure.

In order for a normal cell to transform into a cancer cell, the genes which regulate cell growth and differentiation must be altered.

Oncogenes are genes which promote cell growth and reproduction.

Tumor suppressor genes are genes which inhibit cell division and survival.

Errors likely

Replication of the enormous amount of data contained within the DNA will probably result in some errors (mutations).

Error correction and prevention is built into the process, and safeguards the cell against cancer.

If significant error occurs, the damaged cell can "self-destruct" through programmed cell death, termed apoptosis.

If the error control processes fail, then the mutations will survive and be passed along to daughter cells.

DiagnosisMost cancers are

recognized because of the appearance of signs or symptoms or through screening.

This requires the examination of a tissue sample by a pathologist.

People with suspected cancer are investigated with medical tests.

These commonly include blood tests, X-rays, CT scans and endoscopy.

Classification

Cancers are classified by the type of cell that the tumor cells resembles.

These types include:

Carcinoma: Cancers derived from epithelial cells.

This group includes many of the most common cancers, breast, prostate, lung, pancreas, and colon

Chest X-ray of lung cancer.

Sarcoma

Sarcoma: Cancers arising from connective tissue.

(i.e. bone, cartilage, fat, nerve), each of which develop from cells originating in mesenchymal cells outside the bone marrow.

LymphomaLymphoma and leukemia: These two classes of cancer arise from hematopoietic (blood-forming) cells.

These cells leave the marrow and tend to mature in the lymph nodes and blood.

Leukemia is the most common type of cancer in children accounting for about 30%

Prevention

Most cancers are due to environmental factors.

Many of these factors are controllable by lifestyle choices.

Because of this, cancer is considered a largely preventable disease.

More than 30% of cancer deaths could be prevented by avoiding tobacco, being overweight, bad diet, inactivity and air pollution.

MedicationNSAiDs (advil, aspirin, naproxen (alevel)) reduce the risk of colorectal cancer.

Aspirin reduce risk of cancer by 7%.

Vitamins have not been found effective in preventing cancer.

Vaccines (HPV), hepatitis B vaccine, prevent cancers of the cervix and liver.

Screening

Fight cancer with a check up and a check.

Colonoscopy every other year after age 50.

Prostate check every year after age 50.

Mammography for women every two years after age 50.

Skin and mouth check concurrent with visits to the dentist and doctor.

Germ and Blastoma

Germ cancers arise from pluripotent cells in the testicle or ovary.

Blastoma cancers arise from immature precursor cells or embryonic tissue.

Blastomas are more common in children than adults.

Treatment - Surgery

Primary method of treating isoloated solid cancers.

Part of making a definite diagnosis.

Often the entire mass along with related lymph nodes are removed.

For some types of cancer this is all that is needed.

Treatment - Chemotherapy

This is treating cancer with drugs that kill the cancer cells but do no quite kill the good cells.

Traditionally rapidly dividing cells are targeted which will also affect hair bone marrow and digestive tract.

Newer drugs target abnormal proteins in cancer cells.

Another strategy is to use chemicals that cut off the blood supply to the cancer.

Treatment - Radiation

This is using ionizing radiation to kill the cancer cells.

Usually used in conjunction with chemo and surgery.

For certain cancers in the head and neck it is used alone.

For bone cancer it is effective 70% of the time.

Treatment - Brachytherapy

This is placing a tiny radioactive pellet inside or next to the tumor.

Effective for cervical, prostate, breast, and skin cancer.

This is effective because the radiation affects just that small localized area.

Prognosis

Taken as a whole about half of the people treated for cancer will die.

Survival is worse in the poorer countries.

Those who survive have an increased risk of getting it again.

Steve Jobs died of pancreatic cancer

Charles Schulz died of colon cancer

Harmon Killebrew died of esophageal cancer 2012

Hubert Humphrey died of bladder cancer

Steve McQueen died of lung cancer

Humphrey Bogart died of lung cancer

John Wayne died of lung cancer

Madeline Kahn died of ovarian cancer

Robert DeNiro – survived prostate cancer

Cybill Shepherd – survived skin cancer

On February 16, 2013, at the age of 37, Angelina Jolie underwent a preventive double mastectomy after learning she had an 87% risk of developing breast cancer due to a defective BRCA1 gene