Cancer 101

Everything you need to know about cancer

Cancer is likely the scariest diagnosis a person can be given, but what is cancer and why is it so hard to prevent, treat, and cure?

In Canada, 150,000 people are given this diagnosis. There are over 200 different types of cancer, involving almost every type of cell in the body. The causes vary between types and so do the treatments.

Cancer happens when a group of cells grow and multiply in a disorderly and uncontrolled way. Some of these cells invade neighbouring tissues or spread to distant parts of the body. The normal controls on cell division and the normal requirement of similar cells to live together are lost.

Metastasis is the name for cancer cells growing in a part of the body distant from the primary (original) cancer. Sometimes, the metastasis is found before the primary cancer. Cure is when all evidence of cancer is eliminated and there is no chance of it coming back. Cure is more common when cancers are found early, before it has spread, and some types, like lymphoma, have a higher cure rate. Remission is when the cancer becomes smaller with treatment or has disappeared, but we aren’t confident enough about the effectiveness of the treatment to call it a cure.

Recurrence is when signs of the cancer return after treatment is completed and the patient went into remission.

Causes

The cause of cancer is the question of a lot of research. We know that oncogenes play an important role. These genes normally control cell division but damage prevents them from performing this role. How these genes get damaged, how to prevent or repair the damage would be an important discovery.

Risk factors list different ways oncogenes can be damaged:

* Chemicals in cigarette smoke damage cells in the lungs and other organs including bladder and breast

* Ultra violet light damages skin cells

* Human papilloma virus damages the control mechanisms in many types of surface cells (skin, cervix, throat and others)

* Hepatitis B virus damages liver cells

Some risk factors are not as obvious:

* Low fibre diet increases the risk for colon cancer

* Having children late in life increases the risk for breast cancer

A continuing focus has been on preventing cancer by promoting healthy lifestyles and a healthy environment as well as finding cancers early or preventing them through screening. Mammograms find cancers early, before we can feel them but are not perfect. Pap smears find changes in cells of the cervix that can progress to cancer and starts treatment before cancer starts.

Colon cancer starts with polyps. Finding and removing polyps can prevent cancer. This is done with a colonoscopy (the camera on a tube inserted through the anus to look at the bowel) or with a Fecal Occult Blood Test (FOBT) a small smear of feces that is analyzed for blood. If the FOBT is positive, the next step is a colonoscopy.

Treatment Options

Surgery is the first treatment that most cancer patients undergo. Removing the primary cancer and local lymph nodes allows us to better identify the type of cancer and any sign of spreading. Sometimes a biopsy, the removal of part of the primary or of a lymph node gives enough information to start treatment. Cancer cells are out of control. Treatment tries to take advantage of this difference.

There are only a few cell types in our body that multiply on a daily basis: cells of hair, blood and the lining of the digestive tract. Chemotherapy aimed at reproducing cells will kill cancer cells and these cells. Hence the side effects: hair loss, low blood counts causing infections and nausea, vomiting and diarrhea. Chemotherapy can be valuable to kill cancer cells that have spread from the primary area.

Radiation therapy is used to kill cells in a local area by bombarding the area with radiation. It may seem primitive but we are getting better at only affecting a small area and sometimes it means we don’t need to do surgery to remove cancer cells in a difficult spot.

Newer treatments are called biologic. This includes monoclonal antibodies designed to attach only to cancer cells so the immune system will attack and destroy these cells. Hormone blockers are another important way of blocking chemicals that stimulate cancer cell growth.

Adjuvant therapy is aimed at destroying distant spread of cancer even if we can’t see where those cells have gone. It is usually chemotherapy or biologic treatment and can prevent recurrence.

Cancer is not one disease but 200 and all have their own causes and treatments. A family history is good reason to be screened for cancer and to learn the risk factors for that type of cancer to improve your lifestyle and lower your risk. Perhaps one day we won’t just be better at treating cancer but we will have less to treat.

Breast Self Examination

There has been a lot of controversy about women doing breast exams. Breast screening, looking for breast cancer before there are any symptoms, involves a mammogram and breast exam by a health care professional (usually nurse or doctor). The recommendation is an exam every two years. The reality is that many breast cancers are found by women or their partners between screenings.

There are many reasons for breast lumps, however, of the breast lumps removed before the age of 50, 80 per cent are not cancer. That is a lot of lumps and a lot of worry for no good reason. Two studies done in Russia and in China showed that women finding a lump resulted in extra testing, extra surgery but no change in deaths from breast cancer. I think the value of self-exam is that women become more familiar with the texture of their own breasts and more sensitive to changes in symmetry. Especially in women with fibrocystic breasts, the breasts are more lumpy and tender, differentiating between fibrocystic changes and cancer can be difficult on a mammogram and exam and can lead to biopsies. The most common non-cancerous breast lump is a fibroadenoma, which can feel like a marble and can get quite large but never becomes cancer. Cysts are also common and many resolve on their own but some need to be drained.

I recommend that my patients do self-exams four times per year: Christmas, Easter, First of July and Thanksgiving. This way they will remember when their last exam was and when the next is due. It is best to do the exam after the menses because the breasts are more lumpy, swollen and sensitive before menses. Lifting the arm over your head tightens the muscle under the breast and makes a firmer surface to examine the breast tissue against. Using the other hand, you push the breast tissue onto the chest wall and feel the texture. The breasts should feel like tapioca. They are glands and multiple small ducts and sacs that can develop into milk-producing structures. The texture changes with menses and lumps often appear and resolve with the next menses. Now feel in the armpit for any lumps. Lymph nodes that are enlarged, in the armpit, is uncommon and can occur for reasons that have nothing to do with the breasts but should be investigated.

Because breast lumps are common at all ages, I encourage breast self-exam, so the woman remains in control of her body.

Wilma de Groot, MD is a general practitioner practicing family medicine in Etobicoke.