Best Pediatric Oncologist Ottawa Near Me

4worldlovers: A well-versed Surgical Oncologist, Carolyn Nessim, MD, MSc, FRCSC, FACS works at The Ottawa Hospital, a public academic university teaching hospital offering tertiary care to 1.3 million adults in Ottawa and across Eastern Ontario.

Her main clinical focus is in the treatment of Melanoma and other skin cancers, Soft Tissue Sarcoma/Gastrointestinal Stromal Tumors (GIST) and Gastric Cancer. She also treats Neurodenocrine Tumors and Advanced Cancer/Carcinomatosis.

She is the regional Co-Chair for the Melanoma Communities of Practice within the Ottawa regional cancer program and member of Cancer Care Ontario’s working group for specific guidelines in the treatment of melanoma. She is also the regional Co-Chair for the Gastric Cancer Communities of Practice.

She also serves on staff at the University of Ottawa, as an Associate Professor of Surgery, teaching medical students and residents and is now the Program Director for the Complex General Surgical Oncology (CGSO) Fellowship Program at the University of Ottawa, for subspecialty training in Surgical Oncology.

Dr. Nessim is actively involved in many surgical and cancer societies. She is the Chair of Education and a member of the Executive and Board of the Canadian Association of General Surgeons (CAGS). She is also the President-Elect of the Canadian Society of Surgical Oncology (CSSO) . She is on the Sarcoma Disease Site Working group of the Society of Surgical Oncology (SSO) and a member of the Melanoma Measures Panel and technical expert group of the American Society of Clinical Oncology (ASCO). She is on the Committee on Applicants for the American College of Surgeons (ACS) and is on the Cancer Care Ontario (CCO) Skin Cancer Advisory Board.

4worldlovers:
Cancer is a disease in which some of the body’s cells grow uncontrollably and spread to other parts of the body.


Cancer can start almost anywhere in the human body, which is made up of trillions of cells. Normally, human cells grow and multiply (through a process called cell division) to form new cells as the body needs them. When cells grow old or become damaged, they die, and new cells take their place.

Sometimes this orderly process breaks down, and abnormal or damaged cells grow and multiply when they shouldn’t. These cells may form tumors, which are lumps of tissue. Tumors can be cancerous or not cancerous (benign).


Cancerous tumors spread into, or invade, nearby tissues and can travel to distant places in the body to form new tumors (a process called metastasis). Cancerous tumors may also be called malignant tumors. Many cancers form solid tumors, but cancers of the blood, such as leukemias, generally do not.


Benign tumors do not spread into, or invade, nearby tissues. When removed, benign tumors usually don’t grow back, whereas cancerous tumors sometimes do. Benign tumors can sometimes be quite large, however. Some can cause serious symptoms or be life threatening, such as benign tumors in the brain.

Cancer cells differ from normal cells in many ways. For instance, cancer cells:

Grow in the absence of signals telling them to grow. Normal cells only grow when they receive such signals.

Ignore signals that normally tell cells to stop dividing or to die (a process known as programmed cell death, or apoptosis).

Invade into nearby areas and spread to other areas of the body. Normal cells stop growing when they encounter other cells, and most normal cells do not move around the body.

Tell blood vessels to grow toward tumors. These blood vessels supply tumors with oxygen and nutrients and remove waste products from tumors.

Hide from the immune system. The immune system normally eliminates damaged or abnormal cells.

Trick the immune system into helping cancer cells stay alive and grow. For instance, some cancer cells convince immune cells to protect the tumor instead of attacking it.

Accumulate multiple changes in their chromosomes, such as duplications and deletions of chromosome parts. Some cancer cells have double the normal number of chromosomes.

Rely on different kinds of nutrients than normal cells. In addition, some cancer cells make energy from nutrients in a different way than most normal cells. This lets cancer cells grow more quickly.

Many times, cancer cells rely so heavily on these abnormal behaviors that they can’t survive without them. Researchers have taken advantage of this fact, developing therapies that target the abnormal features of cancer cells. For example, some cancer therapies prevent blood vessels from growing toward tumors, essentially starving the tumor of needed nutrients.

Cancer is a genetic disease—that is, it is caused by changes to genes that control the way our cells function, especially how they grow and divide.

Of damage to DNA caused by harmful substances in the environment, such as the chemicals in tobacco smoke and ultraviolet rays from the sun. (Our Cancer Causes and Prevention section has more information.)

The body normally eliminates cells with damaged DNA before they turn cancerous. But the body’s ability to do so goes down as we age. This is part of the reason why there is a higher risk of cancer later in life.

Each person’s cancer has a unique combination of genetic changes. As the cancer continues to grow, additional changes will occur. Even within the same tumor, different cells may have different genetic changes.

Cancer cells can break away from the original tumor and travel through the blood or lymph system to distant locations in the body, where they exit the vessels to form additional tumors. This is called metastasis.

Cancer is caused by changes to DNA. Most cancer-causing DNA changes occur in sections of DNA called genes. These changes are also called genetic changes.

A DNA change can cause genes involved in normal cell growth to become oncogenes. Unlike normal genes, oncogenes cannot be turned off, so they cause uncontrolled cell growth.

In normal cells, tumor suppressor genes prevent cancer by slowing or stopping cell growth. DNA changes that inactivate tumor suppressor genes can lead to uncontrolled cell growth and cancer.