There are many texts and references that attempt to define cancer. The simplest definition is from the American Cancer Society (ACS). According to the ACS, cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells.
Cancer is a result of changes in the body's cells that cause them to grow out of control.
- A tumor is a mass, or collection, of cells.
- Tumors can be benign or malignant:
- Benign tumors are noncancerous.
- Malignant tumors are cancerous.
- Metastasis is when malignant tumors travel to areas away from the original or primary site and grow in other different parts of the body
If cancer is not controlled and treated effectively, it can result in death.
Cancer OverviewCancer, also called malignancy, is an abnormal growth of cells. There are more than 100 types of cancer, including breast cancer, skin cancer, lung cancer, colon cancer, prostate cancer, and lymphoma. Cancer appears in humans of all ages; but, cancers that occur in children below 18 years of age are mainly different than those that occur in adults. Symptoms vary depending on the type. Cancer treatment may include chemotherapy, radiation, and/or surgery.
Site of Cancer OriginThis classification describes the type of tissue in which the cancer cells begin to develop. Here are some common examples of site of origin classification:
- Adenocarcinoma: originates in glandular tissue
- Blastoma: originates in embryonic tissue of organs
- Carcinoma: originates in epithelial tissue (i.e., tissue that lines organs and tubes)
- Leukemia: originates in tissues that form blood cells
- Lymphoma: originates in lymphatic tissue
- Myeloma: originates in bone marrow
- Sarcoma: originates in connective or supportive tissue (e.g., bone, cartilage, muscle)
- Mixed Types: These have two or more components of the cancer.
Cancer DiagnosisA biopsy (removal of tissue for microscopic evaluation) is preferred to establish, or rule out, a diagnosis of cancer.
Usually, a biopsy, along with with advanced imaging technologies, can confirm and locate the presence of cancer in its primary site and secondary sites if metastasized. A cancer's primary site may determine how the tumor will progress; spread, or metastasize; and may also determine related symptoms that are most likely to occur. A secondary site refers to the body part where metastasized cancer cells develop to form secondary tumors.
The pathologist mainly gives a pathological grade to a tumor according to how malignant the tissue looks under the microscope that will finally confirm the presence of cancer. Cancers are additional classified according to stage.
Cancer StagingStaging is the classification of the extent of the disease of cancer. There are several types of staging methods. We will mainly rely on the below numerical system that will often be used to classify the extent of disease.
|Stage 0||Cancer in situ (limited to surface cells)|
|Stage I||Cancer limited to the tissue of origin, evidence of tumor growth|
|Stage II||Limited local spread of cancerous cells|
|Stage III||Extensive local and regional spread|
|Stage IV||Distant metastases|
Cancers that Develop in ChildrenThe types of cancers that occur most often in children are different from those seen in adults. The most common cancers of children are:
- Brain and spinal cord tumors
- Wilms tumor
- Lymphoma (including both Hodgkin and non-Hodgkin)
- Bone cancer (including osteosarcoma and Ewing sarcoma)
Other types of cancers are rare in children, but they do happen occasionally. In very rare cases, children may also develop cancers that are much more common in adults.
Leukemia is cancer of the blood or bone marrow that is responsible of producing blood cells in the human body. A person, who is diagnosed to have leukemia, suffers mainly from an abnormal production of white blood cells, generally referred to as leukocytes. Leukemia is the most common childhood cancers.
Types of leukemiaChronic and Acute
Leukemia is divided into four large groups. It can be Acute, which is a rapidly progressing disease that results in the accumulation of immature cells in the marrow and blood, or Chronic, which progresses more slowly and allows more mature cells to be produced.
Lymphocytic and Myelogenous
Leukemia is also divided into subcategories according to the type of affected blood cell. If the cancerous alteration occurs in the type of marrow that produces lymphocytes, the disease is called lymphocytic leukemia. A lymphocyte is a kind of white blood cell that is mostly found inside the vertebrae immune system of the body. If the cancerous alteration occurs in the type of marrow cells that go on to produce red blood cells, other types of white cells, and platelets, the disease is called myelogenous leukemia. As a conclusion there are two groups of Leukemia Chronic or acute; Lymphocytic or Myelogenous and therefore we have four main types of leukemia, as illustrated below:
- Acute Lymphocytic Leukemia (ALL)
- Chronic Lymphocytic Leukemia (CLL)
- Acute Myelogenous Leukemia (AML)
- Chronic Myelogenous Leukemia (CML)
Acute Lymphocytic Leukemia (ALL) and Acute Myelogenous Leukemia (AML) are the most common types of Leukemia in children.
Signs and symptoms:
- Petechiae: diffuse red to purple spots on the body, caused by a minor hemorrhage due to poor blood clotting as immature white blood cells crowd out blood platelets, which are essential to stop bleeding.
- Frequent infections: This is due to suppressed white blood cells production responsible for fighting off infection.
- Anemia: due to the shortage of production of good red blood cells.
- Dyspnea: labored respiration due to anemia.
- Pallor: Pale skin color caused by illness.
- Night sweats
- Flu-like symptoms
- Weight loss in case the liver or spleen is enlarged this gives a feeling of fullness and decrease in appetite.
- Headache is more common in cases with the CNS (central nervous system) involvement in cancer.
Treatment of Leukemia:Leukemia needs to be treated typically with chemotherapy as soon as diseases confirmed. Bone marrow transplant may be considered is some cases.
Brain and spinal cord tumors are the second most common cancers in children. There are many types of brain tumors mostly starting in the lower parts of the brain such as the cerebellum, that helps coordinate movement, or brain stem, that helps control breathing and the heart beating. Tumors in the Spinal cord, that helps control muscles, sensation or feeling, and bladder and bowel control, are less common than brain tumors in children.
Although brain tumors rarely spread to other parts of the body, most of them can spread through the brain and spinal cord tissue. The main concerns with brain and spinal cord tumors are how fast they grow and spread through the rest of the brain and/or the spinal cord, and whether they can be removed or treated effectively. However both benign and malignant tumors can be life threatening as they can exercise pressure on surrounding intact nerves and tissues and destroy them.
Parts of the brain and spinal cord:The main areas of the brain include the cerebrum, cerebellum, and brain stem.
Signs and symptoms of Brain and Spinal Cord Tumors in Children:
- Trouble speaking
- A change of mood such as depression
- A change in personality
- Weakness or paralysis in part of the body
- Changes in vision, hearing, or other senses
Other types of Brain and spinal cord tumors:
- Gliomas: Glioma is a general term for a group of tumors that start in glial cells.
- Astrocytomas: These tumors start in cells called astrocytes, a kind of glial cell.
- Oligodendrogliomas: These tumors start in brain glial cells.
- Ependymomas: These tumors start in the ependymal cells that line the ventricles or central canal of the spinal cord.
- Mixed gliomas: These tumors combine more than one cell type.
- Brain stem gliomas: This term refers to the location of the tumor, rather than the type of cell it originates in.
- Primitive neuroectodermal tumors (PNETs): These tumors start in primitive immature cells of the central nervous system called neuroectodermal cells. The central nervous system is the complex of nerve tissues that controls the activities of the body. In vertebrates it comprises the brain and spinal cord.
- Medulloblastomas: are PNETs that start in the cerebellum.
- Craniopharyngiomas: These tumors may press on the pituitary gland and the hypothalamus, causing hormone problems. These tumors also start very close to the optic nerves; as a result, they can also cause vision problems. This makes them hard to remove completely without damaging the childâ€™s vision or hormone balance.
- Choroid plexus tumors: These rare tumors start in the choroid plexus within the ventricles of the brain.
- Schwannomas (neurilemmomas): starts in Schwann cells that surround and isolate cranial nerves and other nerves.
- Meningiomas: These tumors start in the meninges, the layers of tissue that surround the outer part of the brain and spinal cord.
- Chordomas: These tumors start in the bone at the base of the skull or at the lower end of the spine.
- Germ cell tumors: These rare tumors develop from germ cells, which normally form eggs in women and sperm in men.
- Pituitary tumors: Tumors that start in the pituitary gland
- Neuroblastomas: see below in separate section
- Lymphomas: see below in separate section
- Magnetic resonance imaging (MRI) which can identify the site of important areas of the brain and how close they are to the tumor.
- Magnetic resonance spectroscopic imaging (MRSI) which help surgeons direct their biopsies to the most abnormal areas in the tumor and to help doctors direct radiation and evaluate the effects of chemotherapy or targeted therapy.
- Fluorescence-guided surgery. That requires contrast to be swallowed few hours prior to surgery. The dye is taken up mainly by the tumor, which then glows when the specialist looks at it under special lighting from the operating microscope. This lets the physician better separate tumor from normal brain tissue.
- The endoscope is passed through a hole made in the back of the nose, which allows the surgeon to operate through the nasal passages and limits the potential damage to the brain. A similar technique can be used for some tumors in the ventricles, where a small opening in the skull near the hairline serves as the point of endoscope insertion. The use of this technique is limited by the tumorâ€™s size, shape, location, and by how many blood vessels it encompasses.
Brain and spinal cord treatment:
Radiation therapy including:
- Stereotactic radiosurgery,
- 3-dimensional conformal radiation therapy (3D-CRT),
- Intensity modulated radiation therapy (IMRT),
- Proton beam therapy
- Adjuvant chemotherapy: Chemo is given right after surgery to either delay radiation therapy (particularly in infants) or to decrease the radiation dose needed to treat the tumor.
- High-dose chemotherapy and stem cell transplant: allows higher doses of chemo to be given than would normally be possible. First, blood stem cells are removed from either the childâ€™s blood or the bone marrow and are stored in a deep freeze. The child is then treated with very high doses of chemo. The blood stem cells are then thawed and infused back into the body, where they settle in the bone marrow and start making new blood cells.
- Getting chemotherapy directly to tumors: via new approaches using small tubes are placed into the tumor in the brain through a small hole in the skull during surgery
- Targeted drugs: Are newly developed drugs that target changes in tumor cells caused by gene which helps them grow.
- Angiogenesis inhibitors: Are newly developed drugs that attack the new blood vessels created by tumors to keep their cancerous cells nourished
- Hypoxic cell sensitizers: Refers to the use of newly developed drugs that increase the oxygen content in the tumor, which makes tumor cells more likely to be killed by radiation therapy if the drugs are given before treatment.
- Immunotherapy: Refers to the use of vaccination to make the bodyâ€™s own immune system fight the tumor.
Surgical interventionincluding craniotomy and other type of tumor resection is to be considered as part of treatment too.
Neuroblastoma is a type of cancer that starts in some very immature forms of nerve cells found in an embryo or fetus. This type of cancer occurs most often in infants and young children. It is rarely found in children older than 10 years. This type of cancer can start anywhere but mainly it is originated in the abdomen where it is noticed as swelling.
Signs and Symptoms of Neuroblastoma:
- Large lump or swelling in the childrens abdomen
- Weight loss due to feeling full
- Having belly pain
- Tumors in the chest or neck that can be seen or felt usually painless
- Constant diarrhea
- High blood pressure (causing irritability)
- Rapid heartbeat
- Reddening (flushing) of the skin
- Sweating etc...
Neuroblastoma diagnostic tests:
a) Laboratory testing including:Blood and urine catecholamine tests.
The 2 catecholamine metabolites most often measured are:
- Homovanillic acid (HVA)
- Vanillylmandelic acid (VMA)
b) Imaging tests:
- magnetic fields,
- sound waves,
- radioactive substances
- Computed tomography (CT or CAT) scan
- CT-guided needle biopsy
- Magnetic resonance imaging (MRI) scan
- MIBG scan: This scan uses a form of the chemical meta-iodobenzylguanidine (MIBG) that contains a small amount of radioactive iodine.
- Positron emission tomography (PET) scan: with the use of a radioactive substance (usually a type of sugar related to glucose, known as FDG) is injected into the blood.
- Bone scan: that can help show if a cancer has spread to the bones
- Surgical biopsies: including Incisional (open or surgical) biopsy and/or Needle (closed) biopsy
- Bone marrow aspiration and biopsy: (A bone marrow aspiration and biopsy are usually done at the same time).
The types of treatment used for neuroblastoma can include:
- Surgical interventions of tumor removal
- Chemotherapy administration
- Radiation therapy: see above
- High-dose chemotherapy/radiation therapy and stem cell transplant
- Retinoid therapy: which is the use of chemicals related to vitamin A that help some cancer cells mature into normal ones.
- Immunotherapy: see above
Wilms tumor, also known nephroblastoma is a type of cancer that starts in the kidneys.
Most Wilms tumors are unilateral affecting only one kidney. Wilms tumors mainly become relatively large before they are detected. Such tumors tend to occur in young children with average age at about 3 to 4 years.
Signs and Symptoms of Wilms Tumor:
- Loss of appetite
- Shortness of breath
- Blood in the urine
- High blood pressure
- Imaging tests including ultrasounds, x-rays, CTâ€™s, MRIâ€™s, Bone scan etc...
- Surgical biopsies
- Lab tests
Hodgkin lymphoma is a type of lymphoma. This type of cancer that starts in white blood cells called lymphocytes which are part of the immune system. Hodgkin disease can start almost anywhere since lymphoid tissues are found in many different parts of the body. Most often it starts in lymph nodes of the upper part of the body mainly in the chest, in the neck, or under the arms.
There are 2 kinds of lymphomas:
- Hodgkin disease
- Non-Hodgkin lymphoma
Signs and Symptoms:
- Lumps under the skin
- Fever without an infection
- Night sweats
- Weight loss
- Cough, trouble breathing, chest pain
- Physical exam
- Lab test
- Imaging tests including pet-scan
- Biopsies including Bone marrow aspiration and biopsy and fine needle aspiration (FNA)
- Radiation therapy
- High-dose chemotherapy and stem cell transplant
Sarcomas are cancers that develop from connective tissues in the body, such as muscles, fat, bones, the linings of joints, or blood vessels.
Common sites of RMS include:
- Head and neck
- Urinary and reproductive organs
- Arms and legs
- Chest and abdomen
Signs and Symptoms:The symptoms of RMS depend mainly on where the tumor location, size, and if it has spread to other parts of the body.
- Lump or swelling
- Abdominal pain
- Bone pain
- Constant cough
- Weakness Weight loss
Retinoblastoma is a cancer that starts in the retina, the back part of the eye. It is more common in infants and very young children than in older children with average age of children of 2 years old. It rarely occurs in children older than 6 years of age.
Signs and Symptoms:
- White pupillary reflex as, the pupil often appears white or pink instead
- Vision problems
- Eye pain
- Redness of the white part of the eye
- Bleeding in the front part of the eye
- Bulging of the eye
- A pupil that doesnâ€™t get smaller when exposed to bright light
- A different color in each iris
- Physical exam
- Imaging tests including ultrasound, MRIâ€™s, CTâ€™s, bone scan etc...
- Surgical biopsies including Lumbar puncture and Bone marrow aspiration and biopsy
- Genetic testing
- Radiation including intensity modulated radiation therapy (IMRT)
- Other including cryotherapy, laser therapy (photocoagulation), thermotherapy
What Is Osteosarcoma?Osteosarcoma is a type of cancer that starts in the bones. As for the Ewing family of tumors is a group of cancers that start in the bones or nearby soft tissues that share some common features. These tumors can develop at any age, but they are most common in the early teen years.
Signs and Symptoms:
- Pain in the affected bone
- Pain and swelling
- Bone fractures (breaks)
- Physical exam
- Imaging tests including x-rays, MRIâ€™s, CTâ€™s, bone scan, pet-scan, chest x-ray etc...
- Surgical biopsies
- Lab tests
- Targeted drugs