Jacob's Journey - Childhood Cancer Notes

Jacob's Journey

Technical notes on Jacob's cancer.

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Here is a collection of haphazard technical notes that I collected and wrote during Jacob's cancer treatment. I used it as my way helping make sense of the information overload that we experienced. I've included it here on the off-chance it might be useful to someone else.

Jacob's tumor (lymphoma) is located in his posterior nasopharynx. You can’t see your own nasopharynx directly, but if you look inside your mouth in the mirror, it lies above your soft palate (the soft area at the back of the roof of your mouth) and uvula (the dangly bit) at the back of the mouth.

Lymphomas can be found in the nasopharynx. They are cancers of immune system cells called lymphocytes, cells that are normally found in the nasopharynx. To understand what lymphoma is, it helps to know about the body's lymph system.

The lymph system (also known as the lymphatic system) is composed mainly of lymphoid tissue, lymph vessels, and fluid called lymph (a clear fluid containing waste products and excess fluid from tissues). Lymphoid tissue is formed by several types of immune system cells that work together to help the body fight infections. Lymphoid tissue is found in many places throughout the body. The adenoids, which are a lymphoid tissue, are located in the posterior area of the nasopharynx and is probably where the cancer started. Most of the cells found in lymphoid tissue are lymphocytes, a type of white blood cell. The 2 main types of lymphocytes are B lymphocytes (B cells) and T lymphocytes (T cells). Both types can develop into lymphoma cells, but B-cell lymphomas are much more common than T-cell lymphomas in the United States. Normal T cells and B cells do different jobs within the immune system. B cells normally help protect the body against germs (bacteria or viruses) by making proteins called antibodies. The antibodies attach to the bacteria or viruses and attract other immune system cells that surround and digest the antibody-coated germs. Antibodies also attract certain blood proteins that can kill bacteria.

Lab tests identify B cells and T cells by certain substances on their surfaces. Some substances are found only on B cells, and others are found only on T cells. There are also several stages of B-cell and T-cell development (or maturation) that can be recognized by these lab tests. This information is helpful because each type of lymphoma tends to resemble a particular subtype of normal lymphocytes at a certain level of development. Determining the type of lymphoma a person has is the first step in considering treatment options.

There are 2 main types of lymphomas. Hodgkin lymphoma and Non-Hodgkin lymphoma. These 2 types of lymphoma can usually be distinguished from each other by looking at the cancer cells under a microscope. In some cases, sensitive lab tests may be needed to tell them apart.

Jacob's tumor is a type of cancer known as Burkitt Lymphoma. This type makes up about 1% to 2% of all lymphomas. It is named after the doctor who first described this disease in African children and young adults. The cells are medium sized and epress the CD20 cell surface antigen (which is targeted by the chemotherapy drug, rituximab). This is a very fast-growing lymphoma. In the African variety, it often starts as tumors of the jaws or other facial bones. In the more common types seen in the United States, the lymphoma usually starts in the abdomen, where it forms a large tumor mass. It can also start in the ovaries, testes, or other organs, and can spread to the brain and spinal fluid. Close to 90% of patients are male, and the average age is about 30.

Axial CT slice showing the lymphoma protruding into Jacob's nose.
I was shocked by the size of it (3.7 x 4.1 x 4.9 cm).

After going through four months of intense chemotherapy, further PET/CT scans showed that Jacob was in remission. There was a residual polypoid mass that his physicians suspected was left over scar tissue from the tumor. On January 8, 2009, five and a half months after being diagnosed with cancer, Jacob had the residual mass in his nasopharynx surgically removed. Below are the images captured by the ENT physician during the procedure:

The top two images show the nasal polyp as seen in a mirror held near the soft palate. The bottom two images are viewed through the nasal passage (left image is before excision, right image is after excision and shows the cauterized area).

Jacob's Mediport

This is Jacob's actual mediport. We were able to keep it after it was removed. The device was placed under his skin on his chest. A tube went from the mediport under his skin, up his chest to his jugular vein, down the vein and into the right atrium of his heart. It allowed for the best venous access that would thoroughly mix medication with his blood thereby reducing possible irritation of his vasculature. Since it was under his skin it stayed sterile when not in use and reduced the chance of him picking up an infection.

To learn more about Mediports visit the Wikipedia article.

Chemotherapy

The ability of most chemotherapy to kill cancer cells depends on its ability to halt cell division. Usually, the drugs work by damaging the RNA or DNA that tells the cell how to copy itself in division. If the cells are unable to divide, they die. The faster the cells are dividing, the more likely it is that chemotherapy will kill the cells, causing the tumor to shrink. They also induce cell suicide (self-death or apoptosis).

Chemotherapy is most effective at killing cells that are rapidly dividing. Unfortunately, chemotherapy does not know the difference between the cancerous cells and the normal cells. The "normal" cells will grow back and be healthy but in the meantime, side effects occur. The "normal" cells most commonly affected by chemotherapy are the blood cells, the cells in the mouth, stomach and bowel, and the hair follicles; resulting in low blood counts, mouth sores, nausea, diarrhea, and/or hair loss. Different drugs may affect different parts of the body.

Methotrexate exerts its chemotherapeutic effect by being able to counteract and compete with folic acid in cancer cells resulting in folic acid deficiency in the cells and causing their death. This action also effects normal cells which can cause significant side effects in the body, such as: low white, red and platelet blood cell counts, hair loss, mouth sores, difficulty swallowing, diarrhea, liver, lung, nerve and kidney damage. These complications and side effects of methotrexate can be either prevented or decreased by using Leucovorin, which provides a source of folic acid for the body's cells. Leucovorin is normally started 24 hours after methotrexate is given. This delay gives the methotrexate a chance to exert its anti cancer effects.

Cytarabine belongs to the category of chemotherapy called antimetabolites. Antimetabolites are very similar to normal substances within the cell (in this case one of the DNA bases). When the cells incorporate cytarabine into the cellular metabolism, they are unable to divide because the drugs acts like a nucleotide and stops DNA polymerization. Antimetabolites are cell-cycle specific. They attack cells at very specific phases in the cycle.

Hematology 101

Neutrophils (aka polymorphonuclear cells, PMN's, granulocytes, segmented neutrophils, or segs) fight against infection and represent a subset of the white blood count. Neutropenia by definition is an ANC below 1800/mm3 (some sources use a lower value).

-- Absolute neutrophil count (ANC) of 1000-1800: Most patients will be given chemotherapy in this range. Risk of infection is considered low. (Mild neutropenia)
-- Absolute neutrophil count (ANC) of 500-1000: Carries with it a moderate risk of infection.
-- Absolute neutrophil count (ANC) of less than 500: Severe neutropenia - high risk of infection.

Remember that a reduced WBC is known as leukopenia.

The WBC consists of the following (differential):
Lymphocytes: 20-40%
Neutrophils: 50-60%
Basophils: 0.5-2%
Eosinophils: 1-4%
Monocytes: 2-9% (average: 4%).

The ANC (Absolute Neutrophil Count) refers to the total number of neutrophil granulocytes present in the blood.
ANC = Total WBC x (% "Segs" + % "Bands")
Equivalent to: WBC x ((Segs/100) + (Bands/100))

Normal value: ≥ 1500 cells/mm3.
Mild neutropenia: ≥1000 - <1500/mm3.
Moderate neutropenia: ≥500 - <1000/mm3.
Severe neutropenia: < 500/mm3.

Normal Lab Values
WBC 5.0-14.5 10e3/mcL
RBC 4.0-5.2 10e6/mcL
HGB 11.5-13.5 g/dL
HCT 34-40%
PLT Count 145-400 10e3/mcL
ANC Auto 1500- /mcL

Links:

www.chemocare.com

American Cancer Society
http://www.cancer.org

CureSearch unites the world's largest childhood cancer research organization, the Children's Oncology Group, and the National Childhood Cancer Foundation with the mission to cure childhood cancer.
http://www.curesearch.org

Cancer survivors: Managing late effects of cancer treatment
http://www.mayoclinic.com/health/cancer-survivor/CA00073

Quackwatch: A Guide to Quackery, Health Fraud, and Intelligent Decisions
Operated by Stephen Barrett, M.D. There is a lot of non-sense out there promoting itself as a cure for this or that ailment. This site debunks a lot of these fraudulent claims.
http://www.quackwatch.org/
Cancer Treatment Watch: the oncology specific site associated with Quackwatch
http://www.cancertreatmentwatch.org/

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