Statements on Certain Cancer Issues

December 19, 2002

Objective:

To promote a unified and consensual concept on cancer issues among OMMC staff that will be used as a guide in management of patients with cancer in OMMC and that will serve as OMMC’s public health information and education on cancer.

Basic Issues

What is cancer?

Cancer is a condition that affects the health of an individual.

Cancer is a disease that can

Affect the physical, mental, and social well-being of a person;

Cause disability;

Cause death; and

Affect the socioeconomic productivity of a person, a family, and a community.

Cancer is a disease characterized by uncontrolled growth of cells with potential to invade adjacent organs and spread to distant organs and regions in the body.

Cancer represents not one disease but more than 100 different kinds and types.

Usually an affected person is afflicted with one cancer. However, more than one cancer of different kinds occurring in one person is possible and not rare.

There are different kinds and types of cancer.

Different kinds of cancer are based on the organ of origin of the uncontrolled growth of cells.

Examples:

Organ of origin	Kinds of cancer
Brain	Brain cancer
Thyroid gland	Thyroid cancer
Breast	Breast cancer
Blood	Blood cancer
Eye	Eye cancer
Bone	Bone cancer
Lymph node	Lymph node cancer
Intestine	Intestinal cancer
Ovary	Ovarian cancer
Etc.

For each kind of cancer based on organ of origin, there are different types based on specific cells of origin in the organ affected, uncontrolled growth pattern, and behavior (growth rate).

Examples of types of cancer based on cells of origin:

Organ of origin	Cell of origin	Type of Cancer
	Epithelial cells	Carcinoma
	Mesenchymal cells	Sarcoma
Thyroid	Follicular cells	Papillary and follicular carcinoma
	Parafollicular cells	Medullary carcinoma
Breast	Ductal cells	Ductal carcinoma
	Lobular cells	Lobular carcinoma
Skin	Melanocytes	Melanoma
	Epidermal cells	Squamous and basal cell carcinoma

Examples of types of cancer based on uncontrolled growth pattern:

Well-differentiated

Moderately differentiated

Undifferentiated

Examples of types of cancer based of behavior:

Slow growth and spread rate

Moderate growth and spread rate

Fast growth and spread rate

There are other classifications of types of cancer, such as primary (the origin) and secondary or metastatic (the spread site).

Just as no two persons are exactly the same in terms of physical features, personality, and behavior;

Just as no two patients are exactly the same in terms of disease manifestations and disease behavior,

NO two cancers are the exactly the same, even if categorized under the same organ of origin, cells of origin, growth pattern, and behavior.

What causes cancer?

The basic problem of cancer is the uncontrolled growth of cells.

Normally, there are genetic elements and mechanisms within the cells that regulate their growth, death, and regeneration. In cancer, there is the occurrence or development of an abnormality in the genetic elements associated with a breakdown in the genetic mechanisms that normally control cell growth.

Development of abnormality in the genetic elements that lead or predispose to cancer can either be inherited or acquired. Acquired genetic abnormality is more common than inherited abnormality.

Acquired genetic abnormality starts with a genetic predisposition compounded by environmental carcinogens (cancer-causing elements such as radiation, chemicals, and virus). The exact mechanism by which environmental carcinogens cause genetic abnormality that eventually leads to uncontrolled growth of cells is still unknown.

What is the implication of the present knowledge of cancer causation on prevention?

Since the exact mechanism by which environmental carcinogens cause genetic abnormality and the exact nature of the gene (whether abnormal or normal but with predisposition at birth) of any one person is not known, there is no absolute way of prevention.

At the moment, the best preventive effort that can be done is to avoid the environmental carcinogens or so-called risk factors. And the best way to avoid environmental carcinogens is to live in a healthy environment and to live a healthy lifestyle.

To live in a healthy environment means avoiding smoke-filled rooms, polluted atmosphere, and areas that have radiation hazards and chemical irritants.

To live a healthy lifestyle means avoiding excess in anything and everything (indulge in moderation only) particularly stress and food/fluid/drug intake; avoiding toxic substances and chemicals, particularly smoking, prohibited drugs, and alcoholic drinks; working, exercising and relaxing regularly; living a balanced life; and most important of all, learning how to be contented and always feel happy.

What is the implication of the present knowledge of cancer causation on treatment?

Since the exact cause is not known, at present, all treatment modalities being done (such as surgery, radiation therapy, and chemotherapy) target the cancer and not on the cause.

Thus, all treatment modalities that do not control the cause of cancer will always have a certain percentage of failure in the form of cancer recurrence.

What is cancer cure?

With the exact cause of cancer being not known and with the treatment modalities targeting the cancer and not the cause, post-treatment recurrence is always possible and anticipated. In this sense, there is no such thing as absolute cancer cure.

However, the operational definition being used by most oncologists or cancer scientists for cancer cure is in terms of disease free interval with negligible chance of recurrence from the same kind of cancer. Example, based on track records, persons with a head and neck cancer who undergo curative treatment usually have recurrence within 2 years and usually have a negligible chance of recurrence after 5 years of remission. Thus, a particular person who has a head and neck cancer who does not have a recurrence for 5 years after a curative treatment can be considered to be cured of his head and neck cancer.

Different cancers have different estimates or track records of the disease free interval with negligible chance of recurrence.

What is a curative cancer treatment?

Curative cancer treatment is one that is done with intent to cure as contrasted to palliative cancer treatment, one that is done with just the intent to palliate, realizing and accepting that cure is practically impossible.

A realistic intent to cure is present or should be instituted if there is a known treatment regimen (single or combined modality) that will achieve complete response of all evident cancers. If not, then the realistic objective of treatment is just to palliate.

Likewise, a realistic intent to cure is present or should be instituted for cancers in their early stage. For cancers in the advanced stage, the realistic objective of treatment is just to palliate.

What is a palliative cancer treatment?

Palliative cancer treatment is a treatment regimen that relieves symptoms, such as pain, but is not expected to cure the cancer. The main purpose is to improve the patient's quality of life.

Palliative treatment is done for patients with cancers, usually those in the advanced stage, with statistically very little chance for cure.