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P
p53
A "gatekeeper" gene for many cancers. Mutations in this gene tend
to make cells grow without normal controls.
Paclitaxel
A class of chemotherapy drugs that prevents cancer cell division
and growth and promotes cancer cell death.
Paget's
Disease
About three percent of breast cancer patients
have this form of the disease, involving the nipple. Also ee related
article -> Paget's
Disease - A Rare Form of Breast Cancer
Palliative
That which relieves pain and other symptoms of disease, or controls
the disease, without likelihood of cure. In palliative care, the
patient's quality of life and comfort is the focus of concern.
Also
see in Resources -> Facing
a Loss
Palpation
Examining by pressing the surface of the skin to feel the organs
or tissues underneath.
Partial
or Segmental Mastectomy
Removes the tumor, some of the normal breast
tissue around it and the lining over the chest muscle below the
tumor. Some of the axillary lymph nodes may also be removed. Also
see in Resources -> Breast
Cancer Surgery.
Pathologist
A specialist who studies all aspects of disease with an emphasis
on the nature, causes, and development of abnormal conditions, as
well as the structural and functional changes that result from disease
processes A doctor who verifies the identity of diseases by examining
cells and tissue samples.
Pathology
lab
The location, or laboratory, where pathologists study and examine
cell and tissue samples for signs of abnormality and disease.
Peripheral
Stem Cell Transplantation
A method of replacing blood forming cells destroyed
by high dose cancer treatment. Stem cells, immature blood cells
in the circulating blood, are similar to those in the bone marrow.
They are given after treatment to help the bone marrow recover and
resume production of healthy blood cells. Transplantation may be
autologous (the person's blood cells harvested earlier), allogeneic
(blood cells donated by someone else), or syngeneic (blood cells
donated by an identical twin). This procedure may also be called
peripheral stem cell support.
Phase
I Clinical Trial
Following development, in vitro and animal testing,
a drug will be tested on humans. This is the first level of the
clinical trials procedure by which new drugs or combinations of
drugs are tested and approved. A small number of patients are given
a new, experimental treatment. The focus is on determining safety,
dosage and short-term effectiveness.
Phase
II Clinical Trial
The second level of clinical trials in human
beings enrolls a larger number of participants than Phase I. Phase
II trials also focus on effectiveness and on side effects over a
longer period of time.
Phase
III Clinical Trial
The final phase of clinical trials testing.
The experimental treatment is compared with an established testing
treatment for safety, effectiveness, dosage and side effects. These
trials involve large number of patients in many treatment centers.
They are often "double-blinded" so that neither researchers nor
patients know which treatment is being administered. Also see in
Resources -> Breast
Cancer Clinical Trials.
Photo-dynamic
Therapy (PDT)
A new therapy that uses a light source to activate
targeted delivery of a chemotherapy drug. It has been used with
skin metastases with some success.
Physician's
Data Query (PDQ)
A database maintained by the National Cancer
Institute providing the latest treatment information.
Placebo
An substance used in place of an active drug in trials to compare
the effects. It is an established clinical fact that placebos show
some success, possibly as a result of patient expectations. Because
of this "placebo effect," the best clinical trials are "double-blinded,"
meaning that neither patients nor researchers know who is receiving
the drug until the conclusion of the study. Clinical trials where
a new treatment is being tested against established treatments do
not use placebos.
Plastic
Surgeon
A surgeon who specializes in reducing scarring
or disfigurement. Breast reconstructive surgery is performed by
plastic surgeons.
Platelet
Disc shaped blood cell which aids in blood clotting.
Pleura
The membranous lining around the lungs.
Pleural
Effusion
Fluid that has accumulated around the lungs
in the pleural cavity, often the result of metastatic spread of
cancer to the lungs. See effusion.
Polychemotherapy
See Combination
Chemotherapy.
Positive
Predictive Value
The proportion of cases with a positive test
who are found by diagnostic evaluation to have breast cancer. The
higher the positive predictive value, the lower the number of false-
positive results. 10 cancers out of 100 abnormal evaluations equals
a positive predictive value of 10%.
Positron
Emission Tomography Scan (PET Scan)
A computerized image of the metabolic activity
of body tissues used to determine the presence of disease. Studies
report that PET scans are more accurate than mammograms or CAT scans
in discovering very early stage breast cancer
Prevalence
The number of instances of a given disease (e.g. breast cancer)
in a given population at a designated time.
Preventive
Care
Concept of health care in which an emphasis is placed on education
and on early detection of medical conditions. This usually includes
encouraging routine physical examinations, diagnostic tests, immunizations,
physical conditioning and nutrition programs. Also see in Resources
-> Breast
Cancer, Diet & Nutrition. Also see related articles
-> Breast
Cancer & Diet: The Prevention Connection | Watch
Your Weight for Breast Health.
Primary
tumor
Site where a tumor first appeared.
Progesterone
A female hormone.
Prognosis
The likely outcome or course of a disease.
Prosthesis
An artificial replacement of a part of the body. If a total
mastectomy is required to treat breast cancer, many women choose
to wear a prosthetic breast. Also see in Resources -> Breast
Cancer & Prosthetics.
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