Biology (Holt)

bind to DNA. Mutant p53 protein cannot bind to

DNA, thus cell division occurs unchecked.

Mutations that result in cancer, whether they

involve oncogenes or tumor suppressor genes,

can occur spontaneously. Mutations can also be

induced by factors in the environment, such as

X-rays and ultraviolet radiation, cigarette smoke,

asbestos, and even by the human papilloma virus

and the hepatitis B virus.

Surviving Cancer

In the United States, about one of every five

deaths—more than half a million each year—are

caused by cancer. Only heart disease kills more

people. The number of new cancer cases and the

number of cancer deaths for every 100,000 per-

sons have decreased over the past 10 years. The

death rates for children and adults under the age

of 50 have decreased dramatically.

Some kinds of cancer kill more people than

others. Lung cancer is the number one cancer

killer. Colorectal cancer, breast cancer, and

prostate cancer are the next most common.

Cancer survival is measured by the percentage of

cancer patients who survive a specific number of

years. Five-year cancer survival rates for com-

mon cancers are shown in the table at the right.

Cancer survival is influenced by the type of

cancer and by the stage at which a cancer is diag-

nosed. For example, the 5-year survival rate for

colorectal cancer diagnosed in its first stage is 96

percent. When diagnosed in its fourth and most

advanced stage, however, the 5-year survival rate

is only 5 percent. Cancer screenings and early

detection of cancers, such as those of the breast

and colon, greatly increase a person’s chances of

surviving cancer. 

Science • Technology • Society 139

Cancer

Treatment

Career

Science and Society

1 Use library resources or the Internet to research fac-
tors that increase the risk of cancer. List some of the
risk factors and what types of cancer they could lead
to. Why are factors in lifestyle or the environment dif-
ficult to identify? How can people protect them-
selves from exposure to known risk factors?

Technology

2 The type, size, stage, and location of a person’s can-

cer determines which cancer treatment is most

appropriate for that person. A patient should take an

active part in researching and developing an

informed treatment plan. Using library resources or

the Internet, research and identify some therapies

used to treat cancer. What are some advantages and

disadvantages to these treatments?

Oncologist

Analyzing STS Issues

Profile

O

ncologists are cancer specialists—physicians

who care for people who have been diagnosed

with cancer.

Job Description

Oncologists may begin to treat a patient soon after

he or she is diagnosed with cancer. Oncologists work

cooperatively with surgeons, radiologists, and other

physicians to devise the best combination of treat-

ments for the particular patient and cancer being

treated. Oncologists may manage radiation treatment

and/or chemotherapy, as well as other types of can-

cer therapy.

Science/Math Career Preparation

Biology Microbiology

Chemistry Biochemistry

Genetics Mathematics

Lung tumor

A malignant tumor differs from the

tissue that surrounds it.

Cancer site 5-year survival (percent)

Prostate (males only) 98

Breast (females only) 88

Colorectal 63

Leukemia 47

Brain 32

Lung 15

Pancreas 4

All cancers 64