C h a p t e r 7
Neoplasia
155
the highest radiation doses are most likely to have
subsequent cognitive difficulties.
73–75
Growth hormone
deficiency in adults is associated with increased preva-
lence of dyslipidemia, insulin resistance, and cardiovas-
cular mortality.
77
Moderate doses of cranial radiation
therapy (CRT) are also associated with obesity, particu-
larly in female patients. For many years, whole-brain
radiation or cranial radiation was the primary method
of preventing CNS relapse in children with acute lym-
phocytic leukemia. Because of cognitive dysfunction
associated with CRT, other methods of CNS prophy-
laxis are now being used.
Delayed sexual maturation in both boys and girls
can result from chemotherapy with alkylating agents or
from irradiation of the gonads. Cranial irradiation may
result in premature menarche in girls, with subsequent
early closure of the epiphyses and a reduction in final
growth achieved. Data related to fertility and health
of the offspring of childhood cancer survivors is just
becoming available.
Vital organs such as the heart and lungs may be
affected by cancer treatment. Children who received
anthracyclines (i.e., doxorubicin or daunorubicin) may
be at risk for developing cardiomyopathy and conges-
tive heart failure. Pulmonary irradiation may cause lung
dysfunction and restrictive lung disease. Drugs such as
bleomycin, methotrexate, and busulfan also can cause
lung disease.
R E V I EW E X E R C I S E S
1.
A 30-year-old woman has experienced heavy
menstrual bleeding and is told she has a uterine
tumor called a
leiomyoma.
She is worried she has
cancer.
A.
What is the difference between a leiomyoma and
leiomyosarcoma?
B.
How would you go about explaining the
difference to her?
2.
Among the characteristics of cancer cells are the
lack of cell differentiation, impaired cell–cell
adhesion, and loss of anchorage dependence.
A.
Explain how each of these characteristics
contributes to the usefulness of the Pap smear as
a screening test for cervical cancer.
3.
A 12-year-old boy is seen in the pediatric cancer
clinic with osteosarcoma. His medical history
reveals that his father had been successfully treated
for retinoblastoma as an infant.
A.
Relate the genetics of the retinoblastoma
(RB) gene and “two hit” hypothesis to the
development of osteosarcoma in this boy.
4.
A 48-year-old man presents at his health care
clinic with complaints of leg weakness. He is a
heavy smoker and has had a productive cough for
years. Subsequent diagnostic tests reveal he has a
small cell lung cancer with brain metastasis. His
proposed plan of treatment includes chemotherapy
and radiation therapy.
A.
What is the probable cause of the leg weakness
and is it related to the lung cancer?
B.
Relate this man’s smoking history to the
development of lung cancer.
C.
Explain the mechanism of cancer metastasis.
D.
Explain the mechanisms whereby chemotherapy
and irradiation are able to destroy cancer cells
while having less or no effect on normal cells.
5.
A 17-year-old girl is seen by a guidance counselor
at her high school because of problems in keeping
up with assignments in her math and science
courses. She tells the counselor that she had
leukemia when she was 2 years old and was given
radiation treatment to her brain. She confides that
she has always had more trouble with learning than
her classmates and thinks it might be due to the
radiation. She also relates that she is shorter than
her classmates and this has been bothering her.
A.
Explain the relationship between cranial
radiation therapy and decreased cognitive
function and short stature.
B.
What other neuroendocrine problems might this
girl have as a result of the radiation treatment?
SUMMARY CONCEPTS
■■
Although most adult cancers are of epithelial
cell origin, most childhood cancers involve
the hematopoietic system, nervous system, or
connective tissue.
■■
Heritable forms of cancer tend to have an
earlier age of onset, a higher frequency of
multifocal lesions in a single organ, and bilateral
involvement of paired organs or multiple primary
tumors.
■■
The early diagnosis of childhood cancers often
is overlooked because the signs and symptoms
mimic those of other childhood diseases.
■■
With improvement in treatment methods, the
number of children who survive childhood
cancer is continuing to increase. As these
children approach adulthood, there is continued
concern that the life-saving therapy they received
during childhood may produce late effects, such
as impaired growth, cognitive dysfunction,
hormonal dysfunction, cardiomyopathy,
pulmonary fibrosis, and risk for second
malignancies.
