Chapter 081. Principles of
Cancer Treatment
(Part 2)
Figure 81-1 Gompertzian tumor growth.
The growth fraction of a tumor declines exponentially over time (top). The
growth rate of a tumor peaks before it is clinically detectable (middle). Tumor size
increases slowly, goes through an exponential phase, and slows again as the tumor
reaches the size at which limitation of nutrients or auto- or host regulatory
influences can occur.
The maximum growth rate occurs at 1/e, the point at which the tumor is
about 37% of its maximum size (marked with an X). Tumor becomes detectable at
a burden of about 10
9
(1 cm
3
) cells and kills the patient at a tumor cell burden of
about 10
12
(1 kg). Efforts to treat the tumor and reduce its size can result in an
increase in the growth fraction and an increase in growth rate.
Principles of Cancer Surgery
Surgery is used in cancer prevention, diagnosis, staging, treatment (for both
localized and metastatic disease), palliation, and rehabilitation.
Prophylaxis
Cancer can be prevented by surgery in people who have premalignant
lesions resected (e.g., premalignant lesions of skin, colon, cervix) and in those
who are at increased risk of cancer from either an underlying disease (colectomy
in those with pancolonic involvement with ulcerative colitis), the presence of

mass is removed with a small margin of normal tissue surrounding it. If an
excisional biopsy cannot be performed, incisional biopsy is the procedure of
second choice. A wedge of tissue is removed, and an effort is made to include the
majority of the cross-sectional diameter of the tumor in the biopsy to minimize
sampling error. The biopsy techniques that involve cutting into tumor carry with
them a risk of facilitating the spread of the tumor. Core-needle biopsy usually
obtains considerably less tissue, but this procedure often provides enough
information to plan a definitive surgical procedure. Fine-needle aspiration
generally obtains only a suspension of cells from within a mass. This procedure is
minimally invasive, and if positive for cancer it may allow inception of systemic
treatment when metastatic disease is evident, or it can provide a basis for planning
a more meticulous and extensive surgical procedure.