228
Unit 3
Applying concepts from the nursing process
Benign and malignant cells differ in many cellular growth
characteristics, including the method and rate of growth,
ability to metastasise or spread, general effects, destruction of
tissue and ability to cause death. These differences are sum-
marised in Table 11-2. The degree of anaplasia (cells that lack
normal cellular characteristics and differ in shape and organi-
sation with respect to their cells of origin, i.e. lack of differen-
tiation of cells) ultimately determines the malignant potential.
Characteristics of malignant cells
Despite their individual differences, all cancer cells share
some common cellular characteristics in relation to the cell
membrane, special proteins, the nuclei, chromosomal abnor-
malities, and the rate of mitosis and growth. The cell mem-
branes are altered in cancer cells, which affects fluid movement
in and out of the cell. The cell membrane of malignant cells
also contains proteins called
tumour-specific antigens (TSA)
(e.g. carcinoembryonic antigen [CEA] and prostate-specific
antigen [PSA]), which develop as they become less differenti-
ated (mature) over time. These proteins distinguish the malig-
nant cell from a benign cell of the same tissue type. They may
be useful in measuring the extent of disease in a person and
in tracking the course of illness during treatment or relapse.
Malignant cellular membranes also contain less fibronectin, a
cellular cement. They are therefore less cohesive and do not
adhere to adjacent cells readily.
(18,560 cases), bowel cancer (15,840), breast cancer (14,680),
melanoma of the skin (12,510) and lung cancer (11,280)
(Australian Institute of Health Welfare [AIHW], 2012). The
most commonly registered cancer in 2009 in New Zealand was
prostate cancer (16.1%), followed by colorectal and cancer
of the breast. Among males, prostate cancer was the most
commonly registered cancer (30.2% of male registrations), and
among females, breast cancer was the most commonly regis-
tered cancer (28.4% of all female registrations (New Zealand
Ministry of Health, 2009).
The Australian Institute of Health Welfare [AIHW] (2012)
reported that in 2003 the risk of a cancer diagnosis for men
before the age of 75 was 1 in 3 and before 85 was 1 in 2. For
women, the risk was 1 in 4 before the age of 75 and a 1 in 3 risk
before the age of 85. The cancer death rate among Indigenous
Australians was estimated to be 40% higher than the total
non-Indigenous population. In New Zealand, Ma¯ori have a
disproportionate risk of cancer (Cancer Control New Zealand
[CCNZ], 2005). In 2005, 1377 cancer registrations (598 males
and 779 females) and 760 deaths (369 males and 391 females)
from cancer were Ma¯ori and for Pacific peoples, there were 575
registrations (267 males and 308 females) and 244 deaths (115
males and 129 females). Ma¯ori males have a cancer death rate
that is 53.2% higher than the non-Ma¯ori male rate, while the
Ma¯ori female rate is 70% higher than the non-Ma¯ori female
rate.
With global population rates for ageing increasing, it is
estimated that by 2020 there will be between 15–20 million
new cases of cancer per year and 10–12 million deaths (World
Health Organization [WHO], 2003). However, in the devel-
oped world, cancer incidence and death rates stabilised during
the 1990s and have continued to fall as improvements in
health promotion, diagnosis and treatment are made. This
trend has been seen in the Australian statistics with the death
rate for all cancers falling from 210 persons per 100,000 in
1986 to 181 persons per 100,000 in 2004 (AIHW, 2012).
Pathophysiology of the malignant
process
Cancer is a disease process that begins when an abnormal cell is
transformed by the genetic mutation of the cellular DNA. This
abnormal cell forms a clone and begins to proliferate abnor-
mally, ignoring growth-regulating signals in the environment
surrounding the cell. The cells acquire invasive characteristics
and changes occur in surrounding tissues. The cells infiltrate
these tissues and gain access to lymph and blood vessels, which
carry the cells to other areas of the body. This phenomenon is
called
metastasis
(cancer spread to other parts of the body).
Proliferative patterns
During the lifespan, various body tissues normally experience
periods of rapid or proliferative growth that must be distin-
guished from malignant growth activity. Several patterns of
cell growth exist:
hyperplasia
,
metaplasia
,
dysplasia
,
anaplasia
,
and
neoplasia
(see Glossary).
Cancerous cells are described as
malignant
neoplasms.
They demonstrate uncontrolled cell growth that follows no
physiological demand.
Benign
(causing little or no harm) and
malignant growths are classified and named by tissue of origin,
as described in Table 11-1.
Epithelial
Surface
Glandular
Connective
Fibrous
Adipose
Cartilage
Bone
Blood vessels
Lymph vessels
Lymph tissue
Muscle
Smooth
Striated
Neural tissue
Nerve cell
Glial tissue
Nerve sheaths
Meninges
Haematological
Granulocytic
Erythrocytic
Plasma cells
Lymphocytic
Monocytic
Endothelial tissue
Blood vessels
Lymph vessels
Papilloma
Adenoma
Fibroma
Lipoma
Chondroma
Osteoma
Haemangioma
Lymphangioma
Leiomyoma
Rhabdomyoma
Neuroma
Glioma (benign)
Neurilemmoma
Meningioma
Haemangioma
Lymphangioma
Squamous cell carcinoma
Adenocarcinoma
Fibrosarcoma
Liposarcoma
Chondrosarcoma
Osteosarcoma
Haemangiosarcoma
Lymphangiosarcoma
Lymphosarcoma
Leiomyosarcoma
Rhabdomyosarcoma
Neuroblastoma
Glioblastoma, astrocytoma,
medulloblastoma,
oligodendroglioma
Neurilemmal sarcoma
Meningeal sarcoma
Myelocytic leukaemia
Erythrocytic leukaemia
Multiple myeloma
Lymphocytic leukaemia or
lymphoma
Monocytic leukaemia
Haemangiosarcoma
Lymphangiosarcoma
Table 11-1 Tumours and Tissue Types
Tissue type
Benign tumours Malignant tumours
Reproduced with permission from Porth, C. M. & Matfin, G. (2009).
Pathophysiology:
Concepts of altered health states
(8th ed.). Philadelphia: Lippincott Williams & Wilkins.
