Oncology – Chapter 1 Introduction
Definitions
Incidence: the number of new cases of cancer that is registered within a certain
period (mostly 1 year). The incidence is mostly expressed as the number of new
cases per 100.000 inhabitants (persons) each year = the crude incidence rate
Prevalence: comprises all persons who somewhere in time have been diagnosed
with cancer and are still living at a certain date – diverse group ranging from persons
who have been cured from cancer in the past to persons who just have been
diagnosed with cancer
5-year prevalence: all still living cancer patients who have been diagnosed
with cancer during the previous 5 years
Mortality: the number of patients who died as a result of cancer within a certain
period
Survival: the percentage of patients still living at a certain period after diagnosis. The
survival observed is corrected for the expected death within the Dutch population
comparable with respect to gender, age and calendar year.
Basics
The numbers of cancers are increasing because:
1. We have an aging (verouderen) population
2. We can better detect cancer
For female breast cancer is the most common
For male prostate cancer is the most common
Second for both is skin
Third for both in intestine
The cancer mortality also increases because:
1. The population is increasing
2. The population is aging (verouderen)
The survival of cancer increases
Type of cancer related to:
Lung cancer: smoking – men stopped smoking women
started smoking at a later stage
Oesophagus: alcohol drinking
Melanoma: sun exposure
What is cancer
Cancer is a group of diseases – more than 100 cancer types can be
distinguished
Uncontrolled cell growth
Cancer grows invasive and forms metastases
(uitzaaiingen)
Cancer is clonal; all cells in primary tumor arise from a
single cell
, Tumor is a mass of cells and tumors are heterogenous (cancer cells continue
to change and thus show distinct morphological and phenotypic profiles– see
different colours picture above). Heterogenous looks similar to Darwinian
evolution.
o Benign tumours (goedaardig) are no cancer
o Malignant tumours are cancer
Example in endometrium of uterus
Benign tumour: leiomyoma
Malignant tumour: leiomyosarcoma
3 reasons why malignant tumour is life threatening:
1. Invasion of organs disturbs organ function
2. Cancer cells compete with normal cells for nutrients and
oxygen
3. Growing tumours can cause obstructions
Differences between carcinoma, adenocarcinoma, sarcoma and lymphoma
Carcinomas arise from epithelia (±85% of all cancers – so high because epithelia
forms outer surface of the body and outer surface of digestive system
Adenocarcinomas arise from glandular tissue (e.g. breast)
Sarcomas arise from mesodermal tissues (e.g. bone, muscle)
Lymphomas arise from (progenitors of) white blood cells
Carcinogen
Carcinogen is an agent causing cancer
It causes alternations in the DNA of a cell – the accumulation of mutations in the DNA
of a cells causes stepwise development of cancer (carcinogenesis)
Development of cancer (oncogenese/carcinogenesis)
Normal epithelium hyperplasia dysplasia carcinoma in
situ invasive carcinoma lymph node and distant
metastases (uitzaaiingen)
We can characterise tumour progression by:
1. Histological evaluation
2. Molecular markers
a. Chromosomal alterations
b. Gene expression alterations
Normally there is a balance between proliferation, apoptosis and
differentiation
Tumor cell: permanently disturbed balance – this can be caused by
stimulate of cells to proliferate – or this can be caused by inhibition of
differentiation or inhibition of apoptosis
Wound healing: temporary disturbed balance
Oncogenes are the drivers of tumor cell proliferation
Normal genes (proto-oncogenes) which are switched on by mutations; so all
normal cells have genes that have the potential to become oncogenic
Definitions
Incidence: the number of new cases of cancer that is registered within a certain
period (mostly 1 year). The incidence is mostly expressed as the number of new
cases per 100.000 inhabitants (persons) each year = the crude incidence rate
Prevalence: comprises all persons who somewhere in time have been diagnosed
with cancer and are still living at a certain date – diverse group ranging from persons
who have been cured from cancer in the past to persons who just have been
diagnosed with cancer
5-year prevalence: all still living cancer patients who have been diagnosed
with cancer during the previous 5 years
Mortality: the number of patients who died as a result of cancer within a certain
period
Survival: the percentage of patients still living at a certain period after diagnosis. The
survival observed is corrected for the expected death within the Dutch population
comparable with respect to gender, age and calendar year.
Basics
The numbers of cancers are increasing because:
1. We have an aging (verouderen) population
2. We can better detect cancer
For female breast cancer is the most common
For male prostate cancer is the most common
Second for both is skin
Third for both in intestine
The cancer mortality also increases because:
1. The population is increasing
2. The population is aging (verouderen)
The survival of cancer increases
Type of cancer related to:
Lung cancer: smoking – men stopped smoking women
started smoking at a later stage
Oesophagus: alcohol drinking
Melanoma: sun exposure
What is cancer
Cancer is a group of diseases – more than 100 cancer types can be
distinguished
Uncontrolled cell growth
Cancer grows invasive and forms metastases
(uitzaaiingen)
Cancer is clonal; all cells in primary tumor arise from a
single cell
, Tumor is a mass of cells and tumors are heterogenous (cancer cells continue
to change and thus show distinct morphological and phenotypic profiles– see
different colours picture above). Heterogenous looks similar to Darwinian
evolution.
o Benign tumours (goedaardig) are no cancer
o Malignant tumours are cancer
Example in endometrium of uterus
Benign tumour: leiomyoma
Malignant tumour: leiomyosarcoma
3 reasons why malignant tumour is life threatening:
1. Invasion of organs disturbs organ function
2. Cancer cells compete with normal cells for nutrients and
oxygen
3. Growing tumours can cause obstructions
Differences between carcinoma, adenocarcinoma, sarcoma and lymphoma
Carcinomas arise from epithelia (±85% of all cancers – so high because epithelia
forms outer surface of the body and outer surface of digestive system
Adenocarcinomas arise from glandular tissue (e.g. breast)
Sarcomas arise from mesodermal tissues (e.g. bone, muscle)
Lymphomas arise from (progenitors of) white blood cells
Carcinogen
Carcinogen is an agent causing cancer
It causes alternations in the DNA of a cell – the accumulation of mutations in the DNA
of a cells causes stepwise development of cancer (carcinogenesis)
Development of cancer (oncogenese/carcinogenesis)
Normal epithelium hyperplasia dysplasia carcinoma in
situ invasive carcinoma lymph node and distant
metastases (uitzaaiingen)
We can characterise tumour progression by:
1. Histological evaluation
2. Molecular markers
a. Chromosomal alterations
b. Gene expression alterations
Normally there is a balance between proliferation, apoptosis and
differentiation
Tumor cell: permanently disturbed balance – this can be caused by
stimulate of cells to proliferate – or this can be caused by inhibition of
differentiation or inhibition of apoptosis
Wound healing: temporary disturbed balance
Oncogenes are the drivers of tumor cell proliferation
Normal genes (proto-oncogenes) which are switched on by mutations; so all
normal cells have genes that have the potential to become oncogenic
