Oncology Notes 2025
Chapter 1 Introduction: The Nature of Cancer
Lecture 1 – 31st of May 10:00-10:45
The incidence of cancer is defined to be the number of new cases that are registered within a certain
period (mostly 1 year). The incidence is often expressed as the number of new cases per 100.000
inhabitants/people each year The crude incidence rate. This is useful to compare between regions
or to follow the incidence in time.
The prevalence of cancer comprises all people who at any time have been diagnosed with cancer:
and are still alive at a certain date. This includes people who have been cured of cancer in the past to
people who just have been diagnosed with cancer. The period can be unlimited but also defined.
The 5-year prevalence on January 1st, 2025 comprises all still living people who have been diagnosed
with cancer since January 1st, 2020.
The mortality of cancer comprises the number of patients who died as a result of cancer within a
certain period (usually 1 year). It doesn’t include patients with cancer who died of a different cause. It
does not matter when the diagnosis of cancer was made, often this was in a different year. (Hence,
incidence and mortality cannot be directly linked).
Survival is the percentage of patients still alive at a certain period after diagnosis. It is relative and
approaches “cancer-specific survival”. The survival is corrected for the expected death within a
comparable population (with respect to country/region, gender, age and calendar year).
Cancer incidence in 2024 was around 130.000. This means that 130.000 new patients were diagnosed
with cancer in the Netherlands in 2024.
The incidence has about doubled in 30 years. The incidence has always been higher for men than
women. Not a super large difference but there is a difference.
130.000/18.000.000= around 1/138 chance per year. 1/138 times 85 years = 62% chance of getting
cancer in your life. Around 2021 there was a small dip: corona, people didn’t go to the practitioners.
There are differences in cancer incidence across different types of cancers.
Gastrointestinal was always increasing but is now “stabilizing”
Skin cancer has increased a lot
o Exposure to the sun has increased a lot since World War 2, it takes time to develop
cancer.
Lung cancer: the majority of cases were men, but now women are catching up. Until the 50s
men were mainly smoking, after that, it became more normal for women also to smoke.
1
,Cancer prevalence and mortality in the Netherlands
The 5-year prevalence was around 420.000 (2.4%) in 2024. The mortality (2023) was around 46.000.
The mortality has not increased in the last 7 years, because of better treatment and earlier
diagnostics. This is also the reason why incidence has increased more than mortality, (earlier
diagnostics), you might not have known it and it might be slow cancer, and you would not have died
from it because you are already old so died from another cause.
Every decade survival improved.
The 5-year survival doubled from around 35% to around 70% in 50 years.
There are regional differences in cancer mortality. When looking at the picture, in the darker blue
color countries, cancer is the number 1 cause of death. The lighter blue countries have cardiovascular
diseases as the number 1 reason of death and cancer as the second cause. In the red countries,
cancer is the 6th or 7th reason, with other diseases being the primary causes.
Cancer is a group of diseases. There are more than 100 cancer types distinguished (or even every
tumor is different?). Cancer is characterized by: uncontrolled cell growth, invasive, forming
metastases.
If it is not invasive or metastasizing, we don’t call it cancer. A tumor is a mass of cells, can also be
benign, and those are not cancer. Only malignant tumors are cancer.
2
,Why is a malignant tumor life-threatening?
Invasion of organs disturbs organ function
Cancer cells compete with normal cells for nutrients and oxygen
Growing tumors can cause obstructions
What is the difference between carcinoma, adenocarcinoma, sarcoma and lymphoma?
Carcinomas arise from epithelia (around 85% of all cancers)
Adenocarcinomas arise from glandular tissues (e.g. breast)
Sarcomas arise from mesodermal tissues (e.g. bone, muscle)
Lymphomas arise from (progenitors of) white blood cells
The incidence of carcinomas is much higher than that of other cancers because carcinomas are
derived from epithelial cells. Those cells align our body from in and outside. So the epithelial cells are
most exposed to carcinogens.
A carcinogen is an agent causing cancer (compound, radiation, etc.). A carcinogen causes alterations
in the DNA of a cell. Cancer cells contain many alterations in the DNA. The accumulation of
mutations in the DNA of a cell causes stepwise development of cancer (oncogenesis, carcinogenesis)
Development of cancer (oncogenesis) genetic progression model:
Normal epithelium hyperplasia dysplasia carcinoma in situ invasive carcinoma lymph
node and distant metastases
Cancer is clonal, but tumors are heterogeneous. Cancer is clonal because they all start form a single
cell, all daughter cells. But the daughter cells might have different mutations so it will become a
heterogenous mass.
Cancer is a disease of the genome, but is it inheritable?
No, cancer that develops in somatic cells will not be passed to the next generation of offspring.
Cancer in germ cells does not produce viable offspring. However, some inherited germline mutations
can increase the chance of developing cancer and can be passed to the next generation of offspring.
Why does the risk of developing cancer increase at older age?
An accumulation of mutations in the DNA is needed for the development of cancer
It is a matter of chance and time (exposure to carcinogens)
The incidence of cancer is increasing due to longer life expectancy.
Main characteristics of cancer: “hallmarks of cancer” defined by Hannahan and Weingberg.
3
, Heterogenous environment, more than just tumor cells
Cancer requires de-differentiation and proliferation, block in differentiation and block in apoptosis
For the growth of a tumor: oncogenes on, tumor suppressor genes off.
Characteristics of cancer cells:
Cancer cells have a different morphology
Cancers cells can grow at low serum concentration
Cancer cells show no/decreased contact inhibition
Cancer cells can grow without substrate for attachment
Factors playing a role in development of cancer
Environment (soot, sunlight, asbestos).
Diet (fruit and vegetables, fish) and exercise.
Alcohol (head and neck, breast).
Smoking (>80 carcinogens; 40% of all cancer deaths).
Reproduction, contraception, hormone replacement therapy.
Viruses (sexual transmittable)
Own metabolism (by-products of metabolism and errors in DNA replication)
Treatment of cancer
The “conventional” modalities of cancer treatment: basic principles: surgery, radiotherapy,
chemotherapy, prevention of cell division = cytostatic effect, killing of cancer cells = cytotoxic effect
What are the limitations of conventional chemotherapy?
Adverse events/toxicity on normal tissues
The therapeutic index/window of most chemotherapeutics is relatively small
In the book “therapeutic index” but it is the therapeutic window. the difference between
maximum tolerated dose (MTD) and the minimum dose needed to exert anti-cancer activity.
4
Chapter 1 Introduction: The Nature of Cancer
Lecture 1 – 31st of May 10:00-10:45
The incidence of cancer is defined to be the number of new cases that are registered within a certain
period (mostly 1 year). The incidence is often expressed as the number of new cases per 100.000
inhabitants/people each year The crude incidence rate. This is useful to compare between regions
or to follow the incidence in time.
The prevalence of cancer comprises all people who at any time have been diagnosed with cancer:
and are still alive at a certain date. This includes people who have been cured of cancer in the past to
people who just have been diagnosed with cancer. The period can be unlimited but also defined.
The 5-year prevalence on January 1st, 2025 comprises all still living people who have been diagnosed
with cancer since January 1st, 2020.
The mortality of cancer comprises the number of patients who died as a result of cancer within a
certain period (usually 1 year). It doesn’t include patients with cancer who died of a different cause. It
does not matter when the diagnosis of cancer was made, often this was in a different year. (Hence,
incidence and mortality cannot be directly linked).
Survival is the percentage of patients still alive at a certain period after diagnosis. It is relative and
approaches “cancer-specific survival”. The survival is corrected for the expected death within a
comparable population (with respect to country/region, gender, age and calendar year).
Cancer incidence in 2024 was around 130.000. This means that 130.000 new patients were diagnosed
with cancer in the Netherlands in 2024.
The incidence has about doubled in 30 years. The incidence has always been higher for men than
women. Not a super large difference but there is a difference.
130.000/18.000.000= around 1/138 chance per year. 1/138 times 85 years = 62% chance of getting
cancer in your life. Around 2021 there was a small dip: corona, people didn’t go to the practitioners.
There are differences in cancer incidence across different types of cancers.
Gastrointestinal was always increasing but is now “stabilizing”
Skin cancer has increased a lot
o Exposure to the sun has increased a lot since World War 2, it takes time to develop
cancer.
Lung cancer: the majority of cases were men, but now women are catching up. Until the 50s
men were mainly smoking, after that, it became more normal for women also to smoke.
1
,Cancer prevalence and mortality in the Netherlands
The 5-year prevalence was around 420.000 (2.4%) in 2024. The mortality (2023) was around 46.000.
The mortality has not increased in the last 7 years, because of better treatment and earlier
diagnostics. This is also the reason why incidence has increased more than mortality, (earlier
diagnostics), you might not have known it and it might be slow cancer, and you would not have died
from it because you are already old so died from another cause.
Every decade survival improved.
The 5-year survival doubled from around 35% to around 70% in 50 years.
There are regional differences in cancer mortality. When looking at the picture, in the darker blue
color countries, cancer is the number 1 cause of death. The lighter blue countries have cardiovascular
diseases as the number 1 reason of death and cancer as the second cause. In the red countries,
cancer is the 6th or 7th reason, with other diseases being the primary causes.
Cancer is a group of diseases. There are more than 100 cancer types distinguished (or even every
tumor is different?). Cancer is characterized by: uncontrolled cell growth, invasive, forming
metastases.
If it is not invasive or metastasizing, we don’t call it cancer. A tumor is a mass of cells, can also be
benign, and those are not cancer. Only malignant tumors are cancer.
2
,Why is a malignant tumor life-threatening?
Invasion of organs disturbs organ function
Cancer cells compete with normal cells for nutrients and oxygen
Growing tumors can cause obstructions
What is the difference between carcinoma, adenocarcinoma, sarcoma and lymphoma?
Carcinomas arise from epithelia (around 85% of all cancers)
Adenocarcinomas arise from glandular tissues (e.g. breast)
Sarcomas arise from mesodermal tissues (e.g. bone, muscle)
Lymphomas arise from (progenitors of) white blood cells
The incidence of carcinomas is much higher than that of other cancers because carcinomas are
derived from epithelial cells. Those cells align our body from in and outside. So the epithelial cells are
most exposed to carcinogens.
A carcinogen is an agent causing cancer (compound, radiation, etc.). A carcinogen causes alterations
in the DNA of a cell. Cancer cells contain many alterations in the DNA. The accumulation of
mutations in the DNA of a cell causes stepwise development of cancer (oncogenesis, carcinogenesis)
Development of cancer (oncogenesis) genetic progression model:
Normal epithelium hyperplasia dysplasia carcinoma in situ invasive carcinoma lymph
node and distant metastases
Cancer is clonal, but tumors are heterogeneous. Cancer is clonal because they all start form a single
cell, all daughter cells. But the daughter cells might have different mutations so it will become a
heterogenous mass.
Cancer is a disease of the genome, but is it inheritable?
No, cancer that develops in somatic cells will not be passed to the next generation of offspring.
Cancer in germ cells does not produce viable offspring. However, some inherited germline mutations
can increase the chance of developing cancer and can be passed to the next generation of offspring.
Why does the risk of developing cancer increase at older age?
An accumulation of mutations in the DNA is needed for the development of cancer
It is a matter of chance and time (exposure to carcinogens)
The incidence of cancer is increasing due to longer life expectancy.
Main characteristics of cancer: “hallmarks of cancer” defined by Hannahan and Weingberg.
3
, Heterogenous environment, more than just tumor cells
Cancer requires de-differentiation and proliferation, block in differentiation and block in apoptosis
For the growth of a tumor: oncogenes on, tumor suppressor genes off.
Characteristics of cancer cells:
Cancer cells have a different morphology
Cancers cells can grow at low serum concentration
Cancer cells show no/decreased contact inhibition
Cancer cells can grow without substrate for attachment
Factors playing a role in development of cancer
Environment (soot, sunlight, asbestos).
Diet (fruit and vegetables, fish) and exercise.
Alcohol (head and neck, breast).
Smoking (>80 carcinogens; 40% of all cancer deaths).
Reproduction, contraception, hormone replacement therapy.
Viruses (sexual transmittable)
Own metabolism (by-products of metabolism and errors in DNA replication)
Treatment of cancer
The “conventional” modalities of cancer treatment: basic principles: surgery, radiotherapy,
chemotherapy, prevention of cell division = cytostatic effect, killing of cancer cells = cytotoxic effect
What are the limitations of conventional chemotherapy?
Adverse events/toxicity on normal tissues
The therapeutic index/window of most chemotherapeutics is relatively small
In the book “therapeutic index” but it is the therapeutic window. the difference between
maximum tolerated dose (MTD) and the minimum dose needed to exert anti-cancer activity.
4
