Download 23.10.2014 - Introduction to Oncology

INTRODUCTION TO ONCOLOGY
“No matter what area of medicine you will be practicing, you will
have something to do with cancer and will care for people with
cancer.”
Source :
http://www.collaborativecurriculum.ca/en/modules/oncologyintro/oncologyfundamentals-introtooncology-01.jsp
• Cancer in India :
India: cancer statistics from IARC GlobalCan (2012)
Population in 2012:
1258.3m
People newly diagnosed with cancer / yr:
1,014,900
Age-standardised rate, incidence per 100,000 people/yr:
94.0
Risk of getting cancer before age 75:
10.1%
People dying from cancer /yr:
682,800
• Estimated age-standardised incidence and mortality rates: men
( INDIA )
• Estimated age-standardised incidence and mortality rates:
women ( INDIA ) :
• CANCER = Crab
• Hippocrates used the Greek word carcinos, meaning crab or
crayfish, to refer to malignant tumors.
• The Greek term carcinoma is the medical term for a malignant
tumor derived from epithelial cells.
Aulus Cornelius Celsus
• It was Celsus who translated the Greek term into the Latin
cancer, also meaning crab.
• He is credited with recording the cardinal signs of inflammation:
calor (warmth), dolor (pain), tumor (swelling) and rubor
(redness and hyperaemia)
• The ancient physician Galen (129-199 BC) coined the term
when he wrote:
• "Just as a crab's feet extend from every part of the body, so in
this disease the veins are distended, forming a similar figure."
• Oncology: (oncos (Greek) = tumour)
• Who are oncologists?
• Oncologists are physicians and surgeons with specialized
education and training in the diagnosis and management of
cancer
• Oncology is not actually depressing, it is an interesting and
exciting field of medicine that provides the opportunity to:
• Work closely with patients and families in the clinical context
• Stay up to date with rapid developments in research
• Participate in clinical trials and research
• Engage at the community level in prevention, early detection
and education programmes
• Contribute to knowledge and clinical practice from the genetic
level to end of life care
• Cancer Prevention :
• Primary Prevention - Population-based health promotion
programmes and campaigns focus on preventing a disease
from occurring and are examples of primary prevention.
• Secondary Prevention - Screening to find asymptomatic or
previously undiagnosed disease or abnormality is secondary
prevention.
•
• Secondary prevention opens opportunities to prevent the
progression of disease before, or early in, the development of
symptoms.
• Secondary prevention can include the physical examination,
laboratory tests or procedures.
• Tertiary Prevention –
• Efforts to decrease the impact of a disease and restore the
person to their pre-morbid level of function are considered to be
tertiary prevention.
• Knowledge about outcomes, prognosis, survival and quality of
life are essential to tertiary prevention.
• The negative impact of disease can be physical as well as
emotional so attention to symptom control and end of life issues
can have a great effect in lessening the impact of disease and
helping people to live their lives.
The Cancer Patient
• Cancer advocacy - is a blog focused on raising awareness
and money for testicular cancer.
•
When asked for a message to medical students this was the
author’s response:
• 1. Cancer does not equal death.
• The medical community needs to do a better job of enforcing
the fact that cancer does not mean death. I was lucky to have
great doctors that did this, but most people I talk to have a
much different perspective.
• 2. Don’t wait to diagnose people with cancer.
• Stress early prevention to your patients early (young age) and
often. Perform self exams (testicle, breast, etc.) and get cancer
screening tests (blood work, etc.) This does not mean
brochures in the waiting room, but it does mean talking to your
patients and letting them know about cancer
3. Patients are “not just a number” and we want and expect a
relationship with our doctors that is opened, honest and two way.
Not just the doctor telling us things, but also have them listen to
our questions and help us get the answers.
Call the patient by their name.
Do not rush patients through their visit. Take time to ensure you
help them to the best of your ability and direct them to proper
places (web, referrals, etc.) when needed.
4. Quality of information and Complexity of information –
The medical community needs to do a better job of giving quality
information and when things are complex they need to “dumb it
down” so the patient can better understand what they are being
told
Do introduce yourself (I once had a doctor come into a room and
start writing on my chest without introducing himself).
Don’t look horrified when I tell you I have metastatic breast
cancer.
Do ask my permission before turning my
test/appointment/treatment into a lesson for a student.
Don’t talk about me as though I am not in the room.
Don’t ask me questions about my treatment that are irrelevant to
the procedure being performed and/or outside your sphere of
knowledge.
Don’t tell me about your aunt/friend/cousin who was
unsuccessfully treated for cancer.
Don’t tell me that the above mentioned aunt/friend/cousin was
unsuccessfully treated with one of the drugs I have told you has
been part of my regimen.
Do thank me for my patience, especially if the
test/treatment/procedure took twice as long as it normally would
because you are still learning how to do it.
CARCINOGENESIS
• The transformation of a normal cell into a malignant cell
involves a series of mutations in genes, termed “oncogenes”,
that directly contribute to neoplasia when their functions are
altered.
• Oncogenes normally function in cellular processes such as cell
division, apoptosis, and differentiation.
• Examples of oncogenes:
• Growth factor receptors
• Tyrosine kinases play essential roles in transmitting mitogenic
signaling pathways.
• Genes that regulate the cell division cycle
• Genes that regulate programmed cell death
• Genes involved in DNA repair
• Tumour genesis is a multistep process that requires the
accumulation of multiple mutations.
• Carcinogenesis is a multistep process, and the development of
fully malignant cancers requires many independent events.
• Weinberg and Hanahan, in 2000, proposed six essential
capabilities found in tumour cells that encompass the
“hallmarks of cancer.”
• Self-sufficiency in growth signals
• Insensitivity to antigrowth signals
• Evasion of apoptosis
• Limitless replicative potential
• Sustained angiogenesis
• Tissue invasion and metastasis
Sustained Angiogensis: the 5th hallmark of cancer
• In normal tissues, the development of new blood vessels is
highly regulated by both positive and negative signals.
• Tumours often outgrow their blood supply and must actively
recruit vasculature in order to continue to grow.
• Without vascularization tumour nodules cannot grow larger than
1-2 mm.
• Tumor cells promote angiogenesis by upregulating the
pathways that promote blood vessel formation (e.g. increased
expression of growth factors such as vascular endothelial and
fibroblast growth factors) and by reducing the activity of
inhibitory pathways.
• Metastases and invasion: the 6th and most unique of the
hallmarks of cancer :
• Tissue invasion is extension from the primary organ beyond
adjacent tissue into the next organ; for example, from the lung
through the pleura into bone or nerve.
• The capacity to metastasize is a highly lethal - most cancer
fatalities are due to metastasis.
• The last of these six capabilities, tissue invasion and
metastasis, is the most heterogeneous and poorly understood.
• Distant metastases are tumour cells that have broken away
from the primary tumour, have traveled to other parts of the
body, and have begun to grow at the new location.
• Distant stage is also called remote, diffuse, disseminated,
metastatic, or secondary disease.
• In most cases there is not a continuous trail of tumour cells
between the primary site and the distant site.
Mechanisms of Metastasis
• 1. Lymph channel spread
• Travel in lymph channels beyond the first (regional) drainage
area to lymph nodes that are considered remote from the
primary site.
• Tumor cells can be filtered, trapped and begin to grow in any
lymph nodes in the body.
2. Hematogenous or blood-borne metastases
• Invasion of blood vessels within the primary tumor allows
escape of tumor cells or tumor emboli which are transported
through the blood stream to another part of the body where it
lodges in a capillary or arteriole.
• At that point the tumor penetrates the vessel wall and grows
into the surrounding tissue.
3. Spread through fluids in a body cavity
• Example: malignant cells rupture the surface of the primary
tumor and are released into the thoracic or peritoneal cavity.
• They float in the fluid and begin to grow on any tissue reached
by the fluid. This type of spread is also called implantation or
seeding metastases.
• Cancer Treatment :
• Cancer treatment can be:
• Curative
• Adjuvant
• Neoadjuvant
• Palliative
• Curative treatment is given with the intent to eradicate all
disease - to cure the patient.
• Adjuvant treatment is additional treatment given after another
treatment such as surgery, it is treatment after all detectable
disease is gone.
• Neoadjuvant treatment is when one treatment is given before
another for example chemotherapy to decrease tumour bulk
before surgery. T
• Treatments given at the same time are given concurrently, for
example chemotherapy and radiation treatment.
• Palliative treatment is given to decrease the severity of disease
or to alleviate specific symptoms, it is not given to cure or
eradicate disease.
Cancer Staging
• Staging is about the extent of a patient’s tumour and the spread
of that tumour …. The severity of the cancer
• Staging determines the anatomic extent of disease.
• Staging is important to determine prognosis, treatment options
and decision making, benchmarks for future comparison and for
ease of discussion.
• Physical examination, laboratory investigations, diagnostic
imaging, surgical and pathological findings all contribute to
staging
• Staging Systems – TNM :
• There are a variety of systems for staging, the most common is
TNM.
• Tumour
• size, extent and location
• usually 0-4
• Nodes
• lymph node involvement
• usually 0-3
• Metastasis
• presence or absence of distant metastases
• usually 0 or 1
Primary Tumor (T)
TX
tumor cannot be evaluated
T0
no evidence of primary tumor
Tis
Regional Lymph Nodes (N)
T1, T2, T3, T4
size and/or extent of the tumor
NX
nodes cannot be evaluated
N0
N1, N2, N3
Distant Metastasis (M)
carcinoma in situ (early cancer that has
not spread locally)
MX
M0
M1
no nodal involvement
nodal involvement (number and/or extent
of spread)
cannot be evaluated
no evidence of metastasis
metastasis
• Cancer Grading :
• Grading is based on the review of tissue by a pathologist and
has to do with how the cancer cells look and thus about how
they are expected to grow and spread.
• Like staging, tumour grade is important when making decisions
about treatment and when talking with patients about prognosis
and the expected course of disease.
• Grading considers:
• structure
• growth
• pattern of cells
• Histological grade or differentiation is about how closely the
tumour cells resemble the cells from which they originated.
• Well-differentiated tumours are considered to be prognostically
more favourable than undifferentiated.
• Nuclear grade refers to the size and shape of the nucleus in
tumour cells and the percentage of tumour cells dividing - those
with a low nuclear grade grow and spread less quickly than
cancers with high nuclear grade.
• Developing a Treatment Plan
• Understanding prognostic factors can help to set an appropriate
treatment plan, each cancer has an independent set of
predictors and each person is unique.
• The following factors are all considered when discussing
prognosis and making a treatment plan:
• Tumour - grade, stage, histology
• Patient - performance status, co-morbidities,
choice/wishes/expressed goals for treatment
• Treatment - therapeutic ratio, available/effective, intent
• The desire for tumour control and the risk of complications must
both be considered.
•
There will always be a risk and benefit to treatment and the
chance of gain is what makes the risk of possible harm
acceptable.
•
In clinically undetectable disease the risk of harm may feel
much greater than when considered in the face of clinically
evident disease.
• There are good outcomes with treatment for some cancers (for
example: ALL, cervix, Hodgkins Lymphoma, testicular germ
cell).
• Most people have an 80-90% cure rate, depending on stage
and other factors.
• Physicians have roles to play in prevention, screening,
diagnosis, treatment, education and research.
•
“ No matter what area of medicine you make your practice,
you will care for people with cancer.”
THANK YOU!
References
• http://www.collaborativecurriculum.ca/en/modules/oncolo
gyintro