Principles of Oncology
Dr. Murali. U. M.S ; M.B.A.
Prof. of Surgery
D Y Patil Medical College
Mauritius.

Objectives
Biological nature of cancer
Etiology of cancer
Management aspects of cancer
Palliative care – Principles

Historical Perspective
 Hippocrates used the Greek words, carcinos and carcinoma to describe tumors, thus calling
cancer “karkinos” tumor.
 The world's oldest documented case of cancer hails from ancient Egypt, in 1500 B.C.
 Treated by cauterization, a method to destroy tissue with a hot instrument called “fire drill”.
 Rudolph Virchow in late 19th century recognized that even cancerous cells were derived
from other cells. ( Abnormal proliferation )
 Theodar Boveri (1914) - importance of chromosomes abnormalities – cancer cells.
 By 1940, Oswald Avery – DNA genetic material within the chromosomes.
 In 1953, Watson & Crick described the structure of DNA – paved the way for the study of
molecular biology of cancer.

Cancer cells - Psychopath
No respect for the rights of other cells.
Violate the democratic principles of normal cellular
organisation.
Theiir proliferation is uncontrolled.
Ability to spread is unbounded.
Their inexorable, relentless progress destroys first
the tissue and then the host.

Malignant Transformation
 Self sufficiency in growth
signals.
 Insensitivity to growth –
inhibitory signals. [TGF-
β]/[CDKIs]
 Evasion of apoptosis.
 Limitless replicative
potential.

Malignant transformation
Sustained angiogenesis.
Ability to invade and
metastasize.
Defects in DNA repair.
Escape from immune
attack.

Flowchart depicting a simplified scheme of the molecular basis of cancer

Tumour – Growth
 The majority of the growth of a tumour occurs before it is
clinically detectable.
 By the time they are detected, tumours have passed the
period of most rapid growth, that period when they might
be most sensitive to anti-proliferative drugs.
 There has been plenty of time, before diagnosis, for
individual cells to detach, invade, implant and form distant
metastases.
 Cancer cells usually follows “Gompertzian growth” pattern.

Gompertzian Growth

Etiology
Both inheritance and environment are important
determinants of whether or not an individual
develops cancer.
The knowledge we have concerning the causes of
cancer can be used to design appropriate strategies
for prevention or earlier diagnosis.

CAUSES OF CANCER

Management of Cancer
Screening
Diagnosis & classification
Investigation & staging
Therapeutic decision making

Criteria for Screening test
 The disease
- Recognisable early stage
- Treatment at an early stage more effective than at a later age
 The test
- Sensitive and specific
- Acceptable to the screened population
- Safe & Inexpensive
 The programme
- Adequate diagnostic facilities for those with a positive test
- High-quality treatment for screen-detected disease to minimise morbidity and mortality
- Screening repeated at intervals if the disease is of insidious onset
- Benefit must outweigh physical and psychological harm

Diagnosis and Classification
 Accurate diagnosis is the key to the successful management of cancer.
 Precise diagnosis is crucial to the choice of correct therapy.
 Different tumours are classified in different ways: “Gleason system”
Well (G1)
 Moderate (G2)
 Poorly differentiated (G3)

Staging
 It is not sufficient simply to know what a cancer is; it is imperative to
know its site and extent.
 If it is localised, then locoregional treatments such as surgery and
radiation therapy may be curative.
 If the disease is widespread, then, although such local
interventions may contribute to cure, they will be insufficient,and
systemic treatment, for example with drugs or hormones, will be
required.
 Staging is the process whereby the extent of disease is mapped
out – “Will Rogers phenomenon”

TNM method for Staging of Tumor
 T - score: size and extent of invasion of the primary tumor
 N - score: number and location of histologically involved regional lymph nodes
 M - score: presence or absence of distant metastasis.

Decision making
 As the management of cancer becomes more complex, it becomes impossible for any
individual clinician to have the intellectual and technical competence that is necessary to
manage all the patients presenting with a particular type of tumour.
 The formation of multidisciplinary teams represents an attempt to make certain that each
and every patient with a particular type of cancer is managed appropriately.
 Teams should not only be multidisciplinary, they should be multiprofessional.

Principles of Surgery – Cancer
For most solid tumours, surgery remains the definitive treatment and the only
realistic hope of cure. Role of surgery in cancer treatment include –
 Diagnosis & staging
 Removal of primary disease
 Removal of metastatic disease
 Palliation

Surgery in Cancer
 Diagnosis & Staging
> Lap Ultrasound & Biopsy
> Sampling Lymph nodes
 Removal of primary disease
> Removal of primary tumour + lymph node
 Removal of metastatic disease
> Liver metastases - Resection
> Lung metastases – Pulmonary resection
 Palliation
> By pass procedures

Principles of Non-surgical Treatment – Cancer
 In contrast to surgery, it is possible to construct dose–response relationships for both the
benefits (such as tumour cure rate) and harms (such as tissue damage that is both severe
and permanent) associated with non-surgical interventions.
 Principle of selective toxicity : Treatment must be delivered in such a way as to ensure that
the damage done to the tumour is more than the damage done to the normal tissues.
 General Strategy : Spatial distribution of therapies / Adjuvant therapy .

Radiotherapy
 It is pretentious, but true, to state that radiotherapy is a precisely targeted form of
gene therapy for cancer.
 The practicalities of radiation therapy are reasonably straightforward:
> Define the target to treat
> Design the optimal technical set-up to provide uniform irradiation of that target
> Choose that schedule of treatment that delivers radiation to that target in such
a way as to maximise the therapeutic ratio

“5 R’s” – Radiotherapy
Repair of cellular
damage
Reoxygenation of the
tumour
Redistribution within
cell cycle
Repopulation of cells
Radiosensitivity

Chemotherapy
 Selective toxicity is the fundamental principle underlying the
use of CT in clinical practice.
 CT, by itself rarely sufficient to cure cancer.
 Over 95 different drugs - licensed by the FDA for the treatment of
cancer.
 Of these, over 65% - cytotoxic drugs
15% - hormonal therapies
15% - interact with speciific targets -
“targeted therapies”

Combined Therapy – Principles
Combat drug resistance
Use effective agents
Agents with different modes of action (synergy)
Agents with non-overlapping toxicities
Consider spatial co-operation

Palliative Therapy – Principles
 Symptom relief
 Psychosocial interventions
 Physical & practical support
 Information & knowledge
 Nutritional support
 Social support
 Financial support
 Spiritual support