1. GENERAL SURGERY
PRINCIPLES OF ONCOLOGY
Dr. Haydar Muneer Salih

2. History
• Cancer has always been with us:
dinosaur fossils from over 60 million
years ago show evidence of
malignancy; Egyptian mummies had
cancer.

3. Cancer = crab

4. • The characteristics of the cancer cell arise as a
result of mutation.
• Only very rarely is a single mutation sufficient to
cause cancer; multiple mutations are usually
required
• Once a cell has arisen with all the mutations
necessary to make it fully malignant, it is
capable of giving rise to an infinite number of
identical cells, each of which is fully malignant.
These cells divide, invade, metastasize and
destroy but, ultimately, each is the direct
descendant of that original, primordial,
transformed cell

5. Causes of cancer
1.Environmental / behavioral factor
1. Tobacco : associated with lung cancer
and head and neck cancer
2. Alcohol: associated with head and neck ,
oesophageal cancer and hepatoma
3. UV exposure: associated with skin cancer
4. Ionizing radiation: associated with
leukemia, lymphoma and breast and
thyroid cancer
5. Viral infection: HIV associated with kaposi
sarcoma

6. 6. Other infection: bilharzia associated
with bladder cancer
7. Inhaled particles: wood dust associated
with paranasal sinus carcinoma
8. Chemicals:
a. Chemical used in industry : bladder, lung
and nasal cancer
b. Medical : leukemia and lymphoma
9. Obesity / lack of physical exercise:
associated with breast, kidney and colon
cancer

7. 2. Inherited syndromes
associated with cancer
• Peutz–Jeghers syndrome STK11 D
Bowel cancer, breast cancer
• Basal cell naevussyndrome (Gorlin)
PTCH D Basal cell carcinomas
• Xeroderma pigmentosum Deficient
nucleotide R Skin sensitive to sunlight
early onset of cutaneous carcinomas

8. Peutz–Jeghers syndrome

9. Xeroderma pigmentosum

10. Cancer Screening
• Screening involves the detection of
disease in an asymptomatic population in
order to improve outcomes by early
diagnosis.

11. Criteria for screening
The disease
■ Recognisable early stage
■ Treatment at an early stage more
effective than at a later
stage
■ Sufficiently common to warrant
screening

12. Criteria for screening
The test
■ Sensitive and specific
■ Acceptable to the screened
population
■ Safe
■ Inexpensive

13. Criteria for screening
The programme
■ 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

14. Treatment of cancer
4 basic treatment modalities
1.Surgery
2.Radiotherapy
3.Chemotherapy and biological therapy
4.Combination of above

16. Principles of cancer surgery
• For most solid tumours, surgery remains
the definitive treatment
1.Diagnosis and staging
2.Removal of primary disease
3.Removal of metastatic disease

18. Radiotherapy
• Within a month of their discovery in
1895, X-rays were being used to treat
cancer.
• It is pretentious, but true, to state that
radiotherapy is a precisely targeted
form of gene therapy for cancer

19. Radiotherapy Treatment modalities
1. Primary treatment:
• most sites in the oral cavity and oropharynx
• small tumours
• physical status
2. Adjuvant treatment:
• peri-neural or peri-vascular spread;
• large tumours;
• poorly differentiated tumours;
• >1 lymph node involved;
• extra-capsular spread in a lymph node
• Inadequate surgery

21. Chemotherapy
• selective toxicity is the fundamental
principle underlying the use of
chemotherapy in clinical practice.
• chemotherapy is rarely sufficient to cure
cancer. Chemotherapy is often (in effect if
not in intent) a palliative rather than a
curative intervention.

22. Chemotherapy
• The timing of administration of chemotherapy
• Neoadjuvant/induction: given prior to
radiotherapy or surgery with the intention of
improving organ preservation. Little evidence for
this and no evidence of survival advantage.
• Adjuvant: given after radiotherapy or surgery.
Survival benefit when used as an adjuvant to
surgery is less certain, but when given with
radiotherapy as a post-operative adjunct toxicity
rates are very high. This should only be used in
the context of clinical trials

23. Principles of combined treatment
• There is, in addition to synergy and
toxicity, another factor to consider in the
combination of drugs and radiation – the
concept of spatial cooperation.
• Chemotherapy is a systemic treatment;
radiotherapy is not. Radiotherapy is,
however, able to reach sites, such as the
central nervous system and testis, which
drugs may not reach effectively.

25. • The distinction between palliative and
curative treatment is not always clear cut
• Ten years ago, cancer was perceived as a
disease that was either cured or it was not
• Nowadays, we are increasingly aware that
many of the so called curative treatments
are simply elegant exercises in growth
delay.
• They will die with cancer, but not
necessarily of cancer

26. End-of-life care
• End-of-life care is distinct from palliative
care. Patients treated palliatively may
survive for many years; end-of-life care
concerns the last few months of a patient’s
life.
• ‘I don’t mind dying, I just don’t want to
be there when it happens’

27. Role of the dental practitioner in
cancer prevention and diagnosis