Tumor, Neoplasm, Cancer, Causes of cncer, Differentiation & Anaplasia, Pleomorphism & Hyperchromatism, Mitosis in cancer, Metastsis, Cancer Staging, TNM classification, Medicine, Surgery, Mutation, Oncogenes, Tumor-suppressor genes, BRCA 1, BRCA 2, Cell cycle,

1. Introduction to
Oncology
Dr. Abdul Qadeer
MBBS; FCPS; FICS
Assistant Professor
Department of Surgery
King Faisal University College of Medicine

2. Definition of neoplasm
• A neoplasm is an abnormal mass of tissue, the
growth of which exceeds and is uncoordinated
with that of the normal tissues and persists in
the same excessive manner after cessation of
the stimuli which evoked the change.
• Mutation / genetic change is the cause of
neoplastic cells, hence tumors are said to be
clonal

5. Cell cycle

6. Normal regulatory genes
• Four classes of normal regulatory genes:
1. Growth-promoting proto-oncogenes e.g. sis,
K-ras, c-myc etc.
2. Growth-inhibiting tumor suppressor genes
e.g. NF1, NF2, APC, RB1, p53 etc
3. Genes that regulate programmed cell death
(Apoptosis), death receptors CD95/Fas
4. Genes involved in DNA repair

7. Causes of cancer
Hereditary factors
• Abnormalities in
genome exists in all
cells e.g. mutations in
1. BRCA1 and BRCA 2
genes
Environmental factors
• These are carcinogenic
factors. These include:
1. Infections i.e. viral,
bacterial, parasitic
2. Physical i.e. UV
radiation, ionizing
radiation
3. Chemicals

8. Hereditary factors
• Existence of such factors may help to take
preventive measures e.g.
1. Primary prevention: surgical removal of the
tissue at risk
2. Secondary prevention: regular screening

9. Infectious factors (Viral)
• Human papilloma virus (HPV): cervical,
vaginal, vulval and anal cancers
• Epstein-Barr virus (EBV): Burkitt’s lymphoma,
nasopharyngeal carcinoma
• Human herpes virus 8: Kaposi’s sarcoma, more
common in AIDS patients
• Hepatitis B (HBV) and hepatitis C (HCV):
hepatocellular carcinoma

10. Infectious factors (Bacterial/Parasitic)
• Helicobacter pylori (H. pylori): gastric cancer
• Schistosoma hematobium: urinary bladder
carcinoma

11. Radiations
• Ultraviolet (UV) radiation: SCC, BCC (Rodent
ulcer) and melanomas
• Ionizing radiation (Radiotherapy): breast
cancer, thyroid cancer, angiosarcomas

13. Chemicals
• Indirect-acting carcinogens:
 asbestos (mesothelioma),
 aromatic amines/paint (bladder cancer),
benzopyrene in smokers (bronchial ca)
• Direct-acting carcinogens:
 excessive alcohol consumption (head &
neck tumors, breast cancer)

14. Nomenclature
• Neoplasia/Neoplasm = New growth
• Tumor = Swelling (Mostly used now for
neoplasms
• Oncology = Oncos (Greek) = tumor
• Cancer = 2nd most cause of death in USA after
cardiovascular diseases

15. Benign tumors
• Characteristics of benign tumors:
Localized
Amenable to local surgical removal
Named by attaching suffix –oma to the cell of
origin e.g. fibroma, chondroma, adenoma,
papilloma etc.

16. Malignant tumors
• Characteristics of malignant tumors:
Invade or destroy the adjacent structure
Spread to distant sites (metastasize)
Named as; the tumors arising in mesenchymal
tissue = sarcomas; examples: fibrosarcoma,
chondrosarcoma, leiomyosarcoma,
rhabdomyosarcoma
the tumors arising from epithelial tissue =
carcinomas; examples: adenocarcinoma, SCC

17. Differentiation & Anaplasia
• Differentiation refers to the extent to which
neoplastic parenchymal cells resemble the
corresponding normal parenchymal cells, both
morphologically and functionally
• Lack of differentiation is called anaplasia
• Benign tumors are well-differentiated
• Malignant tumors may range from well-
differentiated to un-differentiated

18. Pleomorphism & Hyperchromatism
• Pleomorphism: variation in size and shape.
Cells within the same tumor are not uniform,
but range from large cells to extremely small
and primitive appearing
• Hyperchromatism: the nuclei contain abundant
chromatin and dark staining. The nuclear-to-
cytoplasm ratio may reach to 1:1 instead of
normal 1:4 or 1:6

19. Mitoses
• As compared with benign tumors and some
well-differentiated malignant tumors,
undifferentiated tumors usually posses large
number of mitoses, reflecting the higher
proliferative activity of the parenchymal cells

20. Loss of polarity
• The orientation of the anaplastic cells is
markedly disturbed i.e. they lose normal
polarity
• Sheets or large masses of tumor cells grow in
an anarchic, disorganized fashion

21. Spread of tumors
• Local invasion
• Metastasis:
1. Direct seeding of body cavities or surfaces
e.g. peritoneal, pleural, pericardial,
subarachnoid and joint spaces
2. Lymphatic spread
3. Hematogenous spread

22. Comparisons between benign &
malignant tumors
MalignantBenignCharacteristics
Some lack of differentiation with
anaplasia; structure often atypical
Well-differentiated; structure
sometimes typical of tissue of origin
Differentiation/
Anaplasia
Erratic and may be slow to rapid;
mitotic figures may be numerous and
abnormal
Usually progressive and slow; may
come to a standstill or regress;
mitotic figures rare & normal
Rate of growth
Locally invasive, infiltrating surrounding
tissues
Usually cohesive expansile well-
demarcated (by capsule) masses
that do not invade or infiltrate
surrounding normal tissues
Local invasion
Frequently present; the larger & more
un-differentiated the primary, the more
likely are metastases
AbsentMetastasis

23. Grading & Staging
• Grading: well-differentiated to un-differentiated
• Staging: TNM etc.

24. Treatment
• Surgery: curative,
palliative
• Chemotherapy
• Radiotherapy

25. Role of GP in oncology
• Earlier recognition of symptoms; earlier
referral to specialists
• It will help to improve the chances of recovery
(secondary prevention) or
• Eliminating factors that influence the
development of cancer (primary prevention)
• Supporting patients and their families, good
follow-up by liaison between the specialist
and the patient

26. Warning signs
1. Hoarseness of voice, blood in coughed-up
mucus
2. Difficulty in swallowing
3. Newly changing moles; shape, size,
appearance, itching or bleeding
4. Scaly patch or lump on the skin or body parts
5. Changes in bowel habits or micturition
6. Un-explained weight loss

27. References
1. Robbins Basic Pathology, 9th edition, pages
161-214
2. J. de Vries et al. Essential Oncology for Health
Professionals. 2nd edited edition: pages 5-13