2. Out line of Presentation
•
•
•
•
•
•
•
•
•
•
•
Introduction
Epidemiology
Cancer Etiology
Cancer Biology
Cancer Risk Assessment
Cancer Screening
Diagnosis
Staging
Surgical Approach to Cancer Therapy
Chemotherapy
Radiation Therapy
Sunday, December 08, 2013
Oncology
3. INTRODUCTION
• Tumor - “abnormal mass of tissues the growth of
which exceeds and is uncontrolled with that of
normal tissues” Wills
• Cancer – ”Karanikos”
Sunday, December 08, 2013
Oncology
4. Epidemiology
• In 2008 - 1.44 million new cases in US.
• 565,650 – died in US
• Global Statistics on Cancer Incidence
-10.9 million new cancer cases in 2002.
-Lung cancer is the leading cancer in the world.
- Breast cancer - the second most common
Sunday, December 08, 2013
Oncology
8. • factors may suggest hereditary cancer
1. Tumor development at a much younger age than
usual
2. Presence of bilateral disease
3. Presence of multiple primary malignancies
4. Presentation of a cancer in the less affected sex
5. Clustering of the same cancer type in relatives
6. Occurrence of cancer in association with other
conditions such as mental retardation or
pathognomonic skin lesions
Sunday, December 08, 2013
Oncology
9. • Importance of knowing hereditary cancer
– Examples
• P53 and li-fraumani syndrome
• RB1 Gene and Hereditary Retinoblastoma
• BRCA1, BRCA2, and Hereditary Breast-Ovarian
Cancer Syndrome
• APC Gene and Familial Adenomatous Polyposis
Sunday, December 08, 2013
Oncology
10. Carcinogens
• Environmental factors - 60 to 90%
• Three types - Chemical, Physical, or Viral
• Chemicals carcinogens
• Three groups
1.genotoxins .
2. co carcinogens-potentiate genotoxins.
3.Tumor promoters.
• IARC - 4 Groups
• E.g. of Proven carcinogens - aflatoxins ,tobaco
,aresnic ,benzene etc
Sunday, December 08, 2013
Oncology
11. Physical Carcinogen
• Mechanism
- Induction of inflammation and cell proliferation
- Induce DNA damage
• Radiation
- Best known physical carcinogen
• Ionizing
-DNA break( deletion ,gene rearrangement
-Direct effect
-Indirect effect
-Bystander effect
• Non-ionizing
-UV light-skin cancer
Sunday, December 08, 2013
Oncology
12. Viral Carcinogens
• 15 % cancers world wide
• Mechanism
-Insertional mutagenesis
-Expression of oncogenes
-Alteration of immune system
• DNA virus
-Have their own Oncogen
-Oncoprotiens –bind cellular genes-p53.RB
-activate cellular genes-IL-5,C—MYC,H-ras
-E.g.- HPV, HBV, EBV
Sunday, December 08, 2013
Oncology
13. • RNA virus
- Are retroiviruses
-They have no their own oncogenes
-Transform host proto oncogene
E.G-HTLV-1
Sunday, December 08, 2013
Oncology
25. Evasion of Apoptosis
• Two path ways
-Death receptor path way - Fas(CD95)
-The mitochondrial Path way
Stimulus - DNA damage, free radicals, withdrawal of GFs
• E.g. – Loss of CD 95 In HCC
Sunday, December 08, 2013
Oncology
27. Cancer Invasion
• Carcinoma insitu
• Invasive cancer
• Steps
-Loss of adhesion – cadherins
-Attachemement to ECM
-Degradation of ECM
-locomotion
Sunday, December 08, 2013
Oncology
30. Metastasis
• Hematogenous
• lymphatic
• seeding in to body cavities.
Prerequisites
-Access to circulation
-survive in the circulation.
-Extravasate
-Initiate growth in the new tissues
Organ specific metastasis
- mechanical
-Seed and soil theory
Dormancy.
Sunday, December 08, 2013
Oncology
32. Cancer Risk Assessment
• Initial evaluation of any patient
• Cancer screening - genetic counseling and testing
• Component
-Complete history
-Hx of environmental exposure
-Detailed family history
-Personal history
-Age, race
- E.g.-GAIL model for breast cancer
Sunday, December 08, 2013
Oncology
33. Cancer Screenings
Early detection
Criteria for screening
• The Disease
-Recognizable early stage
-Treatment at an early stage more effective than at a later
Stage
-Prevalence
Sunday, December 08, 2013
Oncology
34. • The Test
- Sensitive and specific
-Acceptable to the screened population
-Safe
-Inexpensive
• The Programme
• Intensive screening
Sunday, December 08, 2013
Oncology
35. Cancer Diagnosis
• The Definitive - Biopsy of the lesion
- histology, grade
• Open biopsy
-Inscisional or Excisional
-More tissue for histologic Dx
• CORE Biopsy
• FNAC
Sunday, December 08, 2013
Oncology
36. Staging
• Anatomic extent of tumor in an individual patients
• Importance
- To predict prognosis
- Selection of Therapy
-Evaluation of Treatment
-Exchange of information among Treatment
centers
Sunday, December 08, 2013
Oncology
44. Surgical Management of Distant Metastases
• Mostly non curative
• Curable in isolated metastasis
• Survival rates depends on
- Disease free interval
- Natural history o f metastatic disease
• The goal is to resect the metastases with negative
margins
Sunday, December 08, 2013
Oncology
45. Principles of Chemotherapy
• Fractional cell kill
- Constant percentage of cells killed
- E.g. 1012 tumor cells, treated with a dose that result in
3 log kill
1012 → 109 cells
•
•
•
•
Selection of chemotherapeutic agent
Conventional dose
High dose
Cyclic Therapy
Sunday, December 08, 2013
Oncology
47. • End Point of Drug Action
- Metastatic Disease
- Localized Tumors
- Adjuvant Therapy
-Sensitizes Tumors to radiation
-As part of adjuvant therapy
-Palliative therapy
• Classification
-Cell-cycle phase–nonspecific agents
-Cell-cycle phase–nonspecific agents
Sunday, December 08, 2013
Oncology
48. • Agents
Alkylating agents
- Kill cells in any phase of the cycle
- MOA : cross linking the DNA strands and direct damage to
the DNA
- Three Groups –Classic ,, miscellaneous DNA Binding Agents
- Classic - Cylophosphamide, Busulfan , Chlorambucil
- Nitrosureas- Streptozocin ,Carmustine
- miscellaneous- cisplatin, Carboplatin
- Toxicity :
Sunday, December 08, 2013
Oncology
49. Antimetabolites
- cell-cycle–specific agents
- Effective in tumors with high growth fraction
-MOA : analogues of naturally occuring
metabolities involved in DNA synthesis
-Eg. - Folic acid Analogue - Methotrexate ,
- Pyrimidine Analogue- 5-FU
- Purine Analogue - Azathioprine , Mercaptopurine
-Toxicity:
Sunday, December 08, 2013
Oncology
50. • Plant Alkaloids
- Derived from vinca rosea plant
- Act by binding to tubulin in the S phase
- Eg. - Vincristin, vinblastin
- Toxicity:
• Combination therapy:
- Maximizes Cell kill
-Broader Range of Coverage of Resistant cell lines
-Delays the emergence of Drug-Resistant cell lines
Sunday, December 08, 2013
Oncology
55. • Planning therapy
-Define Target
- Shield
-Homologues delivery
-Fraction Dose
• Conventional fractionation - 1.8-2 Gy/d,5 day /wk for
3-7 wks
• Ways of delivery
-Tele Therapy
-Brachy Therapy
-Systemic Therapy
• Preop or post op
Sunday, December 08, 2013
Oncology
56. • Indication
- Component of Curative Therapy
-Palliation
- Prevent Development of Disease
• Toxicity- Acute and Chronic
Sunday, December 08, 2013
Oncology
57. • Other Option of Therapy
- Hormonal
- Targeted Therapy
- Gene Therapy
Sunday, December 08, 2013
Oncology
58. REFFERENCE
• SCWARTZ PRINCIPLES OF SURGERY
• ROBINS PHOLOGIC BASES OF DISEASE
• INTERNET
THNK YOU
Sunday, December 08, 2013
Oncology
Editor's Notes
Figure 6-26 A-D, Schematic illustration of the sequence of events in the invasion of epithelial basement membranes by tumor cells. Tumor cells detach from each other because of reduced adhesiveness, then attach to the basement membrane via the laminin receptors and secrete proteolytic enzymes, including type IV collagenase and plasminogen activator. Degradation of the basement membrane and tumor cell migration follow.
genetic model for colorectal tumorigenesis. Tumorigenesis proceeds through a series of genetic alterations involving oncogenes and tumor-suppressor genes. In general, the three stages of adenomas represent tumors of increasing size, dysplasia, and villous content. Individuals with familial adenomatouspolyposis (FAP) inherit a mutation on chromosome arm 5q. In tumors arising in individuals without polyposis, the same region may be lost or mutated at a relatively early stage of tumorigenesis. A ras gene mutation (usually K-ras) occurs in one cell of a pre-existing small adenoma which, through clonal expansion, produces a larger and more dysplastic tumor. The chromosome arms most frequently deleted include 5q, 17p, and 18q. Allelic deletions of chromosome arms 17p and 18q usually occur at a later stage of tumorigenesis than do deletions of chromosome arm 5q or ras gene mutations. The order of these changes varies, however, and accumulation of these changes, rather than their order of appearance, seems most important. Tumors continue to progress once carcinomas have formed, and the accumulated chromosomal alterations correlate with the ability of the carcinomas to metastasize and cause death. DCC = deleted in colorectal cancer gene.(Modified with permission from Fearon et al.6 Copyright Elsevier.)
Figure 6-29 Tumor progression and generation of heterogeneity. New subclones arise from the descendants of the original transformed cell by multiple mutations, as illustrated in Figure 6-27. With progression the tumor mass becomes enriched for variants that are more adept at evading host defenses and are likely to be more aggressive
Gompertzian tumor growth. The growth fraction of a tumor declines exponentially over time (top). The growth rate of a tumor peaks before it is clinically detectable (middle). Tumor size increases slowly, goes through an exponential phase, and slows again as the tumor reaches the size at which limitation of nutrients or auto- or host regulatory influences can occur. The maximum growth rate occurs at 1/e, the point at which the tumor is about 37% of its maximum size (marked with an X). Tumor becomes detectable at a burden of about 109 (1 cm3) cells and kills the patient at a tumor cell burden of about 1012 (1 kg). Efforts to treat the tumor and reduce its size can result in an increase in the growth fraction and an increase in growth rate
io
The probabilities of tumor control and of complications at different doses. A. At lower doses, the probability of complications is low, with a moderate chance of tumor control. B. Increasing the dose may gain a higher chance of tumor control at the price of significantly higher complication risks. (Modified from Eisbruch et al, 240 with permission.)