CA Colon. Mzux

8/2/2019 CA Colon. Mzux

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4/13/12

COLON CANCER

Presenter: Dr. Harrison R. Chuwa, M.Med ClinicalOncology Resident

Special thanks to Dr. Maunda, Consultant Oncologist


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Key Issues/Lay-out

Introduction

Anatomy

Epidemiology Natural history

Pathology

Mode of Spread

Clinical Presentation

Diagnostic Work-up


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Introduction

Is the 2nd leading

cause of cancer

death in thewestern world.

Develops over

a number of years

& normally begins

as a polyp.


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Anatomy


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Arterial Supply


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Venous Supply


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Lymphatic Drainage


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Cross-section of Colon


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Epidemiology

Approximately 6% of individuals inthe US will develop a cancer of thecolon or rectum within their lifetime

Male: female = 1.37:1

The incidence in developingcountries is increasing

At ORCI, 60 cases (0.55%) were Rx-ed for colon ca from 2008 to 2010.70% male


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Etiology & Risk Factors

Aging

Hereditary Risk Factor

Environmental Life style and Dietary Factor

Inflammatory Bowel Diseases


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Genetic SusceptibilitySyndromes

Familial Adenomatous Polyposis(FAP)- APC

Hereditary Nonpolyposis ColorectalCancer (HNPCC)- hMLH1/hMSH2

Turcot syndrome

Peutz-Jeghers syndrome-STK11 MUTYH-associated polyposis


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Colon Cancer

Sporadic(averagerisk)(65%85%)

Fami

lyhistory(10%30%)

Ra

resyndromes(


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Pathogenesis of ColonCancer

i. Tumour suppressor genemutations

APC gene defect DCC

p53

ii. Proto-oncogene amplification

K-ras : Proto-oncogene


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Natural History of

Colon Cancer

Normalepithel

ium

Hyper-prolifera

tive

epithelium

Earlyadeno

ma

Inter-mediat

e

adenoma

Lateadeno

ma

Carcinoma

Metastasis

Loss ofAPC

Activation

ofK-ras

Deletion of

18q

Lossof

P53

Otheralteratio

ns

Adapted from Fearon ER. Cell 61:759,1990


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Pathology

Macroscopically

ulcerative, polypoid, annular, orinfiltrative

Microscopically

Adenocarcinoma >95% Carcinoid tumours

Gastrointestinal stromal tumours (GITS)

Lymphomas


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Distribution of Cancer alongthe Colon


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Mode of Spread

Direct extension

Peritoneal seeding

Lymphatic drainage Hematogeneous

Note: skip metastasis (retrograde

spread) occurs in 1-3% of nodepositive pts


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Clinical Presentation

Early sign

A change in bowel habits

fatigue Late sign

Colon obstruction

Ribbon-like stool

Hematochezia

Cachexia (wasting syndrome)

Di ti W k


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Diagnostic Work-up H&P

Colonoscopy or sigmoidoscopy

Bx

Imaging

- Ba enema

- CXR

- US

- CT scan

- MRI

- PET scan

Blood testing


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Staging

1. Dukes classification for staging in colorectalcancer:

Stage A: Tumour confined w/in bowelwall

-Prevalence at Dx: 10%

- 5yr survival rate: > 90% Stage B: Extension through bowel

wall

Prevalence at Dx: 35%


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TNM Staging

Stage O(in situ)Thetumor issmallandlimited toThemucosa

Stage I

The tumorhasspread tothemuscularis,but not to

theouter wall

Stage II

The tumorhasspread totheouter wall ofthe colon,butnot to

Stage III

The tumorhasspread intonearbylymphnodes, but

notto other

Stage IVThe tumorhasspread tootherorgans suchasthe liver,


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Management

Surgery

Chemotherapy

Targeted therapySometimes used in combination with

standard chemotherapy

Radiation


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Treatment by Stage

Stage O:

Local surgery (polypectomy or removalof larger tumors)

Stage I:

Surgery followed by observation

Stage II: Surgery followed by chemotherapy or

observation

Stage III:


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Surgery

Polypectomy

Laser or diathermy therapy

Radical surgery Total colectomy

Transverse colectomy

Rt hemicolectomy

Lt hemicolectomy

Lymphadenectomy


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chemotherapy

Neoadjuvant down staging

1st line

Adjuvant micro remnants 1st line

Palliative metastatic disease

2nd line + targeted therapy


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Chemotherapy cont...

1st line regimen

5-FU +LV

5-FU + LV + OX (FOLFOX 4/6) 5-FU + LV + Irinotecan (FOLFIRI)

Irinotecan + 5-FU + LV (IFL)

Capecitabine 2nd line regimen

5-FU + LV+ OX + Irinotecan (FOLFOXIRI)

FOLFOX + bevacizumab cetuximab


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Radiation

No clear evidence of survival benefitwith RT

Mainly for stage 4 tumours fixed toabdominal lining

Adjuvant EBR +/- chemo i.e.Adjuvant chemoradiation

Brachytherapy has no role in colonca

XRT also has a role for metastatic


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XRT Techniques

Field should include margin aroundtumor bed, LNs and residual diseasebased on pre-op imaging and/or

surgical clips. 3D simulation to define the tumour

volume

Bladder distension & prone position

Dose 50.4Gy/1.8Gy/28# OR46Gy/2Gy/23#


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Follow-up

Follow-up visits

Serial (CEA) measurements arerecommended

Colonoscopy one year after removalof colon cancer

Surveillance colonoscopy every threeto five years to identify new polypsand/or cancers


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Prognostic factors

- Stage and grade of disease.

- Pre op CEA Level.

- Presence of microsatellite instability& loss of DCC gene.


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Screening

FOBT

Colonoscopy

Sigmoidoscopy Ba enema


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