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Radiotherapy For Colorectal Cancer, Dr. Dewi Syafriyetti Soeis Marzaini, SpRad(K)Onk.Rad - Department Of Radiotherapy, Dharmais National Cancer Center
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D R . D E W I S Y A F R I Y E T T I S O E I S M A R Z A I N I , S P R A D ( K ) O N K . R A D
D E P A R T M E N T O F R A D I O T H E R A P Y ,
D H A R M A I S N A T I O N A L C A N C E R C E N T E R
RADIOTHERAPY FOR COLORECTAL CANCER
COLORECTAL CANCER
The 3rd highest cancer in the world
Age-standardized incidence rate in Indonesia per 100,000 population (GLOBOCAN 2008):
19.1 for men
15.6 for women
MAJOR HEALTH PROBLEM
INDICATION FOR RADIOTHERAPY
Neoadjuvant – given preoperatively to patients with tumor invading outside the rectum or regional lymph nodes;
Adjuvant– given postoperatively to T3 / T4 orDuke’s B /C) tumors;
Palliative – given to advanced, unresectable tumors to reduce tumor burden and relieve symptoms (pain).
Goals of Radiation Therapy
Curative intent reduce recurrence and prolong survival Radiotherapy alone
Chemoradiation
Adjuvant radiation
Trimodality therapy
Palliation Relieve pain
Metastatic sites
Radiation Approach
External radiation: Pre- or post operative
With or without concurrent chemotherapy
Internal radiation or brachytherapy
External Beam Irradiation
Dual-energy linear accelerators generate: Low energy megavoltage x-rays (4-6 MeV)
High energy x-rays (15-20 MeV)
Photon energy
Particle Radiation (electrons, protons, neutrons)
Whole pelvic radiation
25 x 2 Gy
CT Simulator
Position
Simulation
Supine vs Prone
Supine vs. Prone + belly board
Median reduction of exposed volume small bowel – 54 % & Bladder – 62 %
Median dose to small bowel – 24 Gy Supine & 15 Gy - Prone + Belly board
Koebl et al - IJROBP 1999;45:1193-1198
Beam arrangements
AP-PA
3-field (PA + Bilateral)
4-field (AP-PA+ BL) - Ant Extension
Contouring
PLANNING RADIASI
Standard external RT: posteroanterior and laterals in prone position.
Plan Evaluation 3F W/O Wedge
Plan Evaluation
EXTERNAL RADIATION
Rectal IMRT
Limited data
Dosimetric studies favorable: Nuytens (2004)
Duthoy (2004)
Aristu (2005)
Guerrero-Urbano (2006)
Only 1 outcome study
Aritsu (2005) Spain: Phase I dose escalation study
37.5 Gy 42.5 Gy 47.5 Gy
In 19 fractions (preoperative)
No grade > 3 toxicity
Excellent pathologic response
85% down-stage
IMRT
Axial image displaying seven-beam intensity-modulated RT plan for postoperative patient to spare small bowel and femoral heads.
Brachytherapy
Radioactive source in direct contact with tumor Interstitial implants, intracavitary implants or surface molds
Greater deliverable dose
Continuous low dose rate
Advantage for hypoxic or slow proliferators
Shorter treatment times
BRACHYTHERAPY
Endorectal brachytherapy with fiducial markers (arrows) placed endoscopically to delineate the extent of tumor.
HIGH DOSE RATE BRACHYTHERAPY
Novi Sad rectal applicator
High dose rate rectal applicator after insertion.
flexible rectal applicator for high dose rate brachytherapy.
BRACHYTHERAPY
Sagittal plane dose distribution using the endorectal brachytherapy treatment technique.
Complications
Acute Effects Diarrhea
Nausea
Abdominal dyscomfort
Fatigue
Late Effects: Urinary incontinence
Fecal incontinence
Sexual dysfunction , erectile dysfunction
Follow-Up
During radiation: every week
After radiation: 2 weeks after radiation
1.5 -2 months afater radiation
Every 3 months for 2 years
Every 6 months for the next 2 years
Annualy thereafter
Evaluation: History including radiation side effects, clinical examination,
rectoscopy, blood test, imaging for suspected recurrence (CT scan or MRI).
Thank You
Mount Merapi