Mahatma Gandhi Cancer Hospital and Research Institute

Dr P. S. Bhattacharyya, MDRadiation Oncologist.

Elekta Synergy

CT Simulator

Flexitron HDR

Computed tomography assisted High Dose Rate Interstitial Brachytherapy in Gynaecologic Malignancies,

with Inverse Planning Simulated Annealing ; An Institutional experience.

Author-Dr P S Bhattacharyya, MD Co-author-Mr A C prabhu, Med. Phy.

Introduction

Ca. Cx - 40% of all cases treated at MGCH EBRT + CDDP 40 mg/m ICRT / IBT GEC Estro guidelines for 3D ICRT MUPIT

2

Aims of the study

To report IPSA based 3D HDR IBT in cancer Cervix and Vagina

DVH analysis of CTV and OAR

Materials and Methods

May 2012 to Dec 2012 Retrospective analysis 34 IBT applications in 17, Ca.Cx / Vagina patients Duration < 3 hrs Median 19 (17-23) needles used 8 – 9.5 Gy X 2 prescibed dose IPSA

Clinical and Histopathological features PRESENTATIONBleeding P/VWhite dischargePelvic Pain

NO. OF PATIENTS 14 12 06

PERCENTAGE 82 70 35

HPESq. Cell Ca.Adeno Ca.

16 01

94 06

SITEIntact CervixVaultVagina

10 05 02

59 29 12

FIGO STAGE IIBIIIBIIIB with L/3 Vagina involved

07 10 03

41 59 30

Total patients studied-17 Median age -56 Yrs.(18-68 yr)

Perineal Template Indications

Bad Geometry 47% (08) Ca. Vault area 29% (05) Vaginal and para vaginal involvement 12% (02) Non negotiable cervical OS 06% (01) ICRT high dose to bladder 06% (01)

Total No. of patients studied-17

Interstitial applicators

Vienna CT-MRI Ring/ Ovoid Applicator

Syed Neblett Template

MUPIT Applicator

BED and DEQ Equations

BEDExt+HDR= (nd[1+(---)]) + (nd[1+(---)])

DEQ = BEDExt+HDR

d d

d ref 1+ ( ---- )

n = no. Of fractionsd = dose per fraction in Gya/b = alpha / beta, 10 for tumor, 3 for late effects

BED=biologically equivalent doseDEq= Equivalent dose (Gy)d ref= reference dose, 2 Gy

a/b a/b

a/b

IPSA Planning

CTV DVH Interpretations

CTV Range Median BED 10Tumor effects

Dose Eq.Gy

D100 4.87 – 8.49 Gy 5.82 Gy

D95 7.26 – 9.17 Gy 8.42 Gy 84.08 70.06

D90 8.14– 9.60 Gy 8.74 Gy 85.80 71.50

V100 85 – 96.77 % 91.13%

Median Prescribed dose- 8.8 Gy

OAR DVH Interpretation

BladderVolume cc

RangeGy

Median dose Gy

BED 3Late effects

Dose Eq.Gy

0.1 6.25-9.85

8.01 130 78.31

1 5.52-7.90

6.75 115.87 69.80

2 4.98-7.13

6.29 110.95 66.84

5 3.82-6.47

5.63 105.36 63.47

Rectal Volume cc

RangeGy

Median dose Gy

BED 3Late effects

Dose Eq.Gy

0.1 6.47-8.49

7.36 122 73.49

1 5.70-7.27

6.49 113.06 68.11

2 5.30-6.01

6.02 108.20 65.18

5 4.23-6.46

5.40 102 61.44

URINARY BLADDER RECTUM

Median Prescribed Dose- 8.8 Gy

IPSA isodose distribution

Comparision of bladder dose

0.1 cc bladder dose 12 Gy with ICRT 0.1 cc bladder dose 8.1 Gy with IBT

Limitations of the study

All the patients did not recieve 6 cycles of CDDP Total duration of treatment more than 8 weeks Applicator volume in CTV No subdivisions in CTV

Thank you