ESTRO 2024 - Abstract Book

S188

Brachytherapy - GI, paediatric, miscellaneous

ESTRO 2024

Fig.2 - dose distribution seen in coronal section

Informed consent was obtained prior to the procedure. Patient was shifted to Cath Lab and under aseptic precautions with fluoroscopic guidance, the percutaneous transhepatic biliary drain (PTBD), which was retained post operatively, was replaced with a 7-french stiff sheath. Care was taken to pass the sheath at least 4 cm beyond the hepatico-jejunostomy anastomosis (Hep-J) into either the afferent or efferent loop of bowel. A sterile 5-french endobronchial Brachytherapy catheter was passed through the sheath until it has crossed the anastomosis by at least 3 cm (verified by fluoroscopy) and secured with a plaster and tucked into a colostomy bag. A simulation CT was acquired with patient in supine position and of slice thickness 1.5 mm - with and without a dummy inside the catheter. Manual catheter reconstruction of the entire length of the catheter was performed and verified. Contouring was done by first identifying the hepatico-jejunostomy anastomosis. The CTV was contoured along the catheter for a length of 2.5 to 3 cm proximal and 2.5 to 3 cm distal to the anastomosis using a 1 cm diameter brush. A plan was made using geometric optimisation with step size of 5 mm conforming to the CTV to ensure 90% of volume of CTV gets at least 90% of the planned dose. A total dose of 24Gy/ 4Gy per fraction/ 6 fractions (EqD2 - 28 Gy, BED10 - 33.6 Gy) prescribed at 1 cm from the central lumen of the catheter was delivered to all patients over 4-5 days, twice a day using Gamma Med Plus iX (Varian Inc., CA, USA). Five patients were treated, the mean age at diagnosis was 48.8 (range (R) :34 – 66) years with 80% patients being male. The mean Bilirubin at diagnosis was 19.8 (R: 7.7 – 35.6) mg/dL and all patients were stented using PTBD prior to surgery. The mean pre-operative Ca 19.9 was 135.1 (R: 12.4 to 307) U/ml. The most common tumour staging was pT3 (60%) followed by pT2b (40%). The most common nodal staging was pN0 (40%), pN2 (40%) and pN1 (20%). Subdivision of cases as per Bismuth classification of HCCA was as follows: type IIIA (20%), IIIB (40%) and IV (40%). Perineural invasion was seen in all patients. The most common grade of HCCA was grade II (60%) followed by grade III (40%). The mean interval between surgery and start of brachytherapy was 55.4 (R: 36 – 83) days. The mean length of CTV was 5.9 (R: 5.2 – 6.7) cm. The mean dwell time was 49 seconds per fraction (R: 27.7 – 71.1s). The mean D90% was 22.7 (R: 20.3 – 23.3) Gy while the mean V100% was 89% (R: 78 – 90). No patients suffered pain, bleeding, fever or cholangitis during or after the brachytherapy. No patient needed reduction of chemotherapy dose nor delay in initiation. External beam radiotherapy with Capecitabine was given to one patient in view of heavy nodal burden. The median and mean follow-up from date of brachytherapy for all patients was 17 and 15 (R: 6 - 19) months respectively and all patients are alive until data censoring. Three patients (60%) are alive without recurrence while two patients suffered recurrence – both patients had poorly Results: