ESTRO 2024 - Abstract Book

S194

Brachytherapy - GI, paediatric, miscellaneous

ESTRO 2024

This phase II trial was designed to test the hypothesis that, additional brachytherapy boost will lead to a better complete clinical response without increasing toxicity resulting in a higher proportion of patients being managed nonoperatively.

In this study we present the early results of this phase prospective study approved by the hospital ethics committee.

Primary Objective

Rate of complete (cCR) or near complete (nCR) clinical response rate of the primary rectal tumors at 12 weeks.

Material/Methods:

Patients diagnosed with T2-T3, N0-N2 distal rectal cancer treated from July 2022 to May 2023 were accrued. Patient and tumor characteristics are described in Table no.1

All were treated with radiation dose of 45-50Gy in 25 fractions( #) with concurrent capecitabine. All patients received escalated dose of radiation by MR guided high dose rate endorectal brachytherapy of 7 Gy in 3 #s within 2 to 3 weeks post CTRT. Two inflatable balloons were used to push the rectal mucosa (Fig 2). The brachytherapy dose of 7 Gy was prescribed to the periphery of the residual tumor seen on MRI with the applicator in situ

Table 1. Characteristics of patients and tumor

Variable

Number

%

Male

38

64.4

Female

21

35.6

Age – Median 55 years (27-77)

CEA – Median 3ng/ml (1-43)