Dose to pelvic lymph nodes during brachytherapy of locally advanced cervical cancer with 60Co HDR source

Brachytherapy. 2021 Nov 5:S1538-4721(21)00487-6. doi: 10.1016/j.brachy.2021.09.007. Online ahead of print.

ABSTRACT

PURPOSE: This study investigated the correlation between the prescription dose and dose to the Manchester and International Commission on Radiation Units and Measurements-report 38 (ICRU-38) lymphatic trapezoid points during high-dose-rate (HDR) brachytherapy of locally advanced cervical cancer with (Cobalt-60) 60Co .

METHODS AND MATERIALS: A retrospective study was designed for; patients with locally advanced cervical cancer, treated by external beam radiotherapy and concurrent weekly Cisplatin-based chemotherapy, had no extended parametrial invasion and was treated by tandem-ovoid set, from 2017 to 2020. Groupe Européen de Curiethérapie-European Society for Radiotherapy and Oncology (GEC-ESTRO) based target’s volume, ICRU-89 revised version of Manchester points A and B, and ICRU-38 lymph node surrogate points were determined, and their dose was recorded. Paired sample t-test, linear regression analysis, and Pearson correlation analyses were done considering a statistical significance level of 0.05 and using IBM SPSS statistics (Version 23, IBM Crop.).

RESULTS: Seventy-four brachytherapy cases were included. A positive and strong correlation was observed between D₉₀ of clinical target volume (CTV_HR) and points A and B dose for CTV_HR〈 15 cc and 〉 35 cc. Strong and significant (p < 0.05) correlations were achieved between pelvic wall points dose and D₉₀ and D₁₀₀ of the obturator and between D₅₀ and hot points of internal iliac lymph nodes. A strong correlation was obtained between D₅₀ and D₉₀ of external iliac lymph nodes and their ICRU points.

CONCLUSIONS: Strong correlations were obtained between dose to the pelvic lymphatic chains and their historical ICRU-38 surrogate points during HDR brachytherapy of locally advanced cervical cancer patients with 60Co tandem-ovoid applicator sets. The correlation strength between point A and prescription dose highly depends on the CTV_HR volume.

PMID:34750084 | DOI:10.1016/j.brachy.2021.09.007