Combined intra-cavitary and interstitial image-guided adaptative brachytherapy for cervical stump carcinomas: technical and clinical results of six patients

Purpose
According to European guidelines for cervix cancers, the management of cervical stump cancers should follow recommendations for patients without previous sub-total hysterectomy, but may require adaptation of radiotherapy modalities, especially brachytherapy (BT). However, data with modern BT technics are very scarce.

Material and methods
From May 2013 to March 2020, 6 patients (age range, 71-88 years) with cervical stump squamous cell carcinoma (previously treated by sub-total hysterectomy) have been treated with external beam radiotherapy (intensity-modulated radiation therapy – IMRT, 45 Gy in 25 fractions, 5 patients, or 50.4 Gy in 28 fractions, 1 patient), with concomitant chemotherapy in 2 patients, followed by image-guided adaptive brachytherapy with pulsed-dose-rate in 5 patients or high-dose-rate in 1 patient. We used Utrecht BT applicator (Elekta®), with the implant of interstitial needles within the parametrium (unilaterally in 3 and bilaterally in 3 patients), and/or within the residual cervix (3 patients). Dosimetry was based on GEC-ESTRO recommendations.

Results
The median high-risk (HR) and intermediate-risk (IR) clinical target volumes (CTV ) were 14.5 cc (range, 12-35 cc) and 40 cc (range, 31-62 cc), respectively. The median dose (D90) delivered to HR and IR CTVs were 81.2 (range, 78.2-89.8) and 68.95 (range, 64.3-72.3) Gy EQD2, respectively. With a 26.5 months median follow-up (range, 10-92 months), we did not observe any local or distant recurrence. No grade 2 or more acute or late toxicities were reported.

Conclusions
Cervix brachytherapy with Utrecht applicator using interstitial needle is safe and effective in cervical stump cancer patients.