3D-printed free-assembled template speeds needle placement and boosts dose coverage in cervical cancer brachytherapy

Researchers at Sichuan Cancer Hospital have developed a 3D-printed, free-assembled interstitial template (FAIT) for treating locally advanced cervical cancer with brachytherapy, and a new dosimetric study reports that it improved target coverage while shortening the time needed to place needles. In a prospective paired comparison of 55 patients, each of whom underwent both template-guided and free-handed interstitial brachytherapy procedures, the FAIT-guided approach delivered a higher radiation dose to the high-risk clinical target volume and cut implantation time by more than two minutes, with no significant difference in doses to organs at risk.

The study enrolled consecutive patients with FIGO 2018 stage IB3, IIA2, and IIB to IVA disease between February and September 2025. All patients had first received pelvic external beam radiotherapy of 45–50.4 Gy delivered in 25–28 fractions. Most participants had stage IIB disease (34 of 55, or 61.8%) and squamous cell carcinoma (49 of 55, or 89.1%), and the mean post-external-beam high-risk clinical target volume was 61.8 ± 21.3 cubic centimeters. Within three days, each patient underwent both procedures in a randomly assigned sequence, allowing each patient to serve as her own control.

The template itself is a novel design featuring a tandem with optimized non-coplanar needle channels, produced by 3D printing and assembled freely rather than requiring a custom-fabricated fixed template. In the FAIT-guided procedures, clinicians used an average of 4.88 ± 0.90 interstitial needles, compared with 4.76 ± 1.24 in the free-handed procedures, a difference that was not statistically significant (P = 0.30). The comparable needle counts suggest that the template’s benefit did not come from simply placing more needles.

The dosimetric results favored the template-guided approach. The high-risk clinical target volume D90, the dose received by 90% of the target volume, averaged 611.38 ± 35.12 cGy with FAIT guidance versus 580.86 ± 64.65 cGy with free-handed placement, a statistically significant difference (P < 0.01). Because the prescription was 600 cGy in both arms of the comparison, the template-guided plans on average met or exceeded the prescribed dose to the target, while the free-handed plans fell below it on average. Doses to organs at risk, measured as D1cc and D2cc for the bladder, rectum, sigmoid and bowel, were similar between the two techniques (P > 0.05), indicating that the improved target coverage did not come at the cost of higher exposure to nearby healthy structures.

Implantation time showed one of the clearest differences between the techniques. FAIT-guided needle placement took an average of 5.83 ± 1.93 minutes, compared with 8.03 ± 2.71 minutes for free-handed placement, a reduction that was highly statistically significant (P < 0.0001). Shorter implantation times can reduce the duration of a procedure that patients undergo with each brachytherapy fraction, and the authors suggest this procedural efficiency is one of the template’s practical advantages.

Treatment planning was performed in the Oncentra planning system with a 600 cGy prescription for all procedures. Dosimetric parameters, including the target D90 and organ-at-risk doses, were extracted from the plans, and the number of interstitial needles and the implantation time were recorded for each procedure. Data were presented as mean ± standard deviation and compared using paired Student’s t-tests, with statistical significance defined as P < 0.05. The paired design, in which the same patients received both techniques, strengthens the internal comparison by controlling for individual differences in tumor size and anatomy.

The study’s authors conclude that improved target volume dose coverage and shortened needle implantation time were achieved with the novel 3D-printed FAIT, and that the template had high clinical utility and was worthy of further promotion and application. The findings are limited to dosimetric and procedural outcomes: the study did not report long-term clinical results such as tumor control, survival, or toxicity follow-up, and the procedures were performed at a single institution by a single team. Because the article is being shared early as a peer-reviewed accepted manuscript, it remains subject to further editorial edits before the final version of record.

Interstitial brachytherapy plays an important role in the management of locally advanced cervical cancer after external beam radiotherapy, and guidance templates have been expected to improve target coverage while sparing organs at risk. The present study offers prospective, paired evidence that a freely assembled, 3D-printed template can deliver on both of those goals in a single device, combining better dose coverage of the target with faster needle placement and unchanged organ-at-risk doses. Further studies will be needed to establish whether these dosimetric and procedural gains translate into improved clinical outcomes for patients with locally advanced cervical cancer.

Subject of Research: A 3D-printed free-assembled interstitial template for brachytherapy of locally advanced cervical cancer

Article Title: A novel free-assembled template for interstitial brachytherapy of locally advanced cervical cancer: a dosimetric study

Article References: Liang, R., Peng, Q., Yan, G., Ma, J., Huang, D., Bi, B., Tang, T., Lu, S., Wang, X., Tan, Y., & Zhu, J. (2026). A novel free-assembled template for interstitial brachytherapy of locally advanced cervical cancer: a dosimetric study. BMC Cancer. https://doi.org/10.1186/s12885-026-17241-2

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17241-2

Keywords: brachytherapy, cervical cancer, 3D printing, interstitial template, dosimetry, radiation oncology, HRCTV D90, organs at risk, needle implantation, prospective study, high-dose-rate brachytherapy, gynecologic oncology