Rectum separation in patients with cervical cancer for treatment planning in primary chemo-radiation

CT-guided hydrogel injection for brachytherapy in cervical cancer: A case report

Rectal toxicity is a significant concern in cervical cancer radiotherapy. Despite advancements in image-guided brachytherapy (IGBT), rectal morbidity remains a challenge. Injectable hydrogel showed promise in creating a space between the vagina and rectum, reducing rectal radiation dose; however, the traditional ultrasound-guided injection revealed some problems, such as the inadequate separation of the upper edge of the cervix, which can be mitigated through adopting CT-guided injection. This case report presents the successful use of computed tomography (CT)-guided hydrogel injection to limit rectal doses and improve treatment outcomes. A forty-year-old female with stage IIIC1r cervical cancer received external-beam radiotherapy and concurrent chemotherapy. Due to the proximity of the tumor to the rectum, a CT-guided hydrogel injection was performed to increase the distance between the cervix and rectum. Post-injection, magnetic resonance imaging (MRI) demonstrated increased distances between the cervix and rectum. Subsequent MRI-based IGBT achieved high clinical target volume doses while limiting rectal doses. During the six-month follow-up, the patient reported only mild adverse effects. CT-guided hydrogel injection offers advantages over ultrasound-guided injection in cervical cancer radiotherapy. The technique allows for better puncture position adjustment, reduced reliance on specialized ultrasound expertise, and shorter puncture distances. This case report highlights the potential of hydrogel injection as a viable method to reduce rectal morbidity and improve treatment outcomes in a broader range of cervical cancer patients. Further studies are warranted to validate these findings and explore its applicability in larger cohorts.

Integration of Ultrasound in Image-Guided Adaptive Brachytherapy in Cancer of the Uterine Cervix

Cervical cancer continues to be a public health concern, as it remains the second most common cancer despite screening programs. It is the third most common cause of cancer-related death for women, and the majority of cases happen in developing nations. The standard treatment for locally advanced cervical cancer involves the use of external beam radiation therapy, along with concurrent chemotherapy, followed by an image-guided adaptive brachytherapy (IGABT) boost. The five-year relative survival rate for European women diagnosed with cervical cancer was 62% between 2000 and 2007. Updated cervical cancer treatment guidelines based on IGABT have been developed by the Gynecological working group, which is composed of the Group Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology. The therapeutic strategy makes use of three-dimensional imaging, which can be tailored to the target volume and at-risk organs through the use of computed tomography or magnetic resonance imaging. Under anaesthesia, the brachytherapy implantation is carried out. Ultrasonography is utilised to assess the depth of the uterine cavity and to facilitate the dilation of the uterine canal during the application insertion. In this study, we examine data from the international literature regarding the application of ultrasound in cervical cancer brachytherapy.

Gynecological technical notes for appropriate spacer injections

BACKGROUND

Despite its efficacy, if adherence to dose constraints for surrounding normal tissues proves unattainable, the risk of late radiation-related adverse events after primary radiotherapy involving brachytherapy remains a noteworthy concern. Some studies suggest that similar to prostate radiotherapy, spacers may potentially reduce doses to surrounding healthy rectal or bladder tissues. However, guidance on spacer injections for gynecologic brachytherapy is scarce, and the optimal anatomical location for spacer placement remains undefined. We discuss maximizing the effects of spacers from an anatomical perspective.

FINDINGS

As vesicovaginal and rectovaginal septa form part of the endopelvic fascia and are not uniform tissues, spacer injection resistance varies. In pelvic organ prolapse surgery, saline is injected into the anterior and posterior vaginal walls as a spacer, and the vagina, vesicovaginal septum, and bladder can be fluidly dissected. Relatively firm vesicovaginal septum tissue is used as a reconstructive organ, whereas rectovaginal septum tissue is less dense. Cervical cancer is invasive, involving surrounding fascia and ligaments. Ideally, the vesicovaginal and rectovaginal septa should be resected in radical hysterectomy. Here, spacer adaptation and the technical details of injection are described. When using ultrasound guidance for spacer injection, the target site should be adequately magnified, and the spacer ideally injected into the incision layer during radical hysterectomy. Finally, posthysterectomy, the intestinal tract may adhere to the vaginal cuffs. Therefore, artificial ascites may be useful; however, the spread depends on perioperative manipulation.

CONCLUSIONS

Anatomical and surgical viewpoints are advantageous for safe, therapeutic, and replicable spacer injection administration.

SpaceOAR hydrogel spacer in interstitial brachytherapy for intrapelvic recurrent endometrial cancer: a case report

Objective:

We report the use of SpaceOAR hydrogel spacer in interstitial brachytherapy (ISBT) for a patient with intrapelvic recurrent endometrial cancer (EC).

Methods and materials:

A 59-year-old female patient was diagnosed with intrapelvic recurrence of EC after a definitive surgery. Despite administration of adjuvant chemotherapy, the recurrent tumour in the right para-rectal fossa increased in size. Salvage radiotherapy, including external beam radiotherapy followed by ISBT boost, was planned. We planned to inject SpaceOAR between the tumour and rectum to reduce the rectal dose in ISBT; transrectal ultrasound-guided SpaceOAR injection was performed using needle applicator insertion. This was followed by computed tomography-based image-guided brachytherapy.

Results:

The use of SpaceOAR allowed us to achieved both a higher dose for the clinical target volume and a lower dose for the rectum. Furthermore, no ISBT-related complications or acute toxicities were observed.

Conclusions:

The preliminary results suggest that SpaceOAR could be effective in increasing the efficacy of ISBT for intrapelvic recurrent EC, while reducing the associated complications.

Rectum Protection by Rectal Gel Injection in Cervical Cancer Brachytherapy: A Dosimetric Study via Deformable Surface Dose Accumulation and Machine-Learning-Based Discriminative Modeling

PURPOSE

This retrospective study aimed to evaluate the dosimetric effects of a rectal insertion of Kushen Ningjiao on rectal protection using deformable dose accumulation and machine learning-based discriminative modelling.

MATERIALS AND METHODS

Sixty-two patients with cervical cancer enrolled in a clinical trial, who received a Kushen Ningjiao injection of 20 g into their rectum for rectal protection via high-dose rate brachytherapy (HDR-BT, 6 Gy/f), were studied. The cumulative equivalent 2-Gy fractional rectal surface dose was deformably summed using an in-house-developed topography-preserved point-matching deformable image registration method. The cumulative three-dimensional (3D) dose was flattened and mapped to a two-dimensional (2D) plane to obtain the rectal surface dose map (RSDM). For analysis, the rectal dose (RD) was further subdivided as follows: whole, anterior, and posterior 3D-RD and 2D-RSDM. The dose-volume parameters (DVPs) were extracted from the 3D-RD, while the dose geometric parameters (DGPs) and textures were extracted from the 2D-RSDM. These features were fed into 192 classification models (built with 8 classifiers and 24 feature selection methods) for discriminating the dose distributions between pre-Kushen Ningjiao and pro-Kushen Ningjiao.

RESULTS

The rectal insertion of Kushen Ningjiao dialated the rectum in the ambilateral direction, with the rectal column increased from pre-KN 15 cm3 to post-KN 18 cm3 (P < 0.001). The characteristics of DGPs accounted for the largest portions of the top-ranked features. The top-ranked dosimetric features extracted from the posterior rectum were more reliable indicators of the dosimetric effects/changes introduced by the rectal insertion of Kushen Ningjiao. A significant dosimetric impact was found on the dose-volume parameters D1.0cc-D2.5cc extracted on the posterior rectal wall.

CONCLUSIONS

The rectal insertion of Kushen Ningjiao incurs significant dosimetric changes on the posterior rectal wall. Whether this effect is eventually translated into clinical gains requires further long-term follow-up and more clinical data for confirmation.

Development and preclinical testing of a novel biodegradable hydrogel vaginal packing technology for gynecologic high-dose-rate brachytherapy

Purpose

We evaluated the performance of a novel hydrogel-based strategy developed for clinical use as vaginal packing using phantoms and cadavers, and to compare the hydrogel to gauze and balloon packing.

Material and methods

The biocompatible hydrogel is based on a thiol-Michael addition reaction, with delivery of reagents into the vaginal cavity using a custom-made system. Soft-cured cadavers were used for soft tissue-like mechanical properties. Two cadavers with intact uteri had magnetic resonance imaging (MRI) compatible with tandem and ovoids. For one cadaver, the temperature of the vaginal canal was measured before hydrogel application, during polymerization, and after hydrogel removal. The hydrogel packing and applicator was kept in a second cadaver, which was imaged using computed tomography (CT) and MRI. The hydrogel packing and imaging was repeated for an open multichannel MRI compatible, titanium-based vaginal cylinder placed in a post-hysterectomy cadaver.

Results

The gel reaction occurred within 90 seconds, indicating polymerization at clinical quantities with a 5°C increase in vaginal temperature. CT and MRI imaging identified the hydrogel readily and showed a conformance to anatomy with few air pockets. The entire hydrogel packing was readily retrieved upon completion of imaging.

Conclusions

The novel strategy for polyethylene glycol (PEG)-based hydrogel intra-vaginal packing was able to rapidly polymerize in human cadavers with minimal heat production. Delivery was efficient and able to fill the contours of the vaginal cavity and displace tissue away from the applicator axis. The hydrogel has favorable imaging characteristics on CT and MRI, and shows a potential for clinical use, warranting additional studies for the use in humans.

Rectum and bladder spacing in cervical cancer brachytherapy using a novel injectable hydrogel compound

PURPOSE

The aim of this study was to evaluate injection of a novel hydrogel (TraceIT; Augmenix, Waltham, MA) between the cervix, rectum, and bladder in female cadavers compared with, and in addition to, the current standard of gauze packing, for organ-at-risk sparing in cervical cancer brachytherapy planning.

METHODS AND MATERIALS

This brachytherapy cadaver study used T2-weighted MRI and CT imaging to compare three scenarios: (1) gauze packing alone, (2) hydrogel injection placed in the cervical fornices and rectovaginal septum, and (3) gauze packing in conjunction with hydrogel injection. Hydrogel distribution was evaluated. Doses to 2 cm³ volumes (D_2cc) for the rectum, bladder, and sigmoid were collected. Statistical significance (p < 0.05) was evaluated using a two-tailed paired t test.

RESULTS

Hydrogel was successfully injected to space the bladder and rectum from the cervix in all five cadavers. The spacer was easily identifiable on both CT and MRI. The use of hydrogel in addition to packing resulted in a 22% decrease in rectum D_2cc dose (p = 0.02), a 10% decrease in bladder D_2cc (p = 0.27), and no change in sigmoid D_2cc dose. No difference was observed between hydrogel only vs. gauze packing only.

CONCLUSIONS

Our results revealed a significant clinically meaningful decrease in rectal D_2cc associated with the use of hydrogel in addition to gauze packing-TraceIT hydrogel holds promise as a spacer in cervical cancer therapy.

Rectal separation using hydroxypropyl methylcellulose in intracavitary brachytherapy of cervical cancer: an innovative approach

PURPOSE

This study was initiated to prove feasibility of hydrogel application in recto-vaginal space in intracavitary brachytherapy (ICBT) of cervical cancer in order to reduce rectal toxicity.

MATERIAL AND METHODS

In a case of stage IIB cervical cancer, after external beam radiotherapy (EBRT), we planned ICBT 7 Gy × 3 fractions. In 1^st fraction (Plan 1), due to narrow separation between rectum and cervix (0.18 cm), only 5 Gy was delivered at point A (with high-risk clinical target volume [HR-CTV] D₉₀ 5.94 Gy, intermediate risk clinical target volume [IR-CTV] D₉₀ 4.54 Gy, rectum D_2cc 5.72 Gy, bladder D_2cc 5.52 Gy, and sigmoid colon 5.82 Gy). In 2^nd fraction (Plan 2), interstitial brachytherapy (ISBT) was attempted. For the prescription of 5 Gy, we get dose levels almost similar to the 1^st insertion: HR-CTV D₉₀ (6.7 Gy), IR-CTV D₉₀ (3.06 Gy), bladder D_2cc (5.7 Gy), rectum D_2cc (4.8 Gy), sigmoid colon D_2cc (1.3 Gy) (separation = 0.23 cm). During 3^rd fraction (Plan 3), prior doing interstitial insertion, we instilled 50 cc of hydroxypropyl methylcellulose (Viscomet^®) up to the tip of recto-vaginal septum. A repeat computed tomography (CT) scan was done 4 hours after Plan 3 treatment and it was re-planned (Plan 4) to find out migration of hydrogel if any and its dosimetric impact.

RESULTS

9 Gy was delivered to point A with a separation of 1.1 cm in Plan 3 (with HR-CTV D₉₀ 16.4 Gy, IR-CTV D₉₀ 11.3 Gy, rectum D_2cc 3.6 Gy, bladder D_2cc 6.9 Gy, and sigmoid colon 2.2 Gy). We achieved an optimum cumulative EQD₂ dose (HR-CTV D₉₀ 98.4 Gy, IR-CTV D₉₀ 76.1 Gy, rectum D_2cc 67.7 Gy, bladder D_2cc 73.2 Gy, and sigmoid colon 59.3 Gy). Hydrogel volume was decreased in Plan 4 without a major dosimetric changes.

CONCLUSIONS

Hydrogel instillation is a useful tool for recto-vaginal separation during cervical cancer brachytherapy. It increases therapeutic ratio without any adverse event.

Potential role of ultrasound imaging in interstitial image based cervical cancer brachytherapy

In 2012, more than 500,000 cases of cervical cancer were diagnosed worldwide. Over three quarters of these cases occur in less developed countries [1]. Advancements in image-guided brachytherapy are resulting in improved outcomes and reduced morbidity for women with this disease, but its worldwide adoption is hampered by lack of accessibility to advanced imaging techniques. Ultrasound is emerging as a potential option for tumor visualization, brachytherapy catheter placement, and treatment planning. While additional work is needed, ultrasound can potentially serve as the sole imaging modality for catheter insertion and planning. This paper will review our current knowledge on the use of ultrasound in interstitial brachytherapy treatment for cervical cancer.

A new laparoscopic method of bowel radio-protection before pelvic chemoradiation of locally advanced cervix cancers

BACKGROUND

Chemoradiation therapy (CRT) has become the mainstay of locally advanced cervical carcinomas (LACC). However, the price to pay is a significant rate of both early and late colo-rectal toxicities, which may impact on survivors' quality of life. To reduce the incidence of such complications, we suggest a simple technique of pelvic radioprotection.

MATERIALS AND METHODS

An omental flap is created which is placed to fill the Douglas pouch to both increase the space between rectum and uterine cervix and prevent small bowel to fall in and to be exposed to radiation. In addition, a long sigmoid loop is retracted and fixed in the left paracolic gutter to prevent its irradiation as well.

RESULTS

From May 2011 to May 2012, 51 successive LACC patients were offered this procedure in addition of a laparoscopic staging. All but 2 with too small an omentum benefitted from omentoplasty, while sigmoidopexy was performed in all but one patient with a long and free sigmoid loop. No immediate adverse effect was observed. The volume of retro-uterine omental flap averaged 7.17 ± 3.79 cm(3). Sequential measurements of the utero-rectal space throughout CRT duration showed a real and durable increase in the distance between these organs, resulting in a drop in the dose of irradiation to recto-sigmoid. With 10 ± 4.5-month median follow-up, we did not observe any rectal or small bowel early or late adverse effects of CRT.

CONCLUSIONS

Although this series is preliminary, this simple procedure, feasible by laparoscopy (or laparotomy), seems effective to prevent recto-sigmoid as well as small bowel from radio-induced complications due to pelvic CRT.

Serum zinc as a prognostic indicator in locally advanced cancer cervix patients receiving chemo-irradiation: A pilot study

Objective:

To evaluate the prognostic significance of serum Zinc (S.Zn) in locally advanced cancer cervix (LACC) patients treated with chemo-irradiation.

Materials and Methods:

S.Zn values in 34 females with histopathologically (HP) proven LACC (>/= stage II B) were prospectively measured using atomic absorption spectrophotometer pre- and post-treatment. Thirty-four age- and sex-matched healthy individuals were also evaluated for the parameter during the course of the study. After completion of treatment, the patients were divided into 2 groups based on the response, 1 - Complete response (CR) and 2 - Partial/No response (PR/NR). These groups were compared based on the observations of the studied parameter.

Results:

The mean post-treatment S.Zn values were significantly higher in group 1 as compared to group 2 (P < 0.05).

Conclusion:

In our study, patients achieving CR had higher mean levels of S.Zn compared to patients achieving PR/NR. We advocate further in-depth studies to evaluate the role of S.Zn in the prognosis of LACC patients treated with chemo-irradiation.