Temporary intraperitoneal breast implant spacer to facilitate safe stereotactic body radiotherapy for recurrent high-grade serous ovarian carcinoma

Highlights

• •Temporary intraperitoneal spacers can facilitate safe SBRT in recurrent ovarian cancer.
• •Physical displacement of bowel may reduce radiotherapy-related toxicity.
• •Spacer-assisted SBRT expands options for anatomically challenging recurrences.
• •This approach offers local control when surgery or systemic options are limited.
• •Collaboration with radiation oncology enables organ-sparing local therapy.

Abstract

Background

Recurrent ovarian cancer involving the upper abdomen can be challenging to treat with radiation therapy due to the proximity of bowel. Spacer technologies have been used in other malignancies to displace radiosensitive organs, but they are not routinely employed in gynecologic oncology.

Case

We report the case of a 71-year-old woman with a germline BRCA1 mutation and recurrent high-grade serous carcinoma following secondary cytoreduction with right hepatectomy and diaphragmatic resection. Surveillance imaging demonstrated a right upper quadrant abdominal wall recurrence overlying the hepatic flexure, precluding safe stereotactic body radiation therapy (SBRT). Following multidisciplinary review, the patient underwent an exploratory laparotomy with adhesiolysis and placement of a saline-filled breast implant in the right upper quadrant to exclude bowel from the radiation field. Postoperative CT confirmed displacement of the colon, and the patient subsequently received one fraction of SBRT to the abdominal wall. The implant was removed uneventfully two days later. The patient recovered well, and subsequent imaging two months later showed the desired reduction in RUQ disease.

Conclusion

This is the first report, to our knowledge, of the use of a breast implant as a temporary spacer to facilitate safe SBRT in recurrent ovarian cancer. This removable, cost-effective approach offers a feasible solution for anatomically constrained upper abdominal recurrences in close proximity to the bowel.

1. Introduction

Ovarian cancer is the leading cause of gynecologic cancer mortality, with the majority of patients presenting at an advanced stage and experiencing disease recurrence despite aggressive multimodal therapy (Gardner and Chi, 2021, Huo et al., 2025). For selected patients with oligometastatic recurrence, stereotactic body radiotherapy (SBRT) can provide durable local control and palliation (Macchia et al., 2022, Albuquerque et al., 2019). However, lesions abutting the bowel often limit the safe delivery of high-dose radiation due to the risks of enteritis, perforation, or fistula formation (Barney et al., 2012).

Spacer technologies have been developed in other fields of oncology to mitigate these risks and displace critical organs from recurrent sites. The use of perirectal spacers in prostate cancer has demonstrated significant reductions in rectal dose and toxicity during radiotherapy (Miller et al., 2020 Jun 1, Hamstra et al., 2017). Similarly, temporary tissue expanders and balloon devices have been utilized in hepatobiliary, pancreatic, and retroperitoneal cancers to separate bowel from the treatment field (Kosugi et al., 2007, Kishi et al., 2012). In gynecologic oncology, the few reports of spacer use are limited to placement in the lower pelvis for cervical, endometrial, and vulvar cancers (Fatima and Fatima, 2025, Geller et al., 2009 Apr).

We present the case of a woman with BRCA1-associated recurrent high-grade serous ovarian carcinoma with a right upper quadrant abdominal wall recurrence in close proximity to the hepatic flexure. A surgically placed, temporary breast implant spacer was used to displace the bowel and enable safe SBRT. To our knowledge, this represents the first description of breast implant use as a temporary intraperitoneal spacer in the treatment of an abdominal wall recurrence in ovarian cancer.

2. Case description

A 71-year-old gravida 3 para 3 woman with a germline BRCA1 3600del11 mutation and strong family history of breast and ovarian cancer presented to our gynecology practice in October 2023 with right upper quadrant (RUQ) pain, anorexia, fatigue, and weight loss. Her past medical history included hypertension, hyperlipidemia, and gastroesophageal reflux disease. She had previously undergone a risk-reducing total abdominal hysterectomy with bilateral salpingo-oophorectomy in 1998 and prophylactic bilateral mastectomies in 2012.

Initial evaluation with abdominal ultrasound (US) and CT revealed a 17 cm right hepatic lobe mass with thoracic and abdominal lymphadenopathy. An esophagogastroduodenoscopy yielded normal findings and benign biopsies of the stomach and duodenum. US-guided biopsy of the liver lesion demonstrated a high-grade serous carcinoma of gynecologic origin (positive for PAX-8, WT-1, ER, and aberrant p53). Tumor biomarker testing at diagnosis demonstrated positive folate receptor-α (FOLR1) expression and negative HER2 expression. PET scan showed significant liver involvement and extensive metabolic lymphadenopathy, without a pelvic mass.

Given extensive disease and hepatic dysfunction, the patient was initiated on neoadjuvant carboplatin and weekly dose-dense paclitaxel. She received 7 cycles of carboplatin-paclitaxel, resulting in marked radiographic and biochemical response, including reduction in hepatic disease burden and normalization of CA-125. Given this excellent response and desire to further downstage liver involvement in preparation for resection, an additional 7 cycles of platinum-based therapy were administered following consult with Hepatobiliary Surgery. Carboplatin-docetaxel was chosen to minimize worsening neuropathy.

She subsequently underwent a right hepatectomy with diaphragmatic resection, primary diaphragm repair, and cholecystectomy with no evidence of residual disease. Following the resection, final pathology demonstrated near-complete response to neoadjuvant therapy, so the patient was re-initiated on a platinum-based regimen for consolidation. Carboplatin and liposomal doxorubicin were selected to avoid worsening taxane-related neuropathy. Nodal disease, including a right cardiophrenic lymph node, demonstrated interval improvement on serial imaging and was managed non-operatively with systemic therapy and surveillance. After four cycles of adjuvant therapy, she was transitioned to PARP inhibitor maintenance, with niraparib chosen for its activity in BRCA-mutated disease and tolerability considerations. Bevacizumab was deferred and reserved for later lines of therapy if necessary based on institutional practices at the time and considerations around bleeding and wound-healing risks if re-operation were needed. Her treatment timeline is outlined in Table 1.

Table 1.

Summary of diagnostic, treatment, and recurrence timeline.

Date	Event/Treatment
Dec 1998	Risk-reducing total abdominal hysterectomy and bilateral salpingectomy for BRCA1 carrier status. Pathology with benign dermoid cysts.
Feb 2012	Prophylactic bilateral nipple-sparing mastectomy with reconstruction
Oct 2023	Presented with RUQ pain, anorexia, weight loss; imaging shows 17 cm right hepatic mass. US-guided liver biopsy demonstrated high-grade serous carcinoma of gynecologic origin.
Nov 2023 – Apr 2024	Neoadjuvant chemotherapy with carboplatin and paclitaxel for 7 cycles
Apr – Sep 2024	Paclitaxel switched to docetaxel for neuropathy. Underwent additional 7 cycles of carboplatin and docetaxel.
Oct 25, 2024	Right hepatectomy, diaphragmatic tumor resection with repair, and cholecystectomy
Dec 2024 – Mar 2025	Four cycles of adjuvant carboplatin and doxorubicin.
Apr 2025	SBRT (24 Gy/3 fx) to right cardiophrenic node. Maintenance niraparib initiated.
Jul 2025	PET/CT with progression of right upper quadrant abdominal wall/peritoneal implant adjacent to hepatic flexure (max SUV 25)
Sep 10, 2025	Exploratory laparotomy, adhesiolysis, placement of breast implant spacer
Sep 15, 2025	SBRT (20 Gy/1 fx) to RUQ abdominal wall lesion
Sep 17, 2025	Exploratory laparotomy, removal of breast implant spacer
Sep 18, 2025	Discharged; uneventful postoperative recovery
Sep 29, 2025	Follow-up visit: clinically well, continued maintenance niraparib
November 24, 2025	PET/CT with interval decrease in RUQ implants with new SUV of 2.9

Four months later, surveillance imaging with PET/CT demonstrated mild uptake in a right cardiophrenic node and irregular nodularity in the RUQ abutting the hepatic flexure of the colon. The cardiophrenic node was treated with SBRT (24 Gy in 3 fractions) with good local control. Cell-free DNA analysis was performed and confirmed sensitivity to PARP inhibitor therapy, as no reversion mutation was detected. At this time, it was unclear whether the uptake in the RUQ was post-surgical in nature versus neoplastic, so we opted for continued surveillance and maintenance niraparib. A subsequent PET/CT scan demonstrated progression of the RUQ nodularity with presumed peritoneal implants in close proximity to the ascending colon and a maximum standardized uptake value (SUV) of 25 (Fig. 1). Therefore, tumor board consensus favored SBRT followed by resumption of niraparib, but bowel proximity posed prohibitive risk of gastrointestinal toxicity.

Fig. 1.

PET/CT prior to spacer placement demonstrating a hypermetabolic nodule in the right upper quadrant abutting the hepatic flexure (maximum SUV 25). This finding corresponds to the patient’s recurrent peritoneal implant located immediately adjacent to the ascending colon prior to spacer placement.

Other local treatments such as cryotherapy and radiofrequency ablation were considered but were also limited by anatomical constraints. After numerous multidisciplinary discussions, the patient consented to operative bowel mobilization and placement of a temporary spacer to facilitate safe SBRT. She underwent exploratory laparotomy, extensive adhesioloysis, mobilization of the hepatic flexure, and placement of a 950 mL saline-inflated breast implant in the RUQ, which was sutured to the diaphragm and paracolic gutter. Postoperative CT confirmed adequate bowel displacement (Fig. 2).

Fig. 2.

Contrast-enhanced CT following exploratory laparotomy and placement of a saline-filled breast implant in the right upper quadrant. Coronal (A) and sagittal (B) views show successful displacement of the hepatic flexure medially by the implant. The axial view (C) demonstrates the location of the target lesion relative to the temporary spacer and adjacent bowel (outlined in yellow). The SBRT treatment plan shows the adequate displacement that allowed for delivery of a single 20 Gy fraction while meeting dose constraints for organs at risk. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

On postoperative day (POD) 1, she underwent SBRT simulation using intensity modulated radiation therapy to optimize dose constraints with the spacer in place. A single fraction of 20 Gy was delivered on POD 5 without complication, and the implant was removed on POD 7 with minimal blood loss. For both spacer placement and removal, perioperative care followed institutional enhanced recovery principles, including preoperative antibiotic prophylaxis with cefazolin, multimodal analgesia, and intraoperative transversus abdominis plane blocks. The patient tolerated both procedures well without complications, and postoperative pain was adequately controlled. She was discharged on POD 2 following implant removal and resumed maintenance niraparib at her two-week follow up visit. Next-generation sequencing was performed following this operation and did not identify further actionable alterations beyond the patient’s known germline BRCA1 mutation. A post-treatment PET/CT two months later demonstrated interval decrease in the previously present hypermetabolic peritoneal implant along the right colon, with a new max SUV of 2.9 compared to 25 previously.

3. Discussion

Recurrent high-grade serous ovarian carcinoma typically requires multimodal management, including systemic therapy, surgical cytoreduction, and increasingly, local ablative approaches such as SBRT for oligometastatic disease (Gardner and Chi, 2021, Huo et al., 2025, Macchia et al., 2022, Albuquerque et al., 2019). However, recurrent or metastatic lesions in the upper abdomen present a particular challenge when abutting radiosensitive bowel (Barney et al., 2012). This case describes a novel strategy using a temporary surgical spacer to deliver safe, high dose local therapy in this context.

Treatment of locally recurrent ovarian cancer should be individualized to the patient, disease location, and tumor characteristics. Surgical excision may be considered for isolated, resectable lesions in patients with good performance statuses, but repeat surgery in previously treated or irradiated fields carries significant morbidity and limited benefit when disease is near vital structures (Gardner and Chi, 2021). In this case, surgical resection of the recurrent lesion was considered but deferred due to its proximity to critical structures, concern for dense adhesive disease in the region of prior excision, and limited ability to safely access the diaphragm for complete resection. When this decision is unclear, diagnostic laparoscopy may be considered to clarify disease distribution and surgical feasibility of an optimal debulk prior to laparotomy. For this patient, diagnostic laparoscopy was discussed but deferred given the localized nature of recurrence based on multimodal imaging studies and the anticipated need for spacer placement rather than cytoreduction.

Re-irradiation is an option in select cases but is restricted by cumulative dose limits and heightened risk of bowel perforation or fistula formation. SBRT alone offers noninvasive local control and can achieve high response rates in oligometastatic gynecologic disease, but dose-constraints limit the ability to deliver curative-intent therapy (Macchia et al., 2022, Albuquerque et al., 2019). In such scenarios, spacer placement can create a physical buffer zone that expands the therapeutic window, enabling safe delivery of ablative SBRT where neither surgery nor re-irradiation would be otherwise feasible or effective.

Spacer technologies are more frequently employed in treatment of non-gynecological malignancies, with their efficacy most established in prostate cancer (Miller et al., 2020 Jun 1, Hamstra et al., 2017). Prospective trials have demonstrated clear reductions in rectal dose and toxicity with hydrogel spacers during prostate radiotherapy, improving long-term quality of life (Hamstra et al., 2017). The application of spacers in other tumor types, such as hepatobiliary and pancreatic malignancies, remains largely investigational and case based, but the limited evidence suggests high efficacy with significant risk reduction (Kosugi et al., 2007, Kishi et al., 2012).

In gynecologic oncology, spacer use is limited and explored primarily in the pelvic setting. Early studies evaluated saline-filled tissue expanders placed during postoperative radiation for uterine malignancies, demonstrating that bowel loops could be excluded from the lower pelvis with reduced radiotoxicity, but with risks of migration and fistula formation (Geller et al., 2009 Apr, Zouhair et al., 2000). More recent studies have described hydrogel injections into the rectovaginal septum or meso-sigmoid during cervical cancer brachytherapy, which enables higher tumor dosing with acceptable toxicity (Murakami et al., 2022, Inoue and Murakami, 2022). Utilization of a bioabsorbable spacer has also been reported for use in brachytherapy for recurrent cervical cancer (Okuma et al., 2025 Sep 23).

To our knowledge, we describe the first usage of a breast implant as a temporary intraperitoneal spacer to enable SBRT for an upper abdominal wall recurrence of ovarian cancer. The implant was sewn to the diaphragm and paracolic gutter, providing durable displacement of the bowel throughout radiotherapy. The saline-filled implant served primarily as a physical spacer rather than a radiation attenuator, and no clinically meaningful dose perturbation or scatter were identified in multidisciplinary planning efforts. Use of a breast implant offered several advantages; it was readily available, biocompatible, removable, and could be filled to a volume sufficient to achieve substantial bowel displacement. Compared to hydrogels or balloons, breast implants are cost-effective, accessible, and can be surgically anchored in complex anatomic regions. Our utilization of SBRT allowed for the delivery of high dose, targeted radiation in a single fraction, which facilitated completion of this multimodal treatment within a single inpatient admission. The temporary spacer was easily removed without complication following radiation, and the short duration of implantation may mitigate previously reported risks of migration and fistula formation in other cases (Geller et al., 2009 Apr).

Key limitations of this approach include the need for laparotomy and extensive adhesiolysis, which carry inherent risks, particularly in heavily pretreated patients. This technique may not be generalizable to all patients with upper abdominal recurrences, and careful multidisciplinary planning is essential to weigh operative risks against anticipated radiotherapy benefits. Long-term outcomes following this strategy remain unknown.

This case highlights the potential of spacers to extend local treatment options for oligometastatic disease, re-irradiation scenarios, or recurrences in surgically altered fields, where conventional radiation would be otherwise contraindicated. For patients with anatomically constrained recurrent ovarian cancer, surgical spacer placement may increase the feasibility of SBRT by enabling safe delivery of ablative doses while minimizing risk. Integrating this strategy into multidisciplinary planning could broaden local therapy options and improve quality of life for selected patients.

CRediT authorship contribution statement

Caleigh E. Smith: Writing – review & editing, Writing – original draft, Visualization. Emilie K. Sandfeld: Writing – review & editing, Writing – original draft. Sheen Cherian: Writing – review & editing, Visualization, Conceptualization. Peter G. Rose: Writing – review & editing, Supervision, Conceptualization.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.