Surgical Spacer Placement Research Articles

Surgical spacer placement for proton radiotherapy in locally advanced pancreatic body and tail cancers: initial clinical results

BackgroundParticle radiotherapy has increasingly gained acceptance for locally advanced pancreatic cancers owing to superior tumor conformity and dosimetry compared to conventional photon radiotherapy. However, the close proximity of the pancreas to the stomach and duodenum leads to radiation-induced gastrointestinal toxicities, which hinder the delivery of curative doses to the tumor. To overcome this problem, a surgical spacer was placed between the tumor and gastrointestinal tract, and subsequent proton radiotherapy was performed in this study.MethodsData from 9 patients who underwent surgical spacer placement and subsequent proton radiotherapy were analyzed. The safety and feasibility of the spacer placement surgery were evaluated; the impact of the spacer on dosimetry was also assessed using dose volume histogram (DVH) analyses, before and after surgical spacer placement.ResultsSurgical spacer placement and subsequent proton radiotherapy were successfully completed in all cases. Surgical spacer placement significantly improved the dose intensity covering 95%, mean, and minimum doses for the gross tumor volume, and the clinical and planning target volume based on the DVH, while respecting the dose constraints of the gastrointestinal tract. Based on the Common Terminology Criteria for Adverse Events, two patients (22.2%) developed gastrointestinal ulcer (Grade 2) at 1 and 35 months, and one patient (11.1%) developed gastric perforation (Grade 4) at 4 months after proton radiotherapy.ConclusionsSurgical spacer placement in the locally advanced pancreatic body and tail cancers is relatively safe and technically feasible. Comparing radiation plans, surgical spacer placement seems to improve the dose distribution in the locally advanced pancreatic body and tail cancers, which are close to the gastrointestinal tract.

Space-making particle therapy for sarcomas derived from the abdominopelvic region

BackgroundThe primary definitive treatment for abdominopelvic sarcomas (APSs) is resection, although incomplete resection has a negative prognostic impact. Although the effectiveness of particle therapy (PT) as a treatment for APS has already been demonstrated, its application for tumors adjacent to the gastrointestinal tract is frequently restricted, due to extremely low tolerance. Space-making PT, consisting of surgical spacer placement and subsequent PT, has been developed to overcome this limitation. Materials and methodsBetween June 2006 and June 2018, a total of 75 patients with 12 types of APS underwent space-making PT. ResultsThe 3-year local control rate of all patients was 90.3%. Fourteen surgery-related complications were observed in 12 patients (16%), and complications of Grade 3b or higher were observed in 3 patients. Ninety-five PT-related complications were seen in 66 patients (88.0%), and 13 patients (17.3%) had complications of Grade 3 or higher. The median V95% (volume irradiated with 95% of the treatment planning dose) of the gross tumor volume and clinical target volume were 99.9% and 99.5%, respectively. The median D95% (dose intensity covering 95% of the target volume) of the gross tumor volume/planned dose and clinical target volume/planned dose were 99.4%, and 99.1%, respectively. ConclusionThe feasibility and effectiveness of space-making PT have been demonstrated via dosimetric evaluation, and our results indicate that this new strategy may potentially provide an effective and innovative treatment option for advanced APS.

Surgical spacer placement using an expanded polytetrafluoroethylene sheet in proton beam therapy for pediatric solid tumors

Surgical spacer placement using an expanded polytetrafluoroethylene sheet in proton beam therapy for pediatric solid tumors

Space-Making Particle Therapy with Surgical Spacer Placement in Patients with Sacral Chordoma

Sacral chordomas are rare malignant bone tumors and are often very large for complete resection. Particle therapy for these tumors, which are adjacent to the gastrointestinal tract, is restricted because the tolerance dose of the intestine is low. This study aimed to demonstrate the technical aspects and treatment results of space-making particle therapy with surgical spacer placement for sacral chordoma. We aimed to investigate the dosimetric change in the particle therapy before and after spacer placement and the safety, efficacy, and long-term outcomes of space-making particle therapy. Twenty-one patients with sacral chordomas who were excluded from typical particle therapy were enrolled between 2007 and 2015. Gore-Tex sheets (WL Gore & Assoc) were folded and placed between the sacral and rectum. Particle therapy with 70.4 Gy (relative biologic effectiveness) was then performed. The mean volume that allows 95% of the treatment plan dose of the gross tumor volume and clinical tumor volume after spacer placement was improved to 97.7% and 96.4% from preoperative values of 91.0% and 89.5%, respectively. The recurrence rate within the gross tumor volume was only 4.8%. The 4-year local progression-free survival rate was 68.4%. The 5-year overall survival rate was 100% and the adverse events were acceptable. Considering improvements in the dose-volume histogram after spacer placement, low recurrence rates within the gross tumor volume, good survival rates, and low incidences of side effects, treatment of sacral chordoma with space-making particle therapy shows promise.

In silico comparison of the dosimetric impacts of a greater omentum spacer for abdominal and pelvic tumors in carbon-ion, proton and photon radiotherapy

PurposeThe purpose of this study was to compare carbon-ion (C-ion), proton and photon radiotherapy (RT) plans with regard to dose reduction of the gastrointestinal (GI) tract by using a greater omentum spacer (GO spacer).MethodsWe retrospectively retrieved data for ten patients who received the GO spacer as surgical spacer placement for abdominal and pelvic tumors. Simulation plans were created on pre-spacer Computed Tomography (CT) and post-spacer CT for C-ion RT, proton RT and photon RT to compare the dose of the GI tract. The plans were normalized so that at least 95% of the planning target volume (PTV) received 70 Gy (relative biological effectiveness equivalent) delivered in 35 fractions. All plans were created with the lowest possible dose to the GI tract under conditions that meet the dose constraints for the PTV and spinal cord (maximum dose < 45 Gy). The part of the GI tract to be evaluated was defined as that most adjacent to the PTV. C-ion RT plans and proton RT plans were calculated by a spot scanning technique, and photon RT plans were calculated employing by fixed-field intensity-modulated radiation therapy.ResultsD2 cc and V10–70 of the GI tract were significantly lower on post-spacer plans than on pre-spacer plans for all three RT modalities. Regarding post-spacer plans, D2 cc of the GI tract was significantly lower on C-ion RT plans and proton RT plans than on photon RT plans (C-ion vs photon p = 0.001, proton vs photon p = 0.002). However, there was no significant difference between C-ion RT plans and proton RT plans for D2 cc of the GI tract (C-ion vs proton p = 0.992). In the photon RT plan for one patient, D2 cc of the GI tract did not meet < 50 Gy.ConclusionsThe GO spacer shows a significant dose reduction effect on the GI tract.

First-in-Human Phase I Study of a Non-Woven Fabric Bioabsorbable Spacer Combined with Particle Therapy Against Abdominal or Pelvic Sarcomas

Surgical spacer placement (SSP) is useful in particle therapy (PT) for patients with abdominal or pelvic tumors located adjacent to normal organs. We developed a non-woven fabric bioabsorbable spacer made of polyglycolic acid sutures that degrades via hydrolysis. We then conducted this first-in-human phase I study of the combination of SSP and PT using the PGA spacer and we termed space-modulated particle therapy (SMPT). This study aimed to evaluate the safety and efficacy of SMPT in patients with unresectable malignant tumor located adjacent to normal organs. The eligibility criteria included histologically proven malignant abdominal or pelvic tumor adjacent to the intestines, no metastasis, and no previous radiotherapy. Periodic computed tomography (CT) images were obtained before SSP and before, during, and after PT until the spacer disappeared. Treatment planning was performed for each CT image set until the end of PT, and doses for the planning target volume (PTV) and organs at risk were analyzed. The thickness and volume of the PGA spacer were measured in each CT image set. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Events v4.0. Five patients were enrolled in this study. All patients received 70.4 Gy (RBE) of irradiation. V95% of the PTV before SSP, at the beginning of PT, and at the end of PT was 82.1±11.3%, 98.1±1.1%, and 97.1±0.8%, respectively. The PGA spacers maintained enough thickness (≥ 1 cm) until the end of PT and disappeared within 8 months after SSP in all patients. No grade ≥3 acute adverse events were observed. The SMPT is feasible and useful for abdominal or pelvic tumors adjacent to the intestines. This method may be applicable to unresectable tumors located adjacent to normal organs and may expand the indications of particle therapy.

Validation of combination treatment with surgical spacer placement and subsequent particle radiotherapy for unresectable hepatocellular carcinoma.

Validation of combination treatment with surgical spacer placement and subsequent particle radiotherapy for unresectable hepatocellular carcinoma.

Surgical spacer placement prior carbon ion radiotherapy (CIRT): an effective feasible strategy to improve the treatment for sacral chordoma

BackgroundSacral chordoma (SC) is a neoplasm arising from residual notochordal cells degeneration. SC is difficult to manage mainly because of anatomic location and tendency to extensive spread. Carbon ion radiotherapy (CIRT) is highly precise to selectively deliver high biological effective dose to the tumor target sparing the anatomical structure on its path even if when SC is contiguous to the intestine, and a surgical spacer might be an advantageous tool to create a distance around the target volume allowing radical curative dose delivery with a safe dose gradient to the surrounding organs. This paper describes a double approach—open and hand-assisted laparoscopic—for a silicon spacer placement in patients affected by sacral chordoma undergoing carbon ion radiotherapy.MethodsSix consecutive patients have been enrolled for surgical spacer placement—open (three) or hand-assisted (three)—prior carbon ion radiotherapy treatment in order to increase efficacy of carbon ion radiotherapy minimizing its side effects.ResultsResults showed that silicon spacer placement for SC treatment is feasible both via laparoscopic and laparotomic approach.ConclusionsIts use might improve CIRT safety and thus efficacy for SC treatment.

後腹膜脂肪肉腫術後再発に対してスペーサー手術および陽子線照射による2段階治療が奏効した1例

症例は53歳の男性で，脱分化型後腹膜脂肪肉腫およびその局所再発に対して，3回の開腹手術が施行された．3回目の手術では腫瘍が大動脈に浸潤・固着し，外科切除不能であったため，遺残腫瘍に対する粒子線治療を希望して来院した．腫瘍は小腸と近接しており，そのままでは粒子線による根治的照射は不可能であったため，スペーサー留置手術の後，粒子線照射を併用する2段階治療を計画した．まず，開腹下にスペーサーを留置し腫瘍と近接消化管の間に最低1 cmの距離を確保した．術後1か月より陽子線70.4 GyE/32 Frの照射を開始した．腫瘍は緩徐に縮小し，治療後22か月の現時点では腫瘍は縮小を維持し，再発も認めていない．根治的切除が困難な後腹膜脂肪肉腫に対して本療法は有望な治療手段になりえると考えられた．

Surgical spacer placement and proton radiotherapy for unresectable hepatocellular carcinoma

Few potentially curative treatment options exist apart from hepatic resection for patients with huge hepatocellular carcinoma (HCC). Proton radiotherapy is a promising new modality which has an inherent anti-tumor effect against HCC. However, the application of proton radiotherapy for tumors adjacent to the gastrointestinal tract is restricted because the tolerance dose of the intestine is extremely low. A novel two-step treatment was developed with surgical spacer placement and subsequent proton radiotherapy to administer proton radiotherapy with curative intent. This report presents a case of a patient with a huge unresectable HCC treated by this method who achieved disease-free survival of more than 2 years. This new strategy may potentially be an innovative and standard therapy for unresectable HCC in the near future.

Particle beam radiotherapy with a surgical spacer placement for advanced abdominal leiomyosarcoma results in a significant clinical benefit

Leiomysarcoma is a rare malignant tumor originating from smoothmuscle cells. Because of the limited number of cases, the naturalhistory and optimal treatment have not been clarified. In particular,prognosis of leiomyosarcoma originating from large vessels includingthe inferior vena cava (IVC) and aorta is extremely poor. Recent datasupport an aggressive surgical resection combined with adjuvantchemotherapy as the best treatment option for a leiomyosarcoma fromthe IVC [1,2]. However, the long-term outcome of curative resectionsfor leiomyosarcoma from large vessels has been disappointing. The5-year survival rates obtained with absolute curative resections wereobserved to range from 34.8% to 53.3% [1,2]. Hines et al. [2]suggested that radiation therapy after a surgical resection may prolongsurvival. It should be noted, however, that an absolute curativeresection was performed in all of their cases and the effectiveness ofchemotherapy and radiotherapy were assessed in the framework ofadjuvant therapy. There is no report about the treatment of anunresectable leiomyosarcoma and the overall survival rate.Particle beam radiotherapy is a new mode of radiotherapy that hasan inherent advantage over photon radiotherapy. Particle beams, suchas proton and carbon ion beams, show an increase in energy depositionwith penetration depth up to a sharp maximum at the end of their rangeto form the so-called Bragg peak. It thus permits delivery of higherdoses of radiation to the tumor, which may lead to profoundlyimproved tumor eradication. Recent results from major centers haveshown the therapeutic superiority of particle radiotherapy for variouskinds of malignant tumors [3,4]. However, the application of particlebeam radiotherapy for abdominal malignant tumors is restrictedbecause most of them come in contact with the intestine that cannottolerate the radical dose of particle beams. Several studies haveinvestigated the risk factors related to late gastrointestinal tractdisturbance after radiotherapy. Ishikawa et al. [5] assessed that thedosimetric parameter was a very important factor in the occurrence ofgastrointestinal bleeding after particle radiotherapy. Gastrointestinaldisturbances, such as ulcer formation and colitis, generally occurwithin several months after the completion of particle radiotherapy.However, the irradiated volume of a marginal tumor is normallylimited to make it lower than the maximum dose in order to prevent anytoxicity to the nearby gastrointestinal tract. To overcome thislimitation, we developed a novel two-step treatment with a surgicalspacer placement and subsequent proton beam radiotherapy andachieved a significant clinical benefit for three patients.