CT-guidance interstitial (125)Iodine seed brachytherapy as a salvage therapy for recurrent spinal primary tumors

Utility of spectral CT with orthopedic metal artifact reduction algorithms for 125I seeds implantation in mediastinal and hepatic tumors

Background

Virtual monochromatic image (VMI) combined with orthopedic metal artifact reduction algorithms (VMI + O-MAR) can effectively reduce artifacts caused by metal implants of different types. Nevertheless, so far, no study has systematically evaluated the efficacy of VMI + O-MAR in reducing various types of metal artifacts induced by 125I seeds. The aim of this study was to assess the effectiveness of combining spectral computed tomography (CT) images with O-MAR in reducing metal artifacts and improving the image quality affected by artifacts in patients after 125I radioactive seeds implantation (RSI).

Methods

A total of 45 patients who underwent dual-layer detector spectral CT (DLCT; IQon, Philips Healthcare) scanning of mediastinal and hepatic tumors after 125I RSI were retrospectively included. Spectral data were reconstructed into conventional image (CI), VMI, CI combined with O-MAR (CI + O-MAR), and VMI + O-MAR to evaluate the de-artifact effect and image quality improvement. Objective indicators included signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and artifact index (AI) of lesions affected by artifacts. Subjective indicators included assessment of overcorrected artifacts and new artifacts, different morphology of artifacts, and overall image quality.

Results

In artifact-affected lesion areas, SNR and CNR in the CI/VMI + O-MAR groups were better than those in CI groups (all P values <0.05). The AI showed a downward trend as VMI keV increased (all P values <0.001). The AI values of the CI/VMI (50-150 keV) group were all higher than the groups of CI/VMI + O-MAR (50-150 keV) (P<0.001). Overcorrection artifacts and new artifacts were concentrated in the VMI50/70 keV groups. In the evaluation of artifact morphology, as the VMI keV increased, the number of near-field banding artifacts in hyperdense artifacts gradually decreased, whereas the number of minimal or no artifacts increased, and the total number of hyperdense artifacts were decreased. The diagnostic and image quality scores of hyperdense artifacts were higher than those of hypodense artifacts as VMI keV increased.

Conclusions

High VMI level combined with O-MAR substantially improve objective and subjective image quality, lesion display ability, and diagnostic confidence of CT follow-up after 125I RSI, especially at the VMI + O-MAR 150 keV level.

Monte Carlo Dosimetric Study of Percutaneous Vertebroplasty and Brachytherapy for the Treatment of Spinal Metastases

Background

Percutaneous vertebroplasty employs bone cement for injecting into the fractured vertebral body (VB) caused by spinal metastases. Radioactive bone cement and also brachytherapy seeds have been utilized to suppress the tumor growth in the VB.

Objective

This study aims to investigate the dose distributions of low-energy brachytherapy seeds, and to compare them to those of radioactive bone cement, by Monte Carlo simulation.

Material and Methods

In this simulation study, nine CT scan images were imported in Geant4. For the simulation of brachytherapy, I-125, Cs-131, or Pd-103 seeds were positioned in the VB, and for the simulation of vertebroplasty, the VB was filled by a radioactive cement loaded by P-32, Ho-166, Y-90, or Sm-153 radioisotopes. The dose-volume histograms of the VB, and the spinal cord (SC) were obtained after segmentation, considering that the reference dose is the minimum dose covered 95% of the VB.

Results

The SC sparing was improved by using beta-emitting cement because of their steep gradient dose distribution. I-125 seeds and Y-90 radioisotope showed better VB coverage for brachytherapy and vertebroplasty techniques, respectively. Pd-103 seeds and P-32 radioisotope showed better SC sparing for brachytherapy and vertebroplasty, respectively. The minimum mean doses that covered 100% of the VB were 62.0%, 56.5%, and 45.0% for I-125, Cs-131, and Pd-103 seeds, and 28.3%, 28.6%, 32.9%, and 17.7%, for P-32, Ho-166, Y-90, and Sm-153 sources, respectively.

Conclusion

I-125 and Cs-131 seeds may be useful for large tumors filling the entire VB, and also for the extended tumors invading multiple vertebrae. Beta-emitting bone cement is recommended for tumors located near the SC.

Re-Irradiation with Intensity-Modulated Radiation Therapy for the Treatment of Recurrent Cervical Cancer in the Pelvis: An Analysis of Outcomes and Toxicity

Background and Objectives: Treatment options for most patients with recurrent cervical cancer within the previously irradiated field are limited. This study aimed to investigate the feasibility and safety of re-irradiation using intensity-modulated radiation therapy (IMRT) for patients with cervical cancer who experienced intrapelvic recurrence. Materials and Methods: We retrospectively analyzed 22 patients with recurrent cervical cancer who were treated with re-irradiation for intrapelvic recurrence using IMRT between July 2006 and July 2020. The irradiation dose and volume were determined based on the range considered safe for the tumor size, location, and previous irradiation dose. Results: The median follow-up period was 15 months (range: 3-120) and the overall response rate was 63.6%. Of the symptomatic patients, 90% experienced symptom relief after treatment. The 1- and 2-year local progression-free survival (LPFS) rates were 36.8% and 30.7%, respectively, whereas the 1- and 2-year overall survival (OS) rates were 68.2% and 25.0%, respectively. Multivariate analysis revealed that the interval between irradiations and gross tumor volume (GTV) were significant prognostic factors for LPFS. The response to re-irradiation showed borderline statistical significance for LPFS. The GTV and response to re-irradiation were also independent prognostic factors for OS. Grade 3 late toxicities were observed in 4 (18.2%) of the 22 patients. Recto- or vesico-vaginal fistula occurred in four patients. The irradiation dose was associated with fistula formation with borderline significance. Conclusions: Re-irradiation using IMRT is a safe and effective treatment strategy for patients with recurrent cervical cancer who previously received RT. Interval between irradiations, tumor size, response to re-irradiation, and radiation dose were the main factors affecting efficacy and safety.

Efficacy and toxicity of Iodine-125 seed implantation for lymph node recurrence secondary to esophageal cancer after radiotherapy: a multicenter retrospective study

BACKGROUND/OBJECTIVE

This multicenter study aimed to explore the efficacy and toxicity of radioactive Iodine-125 seed implantation for lymph node recurrence in patients with esophageal cancer after external radiotherapy.

METHODS

Clinical data of eligible patients from 5 centers in China were retrospectively reviewed. A total of 126 patients between January 2016 and March 2019 were included. The median interval between previous radiotherapy and radioactive Iodine-125 seed implantation was calculated. The target volume was 2.1-128.1 cm³ (median, 22.2 cm³) and the median postoperative D90 is 120.6 Gy (range, 101.7-192). Short-term efficacy of tumor response, the long-term efficacy of local progression-free survival (LRFS) and overall survival (OS), and treatment-related toxicity were reported.

RESULTS

For tumor response, 37 (29.4%), 51 (40.5%), 14 (11.1%), and 24 (19.0%) patients achieved complete response, partial response, stable disease and progressive disease, respectively. The 1-, 2- and 3-year LPFS and OS rates were 48.8%, 23.0% and 15.9%, and 80.2%, 38.8%, and 24.5%, respectively. Multivariate analysis identified Karnofsky performance status (P = 0.041) and tumor response (P = 0.049) as independent prognostic factors for LPFS; initial tumor stage (P = 0.034), lesion volume (P = 0.017), and tumor response (P = 0.004) as independent prognostic factors for OS. In total, 77 (61.1%) patients suffered from skin reactions and the incidence of grade 3-5 skin toxicity was 5.6% (7/126).

CONCLUSION

Radioactive Iodine-125 seed implantation seems efficient with acceptable toxicity for the treatment of lymph node recurrence secondary to esophageal cancer. A head-to-head study is needed to further evaluate the survival benefit.

Efficacy and safety of CT-guided 125I seed implantation by coplanar template as a salvage therapy for vertebral metastases after failure of external beam radiation therapy: a retrospective study

Purpose

To evaluate the efficacy safety of computed tomography (CT)-guided ¹²⁵I seed implantation by coplanar template for vertebral metastases after failure of external beam radiation therapy (EBRT).

Material and methods

Retrospective analysis of the clinical outcomes of 58 patients with vertebral metastases after failure of EBRT, who underwent ¹²⁵I seed implantation as a salvage treatment with a CT-guided coplanar template-assisted technique from January 2015 to January 2017.

Results

The mean post-operative NRS score decreased significantly at T_4w (3.5 ± 0.9, p<0.01), T_8w (2.1 ± 0.9, p<0.01), T_12w (1.5 ± 0.7, p< 0.01) and T_6m (1.2 ± 0.6, p< 0.01) respectively. The local control rates after 3, 6, 9 and 12 months were 100% (58/58), 93.1% (54/58), 87.9% (51/58), and 81% (47/58), respectively. The median overall survival time was 18.52months (95% CI, 16.24-20.8), and 1- and 2-year survival rates were 81% (47/58) and 34.5% (20/58), respectively. By performing a paired t-test analysis, there was no significant difference in D90, V90, D100, V100, V150, V200, GTV volume, CI, EI and HI between preoperative and postoperative (p>0.05).

Conclusions

¹²⁵I seed implantation can be used as a salvage treatment for patients with vertebral metastases after failure of EBRT.

Spinal brachytherapy

Brachytherapy remains an underrecognized and underutilized radiation therapy modality for the treatment of spinal tumors. This article summarizes the existing body of medical literature on the usage, indications, techniques, and outcomes of brachytherapy for the treatment of spine tumors. The disease pathology most commonly treated with brachytherapy is metastatic spine cancer, rather than primary bone tumors of the spine. Brachytherapy can be used alone, as percutaneous needle injections; however, it is more often used in conjunction with open surgery or cement vertebral body augmentation. Although the data are still relatively sparse, studies show consistent benefit from brachytherapy in terms of improvements in pain, function, local recurrence rate, and overall survival. Brachytherapy is also associated with a favorable complication profile.

Systematic review of brachytherapy for symptom palliation

PURPOSE

Brachytherapy is most often applied in the curative or salvage setting, but many forms of brachytherapy can be helpful for symptom palliation. Declining utilization is seen, for multiple reasons, such as lack of awareness, insufficient expertise, or poor access to equipment. High level evidence for many types of palliative brachytherapy has been lacking. The objective of the current study was to review the evidence for utilization and efficacy of brachytherapy to palliate symptoms from cancer.

MATERIALS AND METHODS

We performed a systematic search in EMBASE and MEDLINE for English-language articles published from January 1980 to May 2022 that described brachytherapy used for a palliative indication in adults with a diagnosis of cancer (any subtype) and at least one symptom related outcome. Individual case reports and conference abstracts were excluded. All publications were independently screened by two investigators for eligibility.

RESULTS

The initial search identified 3637 abstracts of which 129 were selected for in-depth review. The number of studies (total number of patients) included in the final analysis varied widely by tumor site with the majority (68.2%) involving either lung or esophageal cancer. Despite a limited number of prospective trials that assessed the efficacy of brachytherapy for symptom management, there was a positive effect on palliation of symptoms across all tumor types. There was no clear trend in the number of publications over time. The most commonly cited symptom indications for palliation by brachytherapy were dysphagia, dyspnea, pain and bleeding.

CONCLUSIONS

Brachytherapy can provide palliation for patients with advanced cancer, across different tumor sites and clinical scenarios. However, high level evidence in the literature to support palliative applications of brachytherapy is lacking or limited for many tumor sites. There appears to be a strong publication bias towards positive studies in favor of brachytherapy. Beyond anecdotal reports and individual practices, outcomes research can further our understanding of the role of brachytherapy in palliating advanced cancers of all types, and should be encouraged.

Re-Irradiation for Recurrent Cervical Cancer: A State-of-the-Art Review

The recurrence rate of cervical cancer after primary treatment can reach 60%, and a poor prognosis is reported in most cases. Treatment options for the recurrence of cervical cancer mainly depend on the prior treatment regimen and the location of recurrent lesions. Re-irradiation is still considered as a clinical challenge, owing to a high incidence of toxicity, especially in in-field recurrence within a short period of time. Recent advances in radiotherapy have preliminarily revealed encouraging outcomes of re-irradiation. Several centers have concentrasted on stereotactic body radiation therapy (SBRT) for the treatment of well-selected cases. Meanwhile, as the image-guiding techniques become more precise, a better dose profile can also be achieved in brachytherapy, including high-dose-rate interstitial brachytherapy (HDR-ISBT) and permanent radioactive seed implantation (PRSI). These treatment modalities have shown promising efficacy with a tolerable toxicity, providing further treatment options for recurrent cervical cancer. However, it is highly unlikely to draw a definite conclusion from all of those studies due to the large heterogeneity among them and the lack of large-scale prospective studies. This study mainly reviews and summarizes the progress of re-irradiation for recurrent cervical cancer in recent years, in order to provide potential treatment regimens for the management of re-irradiation.

Interstitial 125I Brachytherapy as a Salvage Treatment for Refractory Cervical Lymph Node Metastasis of Thoracic Esophageal Squamous Cell Carcinoma After External Irradiation With a CT-Guided Coplanar Template-Assisted Technique: A Retrospective Study

Purpose: To analyze the outcome and prognosis of patients with refractory cervical lymph node metastasis of thoracic esophageal squamous cell carcinoma after external irradiation, who underwent interstitial ¹²⁵I brachytherapy as a salvage treatment with a CT-guided coplanar template-assisted technique. We also want to compare the dosimetry of 3D printed coplanar template-assisted interstitial ¹²⁵I brachytherapy preoperative and postoperative, and to explore the accuracy of this technology. Material and methods: We retrospectively collected and analyzed the results of 32 patients with refractory cervical lymph node metastasis of thoracic esophageal squamous cell carcinoma after external irradiation, who underwent interstitial ¹²⁵I brachytherapy as a salvage treatment with a CT-guided coplanar template-assisted technique from January 2012 to December 2017. Results: The actual D90 were 114 to 240 Gy, and the median postoperative dosimetry assessment was 177.5 Gy. The local control rates at 3, 6, 9, and 12 months were 87.5%, 59.38%, 40.63%, and 31.25%, respectively. The median local control time was 7.5 months. The median overall survival time was 10.5 months (95% CI, 8.9-13.4), and the survival rates of 1- and 2-year, respectively, were 43.75% and 9.38%. There were 36 lesions in 32 patients. By performing a paired t-test analysis, there was no significant difference in D90, D100, V100, V150, V200, GTV volume, CI, EI, and HI between preoperative and postoperative (P > .05). Conclusions: Interstitial ¹²⁵I brachytherapy can be used as a salvage treatment for patients with refractory cervical lymph node metastasis of thoracic esophageal squamous cell carcinoma after external irradiation. With the auxiliary function of 3D printed coplanar template, the main dosimetry parameters verified after the operation can meet the requirements of the preoperative plan with good treatment accuracy.

High-Dose Rate Interstitial Spine Brachytherapy Using an Intraoperative Mobile Computed Tomography-Guided Surgical Navigation System

BACKGROUND

Up to 15% of previously irradiated metastatic spine tumors will progress. Re-irradiation of these tumors poses a significant risk of exceeding the radiation tolerance to the spinal cord. High-dose rate (HDR) brachytherapy is a treatment alternative.

OBJECTIVE

To develop a novel HDR spine brachytherapy technique using an intraoperative computed tomography-guided navigation (iCT navigation).

METHODS

Patients with progressive metastatic spine tumors were included in the study. HDR brachytherapy catheters were placed under iCT navigation. CT-based planning with magnetic resonance imaging fusion was performed to ensure conformal dose delivery to the target while sparing normal tissue, including the spinal cord. Patients received single fraction radiation treatment.

RESULTS

Five patients with thoracolumbar tumors were treated with HDR brachytherapy. Four patients previously received radiotherapy to the same spinal level. Preimplant plans demonstrated median clinical target volume (CTV) D90 of 116.5% (110.8%-147.7%), V100 of 95.7% (95.5%-99.6%), and Dmax of 8.08 Gy (7.65-9.8 Gy) to the spinal cord/cauda equina. Postimplant plans provided median CTV D90 of 113.8% (93.6%-120.1%), V100 of 95.9% (87%-99%), and Dmax of 9.48 Gy (6.5-10.3 Gy) to cord/cauda equina. Patients who presented with back pain (n = 3) noted symptomatic improvement at a median follow-up of 22 d after treatment. Four patients demonstrated local tumor control of spinal metastatic tumor at a median follow-up of 92 d after treatment. One patient demonstrated radiographic evidence of local tumor progression 2.7 mo after treatment.

CONCLUSION

HDR spine brachytherapy with iCT navigation is a promising treatment alternative to induce local tumor control and reduce pain symptoms associated with metastatic spine disease.

Multiple direction needle-path planning and inverse dose optimization for robotic low-dose rate brachytherapy

PURPOSE

Robotic systems to assist needle placements for low-dose rate brachytherapy enable conformal dose planning only restricted to path planning around risk structures. We report a treatment planning system (TPS) combining multiple direction needle-path planning with inverse dose optimization algorithms.

METHODS

We investigated in a path planning algorithm to efficiently locate needle injection points reaching the target volume without puncturing risk structures. A candidate needle domain with all combinations of trajectories is used for the optimization process. We report a modular algorithm for inverse radiation plan optimization. The initial plan with V100>99% is generated by the "greedy optimizer". The "remove-seed algorithm" reduces the number of seeds in the high dose regions. The "depth-optimizer" varies the insertion depth of the needles. The "coverage-optimizer" locates under-dosed areas in the target volume and supports them with an additional amount of seeds. The dose calculation algorithm is benchmarked on an image set of a phantom with a liver metastasis (prescription dose D_pr=100Gy) and is re-planned in a commercial CE-marked TPS to compare the calculated dose grids using a global gamma analysis. The inverse optimizer is benchmarked by calculating 10 plans on the same phantom to investigate the stability and statistical variability of the dose parameters.

RESULTS

The path planning algorithm efficiently removes 72.5% of all considered injection points. The candidate needle domain consists of combinations of 1971 tip points and 827 injection points. The global gamma analysis with gamma 1%=2.9Gy, 1mm showed a pass rate of 98.5%. The dose parameters were V100=99.1±0.3%, V150=76.4±2.5%, V200=44.5±5.5% and D90=125.9±3.6Gy and 10.7±1.3 needles with 34.0±0.8 seeds were used. The median of the TPS total running time was 4.4minutes.

CONCLUSIONS

The TPS generates treatment plans with acceptable dose coverage in a reasonable amount of time. The gamma analysis shows good accordance to the commercial TPS. The TPS allows taking full advantage of robotic navigation tools to enable a new precise and safe method of minimally invasive low-dose-rate brachytherapy.

Expert consensus on computed tomography-assisted three-dimensional-printed coplanar template guidance for interstitial permanent radioactive 125I seed implantation therapy

Interstitial permanent radioactive seed implantation delivers a high local dose to tumors and sharply drops off at surrounding normal tissues. Radioactive seeds implanted via ultrasound or computed tomography (CT) guidance are minimally invasive and facilitate quick recovery. Transrectal ultrasound-guided ¹²⁵I seed implantation assisted by a transperineal plane template is standard for early-stage prostate carcinoma, with a highly consistent target volume dose distribution. The postplan dose evaluation is consistent with the preplan evaluation. Until now, there was no workflow for seed implantation elsewhere in the body, and it was difficult to effectively preplan for seed implantation because of patients' position changes, organ movement, and bone structure interference. Along with three-dimensional (3D) printing techniques and seed implantation planning systems for brachytherapy, coplanar and X Y axis coordinate templates were created, referred to as 3D-printed coplanar templates (3D-PCT). ¹²⁵I seed implantation under CT guidance with 3D-PCT assistance has been very successful in some carcinomas. Preplanning was very consistent with postplanning of the gross tumor volume. All needles are kept parallel for 3D-PCT, with no coplanar needle rearrangement. No standard workflow for 3D-PCT-assisted seed implantation exists at present. The consensus topics for CT-assisted guidance compared to 3D-PCT-assisted guidance for seed implantation are as follows: Indications for seed implantation, preplanning, definition of radiation doses and dosimetry evaluation, 3D-PCT workflow, radiation protection, and quality of staff. Despite current data supporting ¹²⁵I seed implantation for some solid carcinomas, there is a need for prospectively-randomized multicenter clinical trials to gather strong evidence for using ¹²⁵I seed implantation in other solid carcinomas.

Comparison of pre-implant treatment planning and post-implant dosimetry in I-125 spinal metastases brachytherapy

I-125 seed therapy has been developed and used for the treatment of numerous types of malignancies. It has been suggested that post-implant dosimetry deviates from pre-implant treatment planning; however, to the best of our knowledge, very few studies to date have investigated this discrepancy. In the present study, 11 patients with metastatic spinal tumors, who were treated with I-125 seed brachytherapy, were assessed. Pre- and post-implant dosimetry were compared by assessing: Tumor volume, dose distributions and dose volume histograms. The average doses delivered to 90% of the target volume (D90) in the pre-implant planning images of the spine was 119.07 Gy compared with 94.15 Gy in the post-implant dosimetry (P<0.05). The average V100 in the pre-implant planning images of the spine was 97.85% (range, 96.50–99.80%), compared with 84.46% (range, 66.40–96.70%) in the post-implant dosimetry, of the prescribed doses (P<0.05). Furthermore, both the number of needles and the Dmax of the cord differed between the two groups. Nevertheless, the mean gross tumor volume, the number of seeds, and the V150 and V200 were similar between the two groups. The results of the present study suggest that metastatic spinal tumors of the bone received a lower dose than the pre-implant planned dose coverage in I-125 seed brachytherapy.

Image guidance in spine tumor surgery

Beginning with basic stereotactic operative methods in neurosurgery, intraoperative navigation and image guidance systems have since become the norm in that field. Following the introduction of image guidance into spinal surgery, there has been a dramatic increase in its utilization across disciplines and pathologies. Spine tumor surgery encompasses a wide range of complex surgical techniques and treatment strategies. Similarly to deformity correction and trauma surgery, spine navigation holds potential to improve outcomes and optimize surgical technique for spinal tumors. Recent data demonstrate the applicability of neuro-navigation in the field of spinal oncology, particularly for spinal stabilization, maximizing extent of resection and integration of minimally invasive therapies. The rapid introduction of new, less invasive, and ablative surgical techniques in spine oncology coupled with the rising incidence of spinal metastatic disease make it imperative for spine surgeons to be familiar with the indications for and limitations of imaging guidance. Herein, we provide a practical, current concepts narrative review on the use of spinal navigation in three areas of spinal oncology: (a) extent of tumor resection, (b) spinal column stabilization, and (c) focal ablation techniques.

Personalized Radiation Therapy in Cancer Pain Management

The majority of advanced cancer patients suffer from pain, which severely deteriorates their quality of life. Apart from analgesics, bisphosphonates, and invasive methods of analgesic treatment (e.g., intraspinal and epidural analgesics or neurolytic blockades), radiation therapy plays an important role in pain alleviation. It is delivered to a growing primary tumour, lymph nodes, or distant metastatic sites, producing pain of various intensity. Currently, different regiments of radiation therapy methods and techniques and various radiation dose fractionations are incorporated into the clinical practice. These include palliative radiation therapy, conventional external beam radiation therapy, as well as modern techniques of intensity modulated radiation therapy, volumetrically modulated arch therapy, stereotactic radiosurgery or stereotactic body radiation therapy, and brachytherapy or radionuclide treatment (e.g., radium-223, strontium-89 for multiple painful osseous metastases). The review describes the possibilities and effectiveness of individual patient-tailored conventional and innovative radiation therapy approaches aiming at pain relief in cancer patients.

Efficacy and dosimetry analysis of image-guided radioactive ¹²⁵I seed implantation as salvage treatment for pelvic recurrent cervical cancer after external beam radiotherapy

Objective

To investigate the efficacy of image-guided radioactive ¹²⁵I seed (IGRIS) implantation for pelvic recurrent cervical cancer (PRCC) after external beam radiotherapy (EBRT), and analyze the influence of clinical and dosimetric factors on efficacy.

Methods

From July 2005 to October 2015, 36 patients with PRCC received IGRIS. We evaluated local progression-free survival (LPFS) and overall survival (OS).

Results

The median follow up was 11.5 months. The 1- and 2-year LPFS rate was 34.9% and 20%, respectively. The multivariate analysis indicated recurrence site (central or pelvic wall) (hazard ratio [HR]=0.294; 95% confidence interval [CI]=0.121–0.718), lesion volume (HR=2.898; 95% CI=1.139–7.372), D₉₀ (HR=0.332; 95% CI=0.130–0.850) were the independent factors affecting LPFS. The 1- and 2-year OS rate was 52.0% and 19.6%, respectively. The multivariate analysis suggested pathological type (HR=9.713; 95% CI=2.136–44.176) and recurrence site (HR=0.358; 95% CI=0.136–0.940) were the independent factors affecting OS. The dosimetric parameters of 33 patients mainly included D₉₀ (128.5±47.4 Gy), D₁₀₀ (50.4±23.7 Gy) and V₁₀₀ (86.7%±12.9%). When D₉₀ ≥105 Gy or D₁₀₀ ≥55 Gy or V₁₀₀ ≥91%, LPFS was extended significantly, but no significant difference for OS. The 79.2% of 24 patients with local pain were suffering from pain downgraded after radioactive ¹²⁵I seed implantation.

Conclusion

IGRIS implantation could be a safe and effective salvage treatment for PRCC after EBRT, which could markedly release the pain. Recurrence site, tumor volume and dose were the main factors affected efficacy. Compared with central recurrence, it was more suitable for patients with pelvic wall recurrent cervical cancer after EBRT.

Brachytherapy in Spinal Tumors: A Systematic Review

BACKGROUND

Conventional external beam radiation and stereotactic radiosurgery are common radiation techniques used to treat spinal tumors. Intraoperative brachytherapy (BT) may serve as an alternative when other options have been exhausted or as an adjunct in combination with other therapies. The objective of this study was to systematically review the literature on BT use in spinal tumor surgery.

METHODS

PubMed and Embase databases were systematically queried for literature reporting the use of BT in the surgical treatment of spinal tumors. PRISMA guidelines were followed. A meta-analysis was performed.

RESULTS

Of the 203 initial articles queried, 15 studies were included. Of the 370 total patients described, 78% were treated for spine metastases. Indications for BT included tumors refractory to previous treatments and inability to tolerate chemotherapy, radiation, and/or open surgery. Seed placement was the most common method of delivery (58%) compared with plaques (42%). BT was placed during an open procedure in 52%, and of the remaining percutaneous procedures, 47% were combined with cement augmentation. Tumor recurrence rates varied from 13% to 49%. Seven studies reporting visual analog scale scores reported significant improvement in pain control.

CONCLUSIONS

BT was used to treat metastatic disease in patients who failed previous therapies and could not tolerate open surgery or further therapy. This review summarizes the major findings in the available literature pertaining to patient background, indications, and outcomes. Spinal BT seems to be a viable option for spine tumor treatment and should be made available at treating centers.

Side effects of CT-guided implantation of 125I seeds for recurrent malignant tumors of the head and neck assisted by 3D printing non co-planar template

BACKGROUND

For the recurrence of head and neck cancer after operation and radiotherapy, the local control of radioactive seed implantation is good, and it has a certain palliative effect. This study aims to investigate the acute and late side effects of a three-dimentional printing non co-planar template (3D-PNCT) for computed tomography (CT)-guided radioactive 125I seed (RIS) implantation in recurrent cancer of the head and neck.

METHODS

Between January 2016 and December 2016, forty-two patients with local recurrent malignant tumors of the head and neck received 3D-PNCT-assisted RIS implantation. The prescribed dose was 110-160 Gy. Preoperative planning design, production of individual guide plates, RIS implantation, postoperative dose evaluation, and follow-up were completed for all patients. Side effects in the skin, mucous membranes, blood and spinal cord were evaluated.

RESULTS

All patients underwent surgery successfully. Duration of follow-up was 4-14 (median, of 8.5) months. The activity of a single RIS was 0.34-0.7 (median, 0.6) mCi. The number of RIS was 10-126 (median, 34). The number of implantation needles was 4-31 (median, 11). The mean D2cc (dose to the most exposed 2-cc volume) and D0.1cc (dose to the most exposed 0.1-cc volume) of the skin were 24.9 (7.1-85.5) and 47.5 (9.4-167.2), respectively, whereas those of the spinal cord were 8.4 (4.5-33.3) and 14.2 (13.6-63.0), mucosa were 35.1 (4.2-82.8) and 87.0 (6.6-214.1), parotid glands were 16.2 (12.8-19.7) and 29.8 (26.1-33.4) and those of the trachea were 17.9 (2.5-45.9) and 32.7 (3.9-83.9), respectively. No case had an acute reaction of grade ≥ 3. Three cases had a grade-1 skin reaction. Blood toxicity did not occur, nor spinal-cord injury. Xerostomia was not aggravated than that of before brachytherapy. One case had a grade-3 nerve response.

CONCLUSIONS

3D-PNCT-assisted RIS implantation can provide good accuracy for positioning. For local recurrent malignant tumor of head and neck, there were no obvious adverse reactions.

Dosimetry Verification of 125I Seeds Implantation With Three-Dimensional Printing Noncoplanar Templates and CT Guidance for Paravertebral/Retroperitoneal Malignant Tumors

OBJECTIVE

To compare dose distributions of postoperative plans with preoperative plans for radioactive seed implantation of paravertebral/retroperitoneal tumors assisted by 3-dimensional printing noncoplanar templates and computed tomography.

METHODS

Sixteen patients with paravertebral/retroperitoneal tumors (21 lesions) underwent radioactive seed implantation with 3-dimensional printing noncoplanar templates. Prescribed dose was 110 to 160 Gy. We compared the dose distribution of the postoperative plan with the preoperative plan. Dose parameters were D90, minimum peripheral dose, V100, V150, conformal index and external index of the target volume, and the dose received by 2 cm³ of normal tissue of organs at risk (spinal cord, aorta, and kidney).

RESULTS

Sixteen 3-dimensional printing noncoplanar templates were produced for 21 treatment areas. Mean gross tumor volume (preoperative) of patients was 61.1 cm³, mean needle number was 17, mean number of implanted ¹²⁵I seeds was 65, and mean D90 of postoperative target area (gross tumor volume) was 131.1 Gy. Actual number of seeds postbrachytherapy increased by 1 to 12 in 8 cases. For postoperative plans, the mean D90, minimum peripheral dose, V100, V150 was 131.1 Gy, 67.1 Gy, 90.2%, and 64.1%, respectively, and 135.0 Gy, 64.7 Gy, 90.9%, and 64.1%, respectively, in preoperative plans. Comparing with the preplanned cases, the dose of the target volume was slightly lower and the high-dose area of the target volume was larger in postoperative cases, but the difference was not statistically significant (P > .05). Actual dose conformity of the target volume was lower than preplanned, and the difference was statistically significant (P = .005).

CONCLUSION

Three-dimensional printing noncoplanar templates can provide good accuracy for positioning and direction in radioactive seed implantation.

Surgery Combined with Radiotherapy to Treat Spinal Tumors: A Review of Published Reports

Spinal tumors result in high morbidity and a high rate of lower limb paralysis. Both surgical therapy and radiation therapy (RT) are used to treat spinal tumors; however, how best to combine these two therapies to maximize the benefits and minimize the risks is still being debated. It is also difficult to decide the optimal timing, course and dose of RT, especially in pregnant women and children. The aim of this review is to assist surgeons who are dealing with spinal tumors by providing comprehensive information about advanced techniques for administering RT with greater precision and safety, and about the impact of various ways of combining surgery and RT on therapeutic outcomes. We here review published reports about treating spinal tumors with a combination of these two forms of therapy and attempt to draw appropriate conclusions concerning selection of optimal treatment protocols. Our conclusion is that postoperative radiotherapy, especially with high-precision, low-dose and multiple fractions, and brachytherapy are promising therapies to combined with surgery.

The Protective Roles of ROS-Mediated Mitophagy on 125I Seeds Radiation Induced Cell Death in HCT116 Cells

For many unresectable carcinomas and locally recurrent cancers (LRC), ¹²⁵I seeds brachytherapy is a feasible, effective, and safe treatment. Several studies have shown that ¹²⁵I seeds radiation exerts anticancer activity by triggering DNA damage. However, recent evidence shows mitochondrial quality to be another crucial determinant of cell fate, with mitophagy playing a central role in this control mechanism. Herein, we found that ¹²⁵I seeds irradiation injured mitochondria, leading to significantly elevated mitochondrial and intracellular ROS (reactive oxygen species) levels in HCT116 cells. The accumulation of mitochondrial ROS increased the expression of HIF-1α and its target genes BINP3 and NIX (BINP3L), which subsequently triggered mitophagy. Importantly, ¹²⁵I seeds radiation induced mitophagy promoted cells survival and protected HCT116 cells from apoptosis. These results collectively indicated that ¹²⁵I seeds radiation triggered mitophagy by upregulating the level of ROS to promote cellular homeostasis and survival. The present study uncovered the critical role of mitophagy in modulating the sensitivity of tumor cells to radiation therapy and suggested that chemotherapy targeting on mitophagy might improve the efficiency of ¹²⁵I seeds radiation treatment, which might be of clinical significance in tumor therapy.

CT-Guided 125I Seed Interstitial Brachytherapy as a Salvage Treatment for Recurrent Spinal Metastases after External Beam Radiotherapy

The aim of this study is to evaluate the feasibility, safety, and clinical efficacy of CT-guided ¹²⁵I seed interstitial brachytherapy in patients with recurrent spinal metastases after external beam radiotherapy (EBRT). Between August 2003 and September 2015, 26 spinal metastatic lesions (24 patients) were reirradiated by this salvage therapy modality. Treatment for all patients was preplanned using a three-dimensional treatment planning system 3-5 days before ¹²⁵I seed interstitial brachytherapy; dosimetry verification was performed immediately after seed implantation. Median actual D₉₀ was 99 Gy (range, 90-176), and spinal cord median D_max was 39 Gy (range, 6-110). Median local control (LC) was 12 months (95% CI: 7.0-17.0). The 6- and 12-month LC rates were 52% and 40%, respectively. Median overall survival (OS) was 11 months (95% CI: 7.7-14.3); 6-month and 1-, 2-, and 3-year OS rates were 65%, 37%, 14%, and 9%, respectively. Pain-free survival ranged from 2 to 42 months (median, 6; 95% CI: 4.6-7.4). Treatment was well-tolerated, with no radiation-induced vertebral compression fractures or myelopathy reported. Reirradiation with CT-guided ¹²⁵I seed interstitial brachytherapy appears to be feasible, safe, and effective as pain relief or salvage treatment for patients with recurrent spinal metastases after EBRT.

Palliative treatment of pelvic bone tumors using radioiodine (125I) brachytherapy

Background

Complete resection of pelvic bone tumors, especially recurrent and metastatic ones, is often impossible to achieve using conventional surgery. This study aimed to assess the benefits and adverse effects of computed tomography (CT)-guided radioiodine (¹²⁵I) brachytherapy for inoperable recurrent and metastatic bone tumors of the pelvis.

Methods

This was a retrospective study of 22 patients with confirmed pelvic bone tumors (10 females and 12 males; 15–84 years; 21 with primary pelvic tumor and one with pelvic metastasis). CT-guided ¹²⁵I brachytherapy was performed using 9–21 ¹²⁵I seeds (radioactivity of 0.5–0.7 mCi). Seed implantation was validated by postoperative CT scanning. Complications, pain, survival, and CT-estimated tumor size were carried out to evaluate the therapeutic benefits.

Results

Postoperative CT scans revealed satisfactory ¹²⁵I seed implantation, and the radiation dose delivered to 90% of the target area (D90) was higher than the prescription dose (PD). No obvious complications were observed. Pain was reported by 19 of 22 patients, but 17 reported pain relief after implantation. Follow-up ranged 8–27 (median, 19) months. Tumor size was reduced in 11 patients within 1 month after surgery, nine patients showed no change, and tumor size increased in two patients. Finally, 1- and 2-year survival was 81.8 and 45.5%, respectively; 1- and 2-year local tumor control rates were 59.1 and 36.4%, respectively.

Conclusions

¹²⁵I seed implantation significantly reduced bone tumor size and relieved pain, with a low complication rate. These findings suggest that ¹²⁵I brachytherapy treatment could be a useful palliative approach for pelvic bone tumor treatment.

CT-guided permanent 125I seed interstitial brachytherapy for recurrent retroperitoneal lymph node metastases after external beam radiotherapy

PURPOSE

To evaluate the feasibility, efficacy, and safety of permanent (125)I seed interstitial brachytherapy reirradiation in patients with retroperitoneal lymph node recurrence under CT guidance.

METHODS AND MATERIALS

Seventeen patients with 19 retroperitoneal lymph node recurrence after external beam radiotherapy underwent CT-guided (125)I seed implant brachytherapy from October 2007 to August 2014. Treatment for all patients was preplanned using a three-dimensional radiation therapy planning system 3-5 days before brachytherapy; dosimetry verification was performed immediately after brachytherapy.

RESULTS

The actuarial D90 (dose delivered to 90% of the target volume) was 100-198 Gy (median, 126.5 Gy). In 9 patients, pain intensity decreased to mild pain 1-3 weeks after brachytherapy. Pain-free survival ranged 2-15 months (median, 5 months; 95% confidence interval [CI]: 0.1, 9.9). The overall response rate was 19 of 19 (100%). The median local control time was 15 months (95% CI: 2.3, 27.7). The 6-, 12-, and 24-month local control rate was 88.0%, 63.2%, and 42.1%, respectively. Twelve patients (70.6%) developed distant metastases and died. Two patients (11.8%) are alive with distant metastases but no evidence of local recurrence. Three patients (17.6%) are alive with no evidence of local recurrence. Median overall survival was 10 months (95% CI: 5.7, 14.3); the 1- and 2-year survival rates were 38.1% and 15.3%, respectively. No major complications related to the procedure occurred during or after brachytherapy.

CONCLUSIONS

Reirradiation with CT-guided permanent (125)I seed interstitial brachytherapy is feasible, safe, and effective as pain relief or salvage treatment for patients with recurrent retroperitoneal lymph nodes.