Interstitial permanent implantation of 125I seeds as salvage therapy for re-recurrent rectal carcinoma

125I seed implantation enhances arsenic trioxide-induced apoptosis and anti-angiogenesis in lung cancer xenograft mice

BACKGROUND AND PURPOSE

Arsenic trioxide (ATO) exerts anticancer effects on lung cancer. However, the clinical use of ATO is limited due to its systemic toxicity and resistance of lung cancer cells. The present study aimed to investigate the effects of ATO, alone and in combination with ¹²⁵I seed implantation on tumor growth and proliferation in lung cancer xenograft mice, and investigate the possible molecular mechanisms.

METHODS

The transmission electron microscope observed the tumor ultrastructure of lung cancer xenograft mice. The proliferation index of Ki-67 and the number and morphology of tumor microvessels were detected with immunohistochemical staining. The protein and mRNA expression were examined by western blot and real-time PCR assay.

RESULTS

The in vivo results demonstrated that ATO combined with ¹²⁵I seed significantly inhibited tumor growth and proliferation, as well as promoted apoptosis, and decreased the Ki-67 index and microvessel density in lung cancer xenograft mice. Moreover, ATO combined with ¹²⁵I seed decreased the protein and mRNA expression levels of HIF-1α, VEGF, and BCL-2, and increased those of BAX and P53.

CONCLUSIONS

ATO combined with ¹²⁵I seed significantly inhibited tumor growth and proliferation in lung cancer, which may be accomplished by inhibiting tumor angiogenesis and inducing apoptosis.

Iodine-125 brachytherapy treatment for newly diagnosed brain metastasis in non-small cell lung cancer: A biocentric analysis

Purpose

The aim of the present study is to evaluate the safety and efficacy of iodine-125 brachytherapy for newly diagnosed brain metastasis in patients with non-small cell lung cancer (NSCLC).

Materials and methods

The study included 158 NSCLC patients diagnosed with brain metastasis from December 2003 to August 2017. Ninety-nine patients underwent external beam radiotherapy (EBRT group), and 59 patients received iodine-125 brachytherapy (¹²⁵I group). In addition, the 6- and 12-month progression-free survival (PFS) rates and the 12- and 24-month overall survival (OS) rates were compared between the EBRT group and the ¹²⁵I group. Median OS and PFS were analyzed using the Kaplan-Meier method with a log-rank test.

Results

The 6-month PFS rate was significantly higher in the ¹²⁵I group (p = 0.002) than in the EBRT group, while no differences were found in the 12-month PFS rate (p = 0.184). Additionally, the 12- (p = 0.839) and 24-month (p = 0.284) OS rates were not significantly different between the two groups. No significant differences in median OS (p = 0.525) or PFS (p = 0.425) were found between the two groups.

Conclusions

Iodine-125 brachytherapy is an alternative therapy for patients unable to undergo surgical resection.

Iodine-125 seed represses the growth and facilitates the apoptosis of colorectal cancer cells by suppressing the methylation of miR-615 promoter

BACKGROUND

Colorectal cancer (CRC) represents a common malignancy in gastrointestinal tract. Iodine-125 (¹²⁵I) seed implantation is an emerging treatment technology for unresectable tumors. This study investigated the mechanism of ¹²⁵I seed in the function of CRC cells.

METHODS

The CRC cells were irradiated with different doses of ¹²⁵I seed (0.4, 0.6 and 0.8 mCi). miR-615 expression in CRC tissues and adjacent tissues was detected by RT-qPCR. miR-615 expression was intervened with miR-615 mimic or miR-615 inhibitor, and then the CRC cells were treated with 5-AZA (methylation inhibitor). The CRC cell growth, invasion and apoptosis were measured. The methylation level of miR-615 promoter region was detected. The xenograft tumor model irradiated by ¹²⁵I seed was established in nude mice. The methylation of miR-615, Ki67 expression and CRC cell apoptosis were detected.

RESULTS

¹²⁵I seed irradiation repressed the growth and facilitated apoptosis of CRC cells in a dose-dependent manner. Compared with adjacent tissues, miR-615 expression in CRC tissues was downregulated and miR-615 was poorly expressed in CRC cells. Overexpression of miR-615 suppressed the growth of CRC cells. ¹²⁵I seed-irradiated CRC cells showed increased miR-615 expression, reduced growth rate and enhanced apoptosis. The methylation level of miR-615 promoter region in CRC cells was decreased after ¹²⁵I seed treatment. In vivo experiments confirmed that ¹²⁵I seed-irradiated xenograft tumors showed reduced methylation of the miR-615 promoter and increased miR-615 expression, as well as decreased Ki67 expression and enhanced apoptosis. The target genes of miR-615 and its regulatory downstream pathway were further predicted by bioinformatics analysis.

CONCLUSIONS

¹²⁵I seed repressed the growth and facilitated the apoptosis of CRC cells by suppressing the methylation of the miR-615 promoter and thus activating miR-615 expression. The possible mechanism was that miR-615-5p targeted MAPK13, thus affecting the MAPK pathway and the progression of CRC.

125I seeds inhibit proliferation and promote apoptosis in cholangiocarcinoma cells by regulating the AGR2-mediated p38 MAPK pathway

¹²⁵I seeds can effectively inhibit the growth of a variety of cancer cells. It has been used in the treatment of a variety of cancers, and has achieved certain curative effect. However, to the best of our knowledge, no report has described the effects of ¹²⁵I seeds on the biological functions of cholangiocarcinoma (CCA) and the mechanisms underlying the effects of the seeds on this cancer. In this study, we demonstrated that ¹²⁵I seeds could inhibit the proliferation, migration and invasion of CCA cells, as well as promoting apoptosis and blocking the cell cycle in these cells. Moreover, ¹²⁵I seeds inhibited the growth of CCA xenografts and promoted the apoptosis of CCA cells in vivo. Furthermore, transcriptome sequencing showed that ¹²⁵I seeds could inhibit the growth of CCA by inhibiting the expression of AGR2 and regulating p38 MAPK pathway. Finally, this finding indicated that ¹²⁵I seeds can inhibit proliferation and promote apoptosis in CCA cells by inhibiting the expression of AGR2 and DUSP1 and increasing the expression of p-p38 MAPK and p-p53. This study provides a new research direction for studies investigating the mechanisms underlying the effects of ¹²⁵I seeds on CCA.

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.

Clinical Outcome of CT-Guided Stereotactic Ablative Brachytherapy for Unresectable Early Non-Small Cell Lung Cancer: A Retrospective, Multicenter Study

Objective

To analyze the efficacy and safety of low dose rate stereotactic ablative brachytherapy (L-SABT) for treatment of unresectable early-stage non-small cell lung cancer (NSCLC).

Methods

Data of patients with early-stage NSCLC who received CT-guided L-SABT (radioactive I-125 seeds implantation) at eight different centers from December 2010 to August 2020 were retrospectively analyzed. Treatment efficacy and complications were evaluated.

Results

A total of 99 patients were included in this study. Median follow-up duration was 46.3 months (6.1-119.3 months). The 1-year, 3-year, and 5-year local control rates were 89.1%, 77.5%, and 75.7%, respectively. The 1-year, 3-year, and 5-year overall survival rates were 96.7%, 70.1%, and 54.4%, respectively. Treatment failure occurred in 38.4% of patients. Local/regional recurrence, distant metastasis, and recurrence combined with metastasis accounted for 15.1%, 12.1%, and 11.1%, respectively. Pneumothorax occurred in 47 patients (47.5%) with 19 cases (19.2%) needing closed drainage. The only radiation-related adverse reaction was two cases of grade 2 radiation pneumonia. KPS 80-100, T1, the lesion was located in the left lobe, GTV D90 ≥150 Gy and the distance between the lesion and chest wall was < 1 cm, were associated with better local control (all P < 0.05); on multivariate analysis KPS, GTV D90, and the distance between the lesion and chest wall were independent prognostic factors for local control (all P < 0.05). KPS 80-100, T1, GTV D90 ≥150 Gy, and the distance between the lesion and chest wall was < 1 cm were also associated with better survival (all P < 0.05); on multivariate analysis KPS, T stage, and GTV D90 were independent prognostic factors for survival (all P < 0.05). The incidence of pneumothorax in patients with lesions <1 cm and ≥1cm from the chest wall was 33.3% and 56.7%, respectively, and the differences were statistically significant (P = 0.026).

Conclusion

L-SABT showed acceptable efficacy in the treatment of unresectable early-stage NSCLC. But the incidence of pneumothorax is high. For patients with T1 stage and lesions <1 cm from the chest wall, it may have better efficacy. Prescription dose greater than 150 Gy may bring better results.

Dosimetry verification of three-dimensional printed polylactic acid template-guided precision 125 I seed implantation for lung cancer using a desktop three-dimensional printer

Introduction

The purpose of this study was to verify the effectiveness of polylactic acid (PLA) template puncture route planning by comparing preoperative and postoperative dosimetry using computerized tomography (CT)‐guided implantation of ¹²⁵I radioactive seeds.

Methods

A total of 28 patients who underwent ¹²⁵I seed implantation between January 2018 and June 2019 were selected for the statistical study of seed dosimetry. All patients received preoperative treatment planning system (TPS) planning, of which 13 patients in the experimental 3D template group underwent intraoperative puncture and implantation using the PLA template planning route. The other 15 patients in the traditional control group underwent intraoperative puncture and implantation using CT images for guidance. By calculating the dose‐volume histogram, preoperative and postoperative D90 values and postoperative V90 values were compared between the two groups.

Results

The mean D90 values in the template group before and after surgery were 136.06 ± 7.10 and 134.72 ± 7.85 Gy, respectively. There was no statistically significant difference. The preoperative and postoperative mean D90 values in the traditional group were 132.97 ± 8.04 and 126.06 ± 9.19 Gy, respectively, which were statistically significantly different. The mean postoperative V90 values in the template and traditional groups were 93.80 ± 1.34% and 88.42 ± 6.55 %, respectively, showing a statistically significant difference.

Conclusions

The preoperative TPS plan for the experimental group guided by the PLA template was almost the same as that for the final guided particle implantation. The dose parameters in the experimental group were also better than those in the traditional group, making the use of the presented PLA template more efficient for clinical applications.

The dosimetry evaluation of 3D printing non-coplanar template-assisted CT-guided 125I seed stereotactic ablation brachytherapy for pelvic recurrent rectal cancer after external beam radiotherapy

The aim of this study was to investigate the safety and accuracy of computed tomography (CT)-guided 125I seed implantation assisted by a three-dimensional printing non-coplanar template (3D-PNCT) for treating pelvic locally recurrent rectal cancer (LRRC) patients. A total of 13 patients with 18 masses received 125I seed implantation. The dosimetric parameters of pre-implantation and post-implantation were calculated to evaluate the quality of 125I seed implantation. Doses delivered to the organs at risk (OAR) were also calculated. Differences between pre-implantation and post-implantation were compared by the paired t-test. The mean number of 125I seeds pre-implantation and post-implantation was 67.1 and 68.8, respectively. The mean values of D90 (dose that was delivered to 90% of the target volume), D100 (dose that was delivered to 100% of the target volume), V100 (the target volume receiving 100% of the prescription dose) and V150 (the target volume receiving 150% of the prescription dose) pre-implantation and post-implantation were 136.6 and 135.2 Gy, 63.5 and 71.0 Gy, 90.3% and 90.3% and 62.1% and 62.2%, respectively. Dosimetric outcomes were evaluated quantitatively using the dose volume indices, i.e. coverage index (CI), external volume index (EI) and relative dose homogeneity index (HI). The mean values of those indices pre-implantation and post-implantation were 0.62 and 0.61, 0.31 and 0.33, and 0.31 and 0.31, respectively. The mean doses delivered to OAR pre-implantation and post-implantation for the bladder (D2cc) and bowel (D2cc) were 33.4 and 34.4 Gy, and 58.6 and 61.8 Gy, respectively. The parameters mentioned above fitted well, and no significant difference was found among them. It is concluded that CT-guided 125I seed implantation assisted by 3D-PNCT could be a safe and accurate salvage modality for treating LRRC patients; the ideal pre-prescription dose could be achieved. Also, addition of 3D-PNCT could minimize radiation damage to the surrounding normal tissues.

Dosimetric comparison of computed tomography-guided iodine-125 seed implantation assisted with and without three-dimensional printing non-coplanar template in locally recurrent rectal cancer: a propensity score matching study

Purpose

To compare post-implant dosimetric parameters of computed tomography (CT)-guided radioactive iodine-125 (¹²⁵I) seed (RIS) implantation assisted with and without three-dimensional printing non-coplanar template (3D-PNCT) in locally recurrent rectal cancer (LRRC).

Material and methods

One hundred and fifty-five LRRC patients treated by CT-guided RIS implantation assisted with or without 3D-PNCT from October 2003 to May 2019 were included in this study. Propensity score matching (PSM) method (1 : 1) was used to adjust for differences between the 3D-group (with 3D-PNCT) and the CT-group (without 3D-PNCT). After PSM, dosimetric parameters [D₉₀ (dose that covered 90% of target volume), D₁₀₀ (dose that covered 100% of target volume), V₁₀₀ (percentage of gross tumor volume (GTV) receiving 100% of prescription dose), V₁₅₀ (percentage of GTV receiving 150% of prescription dose), HI (homogeneity index), CI (conformity index), and EI (external index)] of the two groups were compared.

Results

After PSM, 45 pairs of matched cases were selected for analysis and differences in variables between the two groups were balanced. For the 3D-group, median values of D₉₀, D₁₀₀, V₁₀₀, V₁₅₀, EI, and HI were 142.6 Gy (73.7-218.2 Gy), 73.7 Gy (26.2-169.3 Gy), 94.1% (74.3-100%), 71.8% (35.4-98.3%), 0.7 (0.1-30.7), and 0.20 (0-0.60), respectively, and corresponding values were 119.9 Gy (39.8-159.3 Gy), 47.0 Gy (13.0-200.9 Gy), 89.9% (38.6-100%), 62.8% (14.8-100%), 0.39 (0-11.01), and 0.30 (0-0.95), respectively, for the CT-group. Parameters including D₉₀, D₁₀₀, V₁₀₀, V₁₅₀, and EI in the 3D-group were significantly higher than those in the CT-group (p < 0.001, p < 0.001, p < 0.001, p < 0.001, and p = 0.006, respectively).

Conclusions

3D-PNCT can improve the accuracy of radioactive seed implantation by increasing the dose delivered to the tumor and reducing the number of “cold” spots of dose.

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.

Radiation-related Adverse Effects of CT-guided Implantation of 125I Seeds for Thoracic Recurrent and/or Metastatic Malignancy

During radioactive Iodine-125 seed implantation (RISI), Iodine-125 radionuclide is implanted directly into a lesion and kills tumor cells by steadily emitting radiation. In our study, we analyzed the adverse effects of RISI for thoracic malignancy, and investigated the safety, dosage, and adverse effects of RISI for these cases. Between June 2007 and January 2018, 77 patients with thoracic recurrent and/or metastatic tumors who underwent CT-guided RISI were enrolled. Radiation-related adverse effects were analyzed, including pneumonia, esophagitis, hemorrhage, fistula, skin injury, heart injury, and spinal cord injury. We used the Common Terminology Criteria for Adverse Events (CTCAE) v4.03 to evaluate adverse effects and analyzed the relationship between adverse effects and dosimetric parameters of organs at risk (OAR), including D0.1cc, D2cc, Dmean, and V20. The results of the study were as follows: The median follow-up period was 11 months. The median postoperative dose (D90) was 122 Gy (45.7–241.8 Gy). Three patients (3.9%) showed radiation pneumonitis of grade ≥2. Two patients (2.6%) showed radiation-induced esophagitis of grade ≥2. One patient (1.3%) showed an esophageal fistula. Two patients (2.6%) had a tracheal fistula. Five patients (6.5%) had radiation-related skin reactions. One patient (1.3%) reported chest wall pain, while three (3.9%) showed hemoptysis. No patients showed radiation myelitis or cardiotoxicity. The mean D2cc of organs at risk were 165.7 Gy (lung), 10.61 Gy (esophagus), 10.25 Gy (trachea), 18.07 Gy (blood vessel), 12.64 Gy (heart), 14.77 Gy (spinal cord), 17.47 Gy (skin). Dosimetric parameters, such as D0.1cc, D2cc and Dmean, were higher in patients with toxic reactions (above the upper limit of 95% confidence interval among the overall data). Chi-square test showed that skin D0.1cc > 600 Gy, D2cc > 500 Gy, and Dmean >90 Gy were associated with grade ≥2 radiation dermatitis (p < 0.05), but no clear dose-toxicity correlation was found in other OARs. So, we concluded that the overall incidence of toxicity and adverse effects from RISI for the treatment of thoracic tumors is low. The dose-toxicity characteristics have not been fully defined. Doses within the upper limit of the 95% confidence interval may be considered safe. This was a retrospective analysis, and follow-up period was minimal, indicating possible limitations of this study.

Ultrasound-Guided 125I Seed Implantation in Treatment of Abdominal Wall Metastases

Background: The treatment of abdominal wall metastasis presents a challenge, because resection can be followed by poor healing and external radiotherapy is associated with serious adverse events. This study aimed to evaluate the efficacy and safety of interstitial ¹²⁵I seed implantation under ultrasound (US) guidance for treating abdominal wall metastasis. Materials and Methods: The cases of 21 patients with 28 abdominal wall metastases who received brachytherapy with ¹²⁵I seeds at the department from August 2010 to March 2015 were retrospectively reviewed. ¹²⁵I seeds were implanted in the abdominal wall lesions under US guidance and with the help of a treatment planning system. Follow-up was performed using computed tomography at 1 d and at 3, 6, and 12 months after implantation. The lymphocyte count before the surgery was compared with the 3-month postoperative count. The main indicators observed were changes in tumor size, side effects, and complications. Results: All 21 patients were successfully treated with ¹²⁵I seed implantation under US guidance. The median follow-up since ¹²⁵I seed implantation was 15 months (range 6-23 months). The response rates and local tumor control after 3, 6, and 12 months were 78.6% and 89.3%, 64.3% and 85.7%, and 52.4% and 71.4%, respectively. The mean preoperative lymphocyte count was 0.262 ± 0.117 × 10⁹/L, which did not differ significantly from the postoperative count, which was 0.259 ± 0.094 × 10⁹/L (p = 0.122). Procedure-related complications included fever, bleeding, and pain, but all these were Grade 1-2. No severe side effects or complications were noted. Conclusions: Percutaneous interstitial implantation of ¹²⁵I seeds under US guidance is safe and feasible for abdominal wall metastases. However, its long-term efficacy requires further investigation.

Combined resection of re-recurrent lateral lymph nodes and external iliac vein:Case Report and Literature

Herein, we describe the operative procedure for combined resection of re-recurrent lateral lymph nodes and the external iliac vein. There is no consensus on the clinical implications of resection of locally re-recurrent colorectal tumors, as the operative procedure is extremely difficult. We present the case of a 52-year-old woman who underwent abdominoperineal resection. About one year later, we excised a recurrent lymph node in the left lateral obturator area through an extraperitoneal approach. About 18 months later, lymph node re-recurrence in the left external iliac area was observed. Re-recurrent lymph nodes directly invade the left external iliac vein. We removed the re-recurrent lymph node with combined, radical segmental resection of the left external iliac vein, left obturator artery and vein, and left obturator nerve. J. Med. Invest. 65:136-138, February, 2018.

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.

Chiral ruthenium(ii) complex as potent radiosensitizer of 125I through DNA-damage-mediated apoptosis

A chiral ruthenium(ii) complex, Λ-[Ru(bpy)₂(o-tFMPIP)] (ClO₄)₂ (o-tFMPIP = 2′-trifluoromethylphenyl) imidazo [4,5-f][1,10]phenanthroline, was prepared and evaluated for its enhancement of the radiosensitivity of ¹²⁵I seeds. The synthetic Ru(ii) complex, LR042, effectively enhanced growth inhibition against HepG2 human hepatocellular liver carcinoma cells induced by ¹²⁵I seeds and consequently effectively promoted the apoptosis of tumor cells with increasing level of cleave-caspase-3. Furthermore, the results of immunofluorescence indicated that LR042 enhanced the phosphorylation of H2AX by ¹²⁵I seeds vigorously in response to damaged DNA. LR042 improved DNA damage induced by ¹²⁵I seeds, which resulted in apoptosis through the activation of the p53/AKT signal. In conclusion, synthetic LR042 can be further developed as a potential radiosensitizer of ¹²⁵I seed radiotherapy for cancer therapy.

Synthetic LR042 can be further developed as a radiosensitizer of ¹²⁵I by inducing DNA-damage-mediated apoptosis for cancer therapy.

Dosimetric characterization of GMS BT-125-1 125 I radioactive seed with Monte Carlo simulations and experimental measurement

Purpose

To investigate the dosimetric characteristics of the new GMS BT‐125‐1 ¹²⁵I radioactive seed, including dose rate constant, radial dose functions, and anisotropy functions.

Methods

Dosimetric parameters of GMS BT‐125‐1 ¹²⁵I seed including dose rate constant, radial dose functions, and anisotropy functions were calculated using the Monte Carlo code of MCNP5, and measured with thermoluminescent dosimeters (TLDs). The results were compared with those of PharmaSeed BT‐125‐1, PharmaSeed BT‐125‐2 ¹²⁵I, and model 6711 ¹²⁵I seeds.

Results

The dose rate constant of GMS BT‐125‐1 ¹²⁵I seed was 0.959 cGy·h−1·U−1, with the difference of 0.94%, 0.83%, and 0.73% compared with the PharmaSeed BT‐125‐1 ¹²⁵I seed, PharmaSeed BT‐125‐2 ¹²⁵I seed, and Model 6711 ¹²⁵I seed, respectively. For radial dose function, the differences between the Monte Carlo and the experimental g(r) results were mostly within 10%. Monte Carlo results of g(r) for GMS BT‐125‐1 ¹²⁵I seed were found in agreement (within 3.3%) with corresponding results for the PharmaSeed BT‐125‐2 ¹²⁵I seed. The largest differences were 8.1% and 6.2% compared with PharmaSeed BT‐125‐1 ¹²⁵I seed and model 6711 ¹²⁵I seed, respectively. For anisotropy function, the difference between GMS BT‐125‐1 ¹²⁵I seed and PharmaSeed BT‐125‐2 ¹²⁵I seed was typically <10%.

Conclusions

The measured dose rate constant, radial dose functions, and two‐dimensional anisotropy functions for the GMS BT‐125‐1 ¹²⁵I seed showed good agreement with the Monte Carlo results. The dose rate constant of the GMS BT‐125‐1 ¹²⁵I seed is similar to that of the PharmaSeed BT‐125‐1 ¹²⁵I seed, the PharmaSeed BT‐125‐2 ¹²⁵I seed, and the model 6711 ¹²⁵I seed. For radial dose functions and two‐dimensional anisotropy functions, the GMS BT‐125‐1 ¹²⁵I seed is similar to the PharmaSeed BT‐125‐2 ¹²⁵I seed but different from the PharmaSeed BT‐125‐1 ¹²⁵I seed and the model 6711 ¹²⁵I seed.

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.

Combination of Permanent Interstitial 125I-Seed Brachytherapy and Surgery for the Treatment of Large Hepatocellular Carcinoma

The treatment methods available for large primary hepatocellular carcinomas (diameter >5 cm) are inadequate. Here, we report the successful management of 80 cases of large hepatocellular carcinoma, using a combination of custom-designed permanent interstitial iodine-125 seed brachytherapy and palliative surgery. Patients were enrolled in the study between 2011 and 2014. All patients underwent surgical treatment along with permanent interstitial iodine-125 seed brachytherapy; for the latter, patients received minimum doses covering 90% of the target (D90 s) of iodine-125 seeds ranging from 100 to 160 Gy (median: 110 Gy). All patients received 6 cycles of chemotherapy and were followed up at 6, 12, 24, and 36 months postoperatively. The clinical symptom remission rate was 95.3% (61 of 64). Alanine aminotransferase and aspartate aminotransferase levels decreased to normal in 80% (50 of 60) and 75% of the patients (45 of 60), respectively. The posttreatment alpha-fetoprotein levels decreased by 50% in 80% of the patients (40 of 50). The effective therapy rates were 80% (76 of 95) for 95 tumor nodules (diameters 5-10 cm) and 78.6% (33 of 42) for 42 tumor nodules (diameters >10 cm). The 3-year disease-free survival rate was 66.6%. Palliative surgery plus permanent interstitial iodine-125 seed brachytherapy appears to be a reasonable therapeutic alternative for large hepatocellular carcinoma.

125I seed irradiation induces apoptosis and inhibits angiogenesis by decreasing HIF-1α and VEGF expression in lung carcinoma xenografts

The purpose of this study was to examine the effects of irradiation by 125I seeds in human lung cancer xenograft model and to determine the underlying mechanisms involved, with a focus on angiogenesis. A group of 40 mice bearing A549 lung adenocarcinoma xenografts was randomly separated into 4 groups: control group (n=10), sham seed (0 mCi) implant group (n=10), 125I seed (0.6 mCi) implant group (n=10) and 125I seed (0.8 mCi) implant group (n=10), respectively. The body weight and tumor volume, were recorded every four days until the end of the study. At 30 days after irradiation, the microvessel density, proliferative index and apoptotic index were evaluated by quantitative morphometric analysis of the expression of CD34, proliferating cell nuclear antigen (Ki-67) and in situ terminal transferase-mediated fluorescein deoxy- UTP nick-end labeling (TUNEL), respectively. The changes in the expression of hypoxia inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) were detected by real-time PCR and western blot analysis. Consequently, 125I seed irradiation suppressed the growth of lung cancer xenografts in nude mice, while inhibiting cell proliferation and angiogenesis and inducing apoptosis as demonstrated by Ki67, CD34 and TUNEL staining. HIF-1α and VEGF mRNA and protein expression levels were substantially downregulated following 125I seed irradiation. Collectively, our data suggest that irradiation by 125I seeds is a promising new option for lung cancer treatment.

Continuous Low-dose-rate Irradiation of Iodine-125 Seeds Inhibiting Perineural Invasion in Pancreatic Cancer

Background:

Perineural invasion (PNI) is a histopathological characteristic of pancreatic cancer (PanCa). The aim of this study was to observe the treatment effect of continuous low-dose-rate (CLDR) irradiation to PNI and assess the PNI-related pain relief caused by iodine-125 (¹²⁵I) seed implantation.

Methods:

The in vitro PNI model established by co-culture with dorsal root ganglion (DRG) and cancer cells was interfered under 2 and 4 Gy of ¹²⁵I seeds CLDR irradiation. The orthotopic models of PNI were established, and ¹²⁵I seeds were implanted in tumor. The PNI-related molecules were analyzed. In 30 patients with panCa, the pain relief was assessed using a visual analog scale (VAS). Pain intensity was measured before and 1 week, 2 weeks, and 1, 3, and 6 months after ¹²⁵I seed implantation.

Results:

The co-culture of DRG and PanCa cells could promote the growth of PanCa cells and DRG neurites. In co-culture groups, the increased number of DRG neurites and pancreatic cells in radiation group was significantly less. In orthotopic models, the PNI-positive rate in radiation and control group was 3/11 and 7/11; meanwhile, the degrees of PNI between radiation and control groups was significant difference (P < 0.05). At week 2, the mean VAS pain score in patients decreased by 50% and significantly improved than the score at baseline (P < 0.05). The pain scores were lower in all patients, and the pain-relieving effect was retained about 3 months.

Conclusions:

The CLDR irradiation could inhibit PNI of PanCa with the value of further study. The CLDR irradiation could do great favor in preventing local recurrence and alleviating pain.

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.

125I Seeds Radiation Induces Paraptosis-Like Cell Death via PI3K/AKT Signaling Pathway in HCT116 Cells

¹²⁵I seeds brachytherapy implantation has been extensively performed in unresectable and rerecurrent rectal carcinoma. Many studies on the cancer-killing activity of ¹²⁵I seeds radiation mainly focused on its ability to trigger apoptosis, which is the most well-known and dominant type of cell death induced by radiation. However our results showed some unique morphological features such as cell swelling, cytoplasmic vacuolation, and plasma membrane integrity, which is obviously different to apoptosis. In this study, clonogenic proliferation was carried out to assay survival fraction. Transmission electron microscopy was used to analyze ultrastructural and evaluate morphologic feature of HCT116 cells after exposure to ¹²⁵I seeds radiation. Immunofluorescence analysis was used to detect the origin of cytoplasmic vacuoles. Flow cytometry analysis was employed to detect the size and granularity of HCT116 cells. Western blot was performed to measure the protein level of AIP1, caspase-3, AKT, p-Akt (Thr308), p-Akt (Ser473), and β-actin. We found that ¹²⁵I seeds radiation activated PI3K/AKT signaling pathway and could trigger paraptosis-like cell death. Moreover, inhibitor of PI3K/AKT signaling pathway could inhibit paraptosis-like cell death induced by ¹²⁵I seeds radiation. Our data suggest that ¹²⁵I seeds radiation can induce paraptosis-like cell death via PI3K/AKT signaling pathway.

Dosimetry verification of radioactive seed implantation for malignant tumors assisted by 3D printing individual templates and CT guidance

OBJECTIVE

We compared the dose distributions of postoperative plans with preoperative plans for 3D printing template-assisted radioactive seed implantations.

METHODS

A total of 14 patients with malignant tumors enrolled in the study. The dose parameters included D90, minimum peripheral dose, V100, V150, and V200. The statistical method was the paired t-test.

RESULTS

There was no significant difference in P values between the two groups for all parameters except for V100.

CONCLUSIONS

The 3D printing guide template can provide good accuracy for radioactive seed implantation.

Iodine-125 irradiation inhibits invasion of gastric cancer cells by reactivating microRNA-181c expression

Iodine-125 (¹²⁵I) seed implantation has been widely used for the treatment of unresectable advanced tumors. However, the molecular mechanisms underlying the tumor-suppressive effects of ¹²⁵I irradiation have not been fully elucidated. The present study demonstrated that ¹²⁵I irradiation suppresses cell viability and inhibits cell invasiveness of gastric cancer KATO-III and MKN45 cells. Further mechanistic analysis suggested the involvement of microRNA (miR)-181c in the inhibitory effects induced by ¹²⁵I irradiation. Methylated DNA immunoprecipitation coupled with quantitative-polymerase chain reaction demonstrated that treatment with ¹²⁵I irradiation, at the dose of 4 Gy, induced promoter demethylation of the miR-181c gene in KATO-III and MKN45 cells. Following irradiation, the expression of miR-181c was significantly increased, which may be attributed to the demethylation caused by ¹²⁵I irradiation. In addition, upregulation of miR-181c by administration of miR-181c mimics decreased cell invasion, suggesting the role of miR-181c as a tumor suppressor. More importantly, the tumor-suppressive effects of ¹²⁵I irradiation were significantly compromised by the introduction of miR-181c inhibitors. Overall, these results reveal that ¹²⁵I irradiation inhibits invasiveness of gastric cancer cells by reactivating miR-181c at the epigenetic level, thereby providing important molecular evidence for the anticancer effects of ¹²⁵I irradiation.

(125)I Seed Permanent Implantation as a Palliative Treatment for Stage III and IV Hypopharyngeal Carcinoma

OBJECTIVES

The aim of this study was to investigate the feasibility and safety of percutaneous (125)I seed permanent implantation for advanced hypopharyngeal carcinoma from toxicity, tumor response, and short-term outcome.

METHODS

(125)I seeds implant procedures were performed under computed tomography for 34 patients with advanced hypopharyngeal carcinoma. We observed the local control rate, overall survival, and acute or late toxicity rate.

RESULTS

In the 34 patients (stage III, n=6; stage IV, n=28), the sites of origin were pyriform sinus (n=29) and postcricoid area (n=5). All patients also received one to four cycles of chemotherapy after seed implantation. The post-plan showed that the actuarial D90 of (125)I seeds ranged from 90 to 158 Gy (median, 127 Gy). The mean follow-up was 12.3 months (range, 3.4 to 43.2 months). The local control was 2.1-31.0 months with a median of 17.7 months (95% confidence interval [CI], 13.4 to 22.0 months). The 1-, 2-, and 3-year local controls were 65.3%, 28.6%, and 9.5% respectively. Twelve patients (35%) died of local recurrence, fourteen patients (41%) died of distant metastases, and three patients (9%) died of recurrence and metastases at the same time. Five patients (15%) still survived to follow-up. At the time of analysis, the median survival time was 12.5 months (95% CI, 9.5 to 15.4 months). The 1-, 2-, and 3-year overall survival rates were 55.2%, 20.3%, and 10.9%, respectively. Five patients (15%) experienced grade 3 toxic events and nine patients (26%) have experienced grade 2 toxic events.

CONCLUSION

This review shows relatively low toxicity for interstitial (125)I seed implantation in the patients with advanced stage hypopharyngeal cancer. The high local control results suggest that (125)I seed brachytherapy implant as a salvage or palliative treatment for advanced hypopharyngeal carcinoma merit further investigation.

Safety and efficacy of intraoperative iodine-125 seed implantation brachytherapy for rectal cancer patients: A retrospective clinical research

BACKGROUND

This pilot study was performed to evaluate the risk of anastomotic leakage (AL) and pelvic autonomic nerve dysfunction, and the effects of (125) I brachytherapy after intraoperative permanent implantation of iodine-125 seeds within the patients with rectal carcinoma.

METHODS

In a cohort consisting of 80 rectal cancer patients who received potentially curative resection of rectal carcinoma with implantation of (125) I brachytherapy or radical resection of rectal carcinoma underwent total mesorectal excision. The incidences of AL, fecal incontinence, urinary dysfunction, and sexual dysfunction were calculated for comparison, and risk factors for these complications were analyzed by logistic regression. Rates of tumor recurrence and overall survival were evaluated.

RESULTS

Six out of 17 (35.29%) patients in the (125) I implant group and 1 out of 34 (2.94%) patients in the non-implant group were complicated with AL (P = 0.006). The incidences of urinary dysfunction (P = 0.005) and fecal incontinence (P = 0.023) were significantly different between the two groups. Multivariate analyses revealed that (125) I brachytherapy was an independent risk factor for AL (odds ratio, 18.702; 95%CI, 1.802-194.062; P = 0.014) and urinary dysfunction (odds ratio, 4.340; 95%CI, 1.158-16.264; P = 0.029), respectively. At postoperative 2-year, the recurrence rates were 5.56% in the (125) I implant group and 9.09% in the non-implant group (P = 0.029).

CONCLUSIONS

Intraoperative implantation of (125) I brachytherapy significantly increases the risk of AL, fecal incontinence, urinary dysfunction, and improves local control and do not improve overall survival after total mesorectal excision.

Permanent interstitial 125I seed implantation as a salvage therapy for pediatric recurrent or metastatic soft tissue sarcoma after multidisciplinary treatment

BACKGROUND

The management of pediatric recurrent or metastatic soft tissue sarcoma after multimodal treatment remains challenging. We investigated the feasibility, efficacy, and morbidity of permanent interstitial (125)I seed implantation under image guidance as a salvage treatment for pediatric patients with recurrent or metastatic soft tissue sarcoma.

METHODS

This was a retrospective study of 10 patients who underwent percutaneous ultrasound or computed tomography (CT) guided permanent (125)I seed implantation. Postoperative dosimetry was performed for all patients. Actuarial D90 was 121-187.1 Gy (median, 170.3 Gy). The number of (125)I seeds implanted was 6-158 (median, 34.5), with a median specific activity of 0.7 mCi per seed (range, 0.62-0.8 mCi); total activity was 4.2-113.76 mCi. Follow-up time was 6-107 months (median, 27.5 months); no patients were lost to follow-up.

RESULTS

The overall response rate (complete response + partial response) was 8/10 (80 %), including two patients with complete response (CR) (20 %) and five patients with partial response (PR) (60 %). Local control rates after 1 and 2 years were 70.1 and 62.3 %, respectively, with a mean local control time of 70.6 months (95 % confidence interval (CI) 45.1-96.0). Survival rates after 1 and 2 years were 68.6 and 57.1 %, respectively, with a mean survival time of 65.3 months (95 % CI 34.1-96.5). Three patients died from distant metastasis; one died from local recurrence 12 months after seed implantation. Three patients suffered a grade I skin reaction and one developed ulceration. No severe adverse neurologic sequelae or blood vessel damage occurred.

CONCLUSIONS

Image guided permanent interstitial (125)I seed implantation as a salvage treatment appears to have a satisfactory outcome in children with recurrent or metastatic soft tissue sarcoma.

Phase II study of computed tomography-guided (125)I-seed implantation plus chemotherapy for locally recurrent rectal cancer

BACKGROUND AND PURPOSE

This trial evaluated the efficacy and safety of CT guided (125)I-seed implantation (CTII) plus chemotherapy with fluorouracil, leucovorin, and irinotecan (FOLFIRI) compared with FOLFIRI alone as second-line treatment for locally recurrent rectal cancer (LRRC).

MATERIAL AND METHODS

Patients with LRRC who received one prior chemotherapy regimen were enrolled and divided randomly assigned to FOLFORI alone (Arm A) and FOLFORI plus CTII (Arm B). The primary endpoint was local control time (LCT). Overall survival (OS) and treatment related adverse events (TRAEs) were also observed.

RESULTS

Fifty-seven patients were enrolled from October 2008 and December 2014. Twenty-seven were assigned into Arm A and 30 into Arm B. The overall response rate of locally recurrent tumor was improved to 100% in Arm B versus 29.6% in Arm A (P<0.001). A significant longer LCT was observed in Arm A (P<0.001); median LCT was 12 months in Arm B versus 4 months in Arm A. A borderline significant improvement in OS was also observed in Arm B (P=0.0464); median OS was 25 months in Arm B versus 19 months in Arm A. For patients without distant metastases, median OS was 37 months in Arm B versus 21 months in Arm A (P=0.0101). For patients with (neo)adjuvant radiotherapy (ART), a longer LCT and OS were also found in Arm B (P<0.001 and P=0.0217, respectively). TRAEs were not serious generally. There was no statistically significant difference in treatment related toxicity between Arm A and B both for all patients and patients receiving ART.

CONCLUSIONS

CTII plus FOLFIRI improves the LCT with tolerable toxicities as a second-line treatment in patients with local recurrent rectal cancer, and is helpful to prolong the OS, particularly in patients without distant metastases or with a history of radiotherapy.

Image-guided high-dose-rate brachytherapy: preliminary outcomes and toxicity of a joint interventional radiology and radiation oncology technique for achieving local control in challenging cases

PURPOSE

To determine the ability of image-guided high-dose-rate brachytherapy (IG-HDR) to provide local control (LC) of lesions in non-traditional locations for patients with heavily pre-treated malignancies.

MATERIAL AND METHODS

This retrospective series included 18 patients treated between 2012 and 2014 with IG-HDR, either in combination with external beam radiotherapy (EBRT; n = 9) or as monotherapy (n = 9). Lesions were located in the pelvis (n = 5), extremity (n = 2), abdomen/retroperitoneum (n = 9), and head/neck (n = 2). All cases were performed in conjunction between interventional radiology and radiation oncology. Toxicity was graded based on CTCAE v4.0 and local failure was determined by RECIST criteria. Kaplan-Meier analysis was performed for LC and overall survival.

RESULTS

The median follow-up was 11.9 months. Two patients had localized disease at presentation; the remainder had recurrent and/or metastatic disease. Seven patients had prior EBRT, with a median equivalent dose in 2 Gy fractions (EQD2) of 47.0 Gy. The median total EQD2s were 34 Gy and 60.9 Gy for patients treated with monotherapy or combination therapy, respectively. Image-guided high-dose rate brachytherapy was delivered in one to six fractions. Six patients had local failures at a median interval of 5.27 months with a one-year LC rate of 59.3% and a one-year overall survival of 40.7%. Six patients died from their disease at a median interval of 6.85 months from the end of treatment. There were no grade ≥ 3 acute toxicities but two patients had serious long term toxicities.

CONCLUSIONS

We demonstrate a good one year LC rate of nearly 60%, and a favorable toxicity profile when utilizing IG-HDR to deliver high doses of radiation with high precision into targets not readily accessible by other forms of local therapy. These preliminary results suggest that further studies utilizing this approach may be considered for patients with difficult to access lesions that require LC.

A comparison of the biological effects of 125I seeds continuous low-dose-rate radiation and 60Co high-dose-rate gamma radiation on non-small cell lung cancer cells

Objectives

To compare the biological effects of ¹²⁵I seeds continuous low-dose-rate (CLDR) radiation and ⁶⁰Co γ-ray high-dose-rate (HDR) radiation on non-small cell lung cancer (NSCLC) cells.

Materials and Methods

A549, H1299 and BEAS-2B cells were exposed to ¹²⁵I seeds CLDR radiation or ⁶⁰Co γ-ray HDR radiation. The survival fraction was determined using a colony-forming assay. The cell cycle progression and apoptosis were detected by flow cytometry (FCM). The expression of the apoptosis-related proteins caspase-3, cleaved-caspase-3, PARP, cleaved-PARP, BAX and Bcl-2 were detected by western blot assay.

Results

After irradiation with ¹²⁵I seeds CLDR radiation, there was a lower survival fraction, more pronounced cell cycle arrest (G₁ arrest and G₂/M arrest in A549 and H1299 cells, respectively) and a higher apoptotic ratio for A549 and H1299 cells than after ⁶⁰Co γ-ray HDR radiation. Moreover, western blot assays revealed that ¹²⁵I seeds CLDR radiation remarkably up-regulated the expression of Bax, cleaved-caspase-3 and cleaved-PARP proteins and down-regulated the expression of Bcl-2 proteins in A549 and H1299 cells compared with ⁶⁰Co γ-ray HDR radiation. However, there was little change in the apoptotic ratio and expression of apoptosis-related proteins in normal BEAS-2B cells receiving the same treatment.

Conclusions

¹²⁵I seeds CLDR radiation led to remarkable growth inhibition of A549 and H1299 cells compared with ⁶⁰Co HDR γ-ray radiation; A549 cells were the most sensitive to radiation, followed by H1299 cells. In contrast, normal BEAS-2B cells were relatively radio-resistant. The imbalance of the Bcl-2/Bax ratio and the activation of caspase-3 and PARP proteins might play a key role in the anti-proliferative effects induced by ¹²⁵I seeds CLDR radiation, although other possibilities have not been excluded and will be investigated in future studies.

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.

Radioactive (125)I seeds inhibit cell growth and epithelial-mesenchymal transition in human glioblastoma multiforme via a ROS-mediated signaling pathway

Background

Glioblastoma multiforme (GBM) is the most common primary central nervous system neoplasm in adults. Radioactive ¹²⁵I seed implantation has been widely applied in the treatment of cancers. Moreover, previous clinical trials have confirmed that ¹²⁵I seeds treatment was an effective therapy in GBM. We sought to investigate the effect of ¹²⁵I seed on GBM cell growth and Epithelial-mesenchymal transition (EMT).

Methods

Cells were exposed to irradiation at different doses. Colony-formation assay, EdU assay, cell cycle analysis, and TUNEL assay were preformed to investigate the radiation sensitivity. The effects of ¹²⁵I seeds irradiation on EMT were measured by transwell, Boyden and wound-healing assays. The levels of reactive oxygen species (ROS) were measured by DCF-DA assay. Moreover, the radiation sensitivity and EMT were investigated with or without pretreatment with glutathione. Additionally, nude mice with tumors were measured after treated with radiation.

Results

Radioactive ¹²⁵I seeds are more effective than X-ray irradiation in inhibiting GBM cell growth. Moreover, EMT was effectively inhibited by ¹²⁵I seed irradiation. A mechanism study indicated that GBM cell growth and EMT inhibition were induced by ¹²⁵I seeds with the involvement of a ROS-mediated signaling pathway.

Conclusions

Radioactive ¹²⁵I seeds exhibit novel anticancer activity via a ROS-mediated signaling pathway. These findings have clinical implications for the treatment of patients with GBM by ¹²⁵I seeds.

Computed tomography-guided 125I seed interstitial implantation in the treatment of recurrent ovarian cancer

OBJECTIVE

The aim of this study was to evaluate the effectiveness and safety of percutaneous interstitial implantation with (125)I seed under computed tomographic (CT) guidance for recurrent ovarian cancer (ROC).

MATERIALS AND METHODS

A retrospective review was performed on 17 patients with ROC who were treated with (125)I seed brachytherapy. Treatment planning system was used preoperatively to determine the estimated seeds number and distribution; (125)I seeds were implanted into recurrent lesions under CT guidance. Therapeutic effectiveness and complications were noted during follow-up time.

RESULTS

Months are counted from the time of (125)I seed brachytherapy, and the median duration of follow-up was 10.5 months (3-23 months). The objective response rates after 1, 3, 6, 12, and 18 months were 76.5%, 75.0%, 61.5%, 42.9%, and 40%, respectively. The pain relief rate was 61.5%, and the general living quality was improved dramatically. The median progression-free survival time was 5.4 months, the median overall survival time was 11.3 months, and the 1-year survival rate was 41.2%. Complications in this study were very mild; severe adverse events such as massive bleeding, intestinal fistula, and treatment-related deaths did not occur.

CONCLUSIONS

Our initial experience showed that CT-guided (125)I seed interstitial implantation is safe and feasible in the treatment of patients with ROCs after multiple therapies.

Effect of brachytherapy on NF-κB and VEGF in gastric carcinoma xenografts

Iodine-125 (125I) seed irradiation can be used as an important supplementary treatment for unresectable advanced gastric cancer. However, the radiobiological mechanism underlying brachytherapy remains unclear. Therefore, we investigated the influence of continuous and low-energy 125I irradiation on the cell cycle distribution, apoptosis, expression of NF-κB and VEGF and tumor growth in a human gastric cancer xenograft model. To create an animal model of gastric cancer, SGC-7901 cells were surgically implanted into mice. The 60 mice bearing SGC-7901 gastric cancer xenografts were randomly separated into 2 groups. Sham seeds (0 mCi) were implanted into the control group (n=30); 125I seeds (0.6 mCi) were implanted into the treatment group (n=30). At 28 days after irradiation, apoptosis was detected by flow cytometry. fluorescence micrograph detected intense VEGF and NF-κB immunofluorescence in the tumor samples, and changes in NF-κB and VEGF mRNA and protein expression were assessed by real-time PCR and western blot analysis, respectively. The tumor volume and weight were measured 0-28 days after 125I seed implantation. 125I seed irradiation induced significant apoptosis and G2/M phase arrest. Reduction in the intensities of VEGF and NF-κB immunofluorescence in tumor vessels was observed after treatment. NF-κB and VEGF mRNA and protein expression levels were substantially lower in the implantation treatment group than in the control group. Consequently, 125I seed implantation inhibited cancer growth and reduced cancer volume. The present study revealed that 125I seed irradiation significantly induced apoptosis and cell cycle arrest in the human gastric cancer xenografts. 125I-induced changes in NF-κB and VEGF expression are suggested as potential mechanisms underlying effective brachytherapy.

Comparison of Iodine-125 seeds implantation and afterloading radiotherapy in murine models of human cervical cancer

OBJECTIVE

To compare the efficacies and side effects of Iodine-125 (125I) seeds implantation with afterloading radiotherapy on tumor xenografts derived from Hela cells.

METHODS

Mice bearing Hela cells were randomly divided into three groups: two therapeutic groups receiving four 125I seeds implantation and afterloading therapy, respectively, and the one control group without any intervention. Comparisons were evaluated in aspects of curative efficacies (tumor volume, tumor inhibition rate and metastasis) and side effects (body weight, ovarian endocrine functions, skin lesion surrounding the tumor).

RESULTS

The xenografts tumor volume of therapeutic groups were significantly smaller than that of controls(p < 0.05),both of the 125I seeds implantation and afterloading therapy showed excellent tumor inhibition rate. Furthermore, 125I seeds implantation had milder side effects on skin, weight loss, ovarian endocrine functions.

CONCLUSIONS

(125)I seed implantation may be an alternative minimally invasive therapy for cervical cancer.

Continuous low-dose irradiation by I-125 seeds induces apoptosis of gastric cancer cells regardless of histological origin

The efficacy of conventional radiation therapy for gastric cancer is controversial. In this study, we evaluated the in vitro and in vivo effects of continuous low-dose-rate irradiation by I-125 seeds on different histological types of gastric cancer cell lines. Three human gastric cancer cell lines (MKN74, MKN45, and NUGC4) were treated with or without continuous low-dose irradiation by I-125 seeds in vitro and in vivo. Cell viability, apoptosis, caspase-3 assay, and cell-cycle distribution were examined in vitro. Body weight and tumor volumes of BALB/c nude mice bearing MKN74, MKN45, and NUGC4 gastric cancer xenografts were measured, and in vivo cell proliferation and apoptosis assays were performed by Ki67 and TUNEL staining, respectively. Continuous low-dose-rate irradiation by I-125 seeds reduced cell viability and induced cell apoptosis through the activation of caspase-3, and led to the accumulation of cells in the G 2/M phase in vitro. It also suppressed the growth of gastric cancer xenografts in nude mice, while inhibiting cell proliferation and inducing apoptosis as demonstrated by Ki67 and TUNEL staining. Therefore, our data suggest that continuous low-dose-rate irradiation by I-125 seeds could be a promising new option for gastric cancer treatment, regardless of histological origin.

Combined effects of C225 and 125-iodine seed radiation on colorectal cancer cells

Background

To characterize the effect of combined treatment of the anti-epidermal growth factor receptor (EGFR) monoclonal antibody C225 and 125-iodine (¹²⁵I) seed radiation in human colorectal cancer.

Methods

We treated LS180 cells with ¹²⁵I continuous low dose rate radiation in the presence and absence of 100 nM C225. The clonogenic capacity, cellular proliferation, cell cycle distribution, apoptosis, and molecular pathways of the cells following the treatments were analyzed in vitro.

Results

The sensitizer enhancement ratio of C225 was approximately 1.4. Treatment with C225 and radiation alone produced significant inhibition of cell growth, but combination therapy produced greater inhibition than either treatment administered alone. C225 increased the radiation-induced apoptosis and the fraction of γ-H2AX foci positive cells at 48 h after treatment. The Akt phosphorylation level was lower in the cells receiving the combination treatment than in the cells treated with radiation or C225 alone.

Conclusions

These findings indicate that C225 sensitizes LS180 cells to ¹²⁵I seed radiation. Growth inhibition is mediated by inducing apoptosis and not cell cycle arrest. Additionally, we confirmed that C225 impairs DNA repair by reducing the cellular level of the DNA-PKcs and Ku70 proteins. Furthermore, the inhibition of Akt signaling activation may be responsible for the C225-mediated radiosensitization.

Effects of iodine-125 seeds on the methylation of SFRP2 and P16 in colorectal cancer

The current study investigated the effects of iodine-125 seeds on the gene methylation of SFRP₂ and P16 in colorectal cancer. Mouse models of human colorectal cancer were randomly divided into an experimental group (n=25) and a control group (n=25). The control group was implanted with blank seeds (0 MBq) and the experimental group with iodine-125 seeds (14.8 MBq). At 20 days after implantation, the animals were sacrificed. The methylation levels of SFRP₂ and P16 were detected using methylation-specific polymerase chain reactions (MSPs). Following iodine-125 seed irradiation, the level of SFRP₂ methylation decreased. The methylation index of the experimental group (0.67±0.05) was significantly lower than that of the control group (0.84±0.07; P<0.05). In the experimental group, 10 samples (40%) displayed methylation in the P16 promoter region compared with 14 (56%) in the control group, which was a significant difference (P<0.05). Iodine-125 seeds induce the downregulation of methylated tumor suppressor gene promoters, thereby inhibiting the proliferation and growth of tumor cells.

Radioactive ¹²⁵I seed inhibits the cell growth, migration, and invasion of nasopharyngeal carcinoma by triggering DNA damage and inactivating VEGF-A/ERK signaling

Although radiotherapy technology has progressed rapidly in the past decade, the inefficiency of radiation and cancer cell resistance mean that the 5-year survival rate of patients with nasopharyngeal carcinoma (NPC) is low. Radioactive ¹²⁵I seed implantation has received increasing attention as a clinical treatment for cancers. Vascular endothelial growth factor-A (VEGF-A) is one of the most important members of the VEGF family and plays an important role in cell migration through the extracellular-signal-regulated kinase (ERK) pathway. Here we show that radioactive ¹²⁵I seeds more effectively inhibit NPC cell growth through DNA damage and subsequent induction of apoptosis, compared with X-ray irradiation. Moreover, cell migration was effectively inhibited by ¹²⁵I seed irradiation through VEGF-A/ERK inactivation. VEGF-A pretreatment significantly blocked ¹²⁵I seed irradiation-induced inhibition of cell migration by recovering the levels of phosphorylated ERK (p-ERK) protein. Interestingly, in vivo study results confirmed that ¹²⁵I seed irradiation was more effective in inhibiting tumor growth than X-ray irradiation. Taken together, these results suggest that radioactive ¹²⁵I seeds exert novel anticancer activity by triggering DNA damage and inactivating VEGF-A/ERK signaling. Our finding provides evidence for the efficacy of ¹²⁵I seeds for treating NPC patients, especially those with local recurrence.

Efficacy and safety of percutaneous microwave coagulation therapy followed by 125I seed brachytherapy for VX2 hepatic tumors in a rabbit model

The aim of this study was to evaluate the efficacy and safety of percutaneous microwave coagulation therapy (PMCT) followed by ¹²⁵I seed brachytherapy for VX2 liver cancer in rabbits. Eighty New Zealand rabbits were injected with suspensions of VX2 tumor cells to create an animal model. The rabbits were randomly divided into 4 groups (n=20); the control, PMCT, ¹²⁵I seed brachytherapy and combination groups. Group A was treated with PMCT at 40 W for 120 sec, group B was treated with ¹²⁵I seed brachytherapy and group C was treated with PMCT followed by ¹²⁵I seed brachytherapy. Group D were not treated and served as the control group. At 21 days after treatment, the rabbits were sacrificed for pathological assessment. The complete tumor necrosis rate was 19 out of 20 tumors (95%) in group C, 6 (30%) in group A, 0 (0%) in group B and 0 (0%) in the control group. The complete tumor necrosis rate was observed to be significantly different between groups C and A, and between groups C and B (P<0.01). No intraheptic metastasis occurred in group C, compared with an incidence of 7 (35%) in group A, 2 (10%) in group B and 20 (100%) in the control group. Between groups C and A, and between groups C and D, the intraheptic metastasis rate was statistically significant (P<0.01). PMCT followed by ¹²⁵I seed brachytherapy increased the rate of carcinoma necrosis and decreased carcinoma metastasis in the VX2 rabbit model. This combined treatment is a safe, effective and minimally invasive therapeutic option for liver cancer.

The different biological effects of single, fractionated and continuous low dose rate irradiation on CL187 colorectal cancer cells

PURPOSE

To determine the biological effectiveness of single, fractionated and continuous low dose rate irradiation on the human colorectal cancer cell line CL187 in vitro and explore the cellular mechanisms.

MATERIALS AND METHODS

The CL187 cells were exposed to radiation of 6 MV X-ray at a high dose rate of 4Gy/min and 125I seed at a low dose rate of 2.77 cGy/h. Three groups were employed: single dose radiation group (SDR), fractionated dose radiation group (FDR) by 2Gy/f and continuous low dose rate radiation group (CLDR). Four radiation doses 2, 4, 6 and 8Gy were chosen and cells without irradiation as the control. The responses of CL187 cells to distinct modes of radiation were evaluated by the colony-forming assay, cell cycle progression as well as apoptosis analysis. In addition, we detected the expression patterns of DNA-PKcs, Ku70 and Ku80 by Western blotting.

RESULTS

The relative biological effect for 125I seeds compared with 6 MV X-ray was 1.42. 48 hrs after 4Gy irradiation, the difference between proportions of cells at G2/M phase of SDR and CLDR groups were statistically significant (p = 0.026), so as the FDR and CLDR groups (p = 0.005). 48 hrs after 4Gy irradiation, the early apoptotic rate of CLDR group was remarkably higher than SDR and FDR groups (CLDR vs. SDR, p = 0.001; CLDR vs. FDR, p = 0.02), whereas the late apoptotic rate of CLDR group increased significantly compared with SDR and FDR group (CLDR vs. SDR, p = 0.004; CLDR vs. FDR, p = 0.007). Moreover, DNA-PKcs and Ku70 expression levels in CLDR-treated cells decreased compared with SDR and FDR groups.

CONCLUSIONS

Compared with the X-ray high dose rate irradiation, 125I seeds CLDR showed more effective induction of cell apoptosis and G2/M cell cycle arrest. Furthermore, 125I seeds CLDR could impair the DNA repair capability by down-regulating DNA-PKcs and Ku70 expression.

125I seed irradiation induces up-regulation of the genes associated with apoptosis and cell cycle arrest and inhibits growth of gastric cancer xenografts

Background

Iodine 125 (125I) seed irradiation can be used as an important supplementary treatment for unresectable advanced gastric cancer. Here, we aim to comprehensively elucidate the biological effects induced by 125I seed irradiation in human gastric cancer xenograft model by using global expression and DNA methylation analyses.

Methods

The 48 mice bearing NCI-N87 gastric cancer xenografts were randomly separated into 2 groups: sham seeds (O mCi) were implanted into the control group (n = 24); 125 l seeds (0.9 mCi) were implanted into the treatment group (n = 24). The mitotic index and apoptotic index were evaluated by quantitative morphometric analysis of the expression of proliferating cell nuclear antigen (PCNA) and in situ terminal transferase-mediated fluorescein deoxy- UTP nick end labeling (TUNEL), respectively. Global gene expression changes induced by 125I seed irradiation were analyzed by using Nimblegen Human gene expression array. DNA methylation profile in the tumors from control group was investigated with methylated DNA immunoprecipitation (MeDIP) and Nimblegen CpG promoter microarrays. The changes in the methylation status of selected genes were further investigated by using MeDIP-PCR.

Results

125I seed irradiation suppresses the growth of gastric cancer xenografts in nude mice. PCNA staining and tissue TUNEL assays showed that both inhibition of cell proliferation and induction of apoptosis contribute to the 125I-induced tumor suppression in nude mouse model. Gene expression profiles revealed that the expression levels of several hundred genes, many of which are associated with apoptosis or cell cycle arrest, including BMF, MAPK8, BNIP3, RFWD3, CDKN2B and WNT9A, were upregulated following 125I seed irradiation. Furthermore, the up-regulation of some of these genes, such as BNIP3 and WNT9A, was found to be associated with irradiation-induced DNA demethylation.

Conclusions

This study revealed that 125I seed irradiation could significantly induce the up-regulation of apoptosis- and cell cycle-related genes in human gastric cancer xenografts. And some of the up-regulation might be attributed to 125I-irradiation induced demethylation in gene promoter regions. Collectively, these findings provided evidence for the efficacy of this modality for the treatment of gastric cancer.

Clinical application of CT-guided (125)I seed interstitial implantation for local recurrent rectal carcinoma

PURPOSE

The present study aimed to explore the safety profile and clinical efficacy of CT-guided radioactive seed implantation in treating local recurrent rectal carcinoma.

MATERIALS AND METHODS

CT-guided ¹²⁵I seed implantation was carried out in 20 patients with locally recurrent rectal carcinoma. 14 of the 20 patient had prior adjuvant external-beam radiation therapy (EBRT). The treatment planning system (TPS) was used preoperatively to reconstruct three dimensional images of the tumor and to calculate the estimated seed number and distribution. The median matched peripheral dose (MPD) was 120 Gy (range, 100-160 Gy).

RESULTS

Of the 20 patients, 12 were male, 8 were female, and ages ranged from 38 to 78, with a median age of 62. Duration of follow-up was 3-34 months. The response rate of pain relief was 85% (17/20). Repeat CT scan 2 months following the procedure revealed complete response (CR) of the tumor in 2 patients, partial response (PR) in 13 patients, stable disease (SD) in 3 patients, and progressive disease (PD) in 2 patients. 75% of patients had either CR or PR. Median survival time was 18.8 months (95% CI: 3.5-22.4 months). 1 and 2 year survival rates were 75% and 25%, respectively. 4 patients died of recurrent tumor; 4 patients died of distant metastases; 9 patients died of recurrent tumor and distant metastases. 3 patients survived after 2 year follow up. Two patients were found to have mild hematochezia, which was reversible with symptomatic management.

CONCLUSION

CT-guided ¹²⁵I seed implantation appeared to be a safe, useful and less complicated interventional treatment option for local recurrent rectal carcinoma.

Image-guided percutaneous (125)I seed implantation as a salvage treatment for recurrent soft tissue sarcomas after surgery and radiotherapy

The purpose of this study was to evaluate the safety and efficacy of percutaneous iodine-125 ((125)I) seed implantation using computed tomography (CT) or ultrasound guidance in the treatment of recurrent soft tissue malignancies after surgery and radiotherapy. From February 2002 to September 2009, 18 patients with recurrent soft tissue sarcomas were treated under ultrasound or CT guidance. The actuarial median number of (125)I seeds implanted was 35 (range, 6-129), and the actuarial D90 of the implanted (125)I seeds ranged from 107.9 to 204.4 Gy (median, 147.1 Gy). The activity of the seeds ranged from 0.4 to 0.8 mCi (median, 0.7 mCi). Follow-up times ranged from 4 to 78 months (median, 20 months). The median local control was 41 months (95% CI, 15.9-66.1 months). The 1-, 2-, 3-, 4-, and 5-year local controls were 78.8%, 78.8%, 78.8%, 26.3%, and 0%, respectively. The median survival was 32 months (95% CI, 16-48 months). The actuarial 1-, 2-, 3-, 4-, and 5-year survivals were 76.6%, 61.3%, 39.4%, 39.4%, and 39.4%, respectively. Seven (7) patients (38.9%) experienced recurrence after seed implantation. Six (6) patients (33.3%) died of distant metastases and 1 died of stroke. Two (2) patients developed ulceration, 1 case caused by recurrence and another by a reaction of the skin to radiation. Percutaneous (125)I seed implantation for recurrent soft tissue malignancies under CT or ultrasound guidance is safe and is associated with high efficacy and low morbidity.

CT-guided iodine-125 seed permanent implantation for recurrent head and neck cancers

BACKGROUND

To investigate the feasibility, and safety of 125I seed permanent implantation for recurrent head and neck carcinoma under CT-guidance.

RESULTS

A retrospective study on 14 patients with recurrent head and neck cancers undergone 125I seed implantation with different seed activities. The post-plan showed that the actuarial D90 of 125I seeds ranged from 90 to 218 Gy (median, 157.5 Gy). The follow-up was 3 to 60 months (median, 13 months). The median local control was 18 months (95% CI, 6.1-29.9 months), and the 1-, 2-, 3-, and 5- year local controls were 52%, 39%, 39%, and 39%, respectively. The 1-, 2-, 3-, and 5- survival rates were 65%, 39%, 39% and 39%, respectively, with a median survival time of 20 months (95% CI, 8.7-31.3 months). Of all patients, 28.6% (4/14) died of local recurrence, 7.1% (1/14) died of metastases, one patient died of hepatocirrhosis, and 8 patients are still alive to the date of data analysis.

CONCLUSION

CT-guided 125I seed implantation is feasible and safe as a salvage or palliative treatment for patients with recurrent head and neck cancers.

The biological effect of 125I seed continuous low dose rate irradiation in CL187 cells

Background

To investigate the effectiveness and mechanism of ¹²⁵I seed continuous low-dose-rate irradiation on colonic cell line CL187 in vitro.

Methods

The CL187 cell line was exposed to radiation of ⁶⁰Coγ ray at high dose rate of 2 Gy/min and ¹²⁵I seed at low dose rate of 2.77 cGy/h. Radiation responses to different doses and dose rates were evaluated by colony-forming assay. Under ¹²⁵I seed low dose rate irradiation, a total of 12 culture dishes were randomly divided into 4 groups: Control group, and 2, 5, and 10 Gy irradiation groups. At 48 h after irradiation, apoptosis was detected by Annexin and Propidium iodide (PI) staining. Cell cycle arrests were detected by PI staining. In order to investigate the influence of low dose rate irradiation on the MAPK signal transduction, the expression changes of epidermal growth factor receptor (EGFR) and Raf under continuous low dose rate irradiation (CLDR) and/or EGFR monoclonal antibodies were determined by indirect immunofluorescence.

Results

The relative biological effect (RBE) for ¹²⁵I seeds compared with ⁶⁰Co γ ray was 1.41. Apoptosis rates of CL187 cancer cells were 13.74% ± 1.63%, 32.58% ± 3.61%, and 46.27% ± 3.82% after 2 Gy, 5 Gy, and 10 Gy irradiation, respectively; however, the control group apoptosis rate was 1.67% ± 0.19%. G₂/M cell cycle arrests of CL187 cancer cells were 42.59% ± 3.21%, 59.84% ± 4.96%, and 34.61% ± 2.79% after 2 Gy, 5 Gy, and 10 Gy irradiation, respectively; however, the control group apoptosis rate was 26.44% ± 2.53%. P < 0.05 vs. control groups by Student's t-test were found in every treated group both in apoptosis and in G₂/M cell cycle arrest. After low dose rate irradiation, EGFR and Raf expression increased, but when EGFR was blocked by a monoclonal antibody, EGFR and Raf expression did not change.

Conclusion

¹²⁵I seeds resulted in more effective inhibition than ⁶⁰Co γ ray high dose rate irradiation in CL187 cells. Apoptosis following G₂/M cell cycle arrest was the main mechanism of cell-killing effects under low dose rate irradiation. CLDR could influence the proliferation of cells via MAPK signal transduction.