Prediction of seed migration after transperineal interstitial prostate brachytherapy with I-125 free seeds

Seed Density as a New Predictive Index of Seed Migration in Brachytherapy for Prostate Cancer Using Iodine-125 Loose Seed

AIM

This study aimed to examine the usefulness of seed density as a predictor of seed migration in patients with prostate cancer who received brachytherapy using Iodine-125 loose seed.

METHODS

From May 2006 to April 2016, 320 patients with localized prostate cancer underwent transperineal brachytherapy using iodine-125 loose seeds. Among them, 202 (63.1%) patients received brachytherapy monotherapy and 118 (36.9%) received combined brachytherapy and external beam radiotherapy. Seed density was calculated using the following formula: seed density = implanted seed number/prostate volume. All patients underwent radiography of the chest, abdomen and pelvis, and computed tomography at 1 day, 1 month, and 1 year after brachytherapy to evaluate the presence of seed migration.

RESULTS

In total, the number of implanted seeds was 21,876. Seed migration was detected in 92 (28.8%) patients. Of a total of 21,876 seeds, 144 (0.66%) showed migration. The number of needles, number of seeds, and seed density were significantly higher in the group with migration than in the group without migration (p = 0.05). The ROC cutoff values for prostate volume, number of needles, number of seeds, and seed density were 20.9 cc, 21, 65, and 3.0, respectively. In the univariate analysis, prostate volume, number of needles, number of seeds, seed density, and treatment modality were all significant factors in predicting migration (p = 0.05). In the multivariate analysis, seed density and treatment modality were significant factors in predicting migration (p = 0.05).

CONCLUSION

Seed density is useful for predicting seed migration. In cases with seed density > 3.0, it is necessary to take measures such as considering the use of stranded seeds.

Permeable gastric ulcer caused by radioactive 125I seed implantation for adrenal metastasis: A case report and literatures review

Radioactive ¹²⁵I seed implantation as a means of radiotherapy for malignant tumors has been proved to be safe and effective. Although the effectiveness of ¹²⁵I seed implantation in the treatment of tumor metastases has been widely recognized, there is still no standard for the selection of radiation doses. Adrenal blood supply is abundant, and it is a common metastatic site for malignant tumors. CT-guided radioactive ¹²⁵I seed implantation is effective in treating adrenal metastases. However, it may cause certain damage to surrounding organs, especially the stomach. Clinically, for patients with left adrenal metastatic carcinoma and concurrent radioactive seed implantation, the occurrence of permeable gastric ulcer should not be neglected. In order to reduce the effect of radioactive particles on the normal tissue structure around the tumor, low-activity particles should be used.

Late seed migration after prostate brachytherapy with Iod-125 permanent implants

BACKGROUND

Seed migration is a common finding after low dose rate brachytherapy of the prostate. It has often been assessed soon after implantation, but little is known about late seed migration. We evaluated the incidence, site, symptoms, and therapeutic consequences of late seed migration more than 3 years postoperatively.

MATERIALS AND METHODS

We retrospectively examined the data of 63 unselected patients with transrectal ultrasound-guided, transperineal low dose rate brachytherapy of the prostate with stranded seeds between 2001 and 2010. A pelvic X-ray was taken the day after implantation and after 6 weeks in combination with a pelvic computed tomography/magnetic resonance imaging scan (image fusion) for dosimetry. Late radiological follow-up with a further pelvic and chest X-ray was conducted 3 or more years postoperatively. We differed between seed loss without anatomical detection and seed migration into another anatomical region.

RESULTS

We found seed loss up to 3 years and more after brachytherapy in 36 of 63 patients (57%). Between one and nine seeds had been lost. Late seed migration after 3 or more years occurred in two of 36 patients (6%), with pelvic migration of one seed and extrapelvic migration of one seed to the lung and two seeds to the liver, respectively. All late seed migrations were asymptomatic and had no therapeutic consequences.

CONCLUSION

Beside a frequent number of seed losses, seed migration 3 or more years after implantation was as well a frequent finding but seems to be asymptomatic. Long-term follow-up with complementary radiological controls could be helpful in detecting any rare complications.

Evaluation of therapeutic effects of 125I particles brachytherapy for recurrent bladder cancer

The aim of the present study was to evaluate the clinical value of ¹²⁵I particles implantation in the treatment of recurrent bladder cancer. The study is a retrospective analysis of 32 patients with recurrent bladder cancer treated between May 2010 and January 2010. Of these, 16 cases (chemotherapy group) received conventional chemotherapy. A total of 16 patients (¹²⁵I group) received radiotherapy with ¹²⁵I particles, followed by conventional chemotherapy. By guidance of B ultrasound, ¹²⁵I radioactive particles were implanted. All 32 patients were relieved after treatment, and the tumors were significantly reduced after 2 months. However, the tumors in the ¹²⁵I group were significantly smaller than those in the chemotherapy group (P<0.05). The patients were followed-up for 1 year and no recurrence was found. Additionally, no complications occurred. Compared with the chemotherapy group, the tumor volume of the ¹²⁵I group was significantly reduced (P<0.05). The disease-free survival and 5-year survival rates of the patients in the follow-up showed that the disease-free survival and 5-year survival rates of the patients in ¹²⁵I group were significantly improved compared to those in the chemotherapy group. Therefore, the results have shown that ¹²⁵I radioactive particles in the treatment of bladder cancer improve the symptoms of patients with bladder cancer in the short term, and continuously kill residual tumor and prevent recurrence.

Does Seed Migration Increase the Risk of Second Malignancies in Prostate Cancer Patients Treated With Iodine-125 Loose Seeds Brachytherapy?

PURPOSE

To evaluate the risk of second malignancies after migration of seeds (MS) in prostate cancer patients treated with ¹²⁵I loose seeds brachytherapy.

METHODS AND MATERIALS

Data from 2802 prostate cancer patients treated with ¹²⁵I loose seeds brachytherapy in 3 Canadian centers were reviewed. After seeds implant, all patients underwent postimplant pelvic radiography and computed tomography scan for postimplant dosimetry. These images were used to assess whether seed migration occurred. The incidence of second malignancies was determined through the review of patient charts. The 7- and 10-year cumulative incidences of second malignancies and their 95% confidence intervals (CIs) were calculated. Fine and Gray competing risk regression analysis was used to assess the factors associated with the development of second malignancies.

RESULTS

Mean age and median follow-up were 63.5 years and 74 (range, 12-246) months, respectively. Migration of seeds occurred in 263 of 2802 patients (9.4%). Second malignancy occurred in 87 patients (3.1%) for the entire cohort and was not different between patients who experienced MS (9, 3.4%) and those who did not (78, 3.1%) (P = .755). The 7-year cumulative incidence rates of second malignancies were 2.95% (95% CI 1.20%-6.00%) (with MS) versus 2.82% (2.10%-3.70%) (without MS) (P = .756). The corresponding values at 10 years were 6.16% (2.20%-12.3%) versus 4.51% (3.20%-5.50%) (P = .570). Migration of seeds did not seem to be a significant predictive factor for second malignancies development (adjusted hazard ratio 1.27 [95% CI 0.63-2.55]; P = .510). In both models, only advanced age was significantly associated with second malignancies development.

CONCLUSIONS

These results did not show an increased risk of second malignancies associated with MS after ¹²⁵I loose seeds brachytherapy for prostate cancer patients. Longer follow-up and more events are required to better correlate MS and second malignancies.

Analysis of the relationship between prescribed dose and dosimetric advantage of real-time intraoperatively built custom-linked seeds in iodine-125 prostate brachytherapy

Background

The purpose of this study was to investigate the differences in the dosimetric advantage of using intraoperatively built custom-linked (IBCL) seeds between permanent iodine-125 (I-125) seed implantation (PI) alone and PI followed by external-beam radiation therapy (EBRT) for prostate cancer.

Methods

We reviewed the records of 62 patients with localized prostate cancer who received transperineal interstitial brachytherapy with I-125 using free seeds or IBCL seeds. Twenty-four low- and intermediate-risk patients underwent PI alone with the prescribed dose of 160 Gy, and 39 high-risk patients underwent PI with 110 Gy, followed by EBRT with 45 Gy (PI + EBRT). Intraoperative and post-implant dosimetric parameters 1 month after implantation were collected and analyzed.

Results

The numbers of patients implanted with free seeds and IBCL seeds were 14 (58.3%) and 10 (41.7%), respectively, in the PI group and 25 (65.8%) and 13 (34.2%), respectively, in the PI + EBRT group. In the PI group, although there were significant differences in prostate V100 (p = 0.003) and D90 (p = 0.009) and rectum V100 (p = 0.026) on intraoperative dosimetry, these differences were not found on post-implant dosimetry. In the PI + EBRT group, the dosimetric parameters of IBCL seeds, such as prostate V200 (p = 0.013) and V250 (p = 0.010) and urethra D30 (p = 0.038), were better than those of free seeds on intraoperative dosimetry. Furthermore, even on post-implant dosimetry, prostate D90 (p = 0.004), V150 (p = 0.001), and homogeneity index (HI, p = 0.001), as well as V200 (p = 0.001) and V250 (p = 0.020), and urethra D5 (p = 0.008) as well as D30 (p = 0.003) had a better dosimetric quality in IBCL seeds than in free seeds. There was no significant difference in the operation time between free seeds and IBCL seeds in each PI and PI + EBRT group.

Conclusions

Our results reveal that greater dosimetric benefits could be obtained using IBCL seeds in the case of permanent implantation with a lower prescribed dose, such as PI + EBRT, rather than PI alone.

Robustness to source displacement in dual air kerma strength planning for focal low-dose-rate brachytherapy of prostate cancer

PURPOSE

To describe the use of dual source strength implants for focal low-dose-rate brachytherapy.

METHODS AND MATERIALS

An interneedle dual source strength planning strategy is described for focal low-dose-rate brachytherapy of the prostate. The implanted treatment plans were designed using peripheral (except near the rectum) needles loaded with high strength (0.9 U) sources and central needles loaded with low strength (0.4 U) sources ("interneedle" dual strength planning). This approach has been applied for focally treating 3 patients. In this article, we compare the characteristics and robustness to source motion of interneedle dual strength planning with four alternative planning strategies (single strength high, low, and intermediate, and intraneedle dual strength) on 50 simulated cases.

RESULTS

Interneedle dual source strength planning results in greater robustness to source motion and overall lower seed and needle density compared to the standard low source strength planning currently used in our centre. This planning approach is also significantly superior to single strength high, single strength intermediate and intraneedle dual strength planning strategies in terms of high dose to the urethral avoidance structure.

CONCLUSIONS

The use of interneedle dual source strength treatment plans for focal low-dose-rate brachytherapy is possibly the practical solution for limiting the density of sources required to deliver the prescribed dose while limiting proximity of high strength sources to organs at risk.

Brachytherapy with iodine-125 seeds for hepatocellular carcinoma

¹²⁵I seeds have good physical and radiobiological characteristics. Interstitial brachytherapy has advantages of minimal invasive, precise stereotactic treatment and high local control rate and plays an important role in the treatment of hepatocellular carcinoma (HCC). Brachytherapy with ¹²⁵I seeds has been used in unresectable HCC, HCC with portal vein tumor thrombus, intrahepatic cholangiocarcinoma, hepatic metastases, and some other tumors, providing encouraging survival rates. Radiation-related complications are rare in highly selected patients. In a word, ¹²⁵I brachytherapy is a safe and effective treatment for newly diagnosed or recurrent unresectable intrahepatic malignancies and can provide better survival rates and decent quality of life.

A prospective longitudinal survey of erectile dysfunction in patients with localized prostate cancer treated with permanent prostate brachytherapy

PURPOSE

Few studies have evaluated changes in erectile function with time before and after prostate brachytherapy using the International Index of Erectile Function-15, a sensitive, validated tool for assessing male sexual dysfunction. In this prospective study we evaluated the natural history of erectile function after prostate brachytherapy without supplemental therapy (external beam radiotherapy, phosphodiesterase-5 inhibitors or androgen deprivation therapy) using the International Index of Erectile Function-15.

MATERIALS AND METHODS

We identified 119 patients who were followed at least 12 months after prostate brachytherapy between 2004 and 2010. Sexual and erectile function status were assessed before brachytherapy (baseline), and 3, 6, 12, 18, 24 and 36 months postoperatively using the International Index of Erectile Function-15.

RESULTS

Mean total International Index of Erectile Function-15 score, and scores on the erectile function, orgasmic function, sexual desire and intercourse satisfaction domains 3 months after brachytherapy were significantly lower than at baseline (p <0.05). They remained lower until 36 months after prostate brachytherapy. Erectile function was maintained 12 months after brachytherapy in 16 of the 48 men (33.3%) with a baseline erectile function domain score of 11 or greater. There was no significant difference in clinical features except the age of patients who maintained the erectile function domain score and their counterparts 12 months after brachytherapy. Multivariate analysis revealed that age 70 years or greater was the only predictive factor for deteriorating erectile function after brachytherapy (p = 0.035).

CONCLUSIONS

Findings indicate a global decrease in all domains of the International Index of Erectile Function-15 score 12 months after prostate brachytherapy. Also, patient age may influence the preservation of brachytherapy related potency.

Seed migration in prostate brachytherapy depends on experience and technique

PURPOSE

To determine seed loss and pulmonary migration rate over time in permanent seed prostate brachytherapy.

METHODS AND MATERIALS

We analyzed the first 495 patients treated in our department. All patients were treated with loose (125)I seeds with automated seed delivery system and real-time intraoperative planning. Pelvic fluoroscopic imaging was done 30 days after the implant. Patients were divided into five groups of 100 patients according to the order they were treated, and groups were compared using χ(2) test and one-way analysis of variance.

RESULTS

A total of 22.8% of patients lost at least one seed. The highest percentage of patients losing any number of seeds was in the first 100. Thirty-eight percent lost at least one seed. This number decreased gradually and was only 9% in Patients 400-499. The mean total seed loss rate (number of seeds lost/number seeds implanted) changed significantly over time (p<0.001). There was a continuous significant (p<0.001) decline after the first 100 patients (1.25% for the first 100 patients) followed by a rise in Patients 300-399, followed by another decline (0.21% for the last 100 patients). The seed loss rate to the thorax changed significantly over time (p=0.009). It rose after an initial rate of 0.25-0.42% in Patients 200-299 and 300-399 and declined later to a rate of 0.21% in the last 100 patients.

CONCLUSIONS

We found a learning curve for seed migration. Avoiding implanting seeds outside of the capsule and modern transrectal ultrasound imaging can help decrease migration.

Incidence of seed migration to the chest, abdomen, and pelvis after transperineal interstitial prostate brachytherapy with loose (125)I seeds

Background

The aim was to determine the incidence of seed migration not only to the chest, but also to the abdomen and pelvis after transperineal interstitial prostate brachytherapy with loose ¹²⁵I seeds.

Methods

We reviewed the records of 267 patients who underwent prostate brachytherapy with loose ¹²⁵I seeds. After seed implantation, orthogonal chest radiographs, an abdominal radiograph, and a pelvic radiograph were undertaken routinely to document the occurrence and sites of seed migration. The incidence of seed migration to the chest, abdomen, and pelvis was calculated. All patients who had seed migration to the abdomen and pelvis subsequently underwent a computed tomography scan to identify the exact location of the migrated seeds. Postimplant dosimetric analysis was undertaken, and dosimetric results were compared between patients with and without seed migration.

Results

A total of 19,236 seeds were implanted in 267 patients. Overall, 91 of 19,236 (0.47%) seeds migrated in 66 of 267 (24.7%) patients. Sixty-nine (0.36%) seeds migrated to the chest in 54 (20.2%) patients. Seven (0.036%) seeds migrated to the abdomen in six (2.2%) patients. Fifteen (0.078%) seeds migrated to the pelvis in 15 (5.6%) patients. Seed migration occurred predominantly within two weeks after seed implantation. None of the 66 patients had symptoms related to the migrated seeds. Postimplant prostate D90 was not significantly different between patients with and without seed migration.

Conclusion

We showed the incidence of seed migration to the chest, abdomen and pelvis. Seed migration did not have a significant effect on postimplant prostate D90.

Radioactive seed migration after prostate brachytherapy with iodine-125 using loose seeds versus stranded seeds

OBJECTIVES

To assess the incidence and clinical parameters that could influence migration of seeds in localized prostate cancer patients treated by stranded versus loose sources by Iodine-125 brachytherapy.

MATERIALS AND METHODS

100 patients were treated from January/1998 until December/2006. Age, PSA, clinical stage, Gleason, prostate volume, number of seeds, activity of radioactive seeds, and dosimetric parameters, such as V100, V150 and D90 were evaluated.

RESULTS

Mean follow-up was 79 months (18 - 120. CI 95%: 72 - 85). Overall, 6 of 100 patients experienced seed migration. Seed migration was found in 4/50 (8%) patients using loose seeds and in 2/50 (4%) treated by stranded seeds. Mean value dosimetric parameters for stranded seeds were greater than those for loose seeds (V100(%): 88.7/82, D90(Gy): 149.2/140.3, D90(%): 104.2/93.8, V150 (%): 53.8/47, respectively). No significant difference in migration of seeds was detected between loose and stranded seeds considering age (p = 0.33), PSA (p = 0.391), prostate volume (p = 0.397), activity of radioactive seeds (p = 0.109), number of seeds (p = 0.338), V100 (p = 0.332), although significant differences were measured in the values of D90(% and Gy) (p = 0.022 and 0.011) and V150 (p = 0.023).

CONCLUSIONS

Seed migration after brachytherapy might occur and it does affect post-implant dosimetry.

Advances in permanent 125I seed implantation for colorectal liver metastases

Colorectal cancer is one of the most common cancers worldwide and the second most common type of cancer in the Western world. Colorectal cancer is the most common source of metastatic liver cancer, and liver metastasis is an important prognostic factor for colorectal cancer. Hepatic resection is the treatment of choice for colorectal liver metastases. The postoperative 5-year survival rate for patients with colorectal liver metastase now exceeds 50%. However, hepatic resection is indicated for only 10%-25% of patients with colorectal liver metastases. Therefore, non-surgical methods have attracted increasing attention. Permanent ¹²⁵I seed implantation is now becoming a hotspot for treatment of colorectal liver metastases. This review will focus on the recent advances in permanent ¹²⁵I seed implantation for colorectal liver metastases.