Preliminary results of125I interstitial brachytherapy for locally recurrent parotid gland cancer in previously irradiated patients

Clinical application and accuracy assessment of imaging-based surgical navigation guided 125I interstitial brachytherapy in deep head and neck regions

Brachytherapy has the advantages of being minimally invasive and highly conformal, and it achieves good results in head and neck tumors. To precisely implant the radioactive seeds according to the preplan in deep head and neck regions, the surgical navigation is applied. This study aims to explore the clinical application and accuracy of imaging-based surgical navigation-guided 125I interstitial brachytherapy in terms of seed position. We included 41 patients with tumors in deep head and neck regions. The brachytherapy treatment plan was designed, and the preplanned data were transferred to the navigation system. Needle implantation and seed delivery were performed under surgical navigation system guidance with or without the combination of individual template. The treatment accuracy was evaluated by comparing seed cluster locations between the preoperative treatment plan and the postoperative treatment outcome. A total of 2879 seeds were delivered. The range, mean and median distances between the geometric centers of the preoperative seed point clusters and the postoperative seed point clusters were 0.8-10.5 mm, 4.5 ± 2.3 mm and 4.1 mm, respectively. The differences between preoperative and postoperative volumes of the minimum bounding box of seed point clusters were nonsignificant. In conclusion, the imaging-based surgical navigation system is a promising clinical tool to provide the preplanned data for interstitial brachytherapy intraoperatively, and it is feasible and accurate for the real-time guidance of needle implantation and seed delivery in deep head and neck regions.

Clinicopathological Factors are Predictors of Distant Metastases From Salivary Gland Carcinoma After Surgery Combined With 125I Internal Brachytherapy

PURPOSE

Distant metastasis (DM) indicates a poor outcome from cancer treatment. The present study estimated the incidence of DM and identified risk factors associated with development of DM in patients with salivary gland carcinoma that achieved locoregional control after surgery combined with ¹²⁵I internal brachytherapy.

MATERIALS AND METHODS

A retrospective cohort study was performed using consecutive patients treated with surgery combined with ¹²⁵I internal brachytherapy at the Peking University School and Hospital of Stomatology. Variables that might be associated with DM, including clinical, treatment characteristics, pathologic findings, and time to DM were recorded. Kaplan-Meier was performed to estimate incidence of DM, and Cox proportional hazard model was used to identify factors associated with DM.

RESULTS

Data from 156 patients were obtained for statistical analysis. The DM was observed in 16 of 156 with rate being 10.3%. The median interval from diagnosis of primary tumor to DM was 30.0 months. The 3-, 5-, 10-year overall survival rates were 97.0, 94.6, 85.2%, respectively, for patients without DM compared with 60.9, 52.2, 26.1%, respectively, for those with DM (P < .001). Univariate analysis revealed that the factors that significantly influenced DM were primary tumor site (P = .012) and histologic grade (P = .001). Multivariate Cox proportional hazard model indicated that histologic grade was the most important risk factor for predicting the risk of DM (P = .005; hazard ratio: 2.79; 95% confidence interval: 1.36 to 5.72).

CONCLUSIONS

Histologic grade was the major risk factor that significantly influenced DM in patients with salivary gland carcinoma that achieved locoregional control. Patients with high-grade tumors should be under close evaluation for DM.

[125Ⅰ seed brachytherapy for recurrent salivary gland carcinoma after external radiotherapy]

OBJECTIVE

To investigate the clinical application and efficacy of ¹²⁵Ⅰ radioactive seeds implantation in the treatment of recurrent salivary gland carcinoma after external radiotherapy.

METHODS

From July 2004 to July 2016, 43 cases of recurrent salivary gland carcinoma of the neck after external radiotherapy or surgery combined with external radiotherapy were treated. According to the conventional segmentation radiotherapy for head and neck cancer (once a day, 1.8-2.0 Gy each time, 5 days per week), the cumulative radiation dose of the patients in this group was calculated. In the study, 26 patients received 50-60 Gy, 7 patients received less than 50 Gy, 4 patients received 60-70 Gy, and 6 patients received more than 80 Gy (range: 80-120 Gy). The interval between the last external irradiation and local recurrence was 4-204 months, and the median interval was 48 months. Among them, 25 cases were treated with ¹²⁵Ⅰ radioactive seeds implantation only and 18 cases were treated with ¹²⁵Ⅰ radioactive seeds implantation after operation. The prescription dose was 100-140 Gy. The control rate, survival rate and disease-free survival rate were recorded to evaluate the side effects.

RESULTS

The median follow-up time was 27 months (ranging from 2.5 to 149.0 months). Among them, the median follow-up time of adenoid cystic carcinoma patients was 31 months (range: 2.5-112.0 months), and the median follow-up time of mucoepidermoid carcinoma patients was 18 months (range: 5-149 months). The local control rates for 1, 3 and 5 years were 66.5%, 48.8% and 42.7%, respectively. The 1-, 3- and 5- year survival rates were 88.0%, 56.7% and 45.8%, respectively. The disease-free survival rates of 1, 3 and 5 years were 58.3%, 45.4% and 38.1%, respectively. There was no statistically significant difference in local control rate, survival rate, and disease-free survival between the radioactive seeds implantation group and the radioactive seeds implantation group after surgical resection. There were 2 cases of acute radiation reaction Ⅰ/Ⅱ and 3 cases of reaction Ⅲ or above. In the late stage of radiotherapy, there were 8 cases with Ⅰ/Ⅱ grade reaction and 3 cases with Ⅲ grade or above reaction. The incidence of radiation reactions of Grade Ⅲ and above was 7%.

CONCLUSION

¹²⁵Ⅰ radioactive seeds implantation provides an alternative method for the treatment of recurrent salivary gland carcinoma after external radiotherapy. The local control rate and survival rate are improved on the premise of low incidence of side effects.

[Study of surgery combined with 125I brachytherapy for adenoid cystic carcinoma of oral and maxillofacial region]

OBJECTIVE

To retrospectively analyze the results of treatment outcome by surgery combined with ₁₂₅I brachytherapy and correlative factors of adenoid cystic carcinoma (ACC).

METHODS

In the study, 75 patients with primary ACC of oral and maxillofacial region were treated by surgery combined with ₁₂₅I seeds brachytherapy. Radical resection or subtotal resection was applied for the tumor. The brachytherapy treatment planning system was used to create implant plans with the prescribed dose of 60 Gy to 120 Gy. The ₁₂₅I seeds were implanted intraoperatively or postoperatively. The regular follow-up was required. The Kaplan-Meier method was used to assess the tumor control rate and the patients' survival rates. Meanwhile, the Cox regression analysis was used to find out the prognostic factors.

RESULTS

Local control rates at the end of 3 and 5 years were as follows: T1-T2, 92.2% and 82.0%; T3-T4, 82.6% and 82.6%; and overall, 90.0% and 78.8%. The disease-free survival rates were 74.9% and 54.3%, respectively. The overall survival rates for all the patients were 86.0% and 79.6%, respectively at the end of 3 and 5 years and were 91.3% and 91.3% for T1-T2 patients vs. 73.9% and 59.7% for T3-T4 patients. Distant metastasis-free survival rates at the end of 3 and 5 years were 84.4% and 76.7%, respectively. The distant metastasis-free survival rates at the end of 3 and 5 years were 83.4% and 79.6% with T1-T2 lesion compared with 86.0% and 67.8% with T3-T4 lesion. According to the COX univariate analysis and multivariate analysis, the risk of local recurrence would be raised by the age. Tumor stage and tumor site were the prognostic factors of the overall survival rates.

CONCLUSION

₁₂₅I brachytherapy conducted as an adjuvant therapy postoperatively of ACC of oral and maxillofacial region can acquire satisfactory localregional control, distant metastasis-free survival, disease-free survival and overall survival. Tumors are prone to recur on the older patients. Patients having advanced tumor stage or tumor located in the nasal cavity or sinuses will suffer lower survival rates.

Cancer-Targeted Selenium Nanoparticles Sensitize Cancer Cells to Continuous γ Radiation to Achieve Synergetic Chemo-Radiotherapy

Cancer radiotherapy with ¹²⁵ I seeds demonstrates higher long-term efficacy and fewer side effects than traditional X-ray radiotherapy owing to its low-dose and continuous radiation but is still limited by radioresistance in clinical applications. Therefore, the design and synthesis of sensitizers that could enhance the sensitivity of cancer cells to ¹²⁵ I seeds is of great importance for future radiotherapy. Selenium nanoparticles (SeNPs) have been found to exhibit high potential in cancer chemotherapy and as drug carriers. In this study, we found that, based on the Auger-electron effect and Compton effect of Se atoms, cancer-targeted SeNPs in combination with ¹²⁵ I seeds achieve synergetic effects to inhibit cancer-cell growth and colony formation through the induction of cell apoptosis and cell cycle arrest. Detailed studies on the action mechanisms reveal that the combined treatments effectively activate intracellular reactive oxygen species (ROS) overproduction to regulate p53-mediated DNA damage apoptotic signaling pathways and mitogen-activated protein kinase (MAPK) phosphorylation and to prevent the self-repair of cancer cells simultaneously. Taken together, the combination of SeNPs with ¹²⁵ I seeds could be further exploited as a safe and effective strategy for next-generation cancer chemo-radiotherapy in clinical applications.

Radioactive seed migration following parotid gland interstitial brachytherapy

PURPOSE

To evaluate the incidence and associated factors of pulmonary seed migration after parotid brachytherapy using a novel migrated seed detection technique.

METHODS AND MATERIALS

Patients diagnosed with parotid cancer who underwent permanent parotid brachytherapy from January 2006 to December 2011 were reviewed retrospectively. Head and neck CT scans and chest X-rays were evaluated during routine follow-up. Mimics software and Geomagic Studio software were used for seed reconstruction and migrated seed detection from the original implanted region, respectively. Postimplant dosimetry analysis was performed after seeds migration if the seeds were still in their emitting count. Adverse clinical sequelae from seed embolization to the lung were documented.

RESULTS

The radioactive seed implants were identified on chest X-rays in 6 patients. The incidence rate of seed migration in 321 parotid brachytherapy patients was 1.87% (6/321) and that of individual seed migration was 0.04% (6/15218 seeds). All migrated seeds were originally from the retromandibular region. No adverse dosimetric consequences were found in the target region. Pulmonary symptoms were not reported by any patient in this study.

CONCLUSIONS

In our patient set, migration of radioactive seeds with an initial radioactivity of 0.6-0.7 mCi to the chest following parotid brachytherapy was rare. Late migration of a single seed from the central target region did not affect the dosimetry significantly, and patients did not have severe short-term complications. This study proposed a novel technique to localize the anatomical origin of the migrated seeds during brachytherapy. Our evidence suggested that placement of seeds adjacent to blood vessels was associated with an increased likelihood of seed migration to the lungs.

(125)I interstitial brachytherapy for the treatment of myoepithelial carcinoma of the oral and maxillofacial region

PURPOSE

This study evaluated the treatment of myoepithelial carcinoma (MC) of the oral and maxillofacial region with radioactive iodine ((125)I) seed implantation.

METHODS AND MATERIALS

Twenty-seven patients with MC in the oral and maxillofacial region were treated with (125)I seed implantation between March 2006 and October 2012. Thirteen of the 27 patients (8/8 patients with primary disease and 5/19 patients with recurrent disease) were treated on an adjuvant setting after resections, and the other 14 patients were treated by brachytherapy after a recurrence precluding a surgical resection for salvage. The sites of the MC were the parotid for 18 patients, oral cavity for 2 patients, and base of skull for 7 patients. Recurrence-free survival (RFS), overall survival (OS) rates, and side effects were retrospectively reviewed.

RESULTS

Patients were followed for 6-105 months (median 37 months). The 3- and 5-year RFS rates were 51.9% and 46.1%, respectively. The 3- and 5-year OS rates were 68.6% and 51.5%, respectively. The OS and RFS were significantly better among the 8 patients treated upfront in comparison with the 19 patients treated for salvage at relapse. The OS was worst for the 7 patients with base of skull region disease. No severe complications were observed during followup.

CONCLUSIONS

This study showed (125)I brachytherapy is a feasible and effective modality for the treatment of MC. These findings should be interpreted cautiously due to the small number of patients and the relatively short followup.

Clinicopathologic factors associated with recurrence in low- and high-grade parotid cancers

BACKGROUND

The purpose of this study was to determine clinicopathological correlates of outcome among patients with parotid gland cancer.

METHODS

The medical records of 126 patients treated by surgery for localized parotid cancer were retrospectively reviewed to identify the clinicopathologic correlates of recurrence-free survival (RFS) according to histologic grade.

RESULTS

Multivariate analysis revealed that age and lymphovascular invasion were significant factors for recurrence in patients with low-grade cancer (p = .049 and p = .019, respectively), whereas perineural invasion was the only significant factor in patients with high-grade cancer (p = .001). The most frequent recurrence site tends to be different according to histologic grade: local recurrence at low-grade cancer (8.3%) and distant at high-grade cancer (13.6%). The duration of RFS was significantly longer in low-grade cancer than high-grade cancer in regional and distant recurrence (p = .044 and p = .016, respectively).

CONCLUSION

Consideration of different factors may be required for individual low-grade and high-grade parotid cancers when predicting the risk of recurrence. © 2015 Wiley Periodicals, Inc. Head Neck 38: E1788-E1793, 2016.

Three-dimensional verification of ¹²⁵I seed stability after permanent implantation in the parotid gland and periparotid region

Objective

To evaluate seed stability after permanent implantation in the parotid gland and periparotid region via a three-dimensional reconstruction of CT data.

Material and methods

Fifteen patients treated from June 2008 to June 2012 at Peking University School and Hospital of Stomatology for parotid gland tumors with postoperative adjunctive ¹²⁵I interstitial brachytherapy were retrospectively reviewed in this study. Serial CT data were obtained during follow-up. Mimics and Geomagic Studio software were used for seed reconstruction and stability analysis, respectively.

Results

Seed loss and/or migration outside of the treated area were absent in all patients during follow-up (23–71 months). Total seed cluster volume was maximized on day 1 post-implantation due to edema and decreased significantly by an average of 13.5 % (SD = 9.80 %; 95 % CI, 6.82–17.68 %) during the first two months and an average of 4.5 % (SD = 3.60 %; 95 % CI, 2.29–6.29 %) during the next four months. Volume stabilized over the subsequent six months.

Conclusions

¹²⁵I seed number and location were stable with a general volumetric shrinkage tendency in the parotid gland and periparotid region. Three-dimensional seed reconstruction of CT images is feasible for visualization and verification of implanted seeds in parotid brachytherapy.