Long-term Outcomes for the Treatment of Paragangliomas in the Upfront, Adjuvant, and Salvage Settings With Stereotactic Radiosurgery and Intensity-modulated Radiotherapy

Endovascular Embolization as a Stand-Alone Treatment of Head and Neck Paragangliomas with Long-Term Tumor Control

BACKGROUND AND PURPOSE

The impact of therapeutic embolization as a stand-alone treatment of head and neck paragangliomas considered surgically high-risk remains insufficiently understood. The aim of this study was to investigate the procedural risks and long-term volumetric development in head and neck paragangliomas with high surgical risk following therapeutic endovascular embolization as a stand-alone treatment.

MATERIALS AND METHODS

A retrospective database review of patients who underwent endovascular embolization as primary treatment for head and neck paragangliomas lacking appropriate curative treatment options at our institution (from January 2000 to February 2023) was conducted. Tumor volumetric analyses were performed before embolization and during follow-up. To assess the changes in tumor volume over time, the measurements were performed after embolization, first at 6 months and then on a yearly basis up to 6 years (mean follow-up time was 33.7 ± 24.4 months). Subgroup analyses were conducted for vagal and jugular/jugulotympanic paragangliomas.

RESULTS

A total of 32 head and neck paragangliomas in 28 patients (mean age, 56.1 years ± 16.5 [standard deviation]; 18 female) with therapeutic embolization as stand-alone treatment were evaluated, of which 11 were vagal paragangliomas, 15 jugular/jugulotympanic paragangliomas, and 6 carotid body tumors. After a mean follow-up duration of 33.7 ± 24.4 months, tumor control was achieved in 75%, with significant median tumor volume reduction at 6 months (P = .02, n = 21). Vagal paragangliomas responded the most to embolization with a significantly decreased median volume from 22.32 cm3 to 19.09 cm3 (P = .008, n = 8). Transient complications occurred in 3.4%.

CONCLUSIONS

Therapeutic embolization as a stand-alone treatment offers a low-risk control of tumor growth in surgically high-risk lesions, with a significant reduction in tumor volume after treatment. Among the different subtypes, vagal paragangliomas exhibited the strongest and longest regression of the tumor volume.

Treatment for paraganglioma with stereotactic radiotherapy

BACKGROUND

Paragangliomas (PG) are rare neoplasms of neuroendocrine origin that tend to be highly vascularized, slow-growing, and usually sporadic. To date, common treatment options are surgical resection (SR), with or without radiation therapy (RT), and a watch-and-wait approach.

AIM

To evaluate the local control and effectiveness of exclusive fractionated stereotactic RT (FSRT) treatment in unresectable PG (uPG).

METHODS

We retrospectively evaluated patients with uPG (medically inoperable or refused SR) treated with FSRT with a Cyberknife System (Accuray Incorporated, Sunnyvale, California). Toxicity and initial efficacy were evaluated.

RESULTS

From May 2009 to January 2023, 6 patients with a median age of 68 (range 20-84) were treated with FSRT. The median delivered dose was 21 Gy (range 20-30 Gy) at a median isodose line of 75.5% (range 70%-76%) in 4 fractions (range 3-5 fractions). The median volume was 13.6 mL (range 12.4-65.24 mL). The median cumulative biological effective dose and equivalent dose in 2-Gy fractions were 70 Gy and 37.10 Gy respectively. Site of origin involved were the timpa-nojugular glomus (4/6), temporal bone, and cervical spine. In 1 of the 6 patients, the follow-up was insufficient; 5 of 6 patients showed a 5-year overall survival and 5-year progression-free survival of 100%. We observed negligible toxicities during and after RT. The majority of patients showed stable symptoms during follow-up. Only 1 patient developed spine metastases.

CONCLUSION

Our preliminary results on this small cohort of patients suggest that FSRT could be an effective and safe alternative to SR.

Treatment for paraganglioma with stereotactic radiotherapy

BACKGROUND

Paragangliomas (PG) are rare neoplasms of neuroendocrine origin that tend to be highly vascularized, slow-growing, and usually sporadic. To date, common treatment options are surgical resection (SR), with or without radiation therapy (RT), and a watch-and-wait approach.

AIM

To evaluate the local control and effectiveness of exclusive fractionated stereotactic RT (FSRT) treatment in unresectable PG (uPG).

METHODS

We retrospectively evaluated patients with uPG (medically inoperable or refused SR) treated with FSRT with a Cyberknife System (Accuray Incorporated, Sunnyvale, California). Toxicity and initial efficacy were evaluated.

RESULTS

From May 2009 to January 2023, 6 patients with a median age of 68 (range 20-84) were treated with FSRT. The median delivered dose was 21 Gy (range 20-30 Gy) at a median isodose line of 75.5% (range 70%-76%) in 4 fractions (range 3-5 fractions). The median volume was 13.6 mL (range 12.4-65.24 mL). The median cumulative biological effective dose and equivalent dose in 2-Gy fractions were 70 Gy and 37.10 Gy respectively. Site of origin involved were the timpa-nojugular glomus (4/6), temporal bone, and cervical spine. In 1 of the 6 patients, the follow-up was insufficient; 5 of 6 patients showed a 5-year overall survival and 5-year progression-free survival of 100%. We observed negligible toxicities during and after RT. The majority of patients showed stable symptoms during follow-up. Only 1 patient developed spine metastases.

CONCLUSION

Our preliminary results on this small cohort of patients suggest that FSRT could be an effective and safe alternative to SR.

Stereotactic radiotherapy for head and neck paragangliomas: How long should we wait for treatment response?

BACKGROUND AND PURPOSE

Stereotactic radiotherapy (SRT) is an effective treatment for head & neck (H&N) paragangliomas. Nevertheless, the timeline for achieving a tumor-volume-reduction (TVR) remains unclear.

MATERIALS AND METHODS

Sixty-three cases with H&N paragangliomas received definitive SRT and were evaluated retrospectively. Statistical Package for the Social Sciences (SPSS) v23.0 (IBM, Armonk, NY, USA) was used for statistics.

RESULTS

Sixty-eight lesions were irradiated, with glomus jugulotympanicum being the most common location (44 %). Median tumor diameter and volume were 3 cm (range, 1-7.6 cm) and 15.4 cm3 (range,1-185 cm3), respectively. Median dose was 25 Gy (range, 12-37.5 Gy) in 5 fractions (range, 1-5 fractions). Median follow-up was 40 months (range, 3-184 months). Treatment response, evaluated at a median 4.6 months post-SRT (range: 3-11 months), revealed TVR in 26 cases (41 %). During follow-up, 13 additional cases showed TVR, resulting in an overall TVR rate of 62 %. The median duration for attaining TVR was 9 months (range, 3-36 months) after SRT, and TVR occurred ≥ 12 months in 42 % of cases. Patients without prior surgery (p = 0.03) and with a longer follow-up (p = 0.04) demonstrated a higher rate of TVR. The likelihood of TVR tends to increase as the SRT dose increases (p = 0.06). Overall local control (LC) rate was 100 %. No ≥ grade 3 acute or late toxicities were observed.

CONCLUSION

While SRT demonstrates an excellent LC rate for H&N paragangliomas, it's important to note that the response to treatment may require time. TVR may last beyond the initial year of treatment in a substantial proportion of patients.

Clinical consensus guideline on the management of phaeochromocytoma and paraganglioma in patients harbouring germline SDHD pathogenic variants

Patients with germline SDHD pathogenic variants (encoding succinate dehydrogenase subunit D; ie, paraganglioma 1 syndrome) are predominantly affected by head and neck paragangliomas, which, in almost 20% of patients, might coexist with paragangliomas arising from other locations (eg, adrenal medulla, para-aortic, cardiac or thoracic, and pelvic). Given the higher risk of tumour multifocality and bilaterality for phaeochromocytomas and paragangliomas (PPGLs) because of SDHD pathogenic variants than for their sporadic and other genotypic counterparts, the management of patients with SDHD PPGLs is clinically complex in terms of imaging, treatment, and management options. Furthermore, locally aggressive disease can be discovered at a young age or late in the disease course, which presents challenges in balancing surgical intervention with various medical and radiotherapeutic approaches. The axiom-first, do no harm-should always be considered and an initial period of observation (ie, watchful waiting) is often appropriate to characterise tumour behaviour in patients with these pathogenic variants. These patients should be referred to specialised high-volume medical centres. This consensus guideline aims to help physicians with the clinical decision-making process when caring for patients with SDHD PPGLs.

Paragangliomas of the head and neck: a contemporary review

Head and neck paragangliomas (HNPGLs) are slow-growing, vascular, typically benign tumors whose growth may induce significant lower cranial nerve deficits. While most tumors arise sporadically, a significant portion is associated with defined genetic syndromes. While surgical resection has historically been the gold standard, management strategies have evolved with acknowledgement of high surgical morbidity, slow tumor growth rates, and technological advances. Conservative management approaches via observation and newer radiation therapy techniques have become more common. This review seeks to provide an update on contemporary management strategies for HNPGLs and future directions.

Diameter-Based Volumetric Models May Inadequately Calculate Jugular Paraganglioma Volume Following Sub-Total Resection

BACKGROUND

As gross total resection of jugular paragangliomas (JPs) may result in cranial nerve deficits, JPs are increasingly managed with subtotal resection (STR) with postoperative radiological monitoring. However, the validity of commonly used diameter-based models that calculate postoperative volume to determine residual tumor growth is dubious. The purpose of this study was to assess the accuracy of these models compared to manual volumetric slice-by-slice segmentation.

METHODS

A senior neuroradiologist measured volumes via slice-by-slice segmentation of JPs pre- and postoperatively from patients who underwent STR from 2007 to 2019. Volumes from three linear-based models were calculated. Models with absolute percent error (APE) > 20% were considered unsatisfactory based on a common volumetric definition for residual growth. Bland-Altman plots were used to evaluate reproducibility, and Wilcoxon matched-pairs signed rank test evaluated model bias.

RESULTS

Twenty-one patients were included. Median postoperative APE exceeded the established 20% threshold for each of the volumetric models as cuboidal, ellipsoidal, and spherical model APE were 63%, 28%, and 27%, respectively. The postoperative cuboidal model had significant systematic bias overestimating volume (p = 0.002) whereas the postoperative ellipsoidal and spherical models lacked systematic bias (p = 0.11 and p = 0.82).

CONCLUSION

Cuboidal, ellipsoidal, and spherical models do not provide accurate assessments of postoperative JP tumor volume and may result in salvage therapies that are unnecessary or inappropriately withheld due to inaccurate assessment of residual tumor growth. While more time-consuming, slice-by-slice segmentation by an experienced neuroradiologist provides a substantially more accurate and precise measurement of tumor volume that may optimize clinical management.

Contemporary Management of Jugular Paragangliomas With Neural Preservation

OBJECTIVES

Management of jugular paragangliomas (PGL) has evolved toward subtotal resection (STR). The purpose of this study is to analyze neural preservation and adjuvant treatment for long-term local control.

STUDY DESIGN

Retrospective chart review.

SETTINGS

Tertiary neurotology practice.

SUBJECTS AND METHODS

Adults undergoing surgical treatment of jugular PGL between 2006 and 2019. Patients, disease, and treatment variables were collected retrospectively. Single predictor logistic regression was used to ascertain predictors of regrowth or need for salvage radiation.

RESULTS

A total of 41 patients (median age, 47 years; 76% female) were identified. Most patients presented with advanced-stage disease (Glasscock-Jackson stage III-IV = 76%). Subtotal resection (STR) was performed in 32 (78%) patients. Extended STR (type 1) was the most commonly performed conservative procedure (n = 19, 59%). Postoperative new low cranial neuropathy (LCN) involving CN X and XII was rare (n = 3 and n = 1, respectively). Seventeen patients (41%) underwent postsurgical therapy for tumor regrowth or recurrence, including 15 patients who underwent adjuvant (n = 4) or salvage (n = 11) radiation. Overall tumor control of 94.7% was achieved at a mean follow-up of 35 months. All patients treated with combined modality treatment had local control at last follow-up. Logistic regression identified no single predictor for postsurgical radiation treatment or salvage-free survival.

CONCLUSION

Management of jugular PGL with a conservative approach is safe and effective with a low rate of new LCN deficit. Active surveillance of residual tumor with salvage radiation for growth results in excellent long-term tumor control.