Nonmalignant Disease

PV 02 - Poster Viewing Q&A - Session 2

MO_37_3272 - Stereotactic Radiosurgery and Intensity Modulated Radiotherapy for Treatment of Paragangliomas: A Tertiary Medical Center's 17 Year Experience

Monday, September 16
10:45 AM - 12:00 PM
Location: ASTRO Innovation Hub

Stereotactic Radiosurgery and Intensity Modulated Radiotherapy for Treatment of Paragangliomas: A Tertiary Medical Center’s 17 Year Experience
J. L. Anderson1, M. H. Khattab2, A. D. Sherry2, G. Luo2, N. Manzoor2, A. Attia2, J. Netterville2, and A. Cmelak2; 1Vanderbilt University School of Medicine, Nashville, TN, 2Vanderbilt University Medical Center, Nashville, TN

Purpose/Objective(s): Stereotactic radiosurgery (SRS) and intensity modulated radiotherapy (IMRT) are alternative therapies to surgery in the treatment of paragangliomas (PG). We hypothesized that SRS and IMRT could achieve adequate local control (LC) and symptom (sx) control in the treatment of PG with minimal associated toxicity in both upfront and salvage settings.

Materials/Methods: We retrospectively evaluated 31 tumors in 30 non-metastatic patients (pts) treated with linear accelerator (LINAC) based SRS or IMRT at our institution between 2000-2017 for local tumor control and risk of secondary malignancy in an IRB approved study. SRS vs. IMRT was chosen based on PG size and location. Sx control and toxicities were graded according to the Common Terminology Criteria for Adverse Events (CTCAE) v5.0. PG were measured on MRI at radiation oncology (RO) consultation and at last follow up (f/u). Long axis (LA), short axis (SA), and largest craniocaudal dimensions (CC) were compared. LC was defined as no increase in LA, SA, or CC ≥ 3 mm and no salvage therapy by last f/u.

Results: Median f/u was 4.16 years. 6 pts were treated for residual disease status post (s/p) surgery, 6 pts had recurrent disease s/p surgery, and 18 pts (19 PG) received radiotherapy (RT) as primary treatment. Smallest PG dimension ranged 0.72-3.41cm and largest dimension 1.42-5.21 cm. 25 pts received SRS (median largest dimension 2.5cm): 13 in 5 fractions (range 2250-3000 cGy), 3 in 3 fractions (2100-2800 cGy) and 9 in 1 fraction (1400-1800 cGy). 4 pts (one with two PG) received IMRT in 15-27 fractions (range 4500-5400 cGy, average largest dimension 4.17 cm). All pts had tumor-induced neurologic sx’s at RO consultation. 23 pts (76.7%) had improvement in at least one PG-induced sx by last f/u. At last f/u imaging, 30 tumors (93.8%) decreased in at least one dimension, median largest decrease 3.6 mm (range 0-17.6 mm). No tumors increased ≥ 3mm and no pts required salvage therapy (100% LC), developed metastatic disease, or developed secondary malignancy with combined 132.43 years of f/u. No SRS pts experienced acute Gr ≥3 toxicity. IMRT toxicity included Gr 3 hearing loss in one patient with baseline hearing decline, and 1 pt with Gr 3 mucositis and skin rash.

Conclusion: SRS and IMRT are safe and effective alternatives to surgical resection of paragangliomas with high LC rates, minimal acute and late complications, notable improvement of baseline symptoms, and without occurrence of any secondary malignancy or treatment failures requiring re-intervention. Radiotherapy was equally effective as primary treatment, after subtotal resection, or after progression s/p surgery.

Author Disclosure: J.L. Anderson: None. M.H. Khattab: None. A.D. Sherry: None. G. Luo: None. N. Manzoor: None. A. Attia: Advisory Board; AstraZeneca. Honoraria; Brainlab, qfix. Travel Expenses; qfix. Employee; Vanderbilt University. Independent Contractor; AstraZeneca, Novocure. Director of Radiosurgery Program; Vanderbilt University. Nashville Volunteer Leadership Board Member; American Cancer Society. J. Netterville: None. A. Cmelak: None.

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