Citations

Objective: Definitive treatment of sporadic vestibular schwannoma (VS) following documented growth is common practice at most centers in the United States. However, as a natural extension of this paradigm, very little evidence exists surrounding the natural history of growing tumors. The primary objective of the current work was to describe the natural history of sporadic VS following documentation of initial tumor growth. Study Design: Retrospective cohort study. Setting: Tertiary referral center. Patients: Patients diagnosed with sporadic VS between January 1, 2001 and December 31, 2015 who elected continued observation despite having volumetric growth ≥20% of original tumor volume on interval magnetic resonance imaging (MRI). Main Outcome Measure: Survival free of subsequent volumetric growth. Results: Of 361 patients undergoing observation with serial imaging during the study period, 85 patients met inclusion criteria at a median age of 66 years (interquartile ranges [IQR] 55–71). Within this cohort, 40 patients demonstrated subsequent volumetric growth at a median of 1.7 years (IQR 1.0–2.6) from the date of initial MRI that documented growth. The median volumetric growth was 43% (IQR 28–57), and the median growth rate was 0.026 cm3 per year (IQR 0.009–0.107). Survival free of subsequent volumetric growth rates (95% CI; number still at risk) at 1, 2, 3, 4, and 5 years were 93% (87–99; 75), 67% (58–79; 45), 54% (43–67; 29), 44% (33–59; 19), and 41% (30–56; 12), respectively. Conclusions: In a cohort exclusively comprised of sporadic VS with documented growth, over 40% of tumors demonstrated no subsequent volumetric growth after 5 years of continued MRI surveillance. These data challenge the supposition that once growth occurs, all tumors will exhibit sustained growth. Continued observation after documented growth of sporadic VS is a reasonable consideration in appropriately selected cases.

Objective: To report and discuss the effectiveness of stereotactic radiosurgery (SRS) or fractionated radiotherapy (FRT) for tumor control following surgical resection of endolymphatic sac tumors (ELST). Study Design: Retrospective case series. Setting: Multi-institutional academic referral centers. Patients: Patients undergoing surgical resection for ELST followed by SRS or FRT. Intervention(s): Surgical resection followed by radiotherapy. Main Outcome Measures: Local tumor control. Results: Two of the five patients experienced tumor recurrence after gross total microsurgical at 78 and 11 months, respectively. The former patient received salvage 3D conformal radiotherapy (3D-CRT) and while the latter patient underwent three courses of salvage SRS for recurrence, two of which were in-field and was disease-free at last follow up. Two additional patients underwent subtotal tumor resection (STR) followed by intensity-modulated radiation therapy (IMRT) and are currently without disease. One patient underwent STR followed by proton-beam therapy (PBT) and was free of disease at most recent follow-up. Conclusion: SRS/FRT remains a useful adjuvant for treatment of residual or recurrent ELSTs, where the risk of revision microsurgical resection is high.

Abstract Background Consensus in timing of radiotherapy is yet to be established in esthesioneuroblastoma (ENB). Objective This study was aimed to investigate if planned adjuvant radiotherapy improves tumor control after complete margin negative resection of low Hyams' grade (1 or 2) ENB. Methods A retrospective review of patients with pathologically confirmed negative margin resection of Kadish's stage B or C and Hyams' grade 1 and 2 ENBs was conducted. Seventeen patients meeting the criteria were divided into the following two groups for cohort study: (1) those who underwent planned immediate postoperative adjuvant radiotherapy (IR group) and (2) those who did not (delayed radiotherapy [DR] group). Results The IR group included nine patients (Kadish's stage B in one and stage C in eight; Hyams' grade 1 in two and grade 2 in seven). Mean follow-up was 140.8 months. Seven patients (78%) had disease progression (DP) at a median of 88 months (four with cervical lymph node metastasis [CLNM], one with distant metastasis, and two with both local recurrence and CLNM). One patient experienced frontal lobe abscess. The DR group included eight patients (Kadish's stage B in six and stage C in two; all Hyams' grade 2). Mean follow-up was 123.3 months. Four (50%) patients who developed DP (all local recurrence) were salvaged with surgery and adjuvant radiotherapy at a median of 37.5 months. There was no statistically significant difference in DP rate (p = 0.23), time to DP (p = 0.26), or the local tumor control rate (p = 0.23). Conclusion In our limited cohort, immediate postoperative radiotherapy did not demonstrate superiority in tumor control, although risk of radiotherapy toxicity appears low.

Abstract BACKGROUND Stereotactic radiosurgery (SRS) is a safe and effective treatment for acromegaly. OBJECTIVE To improve understanding of clinical and dosimetric factors predicting biochemical remission. METHODS A single-institution cohort study of nonsyndromic, radiation-naïve patients with growth hormone-producing pituitary adenomas (GHA) having single-fraction SRS between 1990 and 2017. Exclusions were treatment with pituitary suppressive medications at the time of SRS, or <24 mo of follow-up. The primary outcome was biochemical remission—defined as normalization of insulin-like growth factor-1 index (IGF-1 i ) off suppression. Biochemical remission was assessed using Cox proportional hazards. Prior studies reporting IGF-1 i were assessed via systematic literature review and meta-analysis using random-effect modeling. RESULTS A total of 102 patients met study criteria. Of these, 46 patients (45%) were female. The median age was 49 yr (interquartile range [IQR] = 37-59), and the median follow-up was 63 mo (IQR = 29-100). The median pre-SRS IGF-1 i was 1.66 (IQR = 1.37-3.22). The median margin dose was 25 Gy (IQR = 21-25); the median estimated biologically effective dose (BED) was 169.49 Gy (IQR = 124.95-196.00). Biochemical remission was achieved in 58 patients (57%), whereas 22 patients (22%) had medication-controlled disease. Pre-SRS IGF-1 i ≥ 2.25 was the strongest predictor of treatment failure, with an unadjusted hazard ratio (HR) of 0.51 (95% CI = 0.26-0.91, P = .02). Number of isocenters, margin dose, and BED predicted remission on univariate analysis, but after adjusting for sex and baseline IGF-1 i , only BED remained significant—and was independently associated with outcome in continuous (HR = 1.01, 95% CI = 1.00-1.01, P = .02) and binary models (HR = 2.27, 95% CI = 1.39-5.22, P = .002). A total of 24 patients (29%) developed new post-SRS hypopituitarism. Pooled HR for biochemical remission given subthreshold IGF-1 i was 2.25 (95% CI = 1.33-3.16, P < .0001). CONCLUSION IGF-1 i is a reliable predictor of biochemical remission after SRS. BED appears to predict biochemical outcome more reliably than radiation dose, but confirmatory study is needed.