Faculty Bibliography

BACKGROUND:A major concern of patients who have stereotactic radiosurgery is the long-term risk of having a secondary intracranial malignancy or, in the case of patients with benign tumours treated with the technique, the risk of malignant transformation. The incidence of stereotactic radiosurgery-associated intracranial malignancy remains unknown; therefore, our aim was to estimate it in a population-based study to assess the long-term safety of this technique. METHODS:We did a population-based, multicentre, cohort study at five international radiosurgery centres (Na Homolce Hospital, Prague, Czech Republic [n=2655 patients]; Ruber International Hospital, Madrid, Spain [n=1080], University of Pittsburgh Medical Center, Pittsburgh, PA, USA [n=1027]; University of Virginia, Charlottesville, VA, USA [n=80]; and NYU Langone Health System, New York, NY, USA [n=63]). Eligible patients were of any age, and had Gamma Knife radiosurgery for arteriovenous malformation, trigeminal neuralgia, or benign intracranial tumours, which included vestibular or other benign schwannomas, WHO grade 1 meningiomas, pituitary adenomas, and haemangioblastoma. Patients were excluded if they had previously had radiotherapy or did not have a minimum follow-up time of 5 years. The primary objective of the study was to estimate the incidence of stereotactic radiosurgery-associated intracranial malignancy, including malignant transformation of a benign lesion or development of radiation-associated secondary intracranial cancer, defined as within the 2 Gy isodose line. Estimates of age-adjusted incidence of primary CNS malignancies in the USA and European countries were retrieved from the Central Brain Tumor Registry of the United States (CBTRUS) and the International Agency for Research on Cancer (IARC) Global Cancer statistics. FINDINGS/RESULTS:Of 14 168 patients who had Gamma Knife stereotactic radiosurgery between Aug 14, 1987, and Dec 31, 2011, in the five contributing centres, 4905 patients were eligible for the analysis (had a minimum follow-up of 5 years and no history of previous radiation therapy). Diagnostic entities included vestibular schwannomas (1011 [20·6%] of 4905 patients), meningiomas (1490 [30·4%]), arteriovenous malformations (1089 [22·2%]), trigeminal neuralgia (565 [11·5%]), pituitary adenomas (641 [13·1%]), haemangioblastoma (29 [0·6%]), and other schwannomas (80 [1·6%]). With a median follow-up of 8·1 years (IQR 6·0-10·6), two (0·0006%) of 3251 patients with benign tumours were diagnosed with suspected malignant transformation and one (0·0002%) of 4905 patients was considered a case of radiosurgery-associated intracranial malignancy, resulting in an incidence of 6·87 per 100 000 patient-years (95% CI 1·15-22·71) for malignant transformation and 2·26 per 100 000 patient-years (0·11-11·17) for radiosurgery-associated intracranial malignancy. Two (0·0004%) of 4905 patients developed intracranial malignancies, which were judged unrelated to the radiation field. Overall incidence of radiosurgery-associated malignancy was 6·80 per 100 000 patients-years (95% CI 1·73-18·50), or a cumulative incidence of 0·00045% over 10 years (95% CI 0·00-0·0034). The overall incidence of 6·8 per 100 000, which includes institutions from Europe and the USA, after stereotactic radiosurgery was found to be similar to the risk of developing a malignant CNS tumour in the general population of the USA and some European countries as estimated by the CBTRUS and IARC data, respectively. INTERPRETATION/CONCLUSIONS:These data show that the estimated risk of an intracranial secondary malignancy or malignant transformation of a benign tumour in patients treated with stereotactic radiosurgery remains low at long-term follow-up, and is similar to the risk of the general population to have a primary CNS tumour. Although prospective cohort studies with longer follow-up are warranted to support the results of this study, the available evidence suggests the long-term safety of stereotactic radiosurgery and could support physicians counselling patients on Gamma Knife stereotactic radiosurgery. FUNDING/BACKGROUND:None.

OBJECTIVES/HYPOTHESIS/OBJECTIVE:To assess patterns of care and outcomes with the use of neoadjuvant chemotherapy followed by definitive radiation in local-regionally advanced nasopharyngeal carcinoma. STUDY DESIGN/METHODS:Retrospective database analysis. METHODS:We queried the National Cancer Database for patients with T3-4N2 or T1-4N3 nasopharyngeal carcinoma who received concurrent chemoradiotherapy or neoadjuvant chemotherapy followed by radiation. Overall survival (OS) was analyzed using the Kaplan-Meier method, propensity-score matching, and a Cox proportional hazards model adjusting for demographic and disease-specific prognostic factors. RESULTS:P = .001). At a median follow-up of 36.6 months, patients had 3-year OS of 66% in the neoadjuvant group compared with 70% in those who received concurrent chemoradiotherapy (log rank P = .29). On subgroup analysis by histology, T stage, and N stage, there remained no differences in OS between the two groups. On multivariable analysis, there was no significant survival difference associated with neoadjuvant chemotherapy (adjusted hazard ratio [HR]: 1.05, 95% confidence interval [CI]: 0.89-1.25, P = .54). In a propensity score-matched population of 1,008 patients (504 with neoadjuvant therapy and 504 without), there was no significant survival difference associated with neoadjuvant chemotherapy (H: 1.13, 95% CI: 0.93-1.38, P = .22). CONCLUSIONS:Neoadjuvant chemotherapy was used in over 25% of patients, and its use is increasing. However, neoadjuvant chemotherapy was not associated with any differences in survival compared to concurrent chemoradiotherapy. LEVEL OF EVIDENCE/METHODS:4 Laryngoscope, 2018.

BACKGROUND:Delays in postoperative head and neck (HN) radiotherapy have been associated with decreased overall survival; however, the impact of delays in postoperative HN chemoradiotherapy remains undefined. METHODS:All patients with nonmetastatic HN cancer (oral cavity, oropharynx, larynx, hypopharynx) who underwent curative intent surgery and received adjuvant chemoradiotherapy were identified from the National Cancer Database (2005-2012). Overall treatment time (OTT) was defined as the time from surgery to the end of radiation therapy. Statistical methods included Cox proportional hazards modeling, which adjusted for clinicopathologic, demographic, and socioeconomic factors. Recursive partitioning analysis (RPA) identified the optimal threshold of OTT via conditional inference trees to estimate the greatest differences in overall survival (OS) on the basis of randomly selected training and validation sets. RESULTS:A total of 16,733 patients were included, with a median follow-up of 37 months. Median OS for OTT in a predefined threshold of ≤ 13 weeks was 10.1 years (95% confidence interval [CI], 9.8 years; not reached) compared with 8.7 years (95% CI, 8.2-9.2 years) in > 13 weeks. On multivariate analysis, OTT of > 13 weeks versus ≤ 13 weeks independently increased mortality risk (hazard ratio, 1.10; 95% CI, 1.04-1.17; P = < 0.001). RPA identified an optimal OTT threshold of 97 days (interquartile range: 96-98 days). The OTT threshold of 97 days was confirmed in a full Cox regression model estimating the risk of death according to overall treatment time as a continuous variable. CONCLUSION/CONCLUSIONS:In this large hospital-based national data, an OTT of greater than approximately 14 weeks most consistently increased the risk of death. LEVEL OF EVIDENCE/METHODS:4. Laryngoscope, 2018.