Assessing survival in non-small cell lung cancer brain metastases after stereotactic radiosurgery: before and after the start of the targetable mutation era.

PURPOSE: Targeted treatment options for non-small cell lung cancer (NSCLC) brain metastases (BMs) may be combined with stereotactic radiosurgery (SRS) to optimize survival. We assessed patient outcomes after SRS for NSCLC BMs, identifying survival trajectories associated with targetable mutations. METHODS: In this retrospective time-dependent analysis, we analyzed median overall survival of patients who received ≥ 1 SRS courses for BM from NSCLC from 2001 to 2021. We compared survival of patients with and without targetable mutations based on clinical variables and treatment. RESULTS: Among the 213 patients included, 87 (40.8%) had targetable mutations-primarily EGFR (22.5%)-and 126 (59.2%) did not. Patients with targetable mutations were more often female (63.2%, p <.001) and nonsmokers (58.6%, p <.001); had higher initial lung-molGPA (2.0 vs. 1.5, p <.001) and lower cumulative tumor volume (3.7 vs. 10.6 cm3, p <.001); and received more concurrent (55.2% vs. 36.5%, p =.007) and total (median 3 vs. 2, p <.001) systemic therapies. These patients had lower mortality rates (74.7% vs. 91.3%, p <.001) and risk (HR 0.298 [95%CI 0.190-0.469], p <.001) and longer median overall survival (20.2 vs. 7.4 months, p <.001), including survival ≥ 3 years (p =.001). Survival was best predicted by SRS with tumor resection in patients with non-targetable mutations (HR 0.491 [95%CI 0.318-757], p =.001) and by systemic therapy with SRS for those with targetable mutations (HR 0.124 [95%CI 0.013-1.153], p =.067). CONCLUSION: The presence of targetable mutations enhances survival in patients receiving SRS for NSCLC BM, particularly when used with systemic therapies. Survival for patients without targetable mutations was longest with SRS and surgical resection. These results inform best practices for managing patients with NSCLC BM based on driver mutation status.

Gross Tumor and Intracranial Control Benefits with Fractionated Radiotherapy Compared with Stereotactic Radiosurgery for Patients with WHO Grade 2 Meningioma.

OBJECTIVE: Surgical resection is the mainstay of treatment for WHO grade 2 meningioma. Fractionated radiation therapy (RT) is frequently used after surgery, though many centers utilize stereotactic radiosurgery (SRS) for recurrence or progression. Herein, we report disease control outcomes from an institutional cohort with adjuvant fractionated RT versus salvage SRS. METHODS: We identified 32 patients from an institutional database with WHO grade 2 meningioma and residual/recurrent tumor treated with either SRS or fractionated RT. Patients were treated between 2007 and 2021 and had at least 1 year of follow-up. Kaplan-Meier estimators were used to determine gross tumor control (GTC) and intracranial control (IC). Univariate Cox proportional hazards models using biologically effective dose (BED) as a continuous parameter were used to assess for dose responses. RESULTS: With a median follow-up of 5.5 years, 13 patients (41%) received SRS to a recurrent or progressive nodule, 2 (6%) fractionated RT to a recurrent or progressive nodule, and 17 (53%) adjuvant fractionated RT following subtotal resection. Five-year GTC was higher with fractionated RT versus SRS (82% vs. 38%, P = 0.03). Five-year IC was also better with fractionated RT versus SRS (82% vs. 11%, P < 0.001). On univariate analysis, increasing BED10 was significantly associated with better GTC (P = 0.039); increasing BED3 was not (P = 0.82). CONCLUSIONS: In this patient cohort, GTC and IC were significantly higher in patients treated with adjuvant fractionated RT compared with salvage SRS. Increasing BED10 was associated with better GTC. Fractionated RT may provide a better therapeutic ratio than SRS for grade 2 meningiomas.

Differentiation of survival outcomes by anatomic involvement and histology with the revised 2023 International Federation of Gynecology and Obstetrics staging system for endometrial cancer.

OBJECTIVES: The International Federation of Gynecology and Obstetrics (FIGO) staging system for endometrial cancer underwent revision in 2023, incorporating histology, lymphovascular space invasion, and molecular classification. Herein, we compare overall survival (OS) outcomes by anatomic and histologic involvement for patients staged by the 2009 system versus 2023 system. METHODS: The National Cancer Database (NCDB) was queried for patients with newly-diagnosed uterine adenocarcinoma from 2004 to 2015, with follow-up data extending through 2020. Stage was determined by both the 2009 and 2023 FIGO staging systems. Kaplan-Meier estimators and Cox proportional hazards models were used for survival analysis. RESULTS: A total of 134,677 patients were analyzed. Per 2023 classification, patients with stage I disease decreased from 96,161 to 70,101 (-27.1%, p < 0.01), while stage II disease increased from 9295 to 36,294 (+390.5%, p < 0.01). Greatest OS change was observed for 2023 stage IA3 patients (low-risk, synchronous endometrial and ovarian tumors with a clonal relationship), whose 10-year OS was 73.4%, compared to 52.6% for 2009 stage IIIA disease. Ten-year OS for 2023 stage IIIB2 (pelvic peritoneal involvement), previously 2009 stage IVB, was 49.4%, compared to 18.7% for 2009 stage IVB patients. Akaike information criterion, Bayesian information criterion, and Harrel's concordance index were used to evaluate OS prognostication of each staging system across all stages, with likelihood ratio favoring the 2023 system (p = 0.020). CONCLUSIONS: With FIGO's 2023 endometrial cancer anatomic and histologic staging system, stage migration is greatest in early-stage disease. New staging groups may offer more precise prognostication. These changes may affect future management.

Patterns of failure after radiosurgery for WHO grade 1 or imaging defined meningiomas: Long-term outcomes and implications for management.

BACKGROUND: We analyzed long-term control and patterns of failure in patients with World Health Organization Grade 1 meningiomas treated with definitive or postoperative stereotactic radiosurgery at the authors' affiliated institution. METHODS: 96 patients were treated between 2004 and 2019 with definitive (n = 57) or postoperative (n = 39) stereotactic radiosurgery. Of the postoperative patients, 17 were treated adjuvantly following subtotal resection and 22 were treated as salvage at time of progression. Patients were treated to the gross tumor alone without margin or coverage of the dural tail to a median dose of 15 Gy. Median follow up was 7.4 years (inter-quartile range 4.8-11.3). Local control, marginal control, regional control, and progression-free survival were analyzed. RESULTS: Local control at 5 and 10 years was 97 % and 95 %. PFS at 5 and 10 years was 94 % and 90 % with no failures reported after 6 years. Definitive and postoperative local control were similar at 5 (95 % [82-99 %] vs. 100 %) and 10 years (92 % [82-99 %] vs. 100 %). Patients treated with postoperative SRS did not have an increased marginal failure rate (p = 0.83) and only 2/39 (5 %) experienced recurrence elsewhere in the cavity. CONCLUSIONS: Stereotactic radiosurgery targeting the gross tumor alone provides excellent local control and progression free survival in patients treated definitively and postoperatively. As in the definitive setting, patients treated postoperatively can be treated to gross tumor alone without need for additional margin or dural tail coverage.

Image-guided preplanning workflow for high-dose-rate interstitial brachytherapy for gynecological malignancies.

PURPOSE: To demonstrate image-guided preplan workflows for high-dose-rate (HDR) brachytherapy for advanced gynecological malignancies. METHODS AND MATERIALS: Two different preplanning scenarios are presented: (1) CT- or MRI-based preplan with partial applicator in place; (2) Preplans generated from prior fractions. The first scenario can be applied to Syed-Neblett template-based implants or hybrid brachytherapy applicators, while the second scenario applies to hybrid applicators. Both scenarios use MRI or CT images acquired with the applicator in place to demonstrate tumor and applicator relative locations and therefore, provide the ability to show optimized suggested needle positions including the implant depths before the actual insertion. RESULTS: The preplanning techniques have demonstrated feasibility and shown five areas of potential improvement: (1) shorter procedure time, (2) decreased number of total needles inserted, (3) shorter physician tumor contour time, (4) shorter planning time, and (5) evaluation of appropriateness for brachytherapy. CONCLUSIONS: The use of image-guided brachytherapy preplanning improves clinical efficiency and is recommended for consideration for adaptation into clinical workflows for HDR interstitial and hybrid brachytherapy.

Dosimetric Evaluation of Organs at Risk From SAVE Protocol.

PURPOSE: The objective of this work was to evaluate dosimetric characteristics to organs at risk (OARs) from short-course adjuvant vaginal cuff brachytherapy (VCB) in early endometrial cancer compared with standard of care (SOC) in a multi-institutional prospective randomized trial. METHODS AND MATERIALS: SAVE (Short Course Adjuvant Vaginal Brachytherapy in Early Endometrial Cancer Compared to Standard of Care) is a prospective, phase 3, multisite randomized trial in which 108 patients requiring VCB were randomized to an experimental short-course arm (11 Gy × 2 fractions [fx] to surface) and SOC arm. Those randomized to the SOC arm were subdivided into treatment groups based on treating physician discretion as follows: 7 Gy × 3 fx to 5 mm, 5 to 5.5 Gy × 4 fx to 5 mm, and 6 Gy × 5 fx to surface. To evaluate doses to OARs of each SAVE cohort, the rectum, bladder, sigmoid, small bowel, and urethra were contoured on planning computed tomography, and doses to OARs were compared by treatment arm. Absolute doses for each OAR and from each fractionation scheme were converted to 2 Gy equivalent dose (EQD23). Each SOC arm was compared with the experimental arm separately using 1-way analysis of variance, followed by pairwise comparisons using Tukey's honestly significant difference test. RESULTS: The experimental arm had significantly lower doses for rectum, bladder, sigmoid, and urethra compared with the 7 Gy × 3 and 5 to 5.5 Gy × 4 fractionation schemes; however, the experimental arm did not differ from the 6 Gy × 5 fractionation scheme. For small bowel doses, none of the SOC fractionation schemes were statistically different than the experimental. The highest EQD23 doses to the examined OARs were observed to come from the most common dose fractionation scheme of 7 Gy × 3 fx. With a short median follow-up of 1 year, there have been no isolated vaginal recurrences. CONCLUSIONS: Experimental short-course VCB of 11 Gy × 2 fx to the surface provides a comparable biologically effective dose to SOC courses. Experimental short-course VCB was found to reduce or be comparable to D2cc and D0.1cc EQD23 doses to rectum, bladder, sigmoid, small bowel, and urethra critical structures. This may translate into a comparable or lower rate of acute and late adverse effects.

Patterns of Care and Utilization Disparities in Proton Radiation Therapy for Pediatric Central Nervous System Malignancies.

Purpose: Proton radiation therapy (PR) is well established in the treatment of pediatric malignancies in the central nervous system (CNS) with dosimetric advantages that reduce late radiation therapy (RT) effects. In this analysis, we sought to evaluate the utilization of PR in children with primary CNS malignancies and characterize the clinical and sociodemographic factors predictive of receipt of PR. Methods and Materials: The National Cancer Database was queried to identify all pediatric patients with primary CNS malignancies treated with curative intent RT from 2004 to 2017. Clinical characteristics and demographics were analyzed using standard t and χ2 testing. Predictors of PR receipt were identified with univariable and multivariable logistic regression. Results: We identified 9126 patients ≤18 years of age treated with RT between 2004 and 2017, of which 1045 (11.5%) received PR. PR usage continued to increase significantly, from <1% in 2004 to 28% in 2017. The proportion of white and Asian patients receiving PR for nonhigh-grade glioma and nonmeningioma CNS malignancies during the study period rose from <1% for both to 35% and 44%, respectively, and in black patients the proportion rose from <1% to 26%. Multivariable predictors of receipt of PR include year of diagnosis, age <6 years, income level, distance from PR facility, and histology; multivariable predictors of receipt of photon RT include black race, rural residence, and Medicaid insurance. These factors remained significant when isolating the most recent 5 years of data. Conclusions: Proton radiation therapy usage for CNS malignancies increased significantly during the study period. Despite the potential clinical advantages of PR for pediatric primary CNS malignancies, there are notable socioeconomic, geographic, and racial disparities in the receipt of PR that persisted despite the increased availability and accessibility. Further study is warranted to identify how to address the disparities and better support these patients.

Delineating the Subarachnoid Space in the Adult Lumbosacral Spine Using Computed Tomographic Myelography: An Aid for Clinical Target Volume Delineation in Craniospinal Irradiation.

Purpose: Our aim was to characterize the patterns of cerebrospinal fluid (CSF) extension in the lumbosacral spine using computed tomography (CT) myelograms to provide an evidence base for clinical target volume (CTV) definition in adults receiving craniospinal irradiation. Methods and Materials: This was a retrospective analysis of diagnostic CT lumbar myelograms performed in 30 patients between the ages of 22 and 50. Lateral extension of CSF beyond the thecal sac was measured along each lumbar and sacral nerve root to the nearest millimeter, as was the distance of inferior extension of CSF beyond the caudal end of the thecal sac. Each patient's lateral and inferior CSF extensions were mapped onto a standardized CT data set to create a model target volume in the lumbosacral spine that would contain the aggregate observed CSF distributions from the analyzed CT myelograms. The median extension distances, interquartile ranges, and 90th percentile for distance at each level were calculated. Results: The median lateral extension of CSF along nerve roots beyond the thecal sac-as measured perpendicular to the longitudinal axis-increased from 0 mm (interquartile range [IQR], 0-4 mm) at L1 to 8 mm (IQR, 6-12 mm) at S1 and 0 mm (IQR, 0-0 mm) at S4. The 90th percentile ranged from 5 to 14 mm laterally, with a pattern partially extending into the S1 and S2 sacral foramen. Median CSF extension inferior to the caudal sac was 5 mm (IQR, 2-8 mm), with 90% of patients within 12 mm. An atlas was generated to guide CTV delineation for highly conformal radiation techniques. Conclusion: These results provide information on patterns of CSF extension in the lumbosacral spine of adults and can serve as a model for CTV guidelines that balance comprehensive coverage of the CSF compartment while minimizing the dose to nontarget tissues.

Incidence and extent of disease progression on MRI between surgery and initiation of radiotherapy in glioblastoma patients.

Background: A post-operative MRI (MRIpost-op) performed within 72 h is routinely used for radiation treatment planning in glioblastoma (GBM) patients, with radiotherapy starting about 4-6 weeks after surgery. Some patients undergo an additional pre-radiotherapy MRI (MRIpre-RT) about 2-6 weeks after surgery. We sought to analyze the incidence of rapid early progression (REP) between surgery and initiation of radiotherapy seen on MRIpre-RT and the impact on radiation target volumes. Methods: Patients with GBM diagnosed between 2018 and 2020 who had an MRIpost-op and MRIpre-RT were retrospectively identified. Criteria for REP was based on Modified RANO criteria. Radiation target volumes were created and compared using the MRIpost-op and MRIpre-RT. Results: Fifty patients met inclusion criteria. The median time between MRIpost-op and MRIpre-RT was 26 days. Indications for MRIpre-RT included clinical trial enrollment in 41/50 (82%), new symptoms in 5/50 (10%), and unspecified in 4/50 (8%). REP was identified in 35/50 (70%) of patients; 9/35 (26%) had disease progression outside of the MRIpost-op-based high dose treatment volumes. Treatment planning with MRIpost-op yielded a median undertreatment of 27.1% of enhancing disease and 11.2% of surrounding subclinical disease seen on MRIpre-RT. Patients without REP had a 38% median volume reduction of uninvolved brain if target volumes were planned with MRIpre-RT. Conclusion: Given the incidence of REP and its impact on treatment volumes, we recommend using MRIpre-RT for radiation treatment planning to improve coverage of gross and subclinical disease, allow for early identification of REP, and decrease radiation treatment volumes in patients without REP.

Radical trachelectomy and adjuvant vaginal brachytherapy to preserve fertility in pediatric cervical adenocarcinoma.

PURPOSE: This case report describes the use of a trachelectomy and adjuvant vaginal brachytherapy for pediatric clear cell adenocarcinoma as definitive fertility-sparing treatment. METHODS AND MATERIALS: A previously healthy 8-year-old female presented with abdominal cramping and heavy vaginal bleeding. Diagnostic imaging revealed a 3.5 cm circumscribed cervical mass, with subsequent biopsy revealing clear cell adenocarcinoma. Fertility preserving treatment was requested. RESULTS: The patient underwent a radical trachelectomy, with final pathology demonstrating a close radial margin. Due to close margin, adjuvant radiotherapy with a vaginal cylinder was delivered to a total dose of 18 Gray in three fractions prescribed to a depth of 5 mm from the vaginal surface using iridium-192. With 2 years of follow-up, the patient continues to do well with no evidence of recurrence or late toxicity from treatment. CONCLUSIONS: Pediatric clear cell adenocarcinoma of the cervix is a rare occurrence that lacks clinical trials to guide effective treatment. Adjuvant vaginal brachytherapy following trachelectomy in a pediatric patient with clear cell adenocarcinoma of the cervix is feasible and well-tolerated.

Outcomes using linear accelerator stereotactic radiosurgery for the treatment of trigeminal neuralgia: A single-center, retrospective study.

Background: Linear accelerator (LINAC)-based stereotactic radiosurgery (SRS) treatment of trigeminal neuralgia (TN) may have similar efficacy to Gamma Knife SRS (GK-SRS), but the preponderance of data comes from patients treated with GK-SRS. Our objective was to analyze the outcomes for LINAC-based treatment of TN in patients at our institution. Methods: We retrospectively analyzed data for patients who underwent LINAC-based SRS for TN from 2006 to 2018. Data were collected from the patients' medical records. Nonparametric statistics were used for the analysis. Results: Of the 41 patients treated with LINAC-based SRS (typically 90 Gy dosed using a 4 mm collimator for one fraction) during that time, follow-up data of >3 weeks post-SRS were available for 32 patients. The median pretreatment Barrow Neurological Institute (BNI) pain score was 5 (range 4-5). The follow-up period ranged from 0.9 to 113.2 months (median 5 months). There was significant improvement in postradiation BNI pain score (P < 0.001), with 23 (72%) patients who improved to a BNI pain score of 1-3. One patient had bothersome hypoesthesia postradiation. Approximately 38% of patients who had initial pain control had recurrence of symptoms (BNI > 3). Survival analysis showed a median time to pain recurrence of 30 months. There was no relationship between prior microvascular decompression (MVD) surgery and change in BNI pain score pre- to posttreatment. Conclusion: The results demonstrate that LINAC-based SRS is an effective means to treat TN. Prior MVD surgery did not affect efficacy of SRS in lowering the BNI score from pre- to posttreatment in this patient cohort.

Vaginal cuff brachytherapy for endometrial cancer: a review of major clinical trials with a focus on fractionation.

The use of vaginal cuff brachytherapy in the adjuvant management of endometrial cancer has increased over time. Recommendations from the American Brachytherapy Society, American Society of Radiation Oncology, and European Society for Medical Oncology help to guide the application of vaginal cuff brachytherapy. However, wide variation in practice remains regarding treatment techniques. This article reviews the use of vaginal cuff brachytherapy in the post-operative management of endometrial cancer. It covers risk stratification, treatment rationale, outcomes, and treatment planning recommendations with a specific focus on dose-fractionation regimens. The authors performed a thorough literature review of articles pertinent to the goals of this review. Also presented are early results of the Short Course Adjuvant Vaginal Cuff Brachytherapy in Early Endometrial Cancer Compared with Standard of Care (SAVE) trial of a two-fraction vaginal cuff brachytherapy regimen.Adjuvant vaginal cuff brachytherapy for early-stage endometrial cancer results in excellent disease control with minimal toxicity. The PORTEC-2 trial showed that vaginal cuff brachytherapy is non-inferior to external beam radiation for vaginal recurrence in patients at high-intermediate risk. Vaginal cuff brachytherapy may also be used as a boost following external beam radiation in combination with chemotherapy for high-risk histologies. Numerous techniques can be used for vaginal cuff brachytherapy, including various medical devices, dose-fractionation schedules, and treatment planning approaches. The early control results of the SAVE trial are promising and we are hopeful that this trial establishes two fraction regimens as a viable option for vaginal cuff brachytherapy.

Risk of secondary malignancies in ovarian cancer survivors: 52,680 patients analyzed with over 40 years of follow-up.

OBJECTIVE: Survivors of ovarian cancer are at risk of developing a secondary malignancy (SM). We sought to evaluate the risk of developing SM, stratified by treatment modality. METHODS: Standardized incidence ratios (SIR, observed-to-expected [O/E] ratio) were assessed in 52,680 patients diagnosed with ovarian cancer between 1975 and 2016 in the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. RESULTS: Of the 52,680 patients, 3366 patients (6.4%) developed SM, which was more than the endemic rate (O/E 1.13; p < .05). Patients who received any radiation (RT) had an increased risk of overall SM compared to those who didn't (O/E 1.42 vs 1.11; p < .05), and specifically, in the bladder (O/E 2.81). Patients who received any chemotherapy (CT) had an increased risk of leukemia (O/E 3.06), and a similar risk of overall SM compared to those not treated with CT (O/E 1.11 vs 1.14; p < .05). The excess risk of developing a solid tumor SM was greatest at latencies of 10-20 years. Patients younger than 50 had the highest risk of developing SM. Non-White patients had a higher risk of SM compared to White patients. CONCLUSIONS: This is the largest study to examine the risk of SM in patients with ovarian cancer and has the longest follow-up. Risk of SM was increased after ovarian cancer and varied with treatment modality, race, latency, and age. These results may help inform SM screening protocols for women diagnosed with ovarian cancer.

Radiation Oncologists' Views on Breast Radiation Therapy Guidelines: Utilizing an Online Q&A Platform to Assess Current Views on Whole-Breast Irradiation Therapy.

INTRODUCTION: Poor adherence to the 2011 American Society for Radiation Oncology (ASTRO) evidence-based guideline on whole-breast irradiation (WBI) has been reported. We utilized theMednet to assess the views of the updated 2018 guideline among radiation oncologists (ROs). METHODS: We identified 11 questions asked by community ROs on theMednet, a web-based platform, between October 27, 2014 and May 2, 2017 that were updated in the 2018 guideline. New answers provided by senior authors of the 2018 guideline, cited guidelines, and polls to survey ROs were disseminated in 3 theMednet's newsletters between March 16, 2018 and May 1, 2018. Any question with less than 60% consensus was resubmitted on October 9, 2019 and assessed on February 13, 2020. RESULTS: A total of 792 ROs responded to the initial surveys. In each survey, the answer choice(s) that received the majority of the votes aligned with the 2018 guideline. The strongest consensus was for the use of hypofractionated (HF)-WBI regardless of histology (97%), followed by HF-WBI boost dose (92%), molecular subtype (90%), grade (88%), and concurrent use of trastuzumab (87%). The least consensus was for age at which HF-WBI should be offered with 53% of respondents, specifically 73% of academic ROs versus 47% of community ROs (P = .001), agreeing with the guideline. The re-submitted survey 19 months later showed 77% of 287 new respondents now agreed with the guideline regarding age. CONCLUSION: The majority of ROs concur with the 2018 WBI guideline in theMednet surveys, with better agreement among academic ROs than community ROs for certain components of the guideline. Further research into the different practice patterns may optimize patient care.

Cervix Cancer in Sub-Saharan Africa: An Assessment of Cervical Cancer Management.

PURPOSE: Underdeveloped nations carry the burden of most cervical cancer, yet access to adequate treatment can be challenging. This report assesses the current management of cervical cancer in sub-Saharan Africa to better understand the needs of underdeveloped nations in managing cervical cancer. METHODS: A pre- and postsurvey was sent to all centers participating in the Cervical Cancer Research Network's 4th annual symposium. The pre- and postsurvey evaluated human papillomavirus and HIV screening, resources available for workup and/or treatment, treatment logistics, outcomes, and enrollment on clinical trials. Descriptive analyses were performed on survey responses. RESULTS: Twenty-nine centers from 12 sub-Saharan countries saw approximately 300 new cases of cervical cancer yearly. Of the countries surveyed, 55% of countries had a human papillomavirus vaccination program and 30% (range, 0%-65%) of women in each region were estimated to have participated in a cervical cancer screening program. In the workup of patients, 43% of centers had the ability to obtain a positron emission tomography and computed tomography scan and 79% had magnetic resonance imaging capabilities. When performing surgery, 88% of those centers had a surgeon with an expertise in performing oncological surgeries. Radiation therapy was available at 96% of the centers surveyed, and chemotherapy was available in 86% of centers. Clinical trials were open at 4% of centers. CONCLUSION: There have been significant advancements being made in screening, workup, and management of patients with cervical cancer in sub-Saharan Africa; yet, improvement is still needed. Enrollment in clinical trials remains a struggle. Participants would like to enroll patients on clinical trials with Cervical Cancer Research Network's continuous support.

Phase-Locking Requires Efficient Ca2+ Extrusion at the Auditory Hair Cell Ribbon Synapse.

Proper perception of sounds in the environment requires auditory signals to be encoded with extraordinary temporal precision up to tens of microseconds, but how it originates from the hearing organs in the periphery is poorly understood. In particular, sound-evoked spikes in auditory afferent fibers in vivo are phase-locked to sound frequencies up to 5 kHz, but it is not clear how hair cells can handle intracellular Ca2+ changes with such high speed and efficiency. In this study, we combined patch-clamp recording and two-photon Ca2+ imaging to examine Ca2+ dynamics in hair cell ribbon synapses in the bullfrog amphibian papilla of both sexes. We found that Ca2+ clearance from single synaptic ribbons followed a double exponential function, and the weight of the fast component, but not the two time constants, was significantly reduced for prolonged stimulation, and during inhibition of the plasma membrane Ca2+ ATPase (PMCA), the mitochondrial Ca2+ uptake (MCU), or the sarcolemma/endoplasmic reticulum Ca2+ ATPase (SERCA), but not the Na+/Ca2+ exchanger (NCX). Furthermore, we found that both the basal Ca2+ level and the Ca2+ rise during sinusoidal stimulation were significantly increased by inhibition of PMCA, MCU, or SERCA. Consistently, phase-locking of synaptic vesicle releases from hair cells was also significantly reduced by blocking PMCA, MCU, or SERCA, but not NCX. We conclude that, in addition to fast diffusion mediated by mobile Ca2+ buffer, multiple Ca2+ extrusion pumps are required for phase-locking at the auditory hair cell ribbon synapse.SIGNIFICANCE STATEMENT Hair cell synapses can transmit sound-driven signals precisely in the kHz range. However, previous studies of Ca2+ handling in auditory hair cells have often been conducted in immature hair cells, with elevated extracellular Ca2+ concentration, or through steady-state stimulation that may not be physiologically relevant. Here we examine Ca2+ clearance from hair cell synaptic ribbons in a fully mature preparation at physiological concentration of external Ca2+ and at physiological temperature. By stimulating hair cells with sinusoidal voltage commands that mimic pure sound tones, we recapitulated the phase-locking of hair cell exocytosis with an in vitro approach. This allowed us to reveal the Ca2+ extrusion mechanisms that are required for phase-locking at auditory hair cell ribbon synapses.

Endocrine therapy and radiotherapy use among older women with hormone receptor-positive, clinically node-negative breast cancer.

PURPOSE: To examine patterns of radiotherapy (RT) and endocrine therapy (ET) use, associations between RT omission and ET adherence, and associations among ET and RT use and disease recurrence in older women with early-stage, estrogen receptor-positive breast cancer. METHODS: Women age 65 and older diagnosed with hormone receptor-positive, clinically node-negative breast cancer between 2005 and 2018 and who did not undergo mastectomy were included. Multinomial logistic regression was used to examine the trends in practice patterns over time and by age. Kaplan-Meier estimates were used to estimate the probability of ET discontinuation. Cox proportional hazards models were constructed to assess associations between recurrence and ET/RT. RESULTS: Of the 484 enrolled patients, 47.9% patients underwent RT and initiated ET, 27.4% received ET alone, 10.2% received RT alone, and 13.8% patients received neither. Older patients had a higher probability of receiving ET alone or neither ET nor RT (both p < 0.001). The probability of initiating ET was greater among patients who underwent RT than those who omitted RT (p < 0.001). Regardless of RT status (RT or no RT), initiation and continuation of ET may be associated with reduced risk of recurrence. CONCLUSION: Patients who opt for no adjuvant therapy, or who do not tolerate ET, are at increased risk of disease recurrence if they omit RT. Clinicians should consider the likelihood a patient will adhere to ET prior to recommending omission of RT.

The use and efficacy of chemotherapy and radiotherapy in children and adults with pilocytic astrocytoma.

PURPOSE: The aim of this study was to understand the use of chemotherapy (CMT) and radiotherapy (RT) in pilocytic astrocytoma (PA) and their impact on overall survival (OS). METHODS: Data from the National Cancer Database (NCDB) for patients with non-metastatic WHO grade I PA from 2004 to 2014 were analyzed. Pearson's chi-squared test and multivariate logistic regression analyses were performed to assess the distribution of demographic, clinical, and treatment factors. Inverse probability of treatment weighting (IPTW) was used to account for differences in baseline characteristics. Kaplan-Meier analyses and doubly-robust estimation with multivariate Cox proportional hazards modeling were used to analyze OS. RESULTS: Of 3865 patients analyzed, 294 received CMT (7.6%), 233 received RT (6.0%), and 42 (1.1%) received both. On multivariate analyses, decreasing extent of surgical resection was associated with receipt of both CMT and RT. Brainstem tumors were associated with RT, optic nerve tumors were associated with CMT. Cerebellar tumors were inversely associated with both CMT and RT. Younger age was associated with receipt of CMT; conversely, older age was associated with receipt of RT. After IPTW, receipt of CMT and/or RT were associated with an OS decrement compared with matched patients treated with surgery alone or observation (HR 3.29, p < 0.01). CONCLUSIONS: This is the largest study to date to examine patterns of care and resultant OS outcomes in PA. We identified patient characteristics associated with receipt of CMT and RT. After propensity score matching, receipt of CMT and/or RT was associated with decreased OS.