Impact of Cochlear Dose on Hearing Preservation Following Stereotactic Radiosurgery in Treatment of Vestibular Schwannomas: A Multi-Center Study.

OBJECTIVE: Stereotactic radiosurgery (SRS) is a well-established treatment for vestibular schwannomas (VS). Hearing loss remains a main morbidity of VS and its treatments, including SRS. The effects of radiation parameters of SRS on hearing remain unknown. The goal of this study is to determine the effect of tumor volume, patient demographics, pretreatment hearing status, cochlear radiation dose, total tumor radiation dose, fractionation, and other radiotherapy parameters on hearing deterioration. METHODS: Multicenter retrospective analysis of 611 patients who underwent SRS for VS from 1990-2020 and had pre- and post-treatment audiograms. RESULTS: Pure tone averages (PTAs) increased and word recognition scores (WRSs) decreased in treated ears at 12-60 months while remaining stable in untreated ears. Higher baseline PTA, higher tumor radiation dose, higher maximum cochlear dose, and usage of single fraction resulted in higher post radiation PTA; WRS was only predicted by baseline WRS and age. Higher baseline PTA, single fraction treatment, higher tumor radiation dose, and higher maximum cochlear dose resulted in a faster deterioration in PTA. Below a maximum cochlear dose of 3 Gy, there were no statistically significant changes in PTA or WRS. CONCLUSIONS: Decline of hearing at one year in VS patients after SRS is directly related to maximum cochlear dose, single versus 3-fraction treatment, total tumor radiation dose, and baseline hearing level. The maximum safe cochlear dose for hearingtbrowd preservation at one year is 3 Gy, and the use of 3 fractions instead of one fraction was better at preserving hearing.

Development of Predictive Models for the Response of Vestibular Schwannoma Treated with Cyberknife®: A Feasibility Study Based on Radiomics and Machine Learning.

PURPOSE: to predict vestibular schwannoma (VS) response to radiosurgery by applying machine learning (ML) algorithms on radiomic features extracted from pre-treatment magnetic resonance (MR) images. METHODS: patients with VS treated with radiosurgery in two Centers from 2004 to 2016 were retrospectively evaluated. Brain T1-weighted contrast-enhanced MR images were acquired before and at 24 and 36 months after treatment. Clinical and treatment data were collected contextually. Treatment responses were assessed considering the VS volume variation based on pre- and post-radiosurgery MR images at both time points. Tumors were semi-automatically segmented and radiomic features were extracted. Four ML algorithms (Random Forest, Support Vector Machine, Neural Network, and extreme Gradient Boosting) were trained and tested for treatment response (i.e., increased or non-increased tumor volume) using nested cross-validation. For training, feature selection was performed using the Least Absolute Shrinkage and Selection Operator, and the selected features were used as input to separately build the four ML classification algorithms. To overcome class imbalance during training, Synthetic Minority Oversampling Technique was used. Finally, trained models were tested on the corresponding held out set of patients to evaluate balanced accuracy, sensitivity, and specificity. RESULTS: 108 patients treated with Cyberknife® were retrieved; an increased tumor volume was observed at 24 months in 12 patients, and at 36 months in another group of 12 patients. The Neural Network was the best predictive algorithm for response at 24 (balanced accuracy 73% ± 18%, specificity 85% ± 12%, sensitivity 60% ± 42%) and 36 months (balanced accuracy 65% ± 12%, specificity 83% ± 9%, sensitivity 47% ± 27%). CONCLUSIONS: radiomics may predict VS response to radiosurgery avoiding long-term follow-up as well as unnecessary treatment.

Brain metastases from primary colorectal cancer: is radiosurgery an effective treatment approach? Results of a multicenter study of the radiation and clinical oncology Italian association (AIRO).

OBJECTIVES: The prognosis of brain metastatic colorectal cancer patients (BMCRC) is poor. Several local treatments have been used, but the optimal treatment choice remains an unresolved issue. We evaluated the clinical outcomes of a large series of BMCRC patients treated in several Italian centers using stereotactic radiosurgery (SRS). METHODS: 185 BMCRC patients for a total of 262 lesions treated were evaluated. Treatments included surgery followed by post-operative SRS to the resection cavity, and SRS, either single-fraction, then hypofractionated SRS (HSRS). Outcomes was measured in terms of local control (LC), toxicities, brain distant failure (BDF), and overall survival (OS). Prognostic factors influencing survival were assed too. RESULTS: The median follow-up time was 33 months (range 3-183 months). Surgery plus SRS have been performed in 28 (10.7%) cases, SRS in 141 (53.8%), and HSRS in 93 (35.5%). 77 (41.6%) patients received systemic therapy. The main total dose and fractionation used were 24 Gy in single fraction or 24 Gy in three daily fractions. Local recurrence occurred in 32 (17.3%) patients. Median, 6 months,1-year-LC were 86 months (95%CI 36-86), 87.2% ± 2.8, 77.8% ± 4.1. Median,6 months,1-year-BDF were 23 months (95%CI 9-44), 66.4% ± 3.9, 55.3% ± 4.5. Median,6 months,1-year-OS were 7 months (95% CI 6-9), 52.7% ± 3.6, 33% ± 3.5. No severe neurological toxicity occurred. Stage at diagnosis, Karnofsky Performance Status (KPS), presence and number of extracranial metastases, and disease-specific-graded-prognostic-assessment (DS-GPA) score were observed as conditioning survival. CONCLUSION: SRS/HSRS have proven to be an effective local treatment for BMCRC. A careful evaluation of prognostic factors as well as a multidisciplinary evaluation is a valid aid to manage the optimal therapeutic strategy for CTC patients with BMs. ADVANCES IN KNOWLEDGE: The prognosis of BMCRC is poor. Several local treatments was used, but optimal treatment choice remains undefined. Radiosurgery has proven to be an effective local treatment for BMCRC. A careful evaluation of prognostic factors and a multidisciplinary evaluation needed.

Image guided hypofractionated radiotherapy and quality of life for localized prostate cancer: prospective longitudinal study in 337 patients.

PURPOSE: We prospectively analyzed quality of life in a cohort of patients with prostate cancer undergoing a course of hypofractionated image guided radiotherapy. MATERIALS AND METHODS: Between August 2006 and January 2011, 337 patients with a median age of 73 years who had cT1-T2N0M0 prostate cancer were eligible for this prospective, longitudinal study of hypofractionated image guided radiotherapy (70.2 Gy/26 fractions) using 1 of 3 image guided radiotherapy modalities (transabdominal ultrasound, x-ray or cone beam computerized tomography) available in our radiation oncology department. Patients completed 4 questionnaires before treatment, and 6, 12 and 24 months later, including the International Index of Erectile Function-5, International Prostate Symptom Score, and EORTC (European Organization for Research and Treatment of Cancer) prostate cancer specific QLQ-PR25 and QLQ-C30. RESULTS: Patient followup was updated to at least the last questionnaire time point. Median followup was 19 months. Significant deterioration in erectile function on the International Index of Erectile Function-5 was documented with time only in patients without androgen deprivation (p = 0.0002). No change with time was observed in urinary symptom related quality of life on the QLQ-PR25 or International Prostate Symptom Score. Slight deterioration in QLQ-PR25 bowel symptom related quality of life was observed (p = 0.02). Overall QLQ-C30 Global Health Status improved with time (p = 0.03). On univariate analysis it significantly correlated with the maximum RTOG (Radiation Therapy Oncology Group)/EORTC urinary and bowel late toxicity scores after radiotherapy. CONCLUSIONS: The regimen of hypofractionated image guided radiotherapy with multiple imaging modalities adopted in our radiation oncology department for localized prostate cancer might be a successful strategy for dose escalation with a limited impact on different aspects of quality of life with time.

Second malignancies following breast cancer treatment: a case-control study based on the Peridose methodology. Allegro project (task 5.4).

AIMS AND BACKGROUND: To calculate peripheral radiation dose to the second primary site in patients who have developed a second malignancy after breast cancer radiotherapy (index cases) and to compare it with dose in the analogous anatomical site in radiotherapy-treated breast cancer patients who did not experience a second malignancy (controls). To evaluate the feasibility of Peridose-software peripheral dose calculation in retrospective case-control studies. MATERIAL AND STUDY DESIGN: A case-control study on 12,630 patients who underwent adjuvant breast radiotherapy was performed. Minimum 5-year follow-up was required. Each index case was matched with 5 controls by 1) year of birth, 2) year of radiotherapy and 3) follow-up duration. Peridose-software was used to calculate peripheral dose. RESULTS: 195 second cancers were registered (19% [corrected] of all patients treated with adjuvant irradiation). Several methodological limitations of the Peridose calculation were encountered including impossibility to calculate the peripheral dose in the patients treated with intraoperative or external electron beam radiotherapy, in case of second tumors located at <15 cm from the radiotherapy field etc. Moreover, Peridose requires full radiotherapy data and the distance between radiotherapy field and second primary site. Due to these intrinsic limitations, only 6 index cases were eligible for dose calculation. Calculated doses at the second cancer site in index cases and in an analogous site in controls ranged between 7.5 and 145 cGy. The mean index-control dose difference was -3.15 cGy (range, -15.8 cGy and +2.7 cGy). CONCLUSIONS: The calculated peripheral doses were low and the index-control differences were small. However, the small number of eligible patients precludes a reliable analysis of a potential dose-response relationship. Large patient series followed for a long period and further improvement in the methodology of the peripheral dose calculation are necessary in order to overcome the methodological challenges of the study.

Robotic image-guided stereotactic radiotherapy, for isolated recurrent primary, lymph node or metastatic prostate cancer.

PURPOSE: To evaluate the outcome of robotic CyberKnife (Accuray, Sunnyvale, CA)-based stereotactic radiotherapy (CBK-SRT) for isolated recurrent primary, lymph node, or metastatic prostate cancer. METHODS AND MATERIALS: Between May 2007 and December 2009, 34 consecutive patients/38 lesions were treated (15 patients reirradiated for local recurrence [P], 4 patients reirradiated for anastomosis recurrence [A], 16 patients treated for single lymph node recurrence [LN], and 3 patients treated for single metastasis [M]). In all but 4 patients, [(11)C]choline positron emission tomography/computed tomography was performed. CBK-SRT consisted of reirradiation and first radiotherapy in 27 and 11 lesions, respectively. The median CBK-SRT dose was 30 Gy in 4.5 fractions (P, 30 Gy in 5 fractions; A, 30 Gy in 5 fractions; LN, 33 Gy in 3 fractions; and M, 36 Gy in 3 fractions). In 18 patients (21 lesions) androgen deprivation was added to CBK-SRT (median duration, 16.6 months). RESULTS: The median follow-up was 16.9 months. Acute toxicity included urinary events (3 Grade 1, 2 Grade 2, and 2 Grade 3 events) and rectal events (1 Grade 1 event). Late toxicity included urinary events (3 Grade 1, 2 Grade 2, and 2 Grade 3 events) and rectal events (1 Grade 1 event and 1 Grade 2 event). Biochemical response was observed in 32 of 38 evaluable lesions. Prostate-specific antigen stabilization was seen for 4 lesions, and in 2 cases prostate-specific antigen progression was reported. The 30-month progression-free survival rate was 42.6%. Disease progression was observed for 14 lesions (5, 2, 5, and 2 in Groups P, A, LN, and M respectively). In only 3 cases, in-field progression was seen. At the time of analysis (May 2010), 19 patients are alive with no evidence of disease and 15 are alive with disease. CONCLUSIONS: CyberKnife-based stereotactic radiotherapy is a feasible approach for isolated recurrent primary, lymph node, or metastatic prostate cancer, offering excellent in-field tumor control and a low toxicity profile. Further investigation is warranted to identify the patients who benefit most from this treatment modality. The optimal combination with androgen deprivation should also be defined.

3D-conformal hypofractionated radiotherapy for prostate cancer with daily transabdominal ultrasonography prostate localization: toxicity and outcome of a pilot study.

AIMS AND BACKGROUND: To evaluate the feasibility, toxicity and patient outcome of hypofractionated 3-dimensional conformal radiotherapy for low- and intermediate-risk prostate cancer, using daily an ultrasound targeting system (BAT). METHODS: Between May 2005 and October 2006, 25 patients (cT1-T2, GS < or = 7, mean initial PSA = 7.06 ng/ml) received a dose of 72 Gy in 30 fractions. Only the prostate was included in the clinical target volume. Immediately before each radiotherapy session, BATTM ultrasound alignment was performed. Acute and late toxicity was evaluated according to the Radiation Therapy Oncology Group criteria; the Phoenix definition (PSA = nadir + 2 ng/ml) was applied to define biochemical failure. BAT localization data were provided for 300 out of 750 procedures. RESULTS: No interruptions in 3-dimensional conformal radiotherapy due to toxicity were registered. There was no acute rectal toxicity in 52% of patients; 28% had G1, 16% had G2, and 1 patient had a G3 event. No acute urinary toxicity was observed in 28% of the patients. G1 toxicity occurred in 40%, G2 in 28%, and G3 in 1 patient; no G4 event was observed. With an average follow-up of 45 months, one biochemical relapse was observed; late toxicity showed an excellent profile: 78% of the patients had no rectal toxicity, 16% had G1, and 1 patient had G2 toxicity. Most of the patients (68%) had no late urinary complications, whereas 32% had G1 toxicity. Localization data showed systematic and random errors in relation to some procedure biases. CONCLUSIONS: Promising tumor control and toxicity profile were observed with this mildly hypofractionated BAT-based 3-dimensional conformal radiotherapy.