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Objective: The frameless linear accelerator (LINAC) based stereotactic radiosurgery (SRS) has been evolving with a reduction in patient discomfort. However, there was limited evidence comparing frame-based and frameless SRS for intracranial arteriovenous malformations (AVM). We aimed to compare the treatment outcomes between frame-based and frameless LINAC SRS. Materials and Methods: This retrospective cohort compared the outcomes of frame-based LINAC SRS (1998-2009) with frameless LINAC SRS (2010-2020). The primary outcome was the obliteration rate. The other outcomes included the neurological, radiological, and functional outcomes after SRS. A matched cohort was identified by propensity scores for further comparisons. Results: A total of 65 patients were included with a mean follow-up time of 13.2 years (158.5 months). There were 40 patients in the frame-based group and 25 patients in the frameless group. The overall obliteration rate was comparable (Frame-based 82.5% vs Frameless 80.0%, p = 0.310) and not significantly different over time (log-rank p = 0.536). The crude post-SRS hemorrhage rate was 1.5% and the incidence was 0.3 per 100 person-years. There were 67.7% of patients with AVM obliteration without new persistent neurological deficits at the last visit and 56.9% of patients with AVM obliteration without any deficits (transient or persistent) during the entire follow-up period. Four patients (8.0%) developed late onset persistent adverse radiation effects (more than 96 months after SRS) among 50 patients with more than 8-year surveillance. In the propensity-matched cohort of 42 patients, there was no significant difference in AVM obliteration (Frame-based vs Frameless, log-rank p = 0.984). Conclusion: Frameless and frame-based LINAC SRS have comparable efficacy in intracranial AVM obliteration. A longer follow-up duration may further characterize the rate of late adverse radiation effects in frameless SRS.
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BACKGROUND: Meta-analysis had shown a significant 5% absolute survival benefit in favour of neoadjuvant chemotherapy (NAC) with cisplatin-based chemotherapy before radical cystectomy (RC) and pelvic lymphadenectomy (PLND) for patients with muscle invasive bladder cancer (MIBC). Those who had pathological complete response (pCR) to NAC could have long-term progression-free survival (PFS) and overall survival (OS). AIM: To identify the treatment and patient factors which could predict a pCR to NAC and the associated PFS and OS in a single institute. METHODS AND RESULTS: We retrospectively reviewed the records of patients who had received NAC with gemcitabine and cisplatin (GC) in our centre from January 2004 to December 2017. The patients' age, tumour stage, baseline estimated glomerular filtration rate (eGFR), chemotherapy chart, and pathological information were recorded. There were 25 men and five women who had received NAC followed by RC. pCR was noted in the surgical specimen of 11 (37%) patients. The mean dose of gemcitabine was significantly higher in the pCR group than the non-pCR group (9850 vs 7852 mg, P = 0.039) as was the dose-intensity of cisplatin (87.4% vs 71.3%, P = 0.044). After a median follow-up of 38 months (range 4.3-154), seven patients had disease progression. The estimated 3-year PFS is 74.9% (95% confidence interval [CI], 66.7%-83.3%). None of the patients who achieved pCR relapsed, while six out of seven patients who had pN1 disease developed distant metastasis (DM). Only two patients died of DM while two other patients died of unrelated causes. The estimated 3-year OS is 88.9% (95% CI 82.8%-95%). CONCLUSIONS: We have demonstrated that the dose intensity of GC is a major determinant of pCR, which predicts longer RFS and OS. Further research in gene expression profiling of MIBC to help selecting patient for NAC is needed.