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Tanaka, Shota

https://orcid.org/0000-0001-6220-5018

Mayo Clinic

University of Tokyo Hospital

Citations 3

Long-term risk of recurrence and regrowth after gross-total and subtotal resection of sporadic vestibular schwannoma
Jacob, Jeffrey T. , Carlson, Matthew L. , Tanaka, Shota , Tanaka, Minoru , Saito, Nobuhito , Lohse, Christine M. , Driscoll, Colin L. W., Link, Michael J. , Nakatomi, Hirofumi

Journal of Neurosurgery | May 19, 2017 | Volume: 133 | Issue: 4 | Pages: 1052-1058

10.3171/2016.11.jns16498 Get It

OBJECTIVEThe management of vestibular schwannoma (VS) remains controversial. One commonly cited advantage of microsurgery over other treatment modalities is that tumor removal provides the greatest chance of long-term cure. However, there are very few publications with long-term follow-up to support this assertion. The purpose of the current study is to report the very long-term risk of recurrence among a large historical cohort of patients who underwent microsurgical resection.METHODSThe authors retrospectively reviewed the medical records of patients who had undergone primary microsurgical resection of unilateral VS via a retrosigmoid approach performed by a single neurosurgeon-neurotologist team between January 1980 and December 1999. Complete tumor removal was designated gross-total resection (GTR), and anything less than complete removal was designated subtotal resection (STR). The primary end point was radiological recurrence-free survival. Time-to-event analyses were performed to identify factors associated with recurrence.RESULTSFour hundred fourteen patients met the study inclusion criteria and were analyzed. Overall, 67 patients experienced recurrence at a median of 6.9 years following resection (IQR 3.9–12.1, range 1.2–22.5 years). Estimated recurrence-free survival rates at 5, 10, 15, and 20 years following resection were 93% (95% CI 91–96, 248 patients still at risk), 78% (72–85, 88), 68% (60–77, 47), and 51% (41–64, 22), respectively. The strongest predictor of recurrence was extent of resection, with patients who underwent STR having a nearly 11-fold greater risk of recurrence than the patients treated with GTR (HR 10.55, p < 0.001). Among the 18 patients treated with STR, 15 experienced recurrence at a median of 2.7 years following resection (IQR 1.9–8.9, range 1.2–18.7). Estimated recurrence-free survival rates at 5, 10, 15, and 20 years following GTR were 96% (95% CI 93–98, 241 patients still at risk), 82% (77–89, 86), 73% (65–81, 46), and 56% (45–70, 22), respectively. Estimated recurrence-free survival rates at 5, 10, and 15 years following STR were 47% (95% CI 28–78, 7 patients still at risk), 17% (5–55, 2), and 8% (1–52, 1), respectively.CONCLUSIONSLong-term surveillance is required following microsurgical resection of VS even after GTR. Subtotal resection alone should not be considered a definitive long-term cure. These data emphasize the importance of long-term follow-up when reporting tumor control outcomes for VS.
Presentation, management, and outcome of newly diagnosed glioblastoma in elderly patients
Tanaka, Shota , Meyer, Fredric B. , Buckner, Jan C. , Uhm, Joon H. , Yan, Elizabeth , Parney, Ian F. , Parney, Ian F

Journal of Neurosurgery | November 23, 2012 | Volume: 118 | Issue: 4 | Pages: 786-798

10.3171/2012.10.jns112268 Get It

Object Optimum management for elderly patients with newly diagnosed glioblastoma (GBM) in the temozolomide (TMZ) era is not well defined. The object of this study was to clarify outcomes in this population. Methods The authors retrospectively reviewed 105 consecutive cases involving elderly patients (age ≥ 65 years) with newly diagnosed GBM who were treated at the Mayo Clinic between 2003 and 2008. Results The patients' median age was 74 years (range 66–87 years), and the median Karnofsky Performance Status (KPS) score was 80 (range 40–90). Half of the patients underwent biopsy and half underwent resection. Patients with deep-seated lesions (19 patients [18%]) or multifocal lesions (34 patients [32%]) were more likely to have biopsy than resection (p = 0.0001 and 0.0009, respectively). New persistent neurological deficits developed in 7 patients (6.7%). Postoperative hemorrhage occurred in 6 patients (5.7%), all of whom underwent biopsy. Complete follow-up data regarding adjuvant treatment was available in 84 patients. Forty-one (49%) were treated with chemotherapy (mostly TMZ) and radiation therapy (RT), and 23 (27%) with RT alone. Nineteen (23%) received only palliative care after surgery (more common with biopsy, p = 0.03). Chemotherapy complications occurred in 28.6% (Grade 3 or 4 hematological complications in 11.9%). The median values for progression-free survival (PFS) and overall survival (OS) were 3.5 and 5.5 months. In a multivariate analysis, younger age (p = 0.03, risk ratio [RR] 0.34, 95% CI 0.13–0.89), single lesion (p = 0.02, RR 0.51, 95% CI 0.30–0.89), resection (p = 0.04, RR 0.54, 95% CI 0.31–0.94), and adjuvant treatment (p = 0.0001, RR 0.24, 95% CI 0.11–0.49) were associated with better OS. Only adjuvant treatment was significantly associated with prolonged PFS (p = 0.0007, RR 0.27, 95% CI 0.13–0.57). With combined therapy with resection, RT, and chemotherapy, the median PFS and OS were 8 and 12.5 months, respectively. Conclusions The prognosis for GBM worsens with increasing age in elderly patients. With important risks, resection and adjuvant treatment are associated with prolonged survival. Although selection bias cannot be excluded in this retrospective study, advanced age alone should not necessarily preclude optimal resection followed by adjuvant radiochemotherapy.
Gamma Knife surgery for the management of glomus tumors: a multicenter study
Sheehan, Jason P. , Tanaka, Shota , Link, Michael J. , Pollock, Bruce E. , Mathieu, David , Duma, Christopher , Young, A. Byron, Kaufmann, Anthony M. , McBride, Heyoung L., Weisskopf, Peter A., Xu, Zhiyuan , Kano, Hideyuki , Lunsford, L. Dade , Kondziolka, Douglas , Yang, Huai‐Che , Mathieu, David

Journal of Neurosurgery | June 8, 2012 | Volume: 117 | Issue: 2 | Pages: 246-254

10.3171/2012.4.jns11214 Get It

Object Glomus tumors are rare skull base neoplasms that frequently involve critical cerebrovascular structures and lower cranial nerves. Complete resection is often difficult and may increase cranial nerve deficits. Stereotactic radiosurgery has gained an increasing role in the management of glomus tumors. The authors of this study examine the outcomes after radiosurgery in a large, multicenter patient population. Methods Under the auspices of the North American Gamma Knife Consortium, 8 Gamma Knife surgery centers that treat glomus tumors combined their outcome data retrospectively. One hundred thirty-four patient procedures were included in the study (134 procedures in 132 patients, with each procedure being analyzed separately). Prior resection was performed in 51 patients, and prior fractionated external beam radiotherapy was performed in 6 patients. The patients' median age at the time of radiosurgery was 59 years. Forty percent had pulsatile tinnitus at the time of radiosurgery. The median dose to the tumor margin was 15 Gy. The median duration of follow-up was 50.5 months (range 5–220 months). Results Overall tumor control was achieved in 93% of patients at last follow-up; actuarial tumor control was 88% at 5 years postradiosurgery. Absence of trigeminal nerve dysfunction at the time of radiosurgery (p = 0.001) and higher number of isocenters (p = 0.005) were statistically associated with tumor progression–free tumor survival. Patients demonstrating new or progressive cranial nerve deficits were also likely to demonstrate tumor progression (p = 0.002). Pulsatile tinnitus improved in 49% of patients who reported it at presentation. New or progressive cranial nerve deficits were noted in 15% of patients; improvement in preexisting cranial nerve deficits was observed in 11% of patients. No patient died as a result of tumor progression. Conclusions Gamma Knife surgery was a well-tolerated management strategy that provided a high rate of long-term glomus tumor control. Symptomatic tinnitus improved in almost one-half of the patients. Overall neurological status and cranial nerve function were preserved or improved in the vast majority of patients after radiosurgery.