Assessment of Volumetric Growth Rates of Spinal Intradural Extramedullary Schwannoma

Brief Title

Assessment of Volumetric Growth Rates of Spinal Intradural Extramedullary Schwannoma

Official Title

Assessment of Volumetric Growth Rates of Spinal Intradural Extramedullary Schwannoma: A Longitudinal Study of Natural History

Brief Summary

      Spinal intradural schwannoma detected incidentally increased recently. Because there is
      little knowledge about natural history of spinal schwannoma, there is no consensus of
      treatment. Our hypothesis is as follows;

        1. Some schwannomas keep growing, the others do not.

        2. Foraminal schwannomas do not usually grow.

      The investigators analyzed natural history and characteristics of 56 spinal schwannomas
      observed initially with accurate and reliable methods. Here the investigators displayed
      growing pattern and differential point of spinal schwannoma.
    

Detailed Description

      Study design and participants

      The investigators included all patients who were diagnosed of spinal IDEM schwannoma by MR
      imaging and checked follow-up MR imaging not undergoing surgical resection (including
      radiosurgery). The patients usually checked follow-up MR imaging annually or biannually. The
      patients who underwent surgical resection during the surveillance interval were also
      enrolled.

      Exclusion criteria of this study were as follows: 1) surgical resection at the diagnosis; 2)
      von Recklinghausen' disease (neurofibromatosis); and 3) recurred or residual tumor. For
      patients lost follow-up, the investigators checked whether the patients underwent a surgery
      or not by telephone and obtained recent radiologic studies as possible.

      Medical record and radiologic studies of enrolled patients were evaluated for patient
      demographics, tumor level, main location (intracanal or foraminal), shape (globus, rugby
      ball, or dumbbell), date at diagnosis, follow-up date at check follow-up MR imaging, and
      length of follow-up. These serial studies were compared with tumor growth to evaluate for any
      correlation.

      Tumor volume measurement and growth

      The investigators measured tumor volume by volume quantification method using the Leksell
      Gamma Plan® system (version, 10.1.1. Elekta Instrument AB, Stockholm, Sweden) in Figure 1. It
      calculates tumor volume by summation of cylindrical masses from each image and has an
      advantage to measure with the best accuracy especially non-globus tumor.6 The process of
      measuring tumor volume was rigorously designed to minimize observer subjectivity. Stack
      images without gap were loaded to the program. The investigators draw the tumor outlining by
      manually in select planes of each orthogonal view. The program measures tumor volume using an
      algorithm based on scattered data interpolation with radial basis functions. All tumor
      volumes were measured independently by two observers. Interobserver reliabilities were
      assessed by the Brand-Altman plot. The plot was applied to look for trends in the data that
      produce similar results and to evaluate the agreement between two observers.7 Under the
      confidence of excellent interobserver agreement marks, the investigators finally estimated
      the tumor volume as the mean value of two measured data.

      Volumetric growth rate (VGR) of the tumor was calculated volume change to the baseline volume
      and presented in percent. Overall VGR (%) was calculated using the following formula: (Final
      volume-Baseline volume)x100/Baseline volume. Annual VGR (%) was calculated as follows; Annual
      VGR (%)=(Final vol.-Baseline vol.)/(Baseline vol.)*FU duration(days)*12/365*100 FU and vol.
      mean follow-up and volume, respectively. There is no consensus about definition and amount of
      tumor growth. A prior study reported that the cut-off value of growth rate of vestibular
      schwannoma extending into the cerebello-pontine angle was 10.4%. The investigators set 10%
      increase of VGR as a cut-off value. The investigators made two standards, 10% increase of
      overall and annual VGR, and evaluate validity by the receiver operating characteristic (ROC)
      curve. Enrolled patients were divided into two groups by the standard. The first group,
      growing tumor, was defined as mean ≥10% increase of tumor volume. The other group, stable
      tumor, was defined as mean <10% increase, stationary, or decrease of tumor volume.

      Statistical analysis

      The investigators used the Brand-Altman plot for interobserver reliability. The investigators
      used the ROC analysis to compare predictive validity of standards by overall VGR and annual
      VGR, and to find out their optimal cut-off values of annual VGR in growing schwannomas.
      Because the area under the curve is a measure of the diagnostic power of a test, larger one
      is chosen as a standard dividing growing versus stable tumor. ROC curves were plotted using
      measures of sensitivity and specificity based on various cut-off values. Cut-off value was
      selected as the values closer to the upper left corner. For comparative analyses between the
      growing and stable tumor group, independent t tests for continuous variables, Fisher's exact
      test, and chi-square test were used. The significance level was set at p < 0.05. The
      investigators used MedCalc Statistical Software version 12.7.2 (MedCalc Software bvba,
      Ostend, Belgium) for the Bland-Altman plot and the SPSS statistical package (Version 20.0;
      SPSS Inc, Chicago, IL, USA) for the other data analysis.
    


Study Type

Observational


Primary Outcome

Volumetric growth rate


Condition

Schwannoma


Study Arms / Comparison Groups

 Growing schwannoma
Description:  Overall volumetric growth rate more over than 10%

Publications

* Includes publications given by the data provider as well as publications identified by National Clinical Trials Identifier (NCT ID) in Medline.

Recruitment Information



Estimated Enrollment

56

Start Date

June 1998

Completion Date

August 2013

Primary Completion Date

February 2012

Eligibility Criteria

        Inclusion Criteria:

          -  All patients who were diagnosed of spinal IDEM schwannoma by MR imaging and checked
             follow-up MR imaging not undergoing surgical resection (including radiosurgery).

        Exclusion Criteria:

          -  1) surgical resection at the diagnosis; 2) von Recklinghausen' disease
             (neurofibromatosis); and 3) recurred or residual tumor.
      

Gender

All

Ages

20 Years - N/A

Accepts Healthy Volunteers

No

Contacts

Chang-Hyun Lee, MD, , 

Location Countries

Korea, Republic of

Location Countries

Korea, Republic of

Administrative Informations


NCT ID

NCT01951365

Organization ID

SNUNS-spine-01


Responsible Party

Principal Investigator

Study Sponsor

Seoul National University Hospital


Study Sponsor

Chang-Hyun Lee, MD, Principal Investigator, Seoul Natl. Univ. Bundang Hospital


Verification Date

September 2013