Thesis Presentation-Abbreviated version

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Thesis

Modeling Survival After Surgery On The Metastatic SpineAhmer Ghori MD, Dana Leonard BA, Andrew Schoenfeld MD, Ehsan Saadat MD, Mitch B Harris MD

Ahmer K Ghori MDHarvard University Orthopaedic Surgery Program

1

My Goal TodayReview the past and present state of managing metastatic spine.Discuss how our model may improve the present state.

2

Historical: No advantage with surgery

Present: Surgery helpsLimitation: Cant predict post op survivalWho to operate on?Our Model

Future: Patient specific management

Evolution of spinal instrumentation

Patient Specific Variables

Predict survival reliably

Historic Management: Why no surgery ? Laminectomy was the only surgical option.No difference in laminectomy + radiation versus radiation alone with regard to: pain relief ambulation sphincter function.

Young et al 1980

Paradigm ShiftEvolution of modern spinal instrumentation.Wider decompressions &Robust stabilization

Modern Literature

Surgery helps in managing metastatic spine Pain.

Ambulation. Maintain independence at end of life.Direct decompressive surgical resection in the treatment of spinal cord compression caused by metastatic cancer: a randomised trial. The Lancet. 2005;366(9486):643648. doi:10.1016/S0140-6736(05)66954-1.

Present LimitationsChoosing surgical candidates Not a reliable process.Existing models:Do not predict survival reliably !Correlation with survival 20-50 %

Ragel, B. T. et al. Life Expectancy and Metastatic Spine Scoring Systems: An Academic Institutional Experience. J Spinal Disord Tech (2014). Wang M, Bnger CE, Li H, Wu C, Hy K, Niedermann B, et al. Predictive value of Tokuhashi scoring systems in spinal metastases, focusing on various primary tumor groups: Evaluation of 448 patients in the Aarhus spinal metastases database. Spine 2012;37: 573-582.

Harrington Score

Tokuhashi Score

Tomita Score

Tomita et al. Surgical strategy for spinal metastases. Spine (2001) vol. 26 (3) pp. 298-306

Modified Bauer Score

Existing scoring systems do not capture patients overall health state.

Ghori et al 2015Why cant we predict survival ?

Lets consider a hypothetical scenario

Bauer Score: 4

Can we predict post op survival from a score of 4 alone?

Consider 2 patients

Female Breast cancerNo visceral metastasesSolitary spine metastasis

Modified Bauer Score 4 Case 1First patient is :

YoungCan AmbulateNormal nutrition status.Modified Bauer Score 4 Case 1

Modified Bauer Score 4: Case 2Second patient is:

Old.Cannot ambulate.Poor nutritional status.

Modified Bauer Score 4 Case 2

Both patients have a Bauer score of 4 !Differences will affect survivalNeed a model that is more specific.Existing Models: Shortcoming

VS.

HypothesisGhori et al 2015

MethodsRetrospective review at four participating institutions (BIDMC, BWH, MGH, Dartmouth).Identify patients who had undergone spine surgery for metastatic disease between 2007 and 2013. Over 300 patients across 5 years included.Ghori et al 2015

Variables we studiedMain predictors of survival we studiedPre-operative modified Bauer scorePre- operative ambulatory statusPre-operative serum albumin level.Pre-operative serum creatinine level.Primary tumor type.Demographics: age, sex, race.Number of comorbidities.We coined these healthiness states

Ghori et al 2015

Ghori et al 2015: Our ModelAnalyzed all permutations of these three variables.Chose combination which has best correlation with survival.High Bauer score (3,4): 2 points Intact ambulatory status: 1 pointNormal serum albumin level : 1 pointCeiling score of 3.

Ghori et al 2015

Ghori et al 2015: Model

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3 vs. 2 vs. 1 vs. 0P < 0.001

Ghori et al 2015Our Model was able to explain 74% of the variation in 1-year survival. What does that mean?

In contrast existing scoring systems : 20- 50 % correlation with survivalRagel, B. T. et al. Life Expectancy and Metastatic Spine Scoring Systems: An Academic Institutional Experience. J Spinal Disord Tech (2014). Wang M, Bnger CE, Li H, Wu C, Hy K, Niedermann B, et al. Predictive value of Tokuhashi scoring systems in spinal metastases, focusing on various primary tumor groups: Evaluation of 448 patients in the Aarhus spinal metastases database. Spine 2012;37: 573-582.

Our Model

Practical advantage ? Let us apply it to our two cases.

High modified Bauer score and Intact ambulationNormal albumin78% survival

Modified Bauer Score (4): 59% survival

Case 1:Bauer 4

High modified Bauer score BUTCANNOT ambulateLow albumin32% survival

Modified Bauer Score (4): 59% survival

Case 2:Bauer 4

Ghori et al 2015

Modified Bauer Score (4): 59%

No additional heath states: 30 % Modified Bauer Score (4): 59%

Intact Ambulation/Normal albumin: 78 %

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Ghori et al 201530% Vs. 78% survival: big difference !Capture patient health state Tell apart patients predict survival reliably

Our Model: AdvantagesSimple to apply.Superior to existing models in predicting survival.300 patients in our analysis: one of the largest cohorts in literature.

Our Model: LimitationsRetrospective nature of our data.Model developed from surgical patients so may not be extrapolated to non-surgical patients.

Future DirectionStudies to validate our model by applying it to:Different databases.Prospectively studying it.

Managing Spine MetastasesWhere did we come from?

Where are we going?

Historical: No benefit with Surgery

Present : Surgery too much ? Who to operate on?Our Model

Future approach: Improve patient selectionOperate on the RIGHT PATIENTEvolution of spinal instrumentation

Include Patient Health State

Predict survival reliably

1-year postoperative survival rates in the present cohort using the modified Bauer score alone as well as the addition of other healthiness states.

Dichotomized Bauer-modified ScoreSurvival Rate at 1 year by Bauer ScoreSurvival Rate at 1 year by Bauer Score and Additional Healthiness States

012

Low (0,1,2)33% (50/150)17% (9/53)35% (22/62)54% (19/35)

High (3,4)59% (92/157)32% (12/38)61% (45/74)78% (35/45)

1-year postoperative survival rates in the present cohort using the modified Bauer score alone as well as the addition of other healthiness states.

Dichotomized Bauer-modified ScoreSurvival Rate at 1 year by Bauer ScoreSurvival Rate at 1 year by Bauer Score and Additional Healthiness States

012

Low (0,1,2)33% (50/150)17% (9/53)35% (22/62)54% (19/35)

High (3,4)59% (92/157)32% (12/38)61% (45/74)78% (35/45)