Molecular Pathology Tests:Choosing Among the Many

Jennifer Laudadio, MDUniversity of Arkansas for Medical Sciences

Disclosures

• None

Objectives

• Assess appropriateness of molecular testing requests and decide among the available methods

• Evaluate quality and cost-effectiveness of testing options when deciding which ones to bring in-house

THE 3PM PHONE CALL

(OR EMAIL)

What Now?

• The test you know absolutely nothing about• The test you know about but don’t know if the

methodology matters and don’t know where to send it

• The test you know all about but don’t know where to send it

• The test request you know how to handle – EASY, DONE

The test you know nothing about

• Spend a couple of hours researching the test• Knock on your colleagues door• Ask your colleague requesting the test to send

you information• Check reference lab test menus• Check www.amp.org test menu

The test you know nothing about

• Is this medically necessary?• What is the cost?• Has the requesting doctor talked to the

patient about this super expensive test?• Do multiple labs offer the test?• Do all labs use the same test method?

Example

“That test that tells me where the primary tumor is”

What tests are available?

• Biotheranostics• Pathwork Diagnostics• Rosetta Genomics

Biotheranostics• CancerType ID• Laser micro-dissection (need special slides)• Real Time RT-PCR• 92 genes

87 tumor associated5 reference

• Classifies 50 cancer types/subtypes87% accurate for 28 main tumor types82% accurate for 50 subtypes

Pathwork Diagnostics• Tissue of Origin Test• DNA based expression array• ~2000 genes• Classifies 15 primary types/ 58 morphologies• 89% positive agreement• FDA-cleared for formalin fixed paraffin

embedded tissue

Rosetta Genomics• miRview Mets 2• Expression levels of micro-RNAs• 64 micro-RNAs• Classifies 42 tumor types• 85% sensitivity

What tissue is available for testing?What are the specimen requirements for

each test?

• Specimen size?• Tumor cellularity?• Decalcified?

• Test methodology can impact what sample is acceptable.

Is each test equally “good”?

• Monzon FA and Koen TJ. Diagnosis of metastatic neoplasms: molecular approaches for identification of tissue of origin. Arch Pathol Lab Med. 2010; 134(2):216-224.

Shipping Requirements?

Don’t forget about the $$!

• Does the company direct patient/insurance bill?

• What is the cost of the test?• Has the oncologist discussed this test with the

patient?

The test you know nothing about

• Yes, there will be preliminary information gathering necessary– Ask the requesting oncologist for information– Ask your colleagues if they have had any

experience with any of the tests and what they thought

• Yes, the second time you get this request, it will go much smoother

The test you have heard about

• Method?– Probably the hardest part– Intro to molecular methods CME– Webinars

• Which reference lab?• Specimen requirements?– Test the primary or metastasis?

Example

KRAS mutation testing for metastatic colorectal carcinoma

Methodology

• Sensitivity• Specific codons targeted by the method• Examples of methods used for KRAS testing– Sequencing– Pyrosequencing– Allele specific PCR

KRAS Methodology• Sequencing

– Get information on entire exon– Need at least 20% mutant allele – Does lab inhibit wild type alleles to increase sensitivity?

• Pyrosequencing– Improves sensitivity– Targets specific mutations– Special instrumentation

• Allele specific PCR– Targets specific codon 12 and 13 point mutations– Sensitivity down to ~1% mutant allele– Is it too sensitive?

Specimen Requirements and Selecting a Reference Lab

• FFPE acceptable– Block– Unstained slides (don’t have to be charged)

• Test either the metastasis or primary • The usual reference lab– all our reference testing has to go to lab X

• Search for a reference lab– Google reference lab test menus

• Mayo Test Menu– Get info on methodology, specimen requirements, clinical

utility, access requisition form, etc

Scenarios have been reactiveWhat about being proactive?

Proactive

• You make that phone call to recommend a test• Reflex testing policy

You recommend a test

You diagnose metastatic colorectal carcinoma in a liver biopsy – call surgeon or oncologist and ask if they want it sent for KRAS testing.

Reflex Testing

HPV for oropharyngeal squamous cell carcinomas

Establishing a Reflex Testing Policy• Communication– Requests from clinicians– Agreement among Pathologists

• Methodology• How to get a reflex testing policy approved?– Medical Center Dependent– How to communicate the new policy once approved

• Monitor adherence

Specifics from experience with HPV

• Multi-disciplinary requestsENT surgeonsMedical oncologistRadiation oncologist

• IndicationsPrognostic and PredictiveDiagnostic

Specifics from experience with HPV• Choosing a Methodology– In situ hybridization

• High specificity• Low sensitivity

– PCR• High sensitivity• Is it too sensitive?

– P16• Surrogate• High sensitivity• Lower specificity

In situhybridization

p16 IHC

Specifics from experience with HPV

• Drafting a Reflex Policy– Specific Diagnoses that would trigger the reflex

test– CPT codes

• Getting the Policy Approved• Communicating the Policy

You want to get into the Molecular Diagnostics Game

What tests to bring in house?

Test VolumesIf you build it, will they come?

Cost savings?

Type of equipment and expertise needed?

• FDA approved testsRequire less expertiseExpenseVerification of performance characteristics

• Lab Developed testsTime for developmentExpertiseMore rigorous validation

What’s Realistic

• Dedicated Research/Development personOne test a month

• Pathologists also involved in patient care3-4 tests per year

• Don’t forget the need for IT support!!

Will I get paid?

• New CPT codesBased on analyte being testedNot method specificReplace “stacking” codesOn clinical lab fee scheduleG code for professional interpretation

• Gap-fill method of determining reimbursement• Critical time to work with payers

Take Home Points

• Yes, it can be taxing to your practice to evaluate molecular testing requests.

• You can handle these requests either proactively or reactively

• Reactive is not necessarily bad• Take advantage of the resources around you –

the requesting MD, other pathologists, On-line test menus, Google, webinars, CME

Take Home Points: Examples of Tests• Tests for tumor of unknown origin– Medical necessity– Methodology and Targeted genes– Specimen Requirements

• KRAS– Methodology and Mutation targets– Finding a reference lab– Mets versus Primary

• HPV– Developing a reflex testing policy– Selecting a method

Take Home Points

• A basic understanding of molecular techniques may prove useful

• Deciding to bring tests in-house– FDA-approved versus lab developed– Performance Characteristics– Cost– Expertise necessary

Thank You