Retinoblastoma: Staging and Grouping


Group

Subgroup

Descriptor

Prognosis

Group I

Ia

Solitary tumor < 4 DD at or behind the equator

Very favorable

Ib

Multiple tumors, none > 4 DD, all at or behind the equator

Group II

IIa

Solitary tumor, 4–10 DD, all at or behind the equator

Favorable

IIb

Multiple tumors, 4–10 DD, behind the equator

Group III

IIIa

Any lesion anterior to the equator

Doubtful

IIIb

Solitary tumors larger than 10 DD behind the equator

Group IV

IVa

Multiple tumors, some larger than 10 DD

Unfavorable

IVb

Any lesion extending anteriorly to the ora serrata

Group V

Va

Massive tumors involving over half the retina

Very unfavorable

Vb

Vitreous seeding



The historical absence of a staging system also reflects the low incidence of extraocular disease in developed countries. Until relatively recently, the fact that extraocular disease is still a clinical issue in developing countries was largely overlooked in publications about retinoblastoma from the Northern Hemisphere. An international perspective on retinoblastoma is presented in Chap.​ 5.



3.4 First International Classification of Retinoblastoma


In this chapter we present the first international classification system for retinoblastoma. It consists of both presurgical grouping to help the ophthalmologist assess the risk of the disease and its treatment to the child’s eye[s] and vision and a staging schema for assessment of the risk the disease poses to the child’s life and well-being (Table 3.2). The organization and content of both the grouping and the staging were developed with unprecedented international cooperation among oncologists and ophthalmologists who treat this disease. The fact that four new cooperative group clinical trials, the first in almost 40 years, have recently opened to assess the management of retinoblastoma gives some testimony to the role of reality-based tumor classification systems (Chap.​ 21). All of the four new clinical trials use the international grouping and staging of retinoblastoma described in this chapter.


Table 3.2
Clinical and investigational aspects of staging and grouping in the international retinoblastoma classification











































































Aspect

Staging

Grouping

Focus

Patient and tumor

Eye

Primary specialist

Oncologist and pathologist

Ocular oncologist

Relation to tumor excision/biopsy

Clinical staging (presurgical)

Presurgical

Pathologic staging (postsurgical)

Outcome measure

Survival of the patient

Survival of the eye/vision

Information required

Has one eye been enucleated?

Results of the grouping EUA

Is tumor confined to the eye?

Is there tumor in one or both eyes?

Is there microscopic orbital disease?

Is the tumor confined to the retina?

Has the tumor grossly invaded regional structures?

Is significant retinal detachment present?

Have metastases occurred?

Are vitreous and/or subretinal seeding present?

Number of metastatic foci?

Has/have the functional and/or structural integrity of the eye(s) been destroyed?

Is there CNS disease?

Sources of information

Medical record including all diagnostic imaging studies and the tumor pathology report

Functional vision, ophthalmic examination, ocular ultrasound (CT rarely necessary)

Designator

Roman numerals

Capital letters A–E

Subgroups

Yes

No

Used in COG clinical trials

Yes

Yes

Time from study entry to:

Event-free survival (EFS)

Event-free ocular survival (EFOS)

 Disease recurrence requiring off-protocol therapy

 Loss to follow-up


3.5 Staging the Patient



3.5.1 Background


Retinoblastoma differs from other pediatric neoplasms in never having had a widely accepted classification system that encompasses the entire spectrum of the disease. The clinical scenario of a patient being treated for intraocular disease where survival is not in significant jeopardy is completely different from the case with metastatic disease in which there is a life-threatening extraocular disease.

The absence of a widely accepted staging system in the recent past made it extremely difficult to design studies or to compare the outcomes from published studies that evaluated disease extension, risk factors for metastatic disease, and/or response to therapy.


3.5.2 Other Staging Systems


There are at least five published reports that included a staging classification; however, none has been widely adopted [59].


3.5.2.1 St. Jude’s Hospital Staging and TNM System


Some classifications, like the St. Jude’s and TNM system, embraced the whole spectrum of retinoblastoma and included ophthalmologic data, and the TNM has been recently updated but was seldom used by ophthalmologists for clinical grouping who preferred the Reese-Ellsworth group classification and more recently the international classification [3, 4, 10].


3.5.2.2 Children’s Cooperative Group Classification


Other classifications, such as the CCG, considered only extraocular disease omitting important pathological features, like choroidal or postlaminar optic nerve invasion [7].


3.5.2.3 Grabowski-Abramson Classification


The Grabowski-Abramson classification, later modified by Abramson, was also used by some groups [8]. In that classification, patients with CNS invasion were categorized as Stage III and those with systemic metastases as Stage IV. The current clinical experience is that patients with Grabowski-Abramson Stage III are seldom curable, while those with Stage IV can often be rescued with high-dose chemotherapy and bone marrow rescue.


3.5.3 International Retinoblastoma Classification: Staging System [11]


At the International Symposium on Retinoblastoma held in Paris in May 2003, a committee of retinoblastoma experts from large centers worldwide drafted yet another staging system. Investigators from centers in South America and North America, Europe, and South Africa edited this draft into a consensus document. This staging system was designed to be used in conjunction with the new intraocular grouping system that was also under development at the same time. This staging system combines clinical and pathologic staging and has a single end point—survival of the patient with retinoblastoma. Patients are classified according to extent of disease including the presence of microscopic or overt extraocular extension and metastatic extension (Table 3.3). Roman numerals are used for stage assignment. This staging system has been recently validated in a large cohort of patients [12].


Table 3.3
Staging system for patients in international retinoblastoma classification




















































Stage

Substage

Descriptor

Comments

Stage 0
 
Intraocular tumor only

No evidence of regional or metastatic disease; patient may not have had an enucleation

Stage I
 
Tumor completely removed by enucleation

Retinoblastoma may be present in the non-enucleated eye. High-risk pathology may be present within the enucleated specimen

Stage II
 
Residual orbital tumor

Microscopic tumor present in the optic nerve at the site of surgical resection (cut end of nerve)

Stage III

(a) Overt orbital extension

Overt regional disease

Orbital or node involvement diagnosed clinically or by neuroimaging

(b) Preauricular or cervical lymph node extension

Stage IV

(a) Hematogenous metastasis without CNS disease

1. Single lesion

Metastatic disease
 

2. Multiple lesions

(b) CNS disease

1. Prechiasmatic lesion

2. CNS mass

3. Leptomeningeal disease
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Jun 30, 2016 | Posted by in OPHTHALMOLOGY | Comments Off on Retinoblastoma: Staging and Grouping

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