Upload
dr-umesh-sharma
View
399
Download
5
Embed Size (px)
Citation preview
Retinoblastoma
Dr. Rupal
Introduction
Retinoblastoma is most common intraocular malignancy in children
Incidence 1:15000 to 1:18000 livebirth
Second to uveal melanoma
No racial or gender predisposition
History The first description : Peter Pawius of
Amsterdam In 1805, William Hey : coined the term fungus
haematodes. In 1809,Scottish surgeon James Wardrop:
described metastasis to optic nerve, brain and different parts of body.
In 1864, Virchow:named glioma of the retina.In 1864, Virchow:named glioma of the retina. In 1891, Flexner of Johns Hopkins : first to In 1891, Flexner of Johns Hopkins : first to
notice rosettes within the tumor.notice rosettes within the tumor.
In 1897, Wintersteiner : proposed the name In 1897, Wintersteiner : proposed the name neuroepithelioma.neuroepithelioma.
Veorhoff : coined the term retinoblastomaVeorhoff : coined the term retinoblastoma
It is bilateral in 25% to 35% cases Average age at diagnosis 18mth Unilateral cases being diagnosed at around
24mth Bilateral cases being diagnosed before 12mth
Genetics of Rb Rb gene is tumor suppressor gene located on
long arm of 13th chromosome 13q14. Produces Rb protein that binds to cellular
protein & suppresses cell growth The gene is recessive oncogene at cellular
level Primitive retinal cells disappear within first few
yrs of life.So Rb is usually is not seen after 3-4yrs of age.
Hereditary Rb(40% of cases)
Patients inherits abnormal allele from parents and 1normal allele which undergoes a subsequent mutation after conception
The risk of 2nd hit is very high hence Rb is inherited as Autosomal Dominant
Risk of bilateral Rb is high as all cells have inherited 1 mutant allele
Risk of nonocular malignancies is also high for same reasons
Early age of presentation -1yr
Nonhereditary Rb(60% of cases)
Both alleles are normal after fertilization but subsequent mutations inactivate both alleles.This are somatic mutation in same retinal cells
No risk of bilateral Rb. In fact most of them are unilateral
No risk of nonocular malignancies
Two hit hypothesis
Proposed by Knudson in 1971 He stated that for retinoblastoma to
develop,two chromosomal mutations are needed.
In hereditary cases the initial hit is a germinal mutation,inherited and found in all cells
Therefore hereditary cases are predisposed to development of nonocular tumors.
Second hit develops in somatic retinal cells
In unilateral sporadic cases,both hits occurs during retina development and are somatic mutations.
Therefore there is no risk of second nonocular tumors.
Clinical manifestations Leukocoria (56.1%) Strabismus
Secondary changes : includes glaucoma, retinal detachment, and inflammation secondary to tumor necrosis. Pseudouveitis : characteristic of an infiltrating type
of retinoblastoma Orbital inflammation mimicking orbital cellulitis
Proptosis
Diagnosis
Ultrasonography : useful in distinguishing retinoblastomas from non-neoplastic conditions. It is also useful in detecting calcifications.
MRI
beneficial in estimating the degree of
differentiation of retinoblastomas
CT scan: delineates
extraocular extension and can detect associated pinealoblastoma
On FFA smaller tumors shows minimally dilated feeding vessels in arterial phase,blotchy hyperflourescence in venous phase and late staining
X-ray studies: identifying intraocular calcium in patients with opaque media.
Histopathology
Poorly differentiated tumors shows small to medium sized round cells with large hyperchromatic nuclei and scanty cytoplasm with mitotic figures
Well differenciated tumors show rosettes and fleurettes.
Flexer Wintersteiner rosettes
consist of columnar cells arranged around central lumen,highly
characteristic of retinoblastoma
Homer Wright rosettes consist of cells arranged around central neuromuscular tangle
Fleurettes are eosinophilic structures composed of tumor cells with pear shaped eosinophilic processes through fenestrating membrane
areas of necrosis and calcifications
Endophytic growthTumor breaks through the internal limiting
membrane and has an ophthalmic appearance of a white-to-cream mass showing either no surface
vessels or small irregular tumor vessels.
Exophytic growthExophytic growth occurs in the subretinal space.
This growth pattern often is associated with subretinal fluid accumulation and retinal detachment.
Diffuse infiltrating growthThis is a rare subtype comprising 1.5% of all retinoblastoma.
It is characterized by a relatively flat infiltration of the retina by tumor cells but without a discrete tumor mass.
It grows slowly compared with typical retinoblastoma.
Differential Diagnosis Congenital cataract Coats disease PHPV ROP Retinal detachment Coloboma Retinal dysplasia Norries disease
FEVR Toxocariasis
International Classification Of Intraocular Retinoblastoma
Management of Retinoblastoma
Primary goal is to save life Salvage of organ and function Needs team approach including an ocular
oncologist,pediatric oncologist,radiation oncologist and physicist,genetic and ophthalmic oncopathologist.
Management strategy depends on the stage of disease.
Management of Rb is highly individualised Based on following considerations:1. age at presentation2. Laterality3. Tumor location4. Tumor staging5. Visual prognosis6. Systemic condition7. Family and societal perception8. Cost effectiveness of treatment
Methods to Manage Intraocular Rb
1. Focal— Cryotherapy Laser
photocoagulation Transpupillary
thermotherapy Transcleral
thermotherapy Plaque
brachytherapy
2. Local— External beam
radiotherapy Enucleation3. Systemic— Chemotherapy
Cryotherapy Performed for small and
peripheral tumors measuring upto 4mmin basal diameter and 2mm in thickness
Triple freeze thaw cryotherapy applied at 4-6wk interval until complete tumor regression
It produces scar larger than tumor
Complications: Transient serous retinal detachment Retinal tear Rhegmatogenous retinal detachment
Cryotherapy administered 2-3hrs prior to chemotherapy increase the drug delivery across the blood retinal barrier and thus has synergistic effect.
Laser Photocoagulation
Used for small posterior tumors 4mm in basal
diameter and 2mm in thickness
Delimits the tumor and coagulate the blood
supply to tumor by surrounding it with two rows
of overlapping laser burns.
It is contraindicated while patient is on active
chemoreduction protocol.
Complications:
Transient serous retinal detachment Retinal vascular occlusion Retinal hole Retinal traction Preretinal fibrosis Less often employed now with advent of
thermotherapy
Thermotherapy
Mechanism: focused heat generated by infrared radiation is applied to tissues at subphotocoagulation levels to induce tumor necrosis
Goal is to achieve slow and sustained temperature range from 40-60degC within tumor,thus sparing damage to retinal blood vessels
Performed for small tumors-4mm in basal diam and 2mm thickness
Complete tumor regression achieved in 85% tumors using 3-4 sessions
TTT done using infrared radiation from a semiconductor diode laser delivered with 1300micron large spot indirect ophthalmoscope delivery system
Can be applied transpupillary through operating microscope or by transcleral route with diopexy probe
Tumor is heated until it turns subtle gray
Complications: Focal iris atrophy Focal paraxial lens opacity Retinal traction and serous detachment Major application :as an adjunct to
chemoreduction This synergistic combination is termed
chemothermotherapy.
Plaque Brachytherapy Involves placing
radioactive implant on sclera corrosponding to base of tumor to transclerally irradiate tumor
Ruthenium 106 and Iodine125 commonly used
Contd
Advantages: Focal delivery of radiation and minimal
damage to normal tissue Minimal periorbital tissue damage Absence of cosmetic abnormality because of
retarded bone growth Reduced risk of second malignant neoplasm Shorter duration of treatment
Contd. Indication: tumors less than 16mm in basl diam and
less than 8mm thickness It could be primary or secondary modality of
treatment Currently performed only in cases where
chemotherapy is contraindicated Most usefull in eyes that fail to respond to
chemoreduction and external beam radiotherapy or for tumor recurrences
Complications: radiation papillopathy and retinopathy
Contd. Plaque brachytherapy requires precise tumor
localisation and measurement of its basal dimensions
Thickness is measured on USG Dose to tomor apex ranges from 4000-
5000cGy Plaque is sutured to sclera after confirming
tumor centration and left for 36-72hrs Results in 90% tumor control
External beam radiotherapy Indication: In eyes where primary chemotherapy and local
therapy has failed When chemotherapy is contraindicated Problems with EBT: Stunting of orbital growth Dry eye Cataract Radiation retinopathy Optic neuropathy
Contd EBT can induce second
malignant neoplasm esp in patients with hereditary form of Rb
The risk of second malignant neoplasm is greater in children under 12 mth of age.
Enucleation Most common method for managing advanced Rb
Treatment of choice for: Advanced intraocular Rb with NVI Secondary glaucoma Anterior chamber tumor invasion Tumor occupying >75% vitreous volume Necrotic tumor with secondary orbital inflammation Tumors associated with hyphema or vitreous
hemorrhage
Special Considerations for Enucleation in Rb
Minimal manipulation Avoid perforation of eye Harvest long (>15mm)optic
nerve stump Inspect the enucleated eye
for macroscopic extraocular extension and optic nerve involvement
Harvest fresh tissue for genetic studies
Avoid biointegrated implant if postoperative radiotherapy is necessary
Chemotherapy
Chemoreduction, defined as the process of reduction in tumor volume with chemotherapy
Chemotherapy alone is not curative and must be associated with intensive local therapy
This can minimize the need for enucleation or EBT without significant systemic toxicity
Commonly used drugs are
Vincristine
Etoposide
Carboplatin
Chemoreduction is most usefull for tumors without associated subretinal fluid or vitreous seeding
Vincristine (Vincasar, OncovinPFS)
Mechanism: Cycle specific and phase specific, which blocks mitosis in metaphase. Blocks ability of tubulin to polymerize to form microtubules, which leads to rapid cytotoxic effects and cell destruction.
Pediatric Dose: For retinoblastoma: 1.5 mg/m2 (0.05 mg/kg for children younger than or = 36 mo and maximum dose, or = 2 mg)Intravenous administration q3wk for 9 cycles
Contraindications: Documented hypersensitivity to vinca alkaloids; pregnancy
Carboplatin (Paraplatin)
Mechanism: Inhibits both DNA and RNA synthesis. Binds to protein and other compounds containing SH group.
Pediatric Dose: For retinoblastoma: 560 mg/m2 (18.6 mg/kg for children, or = 36 mo) IV q3wk for 9 cycles
Contraindications: Documented hypersensitivity; preexisting severe renal impairment and myelosuppression; severe allergy to platinum components
Etoposide (Toposar, VePesid)
Mechanism: Blocks cells in the late S-G2 phase of the cell cycle.
Pediatric Dose: For retinoblastoma: 150 mg/m2 (5 mg/kg for children younger than or = 36 mo) IV q3wk for 9 cycles
Contraindications: Documented hypersensitivity; myelosuppression; liver impairment; IT administration may cause death
Contd
Favourable signs to chemotherapy:1.Considerable shrinkage after 2 cycle2.Reduce vascularization 3.Calcification : cottage cheese appearance 4.Clearing of vitreous seeds5.Resolution of RD
Contd
Adverse effects :1.Myelosuppression 2.Febrile episodes3.Neurotoxicity 4.Nonspecific gastrointestinal toxicity
Periocular chemotherapy
Carboplatin delivered deep posterior subtenon has been demonstrated to be efficacious in management of advanced intraocular retinoblastoma with vitreous seed
It can penetrate sclera & achieve effective concentration in vitreous
This modality is under trial It achieves 70% eye salvage in patients with
RB with diffuse vitreous seeds
Follow up schedule
Chemoreduction therapy: every 3 weeks with each cycle of chemotherapy
Focal therapy: every 4-8 weeks until complete tumor regression
Following tumor regression : 3 mnthly for 1st yr , 6mthly for 3yrs or until child is 6yrs age & yrly there after
Histopathologic high risk factors predictive of metastasis1.Anterior chamber seeding 2.Iris infiltration 3.Ciliary body infiltration4.Massive choroidal infiltration5.Invasion of optic nerve lamina cribrosa6.Retrolaminar optic nerve invasion 7.Invasion of optic nerve transection8.Scleral infiltration 9.Extra scleral extension
Orbital Retinoblastoma
Clinical manifestation:1. Primary2. Secondary3. Accidental4. Overt5. Microscopic
Orbital retinoblastoma
Clinical manifestation: 1.Primary orbital Rb: Refers to clinically or radiologically detected
orbital extension of intraocular Rb at initial clinical presentation with/without proptosis or fungating mass.
2.Secondary orbital Rb : Orbital recurrence following uncomplicated
enucleation for intraocular Rb Unexplained displacement , bulge or
extrusion of previously well fitting conformer or prosthesis is an omnious finding suggestive of orbital recurrence
3.Accidental orbital Rb: Inadvertent perforation , FNAB or intraocular
surgery in eye with unsuspected intraocular Rb
4.Overt orbital Rb: Previously unrecognized extrascleral or optic
nerve extension discovered during enucleation
Enlarged & inelastic optic nerve with/without nodular optic nerve sheath are clinical indicators of optic nerve extension of Rb that should be recognized during enucleation
5.Microscopic orbital Rb: Orbital extension may not be clinically evident
& may only be miocroscopic Detection of full thickness scleral infiltration ,
extra scleral extension & invasion of optic nerve transection on histopathologic evaluation are unequivocal features of orbital Rb
Management of orbital Rb
Primary orbital Rb: High dose chemotherapy(3-6cycles) followed
by surgery (enucleation , extended enucleation or exenteration as appropriate) , orbital radiotherapy & additional 12 cycle std dose chemotherapy
Accidental , Overt or Microscopic orbital Rb: Orbital EBT (fractionated 45-50 Gy) &12 cycle
of dose chemotherapy
Metastatic Rb
Metastatic disease at the time Rb diagnosis is very rare
Common sites for local spread & metastasis include orbital & regional lymph node extension, CNS, bone & bone marrow , liver,spleen, pleura
After the diagnosis of metastasis , the period of survival varies from 6-12 mths
Treatment of metastatic disease:1.Chemotherapy intense: cyclophophamide 20mg/kg IV, vincristine 50mg/kg IV doxorubicin2.Palliative local radiotherapy3.Craniospinal radition4.Intrathecal methotrexate(0.5mg/kg) & intrathecal
diazoquone help to induce remissions
Follow up schedule
Include fundoscopy & IDO under full dilatation under GA
FFA in cases with radio/cryo/photocoagulation is done to detect vascularity
6 wks after therapy every 3mnths for 1st yr every 4mnths for 2nd yr every 6mnth till 6 yrs of age once a yr upto 20 yrs of age
Second cancers / non Rb malignancies
Incidence:hereditary: 6% over lifetime Hereditary Rb with EBT : 1% / yr in field of
radiation Avg. age of diagnosis is 13 yrs Tumors: Osteogenic sarcoma-most common Pineoloblastoma-2yrs after diagnosis of Rb
Beyond 2 yrs:1.Bony and soft tissue tumors:Ewings
sarcoma,chondrosarcoma & rhabdomyosarcoma
2.Skin tumors: malignant melanoma , SCC , sebaceous cell CA
3.Neurobalstoma , medulloblastoma , leukemia
Prognosis
Overall survival rate is 90% 5 yr mortality rate of Rb cases :1.Optic nerve involvement : not involved 8% upto lamina cribrosa 15% beyond lamina cribrosa 44% surgical end of section 65%2.Choroidal invasion 25% 3.Orbital invasion 91%
Newer modalities
1.Thermotherapy: entire eye sparing the anterior segment – u wave strip
line applicator Inducing focal hyperthermia- using ultrasonically
induced hyperthermia2.Radiosensitisers : SR 2508 & SZR 2555 better absorption with lesser
toxicity. Misionidazole-hypoxic cell sensitiser but is toxic for clinical use
3.Local chemotherapy: Serial Aggressive Local Therapy (SALT ): fluorouracil,
methotrexate, cytosine arabinoside, azoquinone 4.Monoclonal antibodies5.PDT
Thank you