New and recurrent tumor foci following local treatment as well as external beam radiation in eyes of patients with hereditary retinoblastoma

Development of New Solitary Retinoblastoma Tumors during and after Chemotherapy

PURPOSE

To review the occurrence of new solitary tumors during and after intravenous chemotherapy against retinoblastoma.

METHODS

From 115 eyes of 78 patients with a diagnosis of intraocular retinoblastoma who underwent intravenous chemotherapy and focal treatment without prior treatment, patient demographics, age at diagnosis, laterality, classification (Reese-Ellsworth and International Classification of Retinoblastoma), and treatment options were recorded. In addition, the occurrence of small tumors during and after chemotherapy was documented with a detailed review of medical records and fundus photographs.

RESULTS

Of a total of 115 eyes of 78 consecutive patients, new solitary tumors were observed in 50 eyes (50 / 115, 43%) of 40 patients (40 / 78, 51%). Multinominal logistic regression analyses showed that age at diagnosis (before 1 year) and vitreal seeding at diagnosis were linked to the development of isolated and miliary tumors, respectively. Kaplan-Meier analyses demonstrated that all small tumors developed with 20 months from the start of chemotherapy. Twenty-eight eyes (28 / 34, 82%) were salvaged with additional focal treatment in 34 eyes with isolated tumors.

CONCLUSIONS

Small tumors were observed during and after chemotherapy against retinoblastoma in patients who underwent intravenous chemotherapy and focal treatment. It is necessary to promptly identify and address small tumors for the preservation of eyeball and vision.

Prognostic Information for Known Genetic Carriers of RB1 Pathogenic Variants (Germline and Mosaic)

PURPOSE

To compare the number of tumors per eye for mosaic carriers of RB1 pathogenic variants with full germline variants and the conversion from unilateral to bilateral disease.

DESIGN

Retrospective cohort study comparing patients with retinoblastoma and different genetic subtypes: high penetrance (HP), low penetrance (LP), and mosaicism.

PARTICIPANTS

Data were analyzed between 1992 and 2018 at the Retinoblastoma Unit, Royal London Hospital, London, United Kingdom. All familial patients had a parent with a known pathogenic variant even if the parent did not manifest the disease.

MAIN OUTCOME MEASURES

Number of tumors per eye in children who developed retinoblastoma in that eye. Other outcomes included total number of tumors per patient, age at diagnosis, laterality at presentation and later, sex, and stage according to International Intraocular Retinoblastoma Classification.

RESULTS

A total of 111 patients were included: 64 full germline, familial patients (53 HP and 11 LP) and 47 mosaic patients. Twelve HP patients (23%) were unilateral, and 8 of 12 patients (67%) developed tumors in their previously unaffected eye. A total of 34 mosaic patients (72%) were unilateral, and only 2 (6%) developed tumors in their unaffected eye. Age at diagnosis was higher in mosaic patients (median, 22 months) than in HP patients (median 7) (P < 0.00002). The number of tumors per eye was fewer in patients with mosaic alleles (median, 1.0; range, 1-6) compared with patients with HP alleles (median, 3.0; range, 1-8) (P < 0.0003). All 3 children (4 eyes) with mosaicism and more than 2 tumors per eye had high levels of mosaicism.

CONCLUSIONS

Children with mosaic alleles have fewer tumors per eye compared with those with known high-penetrant pathogenic variants and are more likely to remain unilateral. The level of mosaicism has an impact on laterality and number of tumors.

MONTE CARLO SIMULATION OF OUT-OF-FIELD ORGAN DOSES AND CANCER RISK IN TANZANIA FOR RADIATION THERAPY OF UNILATERAL RETINOBLASTOMA USING A 60Co UNIT

The use of 60Co teletherapy unit for the treatment of unilateral retinoblastoma (Rb) patients is a very common procedure in many developing countries including Tanzania. The aim of this study was to estimate organ-specific absorbed doses from an external beam radiation therapy 60Co unit for unilateral Rb and to assess the risks of the patients developing a secondary primary cancer. The absorbed dose estimations were based on a Monte Carlo method and a set of age-dependent computational male phantoms. The estimated doses were used to calculate the secondary cancer risks in out-of-field organs using the Biological Effects of Ionising Radiation VII risk models. The survival information and baseline cancer risks were based on relevant statistics for the Tanzanian population. The resulting out-of-field organ doses data showed that organs which are close to the target volume, such as the brain, salivary glands and thyroid glands, received the highest absorbed dose from scattered photons during the treatment of Rb. It was also found that the resulting photons dose to specific organs depends on the patient's age. Younger patients are more sensitive to radiation and also received higher dose contributions from the treatment head due to a larger part of the body exposed to the photon radiation. In all sites considered, the overall risks associated with radiation-induced secondary cancer were relatively lower than the baseline risks. Thus, the results in this article can help to provide good estimations of radiation-induced secondary cancer after radiation treatment of unilateral Rb using 60Co teletherapy unit in Tanzania and other developing countries.

Pediatric Survivors of Retinoblastoma Are at Risk for Altered Bone Metabolism After Chemotherapy Treatment Early in Life

Survivors of childhood cancer frequently suffer from endocrine late effects, which are, at least partly, attributed to toxic effects of chemotherapy. Treatment of retinoblastoma typically involves chemotherapy at a very young age. The authors conducted a cross-sectional study to assess bone health in a pediatric cohort of 33 survivors of retinoblastoma (mean age: 4.4 years) who had undergone chemotherapy treatment at an especially young age (mean age: 0.76 years). Of these patients, 14 had unilateral and 19 bilateral retinoblastoma. Polychemotherapy consisted of treatment with cyclophosphamide, etoposide, vincristine, and carboplatin. Ten patients had undergone external beam radiotherapy. Clinical and biochemical parameters of growth, pubertal development, and bone health were obtained. A vitamin D deficiency was found in 51.7% of the patients, and 13.7% of patients displayed severe vitamin D deficiency. Secondary hyperparathyroidism and altered readings for bone formation or resorption markers were present in 15%. Nine percent reported bone pain or experienced fractures of the long bones after primary diagnosis. No difference between children with bilateral and unilateral disease or irradiated versus nonirradiated children was observed. The parameters of thyroid function, growth, and pubertal development were within age-appropriate norms in almost all children. In conclusion, altered parameters of bone health can be present in survivors of retinoblastoma at a young age and warrant regular follow-up in these children. The endocrine hypothalamic-pituitary axes, however, were not impaired at this early age in this group of survivors of retinoblastoma.

The modern role of radiation therapy in treating advanced-stage retinoblastoma: long-term outcomes and racial differences

PURPOSE/OBJECTIVE(S)

To evaluate the effects of various patient characteristics and radiation therapy treatment variables on outcomes in advanced-stage retinoblastoma.

METHODS AND MATERIALS

This was a retrospective review of 41 eyes of 30 patients treated with external beam radiation therapy between June 1, 1992, and March 31, 2012, with a median follow-up time of 133 months (11 years). Outcome measures included overall survival, progression-free survival, local control, eye preservation rate, and toxicity.

RESULTS

Over 90% of the eyes were stage V. Definitive external beam radiation therapy (EBRT) was delivered in 43.9% of eyes, adjuvant EBRT in 22% of eyes, and second-line/salvage EBRT in 34.1% of eyes. A relative lens sparing (RLS) technique was used in 68.3% of eyes and modified lens sparing (MLS) in 24.4% of eyes. Three eyes were treated with other techniques. Doses ≥45 Gy were used in 68.3% of eyes. Chemotherapy was a component of treatment in 53.7% of eyes. The 10-year overall survival was 87.7%, progression-free survival was 80.5%, and local control was 87.8%. White patients had significantly better overall survival than did African-American patients in univariate analysis (hazard ratio 0.09; 95% confidence interval 0.01-0.84; P=.035). Toxicity was seen in 68.3% of eyes, including 24.3% with isolated acute dermatitis.

CONCLUSIONS

External beam radiation therapy continues to be an effective treatment modality for advanced retinoblastoma, achieving excellent long-term local control and survival with low rates of treatment-related toxicity and secondary malignancy.

Monte Carlo study for designing a dedicated "D"-shaped collimator used in the external beam radiotherapy of retinoblastoma patients

PURPOSE

Retinoblastoma is the most common intraocular malignancy in the early childhood. Patients treated with external beam radiotherapy respond very well to the treatment. However, owing to the genotype of children suffering hereditary retinoblastoma, the risk of secondary radio-induced malignancies is high. The University Hospital of Essen has successfully treated these patients on a daily basis during nearly 30 years using a dedicated "D"-shaped collimator. The use of this collimator that delivers a highly conformed small radiation field, gives very good results in the control of the primary tumor as well as in preserving visual function, while it avoids the devastating side effects of deformation of midface bones. The purpose of the present paper is to propose a modified version of the "D"-shaped collimator that reduces even further the irradiation field with the scope to reduce as well the risk of radio-induced secondary malignancies. Concurrently, the new dedicated "D"-shaped collimator must be easier to build and at the same time produces dose distributions that only differ on the field size with respect to the dose distributions obtained by the current collimator in use. The scope of the former requirement is to facilitate the employment of the authors' irradiation technique both at the authors' and at other hospitals. The fulfillment of the latter allows the authors to continue using the clinical experience gained in more than 30 years.

METHODS

The Monte Carlo code PENELOPE was used to study the effect that the different structural elements of the dedicated "D"-shaped collimator have on the absorbed dose distribution. To perform this study, the radiation transport through a Varian Clinac 2100 C/D operating at 6 MV was simulated in order to tally phase-space files which were then used as radiation sources to simulate the considered collimators and the subsequent dose distributions. With the knowledge gained in that study, a new, simpler, "D"-shaped collimator is proposed.

RESULTS

The proposed collimator delivers a dose distribution which is 2.4 cm wide along the inferior-superior direction of the eyeball. This width is 0.3 cm narrower than that of the dose distribution obtained with the collimator currently in clinical use. The other relevant characteristics of the dose distribution obtained with the new collimator, namely, depth doses at clinically relevant positions, penumbrae width, and shape of the lateral profiles, are statistically compatible with the results obtained for the collimator currently in use.

CONCLUSIONS

The smaller field size delivered by the proposed collimator still fully covers the planning target volume with at least 95% of the maximum dose at a depth of 2 cm and provides a safety margin of 0.2 cm, so ensuring an adequate treatment while reducing the irradiated volume.

Radiotherapy for ocular tumours

Ocular tumours present a therapeutic challenge because of the sensitive tissues involved and the necessity to destroy the tumour while minimising visual loss. Radiotherapy (RT) is one of several modalites used apart from surgery, laser, cryotherapy, and chemotherapy. Both external beam RT (EBRT) and brachytherapy are used. Tumours of the bulbar conjunctiva, squamous carcinoma and malignant melanoma, can be treated with a radioactive plaque: strontium-90, ruthenium-106 (Ru-106), or iodine-125 (I-125), after excision. If the tumour involves the fornix or tarsal conjunctiva, proton therapy can treat the conjunctiva and spare most of the eye. Alternatively, an I-125 interstitial implant can be used with shielding of the cornea and lens. Conjunctival mucosal-associated lymphoid tissue lymphoma can be treated with an anterior electron field with lens shielding and 25-30 Gray (Gy) in 2 Gy fractions. Discrete retinoblastoma (RB), too large for cryotherapy or thermolaser, or recurrent after these modalities, can be treated with plaque therapy, I-125, or Ru-106. For large RB, multiple tumours, or vitreous seeds the whole eye can be treated with an I-125 applicator, sparing the bony orbit, or with EBRT, under anaesthetic, using X-rays or proton therapy with vacuum contact lenses to fix the eyes in the required position. Post-enucleated orbits at risk for recurrent RB can be treated with an I-125 implant with shielding to reduce the dose to the bony orbit. Uveal malignant melanomas can be treated with plaque or proton therapy with excellent local control. Preservation of vision will depend on the initial size and location of the tumour.

Ophthalmic artery chemosurgery for retinoblastoma prevents new intraocular tumors

OBJECTIVE

To determine the incidence and timing of new intraocular tumor foci in genetic retinoblastoma cases after treatment with ophthalmic artery chemosurgery (OAC).

DESIGN

Single-center retrospective review of all genetic retinoblastoma cases managed at Memorial Sloan-Kettering Cancer Center/Weil-Cornell Medical School since May 2006.

PARTICIPANTS

Eighty-one patients (80 with bilateral disease and 1 with unilateral disease with a family history) with genetic retinoblastoma, with a total of 116 eyes treated with OAC since May 2006.

METHODS

Retrospective, single-institution review of patients with bilateral retinoblastoma and unilateral retinoblastoma with a positive family history. New tumors were assessed by clinical notes, retinal drawings, and RetCam digital imaging (Clarity Medical Systems, Pleasanton, CA).

MAIN OUTCOME MEASURES

New intraocular retinoblastoma tumors after treatment with OAC.

RESULTS

Forty-one eyes were treated primarily with OAC (treatment-naïve group) and 75 eyes were treated with OAC after prior treatment with systemic chemotherapy, external beam radiation, or both and focal techniques. Of the 41 treatment-naïve eyes, a new intraocular tumor (one focus) subsequently developed in 1 eye. Of the 75 previously treated eyes, new tumors (single focus in each eye) subsequently developed in 6 eyes.

CONCLUSIONS

Eyes receiving OAC demonstrate fewer new intraocular retinoblastomas after radiation or systemic chemotherapy than has been reported in the literature. This suggests that ophthalmoscopically undetectable tumors are present at the initial diagnosis and effectively are eliminated as a result of OAC.

Incidence of New Tumor Formation in Patients with Hereditary Retinoblastoma Treated with Primary Systemic Chemotherapy: Is There a Preventive Effect?

PURPOSE

To report the incidence of new tumor formation in hereditary retinoblastoma patients treated with primary systemic chemotherapy.

DESIGN

Noncomparative retrospective case series.

PARTICIPANTS

Fifty-eight consecutive patients with hereditary retinoblastoma treated with primary systemic chemotherapy.

METHODS

The charts of 58 consecutive patients with hereditary retinoblastoma treated between January 1996 and August 2005 were reviewed. Data extracted included gender, age at diagnosis, family history of retinoblastoma, laterality of disease, tumors per eye, Reese-Ellsworth grouping of affected eyes, starting and ending dates for chemotherapy, number of cycles of chemotherapy, chemotherapy regimen, need for external beam radiotherapy and/or enucleation, and development and location (macula, midzone, and periphery) of new tumors after the start of systemic chemotherapy.

MAIN OUTCOME MEASURE

New tumor formation after treatment with primary systemic chemotherapy.

RESULTS

Of the 58 patients, 48 had bilateral involvement at diagnosis. Median age at diagnosis was 6.6 months. Thirteen patients had a positive family history. Of the eyes with tumor (n = 106) at diagnosis, 52 (49%) were in Reese-Ellsworth groups I to III, whereas 54 (51%) were in group IV or V. Seven patients (12%) with a median age of 1.6 months at diagnosis formed 36 new tumors in 11 eyes after the start of chemotherapy. Median time from initiation of chemotherapy to detection of the first new tumor was 3 months (range, 1-15). Cumulative incidence of new tumor formation at 2 years was 10+/-3%. An age of <6 months at diagnosis, family history of retinoblastoma, and Reese-Ellsworth grouping of I to III were found to correlate significantly with an increased incidence of new tumor formation (P<0.001, P<0.001, and P = 0.021, respectively). Median follow-up for all patients was 5 years (range, 1-10.1).

CONCLUSION

New tumors continue to form in patients with hereditary retinoblastoma despite treatment with primary systemic chemotherapy. Younger patients and those with a positive family history are more likely to have new tumors formed. However, chemotherapy may impact small previously undetected lesions by slowing their growth and facilitating later focal consolidation.

Beta-ray brachytherapy with 106Ru plaques for retinoblastoma

PURPOSE

A retrospective analysis of 134 patients who received (106)Ru brachytherapy for retinoblastomas (175 tumors in 140 eyes). Treatment and follow-up were analyzed with special emphasis on tumor control organ, preservation, and late complications.

RESULTS

Treated tumors had a mean height and diameter of 3.7+/-1.4 mm and 5.0+/-2.8 disk diameters, respectively. The radiation dose values were recalculated according to the calibration standard recently introduced by the National Institute of Standards and Technology. The recalculation revealed a mean applied dose of 419 Gy at the sclera (SD, 207 Gy) and 138 Gy (SD, 67 Gy) at the tumor apex. The 5-year tumor control rate was 94.4%. Tumor recurrence was more frequent in eyes with vitreous tumor cell seeding or fish-flesh regression. The estimated 5-year eye preservation rate was 86.5%. Previous treatment by brachytherapy or external beam radiotherapy, as well as a large tumor diameter, were significant factors for enucleation. The radiotherapy-induced complications after 5 years of follow-up were retinopathy (22%), optic neuropathy (21%), and cataract (17%). These complications were significantly more frequent after prior brachytherapy or external beam radiotherapy.

CONCLUSION

Brachytherapy using (106)Ru plaques is a highly efficient therapy with excellent local tumor control and an acceptable incidence of side effects.

DE NOVO INTRAOCULAR RETINOBLASTOMA DEVELOPMENT AFTER CHEMOTHERAPY IN PATIENTS WITH HEREDITARY RETINOBLASTOMA

OBJECTIVE

Identification of incidence and risk factors for recurrence of de novo retinoblastomas after chemotherapy treatment in patients with hereditary retinoblastoma.

METHODS

A retrospective, case-control study of 32 patients (50 eyes) with sporadic or familial bilateral retinoblastomas was conducted. Patients received a systemic chemotherapy regimen applying three courses of a combination of three drugs (including vincristine, etoposide, carboplatin, or cyclophosphamide) followed by additional local therapy. The primary outcome analyzed was the development of retinoblastomas, probably arising as the cause of a new mutational event (de novo) after completion of chemotherapy treatment.

RESULTS

Patients were treated with an average of 5.8 +/- 1.8 chemotherapy courses (4.6 +/- 2.4-year follow-up time). Development of de novo tumors occurred in 48% of the treated eyes. These tumors occurred during chemotherapy treatment or within 7 months of chemotherapy completion. No de novo tumors developed in patients older than 3.2 years. Children who developed de novo tumors were significantly younger at the time of diagnosis (6.7 +/- 6.3 months vs 14.4 +/- 11.4 months, P < 0.001), and had a significantly lower number of tumors per eye at treatment begin (2.6 +/- 2.3 tumors vs 4.3 +/- 6.4 tumors, P < 0.001). The difference of the total numbers of retinoblastomas that developed per eye between the patients that developed de novo retinoblastomas during or after chemotherapy and patients who did not was not statistically significant (4.9 +/- 2.7 and 4.3 +/- 6.4, respectively, P = 0.8). No eye was lost because of de novo retinoblastoma development, and 92% of the eyes were preserved.

CONCLUSIONS

De novo retinoblastomas developed both during and after completion of chemotherapy treatment. Younger children were at a significantly higher risk for developing de novo intraocular retinoblastomas. Good tumor control and eye preservation rates were achieved with regular and frequent control examinations in addition to the immediate treatment of de novo retinoblastomas.

Pars Plana Lensectomy and Intraocular Lens Implantation in Pediatric Radiation-Induced Cataracts in Retinoblastoma

OBJECTIVE

To investigate visual outcomes, surgical complications, and tumor recurrence among children with retinoblastoma (RB) undergoing pars plana lensectomy, vitrectomy, and simultaneous intraocular lens insertion for radiation-related cataract secondary to external beam radiotherapy (EBRT).

DESIGN

Retrospective, noncomparative, consecutive case series.

METHODS

The medical records for all patients treated with pars plana lensectomy, vitrectomy, and posterior chamber intraocular lens implantation for radiation-induced cataract after EBRT for RB at a single institution between January 1, 1990, and December 31, 2000, were reviewed.

PARTICIPANTS

The study included 16 eyes of 12 children with Reese-Ellsworth stage V RB.

MAIN OUTCOME MEASURES

Visual acuity, surgical and postoperative complications, postoperative refraction, and tumor recurrence.

RESULTS

The median age at diagnosis of RB was 6 months (range, 1-49 months). All patients received EBRT as primary treatment and experienced radiation-induced cataracts. The median interval from RB diagnosis to cataract surgery was 42 months (range, 28-95 months). Preoperative mean visual acuity was 20/400, with 12 of 16 eyes (75%) having macular tumor involvement. All patients underwent pars plana lensectomy, vitrectomy, and posterior chamber intraocular lens insertion. Vitreous samples were evaluated by cytopathologic examination, and no viable tumor cells were identified in any of the vitreous specimens. Postoperative complications included transient cystoid macular edema in 5 eyes (31%) and iridocyclitis in 3 eyes (19%). The mean follow-up after cataract surgery was 66 months (range, 30-94 months). Final visual acuity was 20/40 or better in 11 of 16 eyes (69%). No late intraocular recurrence, orbital tumors, or metastatic disease was noted in this study.

CONCLUSIONS

Pars plana lensectomy, vitrectomy, and simultaneous intraocular lens implantation is an effective means of managing EBRT-induced cataracts in eyes with previously treated RB. There was no evidence of active tumor in eyes undergoing surgery at least 28 months after the diagnosis and commencement of therapy for RB, and no late intraocular, orbital, or metastatic tumors were detected. Visual acuity was limited by the presence of primary macular tumor pathologic features in a subset of patients, but final vision better than 20/400 may be achieved in these eyes.

New retinoblastoma tumor formation in children initially treated with systemic carboplatin

PURPOSE

To determine the frequency and timing of new intraocular tumor formation in children with hereditary retinoblastoma initially treated with systemic carboplatin.

DESIGN

Retrospective, noncomparative case series.

PARTICIPANTS

This study included 34 children (57 eyes) with hereditary bilateral retinoblastoma initially treated with systemic carboplatin at the Robert M. Ellsworth Ophthalmic Oncology Center at NewYork-Presbyterian Hospital from 1994 through 2000.

MAIN OUTCOME MEASURES

New tumor formation after initial treatment with systemic carboplatin.

RESULTS

There were a total of 165 tumors in 57 eyes. There were 63 new tumors in 27 eyes (47%) after administration of systemic carboplatin, for a mean of 1.1 new tumors per eye. The mean patient age at time of new tumor presentation was 9 months, with 57% of new tumors developing within 4 months of carboplatin treatment. Kaplan-Meier analysis showed that children who were treated when younger than 6 months of age were more likely to have new tumors (60%) compared with those treated after 6 months of age (31%; P = 0.0182).

CONCLUSIONS

New intraocular tumors continue to develop after systemic carboplatin; most new tumors appeared within 4 months of treatment.

Cataract surgery and intraocular lens implantation in a retinoblastoma case treated by external-beam radiation therapy

We report a case of extracapsular cataract extraction with posterior chamber intraocular lens implantation in a pediatric patient with a radiation-induced cataract that developed after combined external-beam radiation therapy and chemotherapy for retinoblastoma. A 12-year follow-up revealed effective tumor regression and sustained visual recovery.

Treatment of retinoblastoma vitreous base seeding

OBJECTIVE

The purpose of the study is to describe results of a new treatment for retinoblastoma vitreous base seeding.

DESIGN

The study design was a retrospective review of patients treated at an ocular oncology referral center.

PARTICIPANTS

Five eyes of five patients with vitreous base seeding that occurred after previous external beam radiation therapy were treated between October 1987 and December 1994.

INTERVENTION

A customized plaque made from iridium-192/platinum wire was placed to deliver 4000 cGy to the tumor apex along its entire length and systemic chemotherapy (consisting of carboplatin, vincristine, and etoposide) was given.

MAIN OUTCOME MEASURES

Eye preservation and tumor control were measured.

RESULTS

Vitreous base seeding was controlled completely and the eye preserved in four of the five treated eyes with an average follow-up of 26.2 months.

CONCLUSIONS

The combination of a customized iridium-192 plaque and systemic chemotherapy is an effective means of treating vitreous base seeding of retinoblastoma.

Long-term results after low dose ocular irradiation for choroidal haemangiomas

AIM/BACKGROUND

The most common choice of treatment for choroidal haemangiomas (CH) in the past has been the employment of scatter photocoagulation of the surface. This management often requires repetitive treatment or additional invasive management due to massive exudative detachment of the retina. The aim of this retrospective study was to investigate the outcome of the alternative application of low dose external beam irradiation with high energetic photons on these tumours.

METHODS

A total absorbed dose of 20 Gy was applied to a total of 51 symptomatic eyes: 36 with a circumscribed CH of the posterior pole and 15 with diffuse CH as part of the Sturge-Weber syndrome. The indication for treatment was an exudative retinal detachment including or threatening the fovea. The mean follow up times in each group were 4.5 and 5.3 years, respectively. Out of a group of 33 patients from whom reliable data could be derived, 17 had symptoms lasting longer than 6 months.

RESULTS

In 23 cases (63.8%) with circumscribed CH complete resolution of the subretinal fluid was achieved; the remaining 13 cases (36.2%) showed residual serous detachment distant to the fovea. The visual acuity improved by two or more lines in 14 cases (38.9%), remained stable in 14 cases (38.9%), and decreased in eight cases (22.2%). The functional success was dependent on the lag duration between onset of first subjective symptoms and treatment. The morphological results with diffuse CH were similar to those of the group of circumscribed CH. The visual acuity (VA) at last examination was improved in seven cases (46.6%); in the remaining eight cases, VA was unchanged or had deteriorated. The poor functional outcome in the latter was mainly attributable to secondary glaucoma.

CONCLUSION

External beam irradiation is a useful and a low invasive therapeutic option for CH. A successful functional outcome is dependent on the time delay between first onset of symptoms and the beginning of therapy, the formation of subretinal fibrosis, and also on secondary glaucoma in the case of Sturge-Weber syndrome.

New and recurrent tumors in germinal retinoblastoma: is there a treatment effect?

Patients with germinal retinoblastoma (those with bilateral disease or positive family history) have a mutation which puts them at risk for developing new tumors. It is unclear whether the frequency of new tumor development is effected by the type of treatment employed. It may be hypothesized that external beam radiation "sterilizes' the whole retina, and thus decreases the risk of new and recurrent tumors. We reviewed our experience with 66 eyes in 47 patients over the past ten years. We did not find a significant difference in the incidence of new and recurrent retinoblastoma among eyes treated with external beam radiation versus focal modalities.

External beam radiation for retinoblastoma: results, patterns of failure, and a proposal for treatment guidelines

PURPOSE

To analyze treatment results and patterns of failure following external beam radiation for retinoblastoma and propose treatment guidelines according to specific clinical variables.

METHODS AND MATERIALS

We analyzed 27 patients (34 eyes) with retinoblastoma who received external beam radiation as initial treatment at Hahnemann University Hospital from October 1980 to December 1991 and have been followed for at least 1 year. Of the 34 eyes, 14 were Groups I-II (Reese-Ellsworth classification), 7 were Group III, and 13 were Groups IV-V. Doses ranged from 34.5-49.5 Gy (mean 44.3 Gy, median 45 Gy) in 1.5-2.0 Gy fractions generally delivered through anterior and lateral wedged pair fields.

RESULTS

At a mean follow up of 35.2 months (range 12-93 months), local tumor control was obtained in 44% (15 out of 34) of eyes with external beam radiation alone. Salvage therapy (plaque brachytherapy, cryotherapy, and/or photocoagulation) controlled an additional 10 eyes (29.5%), so that overall ocular survival has been 73.5%. Local tumor control with external beam radiotherapy alone was obtained in 78.5% (11 out of 14) of eyes in Groups I-II, but in only 20% (4 out of 20) of eyes in Groups III-V. A total of 67 existing tumors were identified prior to treatment in the 34 treated eyes and local control with external beam radiation alone was obtained in 87% (46 out of 53) of tumors measuring 15 mm or less and in 50% (7 out of 14) of tumors measuring more than 15 mm. When analyzing patterns of failure in the 19 eyes that relapsed, a total of 28 failure sites were identified and consisted of progression of vitreous seeds in seven instances (25% of failure sites) recurrences from previously existing tumors in 10 instances (36% of failure sites) and development of new tumors in previously uninvolved retina in 11 instances (39% of failure sites).

CONCLUSIONS

1) We find that external beam radiation to a dose of 45 Gy in fractions of 1.5 to 2.0 Gy provides adequate tumor control in retinoblastoma eyes Groups I-II (Reese-Ellsworth classification) or tumors measuring 15 mm in diameter or less. Eyes in more advanced group staging or containing tumors larger than the 15 mm seem to require higher radiation doses. We propose treatment guidelines for external beam radiation of retinoblastoma that specifically take into account the important clinical variables of tumor stage and patient age. 2) External beam radiation does not prevent the appearance of new tumors in clinically uninvolved retina. Therefore, the traditional belief that external beam radiation can treat the retina "prophylactically" should be seriously questioned. Due to this finding and their significant less morbidity, focal treatment modalities (plaque brachytherapy, photocoagulation, and/or cryotherapy), when clinically feasible, should be considered the treatment of choice for intraocular retinoblastoma. External beam radiation should be considered only when focal treatment modalities are not clinically indicated.

External beam radiotherapy for retinoblastoma: II. Lens sparing technique

A retrospective analysis is presented of the results of external beam radiotherapy for retinoblastoma utilising an accurate lens sparing technique. Local tumour control has been assessed in a consecutive series of 67 eyes in 53 children all of whom received external beam radiotherapy as the primary treatment of retinoblastoma. Follow up ranged from 12 to 82 months (median 35 months) with 76% of the children followed for more than 2 years. Tumour control rates have been analysed with respect to the Reese-Ellsworth classification. The role of adjuvant and salvage focal therapy is emphasised. Following lens sparing radiotherapy with prior adjuvant treatment of anterior tumours, where appropriate, the overall ocular cure rate was 72%. With salvage therapy of persistent, recurrent, or new tumours, 93% of eyes could be preserved in this series which includes mainly eyes classified in Reese-Ellsworth groups I-III. These results compare favourably with those of whole eye external beam radiotherapy for comparable tumours, and with those of lens and anterior segment sparing using other techniques. They were achieved without the ocular morbidity associated with whole eye external beam radiotherapy.

Plaque radiotherapy in the management of retinoblastoma. Use as a primary and secondary treatment

BACKGROUND

Radioactive episcleral plaque brachytherapy is a treatment method for selected retinoblastomas. The authors have used this technique since 1976 as both a primary and a secondary treatment method after other methods failed to achieve tumor control.

METHODS

A review of the records of 400 consecutive children with retinoblastoma showed that solitary plaque radiotherapy was used as a method of management in 103 cases. The authors' overall experience was evaluated, and the results between primary and secondary plaque therapies were compared in these 103 cases.

RESULTS

Of the 103 tumors, the mean basal diameter was 7 mm, and the mean thickness was 4 mm. Overlying vitreous seeds were clinically apparent in 50 cases (48%). The mean proximity of the tumor margin to the optic disc margin was 6 mm and to the foveola was 6 mm. The mean follow-up period was 40 months. In 89 cases (86%), the tumor was controlled by one plaque application, whereas in 13 cases (13%), tumor recurrence after initial tumor shrinkage necessitated subsequent treatment. Final visual outcome was good in 63 cases (62%), poor in 30 (29%), enucleation in 9 (9%), and unknown in 1 case. The poor vision was due to foveal retinoblastoma (with or without amblyopia) in 25 cases (83%). Eight of the nine enucleated eyes were treated initially with external beam radiotherapy then later with plaque radiotherapy. In 31 cases (30%), plaque radiotherapy was used as a primary treatment to the tumor, while in 72 cases (70%), it was a secondary form of management after failure of other methods to control the tumor. Statistical analysis showed that tumors treated with plaque radiotherapy as a primary measure were more likely to be larger in in base (P = 0.01) and thickness (P = 0.01) than secondary treated tumors. The secondary treated retinoblastomas were more likely to have vitreous seeds (P = 0.02) than the primary treated tumors. The rate of tumor control and patient survival was similar between the two groups.

CONCLUSION

Plaque radiotherapy is very effective in treating selected retinoblastomas with a high rate of tumor control and patient survival. It can be used successfully as a primary or a secondary treatment for tumors that have not been adequately controlled by other therapeutic methods.