Craniospinal irradiation for trilateral retinoblastoma following ocular irradiation

A case study is presented. Craniospinal radiotherapy and a three-fold pineal boost for trilateral retinoblastoma were delivered to a patient previously irradiated for ocular retinoblastoma. The availability of CT-based three-dimensional treatment planning provided the capability of identifying the previously irradiated volume as a three-dimensional anatomic structure and of designing a highly customized set of treatment beams that minimized reirradiation of that volume.

Seed strength determination for eye plaque therapy

Standardized radioactive plaques have been used in the irradiation of intraocular tumors. These plaques have defined slots to accommodate 125I seeds and hence produce predictable isodose distributions. The seed strength has to be adjusted to deliver 100 Gy to the prescription point, which varies with the tumor size. The purpose of this work is to develop lookup tables that relate the seed strength to different prescription distances. Dose rates were determined for a set of standardized eye plaques. Using these dose rates and the source strength decaying expression, the seed strengths were determined as a function of distance along a line through the plaque. Two seed-strength tables were created based on four-day and five-day treatment times delivering a 100 Gy to the prescription distance.

Multiagent chemotherapy in the salvage cure of ocular lymphoma relapsing after radiotherapy

The eye has traditionally been regarded as a sanctuary site for drugs, but recent publications have shown evidence of penetration by drugs and subsequent clinical response of intraocular lymphomas. In this report, a chemotherapy regimen, including high dose methotrexate and cytosine arabinoside, was used to re-induce remission in a patient with intraocular lymphoma relapsing locally after prior radiotherapy. She remains disease free 18 months later.

Relationship of regression pattern to recurrence in retinoblastoma

A retrospective analysis has been conducted of regression patterns following treatment of retinoblastoma by external beam irradiation. There were 180 tumours in 105 eyes of 83 patients. Type I regression was found to be the commonest pattern and occurred in 50% of cases. Initial tumour size was found to be the only statistically significant determinant of regression pattern (p < 0.01). Thirteen tumours (7%) recurred within a median interval to recurrence of 12 months. All recurrences occurred within 40 months of completion of treatment and none occurred after age 4 years. No tumour less than 6 mm in diameter recurred. Although 10 out of 13 recurrences were of Type I, Cox model regression analysis showed initial tumour size to be the only independent predictor of recurrence (p < 0.01).

Radioimmunodetection and radioimmunotherapy of malignant melanoma. A review

Radioimmunodetection utilizing monoclonal antibodies to various melanoma-associated surface antigens has been studied by several investigators during the past ten years. In the early trials, antibodies were labeled with 131I or 111In, but now 99mTc is almost exclusively used because of its more favorable energy for gamma camera imaging. Excellent specificity has been achieved in most studies, whereas sensitivity has been less good. In a recent European multicenter study on 493 patients sensitivity was 79% and specificity 96%. In this largest study on melanoma so far performed many previously unknown metastatic deposits were identified indicating that radioimmunodetection has a role in the management of metastatic disease. The clinical utility of immunoscintigraphy in localization of regional lymph node metastases has been documented in several investigations in recent years, indicating that this method can be used in the preoperative evaluation of patients. Radioimmunodetection has also been successfully used in the differential diagnosis of ocular lesions. However, conclusive evidence of improved patient outcome resulting from the earlier detection of melanoma lesions by immunoscintigraphy is still lacking. Anti-melanoma antibodies labeled with alpha- and beta-emitting isotopes are potential therapeutic agents, but so far there is little clinical experience with radioimmunotherapy of metastatic melanoma.

125I embedded in an orbital prosthesis for retreatment of recurrent retinoblastoma

The application of radiation therapy in the retreatment of unilateral recurrent retinoblastoma presents a very difficult dilemma in which consideration must be given to preservation of vision in the remaining eye while tumoricidal doses of irradiation are delivered. A technique is described in which a methylmetraculate eye sphere carrying a single Iodine-125 seed was used to deliver local irradiation to the orbital tissues in a patient with multiple episodes of recurrent retinoblastoma. The tissue dose at 2 mm depth was 2630 cGy while the dose to the retina of the remaining eye and to the optic chiasm was negligible.

[Leopard spot chorioretinopathy. Initial manifestation of recurrent acute lymphocytic leukemia]

An 11-year-old girl with a history of acute lymphocytic leukemia of the central nervous system had attained complete remission for almost 3 1/2 years after combination chemotherapy and radiotherapy when she developed iritis and chorioretinopathy of the right eye. Neither an anterior chamber tap nor a diagnostic vitrectomy revealed leukemic cells. Both nonspecific anti-inflammatory therapy and antiviral treatment were unsuccessful. Finally, lymphoblasts were detected in the cerebrospinal fluid and in the bone marrow after repeated lumbar puncture and bone marrow aspiration. Combination chemotherapy alone was resumed, resulting in the resolution of all acute ocular symptoms and bone marrow involvement. Only the leopard-spot-like pigmentary fundus changes persisted. The child has now remained in continuous complete remission for 1 1/2 years.

Critical analysis of methods of reconstruction of exenterated orbits

Reconstructive procedures were used on 14 patients who had undergone orbital exenteration and radiotherapy for malignant tumours. All patients were tumour free after a follow-up of between 5 and 18 years. Reconstruction was carried out in 3 stages. In the first operation the orbit was filled, in the second the orbital rims and eyelids were shaped, and in the third a cavity for a static eye prosthesis was created. Critical assessment of results showed that the first stage alone produced a marked improvement in appearance and occluded existing fistulae. The subsequent procedures improved aesthetic results further. Difficulties were encountered from retraction of the tissues and insufficient tissue mobility.

Sinonasal small cell neoplasm developing after radiation therapy for retinoblastoma: an immunohistologic, ultrastructural, and cytogenetic study

Patients with retinoblastoma have an increased risk of developing second primary tumors. Only a few examples of sinonasal small cell neoplasms developing after radiation therapy for retinoblastoma have been reported. We report one such case that developed 18 years after treatment for retinoblastoma. Histologic examination revealed a small, blue, round cell tumor without rosettes or cytoplasmic glycogen. Immunohistochemically, the tumor cells were positive for neuron-specific enolase, synaptophysin, and S-100 protein, but negative for epithelial and mesenchymal markers, suggesting that this was a primitive neuroectodermal tumor. Cytogenetic studies of this tumor failed to reveal the chromosome 13 abnormality typical of retinoblastoma and the t(11:22) translocation typical of the group of peripheral neuroepitheliomas.

Skin injury in an infant with pulse oximetry

An 11-month-old girl received 23 propofol anaesthetics for radiation treatment of a retinoblastoma. After the first two anaesthetics, a skin injury appeared on the pulp of the toes, where the light source of a pulse oximeter probe had been placed. During the remaining 21 anaesthetics the light source of the probe was placed over the nails, and no other skin lesions occurred. Examination of the equipment revealed no malfunction. Thermal and other possible causes of the skin injury are discussed.

Sinonasal primitive neuroectodermal tumor arising in a long-term survivor of heritable unilateral retinoblastoma

BACKGROUND

Patients who survive retinoblastoma (RB) are at risk for having second nonocular tumors, usually osteosarcomas, which often are fatal. Such patients almost always have bilateral RB.

METHODS

This article reports a woman who, at the age of 1 year had been cured of a unilateral RB by radiation therapy and enucleation. Eighteen years later, she had a sinonasal small cell tumor that rapidly recurred and proved fatal 2 months after surgical debulking. The tumor was studied by immunohistochemistry and electron microscopic (EM) examination.

RESULTS

It showed diffuse neuron-specific enolase staining, focal weak staining for chromogranin, synaptophysin, and Leu-7 monoclonal antibodies in paraffin-embedded, B5-fixed tissue (Great Lakes Diagnostics, Troy, MI). EM study showed an undifferentiated primitive neuroectodermal tumor with many polyribosomes, simple cell junctions, few microtubules, and rare dense core granules.

CONCLUSIONS

The combined immunohistochemical, ultrastructural, and clinical features of the tumor were interpreted as a sinonasal primitive neuroectodermal tumor with early neuronal differentiation. The tumor was pathologically indistinguishable from poorly differentiated olfactory neuroblastoma (ONB) and Ewing sarcoma.

Successful therapy for trilateral retinoblastoma

Trilateral retinoblastoma, the intracranial malignancy associated with bilateral retinoblastoma, is an uncommon and clinically aggressive malignancy with a uniformly fatal outcome. Three children with newly diagnosed trilateral retinoblastoma were treated with systemic (cyclophosphamide and vincristine) and intrathecal (methotrexate, hydrocortisone, and cytarabine) chemotherapy, as well as craniospinal irradiation (one patient) in addition to therapy of the eye lesions. All three patients have had partial or complete response of the pineal tumors to chemotherapy, with no active disease eight or more years, 33 or more months, and 12 or more months, respectively, after diagnosis of the lesions.

[Radiation management of retinoblastoma]

Forty-five patients with retinoblastoma were treated at Keio University Hospital from 1970 to 1990. Thirty-two patients had unilateral lesions and 13 had bilateral lesions. Twenty-nine patients with unilateral and 12 with bilateral lesions underwent enucleation for advanced tumor. As a result, 3 patients with unilateral retinoblastoma and all patients with bilateral disease were treated with radiotherapy (40-50 Gy) combined with or without cryotherapy and/or photocoagulation. One patient with unilateral lesion treated with radiotherapy and chemotherapy had metastases at the first visit to our clinic and was excluded from this analysis. Among 16 eyes (15 patients) treated with radiotherapy, 6 eyes had recurrence and needed retreatment. Cataract occurred in 6 of 12 eyes and good vision was preserved in 5 of 10 eyes in which function could be evaluated.

[Treatment of eye tumors by accelerated proton beams. 7 years experience]

The therapeutic results of 1070 cases of intraocular tumors treated with an accelerated proton beam at the University Eye Clinic of Lausanne and at the Paul Scherrer Institute of Villigen are analysed. This total is composed of 981 cases of uveal melanomas treated by proton beam as first treatment modality, 42 cases of recurrent choroidal melanomas, 16 cases of conjunctival melanomas, 8 cases of choroidal hemangiomas, 18 cases of uveal metastases and of 5 other ocular tumors. The mortality rate at 5 years for tumors treated with an accelerated proton beam as first treatment modality was 13%, and the mortality rate of recurrent melanomas was 23%. The risk factor for life expectancy analysed with the Cox model pointed out that the largest tumor diameter, the width of the tumor, the presence of an extrocular extension and the age of the patient were the most significant parameters. The conclusions of this study are compared with those found in available literature.

Visual acuity after successful treatment of large macular retinoblastoma

Recent trends in the treatment of retinoblastoma have favored radiation therapy as opposed to enucleation. A major determining factor in selecting radiation therapy is the possibility of useful posttreatment visual function. While the treatment of nonmacular tumors seems reasonable, little information is available about the posttreatment visual outcome of large posterior pole tumors. We treated 17 patients (20 eyes) with group III-V retinoblastoma and large posterior pole tumors with external beam radiation. Visual acuity after treatment ranged from 5/200 to 20/50. Potential posttreatment visual function was difficult to predict using such pretreatment factors as age at diagnosis, funduscopic appearance, and the number, size, and location of the tumors. Surprising visual function was obtained in some patients with multiple large macular tumors. Follow up ranged from 1 to 8 years. No patient developed metastatic disease; however, four patients required subsequent cataract extraction. This study supports the consideration of radiation therapy as the primary treatment in eyes previously felt to have a poor visual outcome.

Boron neutron capture therapy of anterior chamber melanoma with p-boronophenylalanine

Boron neutron capture therapy (BNCT) is a form of radiation therapy that requires selective uptake of boron by the tumor and irradiation with thermal neutrons. Phenylalanine is an amino acid precursor of melanin and when boronated (p-boronophenylalanine [BPA]) was found to be selectively taken up by Greene melanoma cells in the anterior chamber of rabbits. This tumor model was irradiated 24 hr after oral administration of BPA and was used for biodistribution studies that compared BPA and sodium pentaborate. Three groups were irradiated: group 1 (11 rabbits) received BPA followed by thermal neutron irradiation, group 2 (9 rabbits) received thermal neutron irradiation only, and group 3 (9 rabbits) served as unirradiated, undrugged control animals. Eight of the 11 tumors in group 1 were treated successfully; all tumors in groups 2 and 3 grew. Histopathologic examination did not reveal vascular or retina damage in group 1. These preliminary experiments confirm that newer boronated compounds, such as BPA, used in BNCT and improved neutron beams can provide selective irradiation of ocular melanomas.

Optimal electron-beam treatment planning for retinoblastoma using a new three-dimensional Monte Carlo-based treatment planning system

Electron-beam treatment planning for retinoblastoma was investigated and an optimal treatment plan was devised for a particular case using a new three-dimensional Monte Carlo-based treatment planning system known to be capable of correctly predicting dose perturbations caused by body surface obliquities and tissue heterogeneities. Computed tomography (CT) data files were used to construct a three-dimensional eye phantom representing the anatomy of a child's orbit. Dose distributions in sagittal, transverse, and coronal planes were predicted with 1-mm resolution. Study of these distributions led to an optimal treatment plan consisting of an anterior-lateral pair, with the anterior field being a 10-MeV, 30-mm-diam circular field, centrally blocked by a 10-mm-diam lucite lens shield and the lateral field being a 16-MeV, 30 x 25-mm D-shaped field. The anterior field delivers a therapeutic dose to the ora serrata, but it underdoses the posterior retinal surface behind the lens shield; the lateral field provides the necessary boost dose to the posterior retinal surface. An equally weighted combination of the two fields produces a dose distribution in which the entire retinal surface receives a therapeutic dose, with less than 10% of that dose being delivered to the lens, brain, and the contralateral orbit.

An interactive beam-weight optimization tool for three-dimensional radiotherapy treatment planning

A computer software tool has been developed to aid the treatment planner in selecting beam weights for three-dimensional radiotherapy treatment planning. The program consists of a feasibility search algorithm embedded in an interactive, user-friendly driving program. The feasibility search algorithm is based on the iterative relaxation algorithm of Cimmino [La Ricerca Scientifica, Vol. I, pp. 326-333 (1938)] as applied to the radiotherapy inverse problem by Altschuler et al. [Med. Phys. 13, 590 (1986)]. Relative importances of structures based upon clinical considerations can be incorporated into the algorithm. In order to speed convergence, the relaxation parameter is made to vary, with its value based upon a measure of deviation from feasibility. The interactive driving program is designed so that the treatment planner can make reasonable judgments regarding the acceptability of a plan in the event that the dose constraints yield no feasible solution. An example of the use of this program applied to a problem in three-dimensional radiotherapy treatment planning is illustrated.