Lens-sparing Technique Research Articles

Long-Term Follow-Up of Patients with Conjunctival Lymphoma after Individualized Lens-Sparing Electron Radiotherapy: Results from a Longitudinal Study.

Irradiation with electrons is the primary treatment regime for localized conjunctival low-grade lymphomas. However, radiation-induced cataracts are a major cause of treatment-related morbidity. This study investigates whether lens-sparing electron irradiation produces sufficient disease control rates while preventing cataract formation. All consecutive patients with strictly conjunctival, low-grade Ann Arbor stage IE lymphoma treated with superficial electron irradiation between 1999 and 2021 at our department were reviewed. A total of 56 patients with 65 treated eyes were enrolled with a median follow-up of 65 months. The median dose was 30.96 Gy. A lens-spearing technique featuring a hanging rod blocking the central beam axis was used in 89.2% of all cases. Cumulative incidences of 5- and 10-year infield recurrences were 4.3% and 14.6%, incidences of 5- and 10-year outfield progression were 10.4% and 13.4%. We used patients with involvement of retroorbital structures treated with whole-orbit photon irradiation without lens protection-of which we reported in a previous study-as a control group. The cumulative cataract incidence for patients treated with electrons and lens protection was significantly lower (p = 0.005) when compared to patients irradiated without lens protection. Thus, electrons are an effective treatment option for conjunctival low-grade lymphomas. The presented lens-sparing technique effectively prevents cataract formation.

Comparing Incidence of Cataract Formation in Lens-Sparing Versus Whole-Eye Irradiation in Patients with Retinoblastoma

Retinoblastoma is the most common intraocular tumor in children with an incidence of about 300 cases per year. Thanks to treatment advances, the prognosis for retinoblastoma patients is excellent with a five-year overall survival rate of 95%. However, previous work has suggested that radiotherapy for patients with retinoblastoma results in a high risk of developing cataracts. Based on each patient’s individual stage at presentation, treatment plans were developed to either irradiate the whole eye or a smaller volume that excluded the lens. In this study, we investigated whether lens-sparing IMRT treatment plans resulted in a significantly lower incidence of post-radiation cataracts when compared to the whole-eye radiation treatment plans. We conducted a retrospective analysis of 66 patients (74 eyes) treated for retinoblastoma with IMRT at our institution from 1999-2015. Of these 66 patients, 7 patients were lost to follow-up, 1 patient died before meeting the 1-year minimum requirement of follow-up, and 2 patients received orbit radiation after bilateral enucleation. A total of 56 patients (35 males, 21 females) were included in our results. Two eyes were excluded for having cataracts prior to treatment and one orbit was excluded for receiving radiation after enucleation. Of the remaining 71 eyes, 57 eyes received whole-eye irradiation and 14 were treated with lens-sparing IMRT. Treatment groups did not differ significantly by age or sex but the whole-eye group had higher stage disease (p < .001). All patients were examined by ophthalmologists at our institution. We recorded the incidence of cataracts and enucleation post radiotherapy. Cataract incidence was reported as “cataract-free eye survival” and the percentage of eyes not enucleated was reported as “globe salvage rate”. Cataract-free eye survival was estimated as Kaplan-Meier survival curves. Five-year cataract-free eye survival was significantly higher (p < .001) for eyes treated with a lens-sparing approach (64.5%) than those treated with whole-eye irradiation (11.6%). There was no significant difference in 5-year globe salvage rates, which were 45/57 (78.9%) for whole-eye and 13/14 (92.9%) for lens-sparing patients. There was a significant difference (p = 0.005) in mean lens dose received by eyes that developed cataracts (33.8 Gy) versus eyes that remained cataract-free (21.7 Gy). Median follow-up time was 4 years for eyes that remained cataract-free. Patients treated with a lens-sparing technique were less likely to develop cataracts than patients treated with whole-eye irradiation. We did not find any difference in globe salvage rates between the two techniques. These findings suggest that a lens-sparing approach may reduce late effects compared to whole-eye irradiation for treatment of carefully selected cases of retinoblastoma. Whole-eye irradiation is recommended for advanced stages of disease complicated by retinal detachment or extensive vitreous seeding.

Special considerations for pediatric vitreoretinal surgery.

In this review, the authors present special considerations a vitreoretinal surgeon should take into account before embarking on surgery in a pediatric eye. First, the anatomy of a pediatric eye is different from an adult and changes as the child grows. This is important especially in relation to the placement of transconjunctival ports. The structural characteristics of the sclera are also different, with lower scleral rigidity found in pediatric eyes. When considering vitrectomy, a posterior pars plicata lens-sparing technique should be considered. However, this may not be possible in complicated total detachments where anterior translimbal vitrectomy may be the method of choice. Scleral buckles are preferred for certain cases, and division of the encirclage is advocated in children below the age of 2 years, once the retina has stabilized. Enzymatic vitreolysis has been described as a preoperative adjunct to enhance complete detachment of the posterior hyaloid and reduce iatrogenic retinal breaks. However, its use in pediatric eyes has been limited, and larger studies are warranted. Finally, postoperative visual rehabilitation and treatment of amblyopia are key to maximizing functional outcomes in the pediatric patient. Co-management with a pediatric ophthalmologist and enlisting the co-operation of the parents are essential.

Outcomes of Primary Lymphoma of the Ocular Adnexa (Orbital Lymphoma) Treated with Radiotherapy

AimsLow-grade ocular adnexal lymphoma is a rare disease and often treated with local radiotherapy to varying doses. Most previously reported studies have a very heterogeneous patient population and treatments. We report the outcomes from a 10 year cohort of patients at our institution treated with primary radiation therapy. Materials and methodsWe analysed a retrospective case series of patients with stage IE low-grade ocular adnexal lymphoma including a review of case notes, histological reports and radiotherapy charts. We assessed local and distant tumour control and relapse rates in addition to toxicity. Disease-free survival was estimated using the Kaplan–Meier method. ResultsIn total, 81 patients and 85 orbits were treated with primary radiotherapy to a median dose of 30 Gy in 15 fractions over 3 weeks. Seventy-nine per cent were treated with standard MV external beam radiotherapy to the whole orbit and 21% with a lens-sparing technique. The median follow-up was 4.4 years (range 0.2–10.4). Local control rates were 100%, with 5% of patients experiencing disease relapse elsewhere. No patients died from lymphoma. Cumulative acute toxicity rates were 51% (mainly erythema and conjunctivitis) and late toxicity rates were 8% (mainly cataract). The lens-sparing technique was associated with a significant reduction in cataract rate (P = 0.013) and an increase in acute toxicity (P < 0.001). ConclusionsThis study has shown excellent local control rates and acceptable toxicity from the treatment of stage IE low-grade ocular adnexal lymphoma with localised radiotherapy to a median dose of 30 Gy in 15 fractions over 3 weeks.

Lens sparing technique using multi‐leaf collimators in irradiation of the unilateral retro‐orbital space for benign disease

AbstractThe authors present a case of a 30‐year old woman with pseudolymphoma of the left medial rectus muscle. A multi‐field technique was planned for irradiating the unilateral retro‐orbital space to 20 Gray (GY) in 15 fractions while keeping the average dose to the lens of 8 Gy and the peak dose to the lens of 11 Gy using multi‐leaf collimators is described.

Curative radiotherapy for primary orbital lymphoma

Purpose : To review our institutional experience with primary orbital lymphoma and determine the prognostic factors for survival, local control, and distant metastases. In addition, we also analyzed the risk factors for complications in the radiotherapeutic management of this tumor. Methods and Materials : Between 1973 and 1998, 47 patients (29 women [62%] and 18 men [38%], median age 69 years, range 32–89) with Stage IAE orbital lymphoma were treated with curative intent at one department. Five had bilateral orbital involvement. The tumor was located in the eyelid and extraocular muscles in 23 (44%), conjunctiva in 17 (33%), and lacrimal apparatus in 12 (23%). The histologic features according to the World Heath Organization classification of lymphoid neoplasms was follicular lymphoma in 25, extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue type in 8, diffuse large B-cell lymphoma in 12, mantle cell lymphoma in 6, and peripheral T-cell lymphoma in 1. For the purposes of comparison with the existing literature on orbital lymphomas, the grading system according to the Working Formulation was also recorded. The histologic grade was low in 33 (63%), intermediate in 18 (35%), and high in 1 (2%). All patients were treated with primary radiotherapy alone. The median dose for low-grade tumors was 3000 cGy (range 2000–4020); the median dose for intermediate and high-grade tumors was 4000 cGy (range 3000–5100). A lens-sparing approach was used in 19 patients (37%). Late complications for the lens and cornea were scored according to the subjective, objective, management, and analytic (SOMA) scale of the Late Effects of Normal Tissue (LENT) scoring system. The median follow-up was 55 months (range 6–232). Results : The local control rate was 100% in the 52 orbits treated. The 5-year overall survival and relapse-free survival rate was 73.6% and 65.5%, respectively. Tumor grade and location did not predict for overall survival or relapse-free survival. Seven patients (15%) developed distant recurrence (brain 2, extremity 2, mediastinum 1, liver 1, and retroperitoneum 1). One patient (2%) developed cervical node metastasis. The 5- and 10-year cataract-free survival rate was 56.7% and 32.9%, respectively. Of the 12 lens complications, 8 were LENT Grade 1 and 4 were Grade 3 toxicity. Only male gender predicted for an increased risk of cataract formation. Radiotherapy dose and technique did not predict for cataract formation; however, none of the patients who underwent the lens-sparing technique developed Grade 3 lens toxicity or required surgical correction. Of the nine corneal events, two were Grade 1, four Grade 2, and three were Grade 3 toxicity. Ten dry eyes were recorded; all were mild, and no patient had severe dry eye syndrome. Neovascular glaucoma was seen in 1 patient. No injury to the retina or optic nerve was reported. Conclusion : Radiotherapy alone is a highly effective modality in the curative management of primary orbital lymphoma. Most complications were minimal and did not require medical or surgical intervention. Although the use of the lens-sparing technique did not influence the incidence of cataractogenesis, we continue to recommend this approach whenever possible, because our experience indicates a higher grade of toxicity occurs and a higher incidence of corrective surgery is needed in patients treated without lens protection.

Curative radiation therapy for primary orbital lymphoma

Purpose: To review our institutional experience with primary orbital lymphoma and determine prognostic factors for survival, local control and distant metastases. In addition, we also analyzed the risk factors for complications in the radiotherapeutic management of this tumor. Materials and Methods: Tumor registry records of 91 patients (pts) with orbital lymphoma from 1973 to 1998 treated at one institution were reviewed. Pts were excluded from the study if they had pseudolymphoma, intraocular lymphoma, metastases to the orbit, palliative radiation therapy or follow-up of less than 6 months. A total of 47 pts with primary orbital lymphoma were treated for cure with radiation therapy. There were 18 males and 29 females with a median age of 69 years (range, 32 to 89 years). Four pts had bilateral involvement. Tumor was located in the eyelid and extraocular muscles in 58%, lacrimal gland 21% and conjunctiva in 21%. Histology was low grade in 68%, intermediate in 30% and high grade in 2%. All pts were stage IAE. Median dose for low grade tumors was 3000 cGy with a range of 2000 – 4020 cGy, while the median dose for intermediate and high grade tumors was 4140 cGy with a range of 3000 – 5100 cGy. Fraction size was 200 cGy in 32 pts, 180 cGy in 14 pts and 170 cGy in 1 patient. Beam energy was 4 MV photons in 62%, 6 MV in 13%, 1.25 MV in 8% and orthovoltage in 2%. Electrons were used in 9% of pts. A single anterior field was employed in 32% pts; the remaining pts were treated with a two field technique that included an anterior and an oblique field or two oblique fields. Pts with bilateral involvement were treated with two lateral fields. Lens sparing technique was used in 34% of pts. None of the pts received chemotherapy for initial management of the tumor. Median follow-up time was 55 months (range 6 to 232 months). Log rank analysis was performed to determine the factors which influenced overall survival and distant metastases. Multivariate logistic regression analysis was employed to determine risk factors for cataract formation and corneal injury. Lens and corneal complications were graded according to objective portion of the SOMA scale of the Late Effects of Normal Tissue (LENT) Scoring System. Results: Local control was 100% in the 51 orbits treated. The overall survival at 5 years was 73.6%. Tumor grade and location within the orbit had no prognostic significance for overall survival or distant metastases. Seven pts developed distant metastases. Sites of metastases included mediastinum, abdomen, extremity and CNS. Cataracts were LENT grade 1 in 8 and grade 2 / 3 in 4 pts. Corneal toxicity was LENT grade 1 in 17 and grade 3 in 1 patient. All pts who had corrective surgery had grade 2 or 3 complications. On multivariate analysis, only male gender predicted for increased risk of cataract formation. Age, radiation dose, fraction size, steroid use and lens sparing technique did not affect the rate of complications. None of the pts who had a lens block had a grade 2 or 3 complication or required surgical correction. Conclusion: Radiation therapy alone is a highly effective modality in the curative management of primary non-Hodgkin’s lymphoma of the orbit. Excellent local control is achievable with radiation doses of 3000 cGy in low-grade and 4000 cGy in intermediate/high grade tumors using conventional fractionation. Although the use of lens sparing technique did not influence cataractogenesis, we continue to recommend lens blocks whenever possible because our experience indicates a higher grade of toxicity and corrective surgery in pts treated without lens sparing technique.

A stereotactic radiation therapy device for retinoblastoma using a noncircular collimator and intensity filter.

The proximity of the lens to the retina makes the treatment of retinoblastoma a challenge for external beam radiation therapy. The approximately 1 mm separation between the posterior edge of the lens and the anterior region of the retina causes a trade-off between coverage of the entire retina and excessive dose to the lens. A stereotactic, LINAC based, lens sparing technique for treating retinoblastoma is presented. The technique uses noncoplanar arcs with the lens at isocenter. A special noncircular collimator blocks the lens but it also causes the dose distribution to vary across the retina. A fluence modulation filter is used to reduce the dose inhomogeneity across the target. The resulting dose distribution is roughly hemispheric, providing both anterior coverage of the retina and lens blocking unlike conventional techniques. The method used to develop the collimator and filter assembly is presented. Dosimetry of the assembly was carried out using radiochromic film, and the results were entered in a treatment planning system. The dose distribution as measured in a phantom is provided and compared to calculations.

Choroidal neovascular membranes: treatment with reirradiation.

To evaluate re-treatment with an additional course of low-dose irradiation in patients with progressive or recurrent choroidal neovascular membranes (CNVMs). Ten patients who had received 14 Gy of external-beam radiation therapy in seven fractions for subfoveal CNVMs were found to have recurrent or persistent neovascularization at follow-up. They received an additional 15 Gy of radiation therapy administered in five daily fractions with a standard lens-sparing technique. Before reirradiation, visual acuity ranged from 20/80 to counting fingers. The median time between radiation courses was 6.5 months (range, 2-16 months). After re-treatment, the patients were followed up with angiography and visual field testing. The median follow-up was 18.5 months (range, 12-21 months). Eight of 10 patients (80%) maintained their visual acuity at 1 year and three of seven (43%) at 18 months. Visual acuity was stabilized in five of the 10 patients at their last follow-up. No acute or late side effects of irradiation were noted. Additional radiation therapy in selected patients with CNVMs who have failed to benefit from previous irradiation is well tolerated and appears to stabilize the disease process in a substantial proportion of these patients.

Radiotherapy of choroidal metastases

Purpose: This retrospective study was undertaken to clarify the role of high energy external beam radiation therapy (EBRT) and to determine its safety and efficacy on local control and visual acuity in patients suffering from choroidal metastases (CM). Materials and methods: The records of 58 consecutive patients treated with EBRT between 1970 and 1993 were analyzed. The female to male ratio was 2.9 and the median age was 59 years (range 40–81 years). Thirty-six patients (62%) had unilateral CM and 22 patients had bilateral CM. The mean number of lesions per eye was two. Retinal detachment was present in 65% of cases. The primary tumour (PT) was breast carcinoma for 38 patients (75%), lung carcinoma for 10 patients (17%) and gastrointestinal, genitourinary or unknown PT for the remaining 10 patients. The median interval of time between the PT and the CM was 55 months (range 0–228 months). All patients were treated with megavoltage irradiation. The median prescribed dose was 35.5 Gy (range 20–53 Gy) normalized at a 2 Gy per fraction schedule with an α/ β value of 10 Gy. Various techniques were used and whenever possible the lens was spared. Ten patients with unilateral disease were treated in both eyes. Results: The tumour response was slow. When assessed after 3 months or more, the complete response rate was 53% with significantly better results for doses higher than 35.5 Gy (72 versus 33%; P=0.009). Visual acuity was improved or stabilized in 62% of patients, with also significantly better results when doses higher than 35.5 Gy ( P=0.014) were administered. Amongst 26 patients with unilateral CM who had no elective contralateral irradiation, three developed metastasis in the opposite eye versus none of the 10 patients who had bilateral irradiation. Five complications occurred (three cataracts, one retinopathy and one glaucoma). Conclusion: Radiation therapy is an efficient and safe palliative treatment for choroidal metastases and it helps the preservation of vision. Thus, there is a major impact on the quality of life in a group of patients with an almost uniformly fatal prognosis. Both tumour response and visual acuity are significantly improved if doses higher than 35.5 Gy are administered. Whenever possible, a lens sparing technique should be used.

External Radiotherapy in Macular Degeneration: Our Technique, Dosimetric Calculation, and Preliminary Results

Purpose: This study was performed to determine the toxicity and efficacy of external-beam radiotherapy in patients with age-related subfoveal neovascularization. Methods and Materials: Between January 1996 and September 1996, 25 patients with a mean age of 70.5 (60–84) years were enrolled. All patients underwent fluorescein angiographic evaluation and documentation of their neovascular disease prior to irradiation. A total of 25 patients were treated with a total dose of 12 Gy in 6 fractions over 8 days. We used a lens-sparing technique and patients were treated with a single lateral 6-MV photon beam. To assess the risk of radiation carcinogenesis after treatment of age-related subfoveal neovascularization, we estimated the effective dose for a standard patient on the basis of tissue-weighting factors as defined by the International Commission on Radiological Protection (ICRP). The calculations were made with TLD on a male randophantom. The lens dose was found to be 0.217 Gy per fraction. Results: No significant acute morbidity was noted. Visual acuity was maintained or improved in 76% and 80% of treated patients at their 1- and 3-month follow-up examinations, respectively. On angiographic imaging, there was stabilization of subfoveal neovascular membranes in 23 patients (92%) at 3 months after irradiation. Conclusion: Our observations on these 25 patients in this study indicate that many patients will have improved or stable vision after radiotherapy treatment with low-dose irradiation.

External beam irradiation for choroid metastases: Identification of factors predisposing to long-term sequelae

Purpose : To improve overall quality of life, palliative treatments shoudl attempt to minimize associated complications while effectively controlling specific symptoms. We reviewed our experience treating posterior uveal metastases with external beam radiotherapy (EBRT) to determine the complication rate and to identify the relationship between patient, tumor, or treatment-related factors and the development of ocular complications. Methods and Materials : 483 consecutive patients (pts) (578 eyes) were diagnosied with intraocular metastatic disease from solid tumor between 1972–1995. Of these, 233 eyes (188 pts) had lesions of the posterior uveal tract and received EBRT. Median follow-up time was 5.8 months (range: 0.7–170.0 months). Follow-up information regarding the development of complication was documented for 230 eyes. Complete EBRT details were available for 189 eyes. seventy-two percent of the patients received 30.0–40.0 gy in 2.0–3.0 Gy fractions. Biologically effective dose (BED) was calculated to allow meaningful comparison between various fractionation regimens and total doses. Concurrent chemotherapy and/or hormonal therapy was used for 101 eyes (44%). Results : Median BED was 61 Gy 3 (range, 6.7–105 Gy 3), and of treated eyes received BED 50–70 Gy 3. (2%). Lens-sparing techniques were used in 136 eyes (71%). At last follow-up 28 eyes (12%) developed one or more significant complications, including cataracts (16 eyes), radiation retinopathy (6 eyes), otpic neuropathy (5 eyes), exposure keratopathy (5 eyes), and neovascularization of the iris (4 eyes). Two eyes developed narrow-angle glaucoma, and one of these required enucleation. on univariate analysis, Caucasian race (vs. Black/Hispanic, p = 0.03), increased intraocular pressure at diagnosis (>21 mmHg, p = 0.02, and diagnosis by biopsy (vs. no biopsy, p = 0.03) predisposed toward the developmetn of complications. Factors not correlated with complications included BED ( p = 0.18), energy type ( p = 0.81), lens-sparing technique (versus whole globe, p = 0.57, and concurrent systemic treatment ( p = 0.60. The small number of complications did not support a multivariate analysis. Conclusion : Despite the employment of a variety of EBRT treatment techniques and the proximity of choroidal metastases to radiosensitive structures, significant complications of pallitive EBRT were infrequent. Although complications do occur, they are realted to host factors and do not appear to be a functional of irradaition parameters. We conclude that the potential benwefits of vision and globe preservation after palliative EBRT outweigh the small risk of treatment induced complication

Treatment outcome and dose-response relationship in infants younger than 1 year treated for retinoblastoma with primary irradiation

Thirty-three infants ( < 1 year at diagnosis) were treated for retinoblastoma with primary irradiation at St. Jude Children's Research Hospital (SJCRH) between 1963 and June 1992. Staging of the 44 treated eyes was as follows: Reese-Ellsworth (R-E) Groups I (n = 20), Group II (n = 9), Group III (n = 6), Group IV (n = 2), Group V (n = 7). Irradiation was delivered using either a single anterior field (31 eyes) or lens-sparing techniques (13 eyes). Total doses ranged from 21-45 Gy (median = 36 Gy) in fractions of 150-180 cGy (n = 34) or > 180 cGy (n = 10). One child died of metastatic disease at 42 months. Three patients have developed second malignant neoplasms; two have succumbed at 88 and 125 months post-RB diagnosis; the remaining patients are alive at 6-259 months postdiagnosis (median follow-up = 127 months). Local control with irradiation alone and supplemented cryotherapy given within 2 months (n = 2) was maintained in 29 eyes, with no statistical difference seen for total doses < or = 36 Gy (21/8 eyes) vs. > 36 Gy (8/16). Of 15 eyes that required salvage therapy, tumor control has been maintained in 13. Enucleation was required for four patients, two with recurrent retinoblastoma and one with a phthisical eye. Cataract formation was documented in 23 eyes (87.5%) treated with lens-sparing techniques developed cataract. At last follow-up, 23 of 30 patients tested (77%) had visual acuity of 20/100 or better. This experience confirms early observations in that doses > or = 36 Gy do not appear to improve local control with irradiation alone in infants ( < 365 days) with retinoblastoma.

Treatment outcome and dose‐response relationship in infants younger than 1 year treated for retinoblastoma with primary irradiation

Thirty-three infants (<1 year at diagnosis) were treated for retinoblastoma with primary irradiation at St. Jude Children's Research Hospital (SJCRH) between 1963 and June 1992. Staging of the 44 treated eyes was as follows: Reese-Ellsworth (R-E) Groups I (n = 20), Group II (n = 9), Group III (n = 6), Group IV (n = 2), Group V (n = 7). Irradiation was delivered using either a single anterior field (31 eyes) or lens-sparing techniques (13 eyes). Total doses ranged from 21–45 Gy (median = 36 Gy) in fractions of 150–180 cGy (n = 34) or >180 cGy (n = 10). One child died of metastatic disease at 42 months. Three patients have developed second malignant neoplasms; two have succumbed at 88 and 125 months post-RB diagnosis; the remaining patients are alive at 6–259 months postdiagnosis (median follow-up = 127 months). Local control with irradiation alone and supplemented cryotherapy given within 2 months (n = 2) was maintained in 29 eyes, with no statistical difference seen for total doses ≤36 Gy (21/28 eyes) vs. >36 Gy (8/16). Of 15 eyes that required salvage therapy, tumor control has been maintained in 13. Enucleation was required for four patients, two with recurrent retinoblastoma and one with a massive retinal hemorrhage, one with a phthisical eye. Cataract formation was documented in 23 eyes (87.5%) treated with anterior field. Three patient treated with lens-sparing techniques developed cataract. At last follow-up, 23 of 30 patients tested (77%) had visual acuity of 20/100 or better. This experience confirms early observations in that doses ≥36 Gy do not appear to improve local control with irradiation alone in infants (<365 days) with retinoblastoma. © 1996 Wiley-Liss, Inc.

External beam radiation therapy and retinoblastoma: Long-term results in the comparison of two techniques

Purpose : This study compares the long-term actuarial local control, eye conservation rate, survival, and ocular complications in children with retinoblastoma treated with two different external beam treatment techniques. Methods and Materials : From 1979–1991, 182 eyes in 123 children (104 bilateral) received primary external beam radiation therapy. An anterior lens-sparing electron beam technique delivering 38 to 50 Gy in 2.5 Gy fractions was used in 67 eyes from 1979–1984 and a modified lateral beam technique, delivering 42 to 46 Gy in 2 Gy fractions, was used in 113 eyes from 1984–1991. These groups were balanced with respect to known prognostic variables. Results : For Group I–III eyes, the 5- and 8-year local control was significantly improved using the modified lateral beam technique (84%) compared to (38%) using the anterior lens sparing technique ( p p ≤ 0.0001). For Group IV–V eyes, the 5- and 8-year local control rates were not statistically different, despite a trend favoring the modified lateral beam technique. Survival endpoints including eye survival (no enucleation), cause-specific survival, and overall survival comparing the two treatment techniques were not significantly different. Overall, 22% of eyes developed cataracts. There was no difference between the two treatment groups in terms of cataract development. No eyes required enucleation for ocular complications. Conclusion : There is a significant improvement in local control using the modified lateral beam technique compared to an anterior lens-sparing approach for Group I–III eyes. However, there was no difference in survival end points between the two treatment techniques. The incidence of ocular complications using these two external beam techniques is acceptable.

Radiation Therapy for Subfoveal Choroidal Neovascular Membranes in Age-Related Macular Degeneration: A Pilot Study

• Background: The natural course of the visual acuity of age-related subfoveal choroidal neovascularisation (CNV) membranes is poor. Laser photocoagulation of subfoveal CNV is recommended if the patient is willing to accept a large decrease in visual acuity immediately after treatment. A large proportion of patients with subfoveal CNV do not meet the Macular Photocoagulation Study Group (MPS) guidelines for laser photocoagulation. The fact that so few patients meet these criteria makes further research into new treatment techniques warranted. Ionising radiation may prevent the proliferation of endothelial cells of newly formed subretinal capillaries and may induce obliteration of the aberrant new vessels. • Methods: In this study, the effect of radiation therapy on subfoveal CNV membranes was evaluated. Four groups of ten patients were treated with external beam radiotherapy (16-MV photons) on an area of 1 cm2 (macular region) using a lens-sparing technique and total doses of 8–24 Gy. The first group received 8 Gy in one fraction. The second, third and fourth groups received 12 Gy in 2 fractions, 18 Gy in three fractions and 24 Gy in four fractions respectively. The studied parameters included best-corrected visual acuity and membrane size and leakage on the fluorescein angiogram. we included 17 occult and 23 classic CNV membranes as defined by the MPS, with a duration of less than 5 weeks at presentation. Complete ophthalmic examination including fluorescein angiography was performed before and 3, 12 and 18 months after radiation treatment. We analysed the angiogram using a standard over-projection sheet. The results concerning the visual acuity and fluorescein angiography (FA) were compared with the extensively published, natural course data. • Results: The first group (including three cases of occult CNV) received 8 Gy in a single fraction. In this group only four of ten patients had stable visual acuity and stable FA appearance after 21 months follow-up. The visual acuity and FA remained stable after 13.6 months follow-up in seven of the patients in group 2 (12 Gy in two fractions, four occult CNV). The third group (18 Gy in three fractions, seven occult CNV) contained six patients with stable visual acuity, although two of them had CNV deterioration on the FA (11.1 months follow-up). In the last group (24 Gy in four fractions, three occult CNV), with a short follow-up of 5.6 months, eight patients had stable visual acuity and FA appearance. We did not note any regression of the CNV membrane on the angiogram. The visual acuity in groups 2, 3 and 4 decreased to 0.1 or worse in only three cases, three cases and one case respectively after at least 6 months follow-up. • Conclusion: Comparison of these findings with the natural history data of subfoveal age-related CNV suggests a beneficial effect of radiation therapy with a total dose of 12 Gy or more on the progression of CNV To date no negative side effects have been observed.

737Ophthalmic radiotherapy — Introduction and improvement of lens sparing techniques in Hungary

737Ophthalmic radiotherapy — Introduction and improvement of lens sparing techniques in Hungary

Use of Irradiation for Therapy of Retinoblastoma in Children More Than 1 Year Old: The St. Jude Children's Research Hospital Experience and Review of Literature

Fifteen children (> 1 year old at diagnosis) were treated for retinoblastoma (RB) with primary irradiation at St. Jude Children's Research Hospital between January 1963 and January 1992. Staging of the 19 treated eyes was as follows: Reese-Ellsworth (R-E) Groups I and II, n = 7; Group III, n = 3; Group IV, n = 1; Group V, n = 7; information on one globe is incomplete. Total dosage ranged from 25 to 45 Gy (median = 40 Gy) in fractions of 170-225 cGy delivered 5 x/week (n = 13) or 225-265 cGy delivered 4 x/week (n = 4 eyes) or x 5/week (n = 2 eyes). Treatment techniques included anterior field (n = 11) or lens-sparing technique (n = 8). One patient has died of progressive central nervous system (CNS) disease at 13 months; one patient succumbed to second malignant neoplasm within the irradiated field at 194 months; the remaining 13 patients remain alive from 27 to 301 months (median = 178 months). Local control with irradiation alone has been maintained in 12 eyes. Four eyes with local recurrence were salvaged using cryotherapy or reirradiation. Enucleation was required for three eyes for progressive disease at 4, 7, and 7 months postirradiation. Cataract formation was documented in nine eyes treated with anterior fields and in one patient treated with lens-sparing technique. At last follow-up, 7 patients had visual acuity of 20/100 or better. Radiation dose of 40 Gy appears to be adequate for local control of early stage RB (R-E Groups I-III and VB whose tumors are R-E Groups I-III) in patients > 1 year old. The results of this limited series which has lengthy follow-up is compared with the results of previously published data in an effort to define the benefits and disadvantages of the different treatment techniques which have been reported in the treatment of RB in children > 1 year old.

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.

Radiation therapy for age-related subfoveal choroidal neovascular membranes

In this pilot study the effect of radiation therapy on subfoveal CNV membranes associated with age-related macular degeneration was evaluated. Four groups of 10 patients were treated with external beam radiotherapy (16 MV photons) on an area of 1 cm2 (macular region) using a lens-sparing technique and total dose of 8 to 24 Gy. The first group received 8 Gy in a single fraction. In this group only 30% had a stable visual acuity and a stable FA after 18 months follow-up. In 50% of patients in group 2 (12 Gy) and 40% of patients in group 3 (18 Gy) the visual acuity and FA appearance remained stable after 18 months of follow-up. In the last group (24 Gy) 80% of patients had a stable visual acuity and FA appearance after 12 months follow-up. Comparison of these findings with the natural history data of subfoveal age-related CNV, suggests a beneficial effect of radiation therapy with a total dose of 12 Gy or more on the progression of CNV membranes.