The use of transpupillary thermotherapy (TTT) as a treatment for retinoblastoma and small choroidal melanomas has been demonstrated in multiple case series studies to have a significant positive impact on the health outcomes of patients with these conditions. In a study of TTT for retinoblastoma in children, tumor regression was achieved in 96.1% of patients. In this same study 97% of affected eyes were successfully preserved. In a case series study with 256 patients with small choroidal melanomas, TTT resulted in a tumor control rate of 92% (Shields, 2002). In patients who had relapse, 54% also gained tumor control.
Shields et al. published a large study of retinoblastoma treated by TTT in 188 retinoblastomas in 80 eyes of 58 patients. Small tumors were managed by TTT alone, and larger tumors were managed by chemo-reduction, followed by tumor consolidation with thermotherapy. Complete tumor regression was achieved in 161 tumors (85.6%), 27 tumors (14.4%) developed recurrence. Complications of thermotherapy included focal iris atrophy in 29 eyes (36%), peripheral focal lens opacity in 19 eyes (24%), retinal traction in four eyes (5%), and retinal vascular obstruction in two eyes (2%). There were no cases of corneal scarring, central lens opacity, iris or retinal neovascularization, or rhegmatogenous retinal detachment. All eyes with focal lens opacity demonstrated adjacent focal iris atrophy. The investigators found that larger tumors require more intense treatment than smaller tumors and are at greatest risk for ocular complications such as focal iris atrophy and focal paraxial lens opacity.
The authors explained that there is little or no role for thermotherapy alone for retinoblastomas that have produced significant vitreal or subretinal tumor seeds. Such tumors are generally best managed by chemo-reduction, followed by plaque brachytherapy or external beam irradiation.
However, supplemental thermotherapy can often be employed in such cases if vitreal or subretinal seeds have resolved following irradiation.
The evidence supporting the use of transpupillary thermotherapy for choroidal melanoma is based on the results of short-term uncontrolled case series. Transpupillary thermotherapy has been reported to cause tumor necrosis in choroidal melanomas up to 4 mm in thickness. Shields et al. (1998) reported the results of the largest published case series of transpupillary thermotherapy for choroidal melanoma at that time. After a mean of three treatment sessions and 14 months of follow-up, tumor control was successful in 94% of patients. The six eyes (6%) classified as treatment failures included four eyes with tumors that showed partial or no response to thermotherapy, thus requiring plaque radiotherapy or enucleation, and two eyes with recurrence, subsequently controlled with additional thermotherapy. In more than half (58%) of patients, visual acuity was the same (within one line) or better than before treatment, depending primarily on tumor location. Complications are generally limited to the site of treatment. The most common complications of transpupillary thermotherapy for choroidal melanoma were retinal vascular obstruction (5%), retinal traction (10%), and optic disc edema (1%). Tumors located temporal to the fovea demonstrated a statistically higher risk for retinal traction than those located in other quadrants.
In a study by Shields et al. in 2002 the authors concluded that transpupillary thermotherapy is an effective treatment for certain small choroidal melanomas. Appropriate tumor selection is critical to successful treatment. Patients with tumors abutting or overhanging the optic disc or those requiring more than three sessions for tumor control are more likely to develop ultimate tumor recurrence to the retina, leading to visual loss shortly after treatment.
There are minimal published data regarding TTT. Reichel and colleagues reported on a case series of 16 eyes in 15 patients who presented with occult subfoveal choroidal neovascularization secondary to age-related macular degeneration. Three eyes showed a two or more line improvement in visual acuity over a period of 6 to 25 months. Visual acuity remained stable in nine treated eyes. The remaining four eyes showed a decline in visual acuity. The remaining four eyes showed a decline in visual acuity. Newson and colleagues reported on a case series of 44 eyes in 42 patients consisting of 12 eyes with classic CNV and 32 eyes with occult CNV. The mean follow-up was six months. The mean change in vision in those with classic and occult CNV was –0.75 and –0.66 Snellen lines, respectively. Further data were needed to confirm these preliminary results.
One prospective nonrandomized study of 21 eyes with idiopathic CNV reported 81% of patients treated with TTT were improved or stabilized at a mean of 5.1 months’ follow-up. Three other nonrandomized studies of TTT in eyes with CNV related to ARMD were reported. Nagpal and colleagues reported on TTT for CNV in 160 eyes (99 classic and 61 occult) of patients of Indian descent. The authors reported in classic CNV, 29.3% improved, 39.4% stabilized, and 31.3% deteriorated at 12 months’ follow-up. In occult CNV, 19.6% improved, 57.4% stabilized, and 22.9% deteriorated. Nagpal and colleagues concluded that there was effectiveness with TTT in Indian eyes, which responded to lower energy levels than did Caucasian eyes in their experience. In a study by Thach and colleagues, 69 eyes with occult CNV were treated with TTT. After a minimum of six months’ follow-up, 71% of patients improved or stabilized. Finally, in the Algvere study of TTT in predominately occult CNV, 8% improved, 40.7% stabilized, and 51.3% deteriorated after 12 months’ follow-up. Algvere and colleagues reported minimally classic CNV responded poorly to TTT. While there appears to be some improvement or stabilization in occult CNV in these studies, further study is needed to demonstrate that improvements in health outcomes occur with acceptable levels of adverse effects with TTT over the natural course of the disease.
In a presentation at the American Academy of Ophthalmology meeting in October 2004, in New Orleans, Iridex Corporation announced preliminary results of the TTT4 CNV study. The TTT4 CNV study is a nationwide study involving 22 centers that was started in March 2000 (available online at: http://www.eyesight.org . A total of 336 patients with symptomatic occult CNV that shows signs of exudation are being recruited. Two-thirds of eyes will be treated and one-third will receive sham treatment. Patients will be followed up for two years. Iridex reported preliminary results did not show TTT for CNV resulted in significant benefit over sham treatment. Only 47% of 303 patients who received TTT for CNV had modest or severe visual loss after two years, compared with 43% in those who received sham treatment. Further analysis of the data will be performed, according to Iridex Chief Executive Theodore Boutacoff.
An October 2005 Blue Cross Blue Shield Association (BCBSA) Technical Evaluation Center (TEC) Special Report on the treatment of ARMD supports the conclusions given above noting TTT, when used alone, has not been efficacious.
In a retrospective, non-randomized study, Tsai et al assessed the therapeutic outcome and the recurrence of CNV secondary to ARMD after TTT in light-brown retinas (n = 58 eyes in 55 patients). Power settings were set about half the value for Caucasian eyes. The outcome was assessed with best-corrected visual acuity, fluorescein angiography, indocyanine green angiography, and funduscopic examination. Forty-four membranes were occult, six classic, and eight mixed. Mean follow-up was 16.6 +/- 10.7 months (range of 6 to 48 months). Membranes closed in 46 eyes. Iatrogenic complications included three subretinal hemorrhages, two retinal pigment epithelium tears, and two macular area cystic changes. In eyes with occult CNV, visual acuity improved in six (13.6%), 14 (31.8%) remained unchanged, and 24 (54.6%) deteriorated. For various CNV, average logMAR changes from baseline at last follow-up were 0.30 in occult, -0.08 in classic, and 0.59 in mixed (p < 0.01). Thirty eyes experienced recurrence within 9.2 +/- 6.2 months (range of 2 to 22 months). Cumulative recurrence rate was 45% at 12 months and 71% at 22 months, with no significant difference between occult and non-occult type CNV. The authors concluded that TTT does not cure CNV secondary to AMD. High recurrence was found independent of CNV type. Most improved vision was found mostly in classic CNV. Complications associated with high energy level should be considered in light-brown retinas.
Ozdek et al. examined the effect of TTT on CNV secondary to angioid streaks. A total of six eyes of five patients with an average age of 61 years were diagnosed to have subfoveal CNV secondary to angioid streaks. Four of the CNVs were predominantly classic and two were occult with no classic. Visual acuity (VA) measurement, ophthalmoscopic and fluorescein angiographic examination, and optic coherence tomography (OCT) were carried out before TTT treatment and at each follow-up visit. Activity scores (AS) based on and OCT findings were also recorded. The mean follow-up was 12 months. The VA initially ranged from counting fingers to 20/100 and remained stable in all patients. The mean greatest lesion diameter increased significantly from 2221 microm to 3109 microm at last follow-up (p = 0.046). The mean AS decreased significantly from 6.5 to 4.8 at the third month (p = 0.039), but tended to increase thereafter. Re-treatment with TTT was applied to five eyes after a mean of 7.8 months but did not decrease CNV activity as effectively as the first treatments. A fibrotic scar developed in one eye after the first treatment. The authors concluded that TTT may decrease the activity of CNVs secondary to angioid streaks in the short-term, but re-treatment may be necessary with unfavorable results. Transpupillary thermal therapy appears to stabilize VA but not lesion size in this group of patients, which may be the natural history rather than a treatment effect.
In a pilot study, Tewari et al. compared the visual outcomes of photodynamic therapy (PDT) with verteporfin and TTT for classic subfoveal choroidal neovascularization (CNVM) secondary to AMD. Patients with subfoveal classic CNVM caused by AMD attending vitreo-retinal services at a tertiary care setup were included in this non-randomized, open label, prospective, clinical, comparative pilot trial. Standardized refraction, VA testing, evaluation of fundus and serial color photography and fundus fluorescein angiography were carried out to evaluate the effects of treatment in 32 eyes each undergoing either PDT or TTT. Follow-up was carried out at four weeks, 12 weeks and six months. Re-treatment, if indicated, was carried out three months post-treatment. Stabilization or improvement occurred in 69 % of patients undergoing PDT and 50 % patients undergoing TTT at six-month follow-up. Among patients with a pre-treatment VA greater than or equal to 20/63, only one out of six patients who underwent PDT had a drop of VA greater than two lines as compared to four patients (100 %) who underwent TTT (p = 0.0476, two-tailed Fisher's exact test). The authors concluded that for short-term preservation of vision in patients of classic CNVM due to AMD, PDT seems to be better than TTT if the pre-laser best corrected visual acuity is greater than 20/63 but both are equally effective if pre-laser best corrected visual acuity is less than 20/63.
In a prospective study, Kuo et al. carried out a safety and effectiveness study of TTT in Chinese patients with CNV secondary to AMD. A total of 26 patients (27 eyes) completed greater than or equal to six months of follow-up and were included in this report. Fourteen eyes (52 %) had improved or stable VA (loss of less than three lines) and 13 eyes (48 %) had vision loss of greater than or equal to three lines. The serial mean VA initially decreased during follow-up, and then stabilized by six months. In the subgroup of occult or minimally classic CNV (20 eyes), 13 eyes (65%) had improved or stable vision. The major complication of TTT included laser-related retinal pigment epithelium (RPE) atrophy in 10 eyes (37%). Six eyes had mild RPE atrophy; four eyes had severe RPE-choroid atrophy (macular burn). Analysis of possible risk factors for macular burn showed that three eyes had to have the power amplified due to nuclear sclerosis, and one pseudophakic eye had regular power. The authors concluded that TTT in AMD patients with occult or minimally classic CNV prevented severe vision loss in the majority of patients, but power amplification due to medium lens opacity induced RPE atrophy or burn in some patients.
A search of peer reviewed literature through July 2011 identified no new clinical trial publications or any additional information that would change the coverage position of this medical policy.
Two small randomized trials (28 and 25 patients) reported no benefit of TTT in preventing further visual loss in patients with occult CNV, while a case series reported macular burn as a complication of TTT in 8.6% of 35 patients available for follow-up. One randomized, non- blinded study of 26 patients did not find a statistically significant improvement for combination treatment with triamcinolone and TTT in comparison with TTT alone.
Two small studies from Asia indicated that the rationale for using TTT was the lower cost of this treatment in comparison with photodynamic therapy (PDT) with verteporfin. In the controlled trial, patients chose PDT or TTT after an explanation of the costs, benefits, and risks of each treatment. Sixteen patients (16 eyes) selected PDT, and 14 patients (16 eyes) selected TTT; treatments were repeated if dye leakage was evident at follow-up. The average pre-treatment visual acuity was similar in the two groups. At six months’ follow-up, loss of visual acuity was 15 letters or less in 14 (87%) eyes treated with TTT and in 13 (81%) eyes treated with PDT; however, more patients with good initial visual acuity (20/63 or greater) had a loss of two or more lines following TTT (4 of 4), than following PDT (1 of 6). Although the authors concluded that patients with good initial visual acuity should be treated with PDT, the study is limited by selection bias and small subject number.
A European trial with 98 patients reported similar outcomes between TTT (136 mW/mm) and PDT. Patients with occult CNV were randomly assigned to either TTT with sham PDT (n=52), or to PDT with sham TTT (n=46); retreatment was given if leakage was documented by fluorescein angiography (follow-up of 6, 12, 18, 24, 36, and 48 weeks). With a mean of 3.0 treatments in the TTT group and 2.3 treatments in the PDT group, a similar percentage of patients had lost fewer than 15 letters at 12 months (75% for TTT and 74% for PDT). There were non-significant trends for a larger percentage of patients to have preserved or improved best corrected visual acuity in the TTT group (37%) than in the PDT group (24%), and to have less of a decrease in foveal thickness (15% vs. 24%).
In a publication on patient-reported visual function from the randomized trial described above, outcomes on the National Eye Institute Visual Function Questionnaire 25 were similar in patients treated with TTT (change of +1.2) or PDT (change of +0.7) at 12 months. It was reported that the study was underpowered and unable detect differences in outcome measures.
Disclaimer for coding information on Medical Policies
Procedure and diagnosis codes on Medical Policy documents are included only as a general reference tool for each policy. They may not be all-inclusive.
The presence or absence of procedure, service, supply, device or diagnosis codes in a Medical Policy document has no relevance for determination of benefit coverage for members or reimbursement for providers. Only the written coverage position in a medical policy should be used for such determinations.
Benefit coverage determinations based on written Medical Policy coverage positions must include review of the member’s benefit contract or Summary Plan Description (SPD) for defined coverage vs. non-coverage, benefit exclusions, and benefit limitations such as dollar or duration caps.