JOURNAL CLUB

Minimal Invasive Procedures in TA

• Thyroid surgery (lobectomy/hemithyroidectomy) is one of the modalities of choice in the management of large thyroid adenoma

• Owing to the cosmetic and clinical morbidity associated with thyroid surgery, many new minimally invasive procedures have been developed for patients who refuse surgery or who do not qualify for surgery

Alternatives for surgery

• ethanol ablation (EA)• radiofrequency ablation (RFA)• percutaneous laser ablation (PLA)• high-intensity focused ultrasound• microwave ablation

• Laser ablation has been reported to be an effective option in treating thyroid nodules

• Principle: -focused laser energy causes coagulative necrosis of the tissue in focus (i.e. a toxic adenoma)

-gradually causes a reduction in the tissue volume with reabsorption of

the necrosed tissue -simultaneously leads of the resolution of hyperfunctional state of the adenoma

OBJECTIVE

• to assess the efficacy of combined laser ablation treatment (LAT) and radioiodine 131 (131I) treatment of large thyroid toxic nodules

• rapidity of control of local symptoms• hyperthyroidism• reduction of administered 131I activity - patients at refusal or with contraindications to surgery

DESIGN AND SETTING

• Pilot study at a single center specializing in thyroid care

• Fifteen patients were treated with LAT, followed by 131I (group A) (10 males, 62±16 y)

• series of 17 matched consecutive patients were treated by 131I only (group B) (11 males, 59±15 y)

INTERVENTIONS

• LAT: Laser energy was delivered with an output power of 3 W (1800 J per fiber per treatment) through two 75-mm, 21-gauge spinal needles

• 131I: Radioiodine activity was calculated to deliver 200 Gy to the hyperfunctioning nodule

MAIN OUTCOME MEASURES

• Thyroid function• Thyroid peroxidase antibody• Thyroglobulin antibody• Ultrasound• local symptoms - at baseline - up to 24 months

NODULE VOLUME ASSESSMENT

• US evaluation was conducted at baseline and 1, 12, and 24 months after LAT or 131I with a commercially available US scanner (Mylab 70; Esaote) equipped with a 7.5- to 13.0-MHz linear transducer

• Volume was calculated with the ellipsoid formula as the mean of two measurements

• In patients with coexistent cold nodules, malignancy was ruled out by US-guided FNAC

ASSESSMENT OF LOCAL SYMPTOMS

• Arbitrary visual analog scale (symptom score [SYS]) developed on occasion of a previous study in cold nodules by the same study group (Papini et al, Thyroid. 2007;17:229 –235)

• Ranged between 1 and 5 (1, absent; 5, constant cervical symptoms and dysphagia)

• calculated at entry and at 1, 12, and 24 months after LAT or 131I

LASER ABLATION TREATMENT• Two 75-mm, 21-gauge spinal needles (Becton-Dickinson) were

inserted into thyroid lesions under US guidance

• Energy was delivered with an Nd:YAG laser with output power of 3W and an illumination period of 10 minutes (total energy delivery of 1800 J per fiber per treatment)

• The total amount of energy delivered to the nodules ranged from 1800 to 3600 J

• Monitored for 60 minutes in the outpatient clinic and had a subsequent US control

• Patients were given an im injection of betamethasone (4mg) to limit edema and possible pain

RAIU + THYROID SPECT

• At the time of treatment and during follow-up, patients underwent thyroid SPECT 20 minutes after iv injection of 185 MBq of 99mTcO4-

• Studies were performed with a dual-head gamma camera system equipped with LEHR, parallel-hole collimators (Forte; Philips)

• RAIU was measured using a gamma probe(l’ACN) 6 and 24 hours after the oral administration of 370 kBq of 131I

RADIOIODINE THERAPY

• In patients treated with MMI, this was discontinued to obtain suppressed levels of TSH at the time of 131I administration

• 131I therapeutic activity was aimed at delivering 200 Gy to the hyperfunctioning nodule

• Group A patients underwent 131I treatment 1 month after LAT

• Group B patients received radioiodine after preliminary evaluation with the same modalities

STATISTICAL ANALYSIS

• Results are expressed as mean ± SD

• Student’s t test for paired data was used to compare data within the same group

• Student’s t test for unpaired data was used to compare data between groups

RESULTS

• Baseline characteristics were not significantly different in the two groups

• No complications occurred, as assessed by post-procedure neck US, and discomfort was minimal (mild cervical pain)

NODULE VOLUME

• Laser-induced nodule reduction depended on energy delivered with no relation to nodule volume

• Volume reduction was faster in group A

• Two years after LAT, nodule volume showed a reduction of 71.3±13.4% (10.1±8.3 mL) in group A vs 29.4±10.6% (15.3±5.1 mL) in group B

TSH

• showed a progressive increase, reaching normal values after 12 months in all patients in both groups

• Group A: normalization occurred in 9/15 patients (60%) already 1 month after LAT; 3 did not require 131I (Nodule: 3.8, 4, 5 cm)

• No relapse of hyperthyroidism• second 131I activity was not needed• No increase of TPOAb• Late hypothyroidism in one patient

RAIU AND 131I THERAPY

• Group A: 6% reduction in 24 hr RAIU% 21.1±8.1% in 131I activity after LAT activities < 600 MBq (480.1±119.6)

• Group B: higher activities were required (622.8±147.7 MBq; P=0.01)

8/17 required hospitalization(> 600 MBq)

DISCUSSION

• 131I is effective for the treatment of toxic thyroid nodules with a good outcome profile and has been a tried and tested non-surgical treatment modality

• Volume reduction, however, is a slow process that is wholly obtained 6 to 36 months after treatment

• Large TTNs are frequently considered a relative contraindication to the use of 131I because the risk of local symptoms due to radioiodine therapies is increased

REVIEW OF LITERATURE

• In most patients, 1 to 3 sessions of PLA or a single session with multiple fibers induces a clinically significant decrease in nodule volume and amelioration of local symptoms

• Because of the novelty of the PLA technique, longterm follow-up studies are lacking

• should be restricted to patients with pressure symptoms or cosmetic concerns who decline surgery or are at surgical risk

PERCUTANEOUS ETHANOL WITH 131I

• US-guided percutaneous ethanol injection (PEIT) combined with 131I treatment was reported to be effective in patients with large toxic thyroid nodules (Zingrillo et al, JNM 2003)

• However, presents limitations in solid nodules and is currently recommended for cystic lesions only (Guglielmi et al, Thyroid 2004)

ADVANTAGES OF LAT WITH 131I

• LAT can be done on a day-care basis; prevents morbidity associated with surgery

• Reduction in the volume of thyroid nodule is more as compared to 131I alone

• Reduction the dosage of the 131I administered

• Can be a feasible adjunct along with 131I in patients with large toxic nodules who do not qualify for/who refuse surgery

Disadvantages of LAT

• Repeated sessions may be necessary

• Increased cost and discomfort

• Only 3/15 patients required only LAT for completion resolution of symptoms; the remaining patients required 131I treatment as an adjunct

• Feasibility in toxic MNG?

THANK YOU