Guidelines for the indications for 131I remnant ablation on differentiated thyroid cancer: a distillation and comparison of guidelines from seven organizations.
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Guidelines for the indications for 131I remnant ablation on differentiated thyroid cancer: a distillation and comparison of guidelines from seven organizations.
1. Guidelines for the indications for 131I remnant ablation on differentiated thyroid cancer:
a distillation and comparison of guidelines from seven organizations.
Guan H1, Van Nostrand D2, Li Y3, Orquiza M2, Teng W1, Khorjekar G2
1Dept Endocrinology & Metabolism and Inst of Endocrinology, The First Hosp of China Med Univ, Shenyang, Liaoning Province 110001, P.R.China
2Div of Nuclear Medicine, Dept of Medicine, MedStar Washington Hosp Ctr, Washington, D.C.
3Dept Nuclear Medicine, The First Hosp of China Med Univ, Shenyang, Liaoning Province 110001, P.R.China
Abstract
Objectives:
The objective of this educational exhibit is to compare the indications for
131I remnant ablation in patients with differentiated thyroid cancer (DTC)
as proposed by the following professional organizations:
- American Thyroid Association (ATA)
- European Society for Medical Oncology (ESMO)
- British Thyroid Association (BTA)
- National Comprehensive Cancer Network (NCCN)
- Society of Nuclear Medicine (SNM)
- European Association of Nuclear Medicine (EANM)
- Chinese Society of Endocrinology (CSE) / Chinese Society of
Surgery (CSS) / Chinese Anti-Cancer Association (CACA) /
Chinese Society of Nuclear Medicine (CSNM)
Summary:
131I is an important treatment modality for patients with
differentiated thyroid cancer, and 131I has been documented as having
utility for remnant ablation. However, the indications for 131I remnant
ablation are controversial, and multiple professional organizations
worldwide have published guidelines addressing the indications of 131I
remnant ablation. This educational exhibit begins with a discussion of
the various definitions of 131I remnant ablation and then attempts to
distill and compare the various professional organizations’ guidelines for
the indications of 131I remnant ablation.
By being more aware of the various organizational definitions and
guidelines, this educational exhibit hopes to help encourage over time
the standardization of definitions, and potentially even guidelines, for
the indications of 131I remnant ablation.
Definitions of Remnant Ablation
Guidelines Discussion
Guidelines Recommendation
ATA 2009
RAI ablation is recommended for: All patients with known distant metastases, gross extrathyroidal extension of the tumor regardless of tumor size, or primary tumor
size >4 cm even in the absence of other higher risk features. Selected patients with 1–4cm thyroid cancers confined to the thyroid, who have documented lymph
node metastases, or other higher risk features when the combination of age, tumor size, lymph node status, and individual histology predicts an intermediate to high
risk of recurrence or death from thyroid cancer (for selective use in higher risk patients).
RAI ablation is not recommended for: Patients with unifocal cancer <1 cm without other higher risk features. Patients with multifocal cancer when all foci are <1 cm
in the absence of other higher risk features.
ESMO 2010
Radioiodine ablation is recommended for all patients except those at very low risk (those with unifocal T1 tumors, <1 cm in size, with favorable histology, no
extrathyroidal extension or lymph node metastases). No indication for radioiodine ablation in very low-risk patients [unifocal T1 (<1 cm) N0 M0, no extension
beyond the thyroid capsule, favorable histology]. Definite indication in high-risk patients (any T3 and T4 or any T, N1, or any M1). Probable indication in low-risk
patients [T1 (>1 cm) or T2 N0 M0 or multifocal T1 N0 M0, or unfavorable histology].
BTA 2007
No indication for 131I ablation (low risk of recurrence or cancer-specific mortality): Patients should satisfy all the criteria below for 131I ablation to be omitted:
complete surgery; favorable histology; tumor unifocal, ≤1cm in diameter, N0, M0, or minimally invasive FTCs, without vascular invasion smaller than 2 cm in
diameter; no extension beyond the thyroid capsule. Definite indications: Any of the following criteria constitute an indication for 131I ablation: distant metastases;
incomplete tumor resection; complete tumor resection but high risk of recurrence or mortality (tumor extension beyond the thyroid capsule, or more than 10
involved lymph nodes and more than three lymph nodes with extracapsular spread. Probable indications: The list of indications below applies to patients who do
not fall under categories above. Any one of the following categories is a ‘probable’ indication for 131I ablation: less than total thyroidectomy (inferred from operation
notes or pathology report, or when an ultrasound scan or isotope scan shows a significant postoperative thyroid remnant); status of lymph nodes not assessed at
surgery; tumor size >1 cm and <4 cm in diameter; tumors <1 cm in diameter with unfavorable histology (tall-cell, columnar-cell or diffuse sclerosing papillary cancers,
widely invasive or poorly differentiated follicular cancers); multifocal tumors <1 cm.
NCCN 2011
For papillary and follicular thyroid cancer: Ablation using adjuvant radioiodine to destroy residual thyroid function can be considered for suspected (based on
pathology, postoperative Tg, and intraoperative findings) or proven RAI uptake in the thyroid bed in patients who have had total thyroidectomy and who have no
gross residual disease in the neck.
SNM 2012
131I ablative or tumoricidal treatment of differentiated thyroid cancer with radioiodine should be considered in the postsurgical management of patients with a
maximum tumor diameter greater than 1.0 cm or with a maximum tumor diameter less than 1.0 cm in the presence of high-risk features such as aggressive histology
(Hürthle cell, insular, diffuse sclerosing, tall cell, columnar cell, trabecular, solid, and poorly differentiated subtypes of papillary carcinoma), lymphatic or vascular
invasion, lymph node or distant metastases, multifocal disease, capsular invasion or penetration, perithyroidal soft-tissue involvement, or an elevated
antithyroglobulin antibody level after thyroidectomy (so that scintigraphy can be used for surveillance).
The treatment of very low and low-risk thyroid cancers with 131I is controversial, as most data suggest no statistically significant improvements in disease-specific
survival, although the recurrence rates may decrease.
EANM 2008
Radioiodine ablation after total or near-total thyroidectomy is a standard procedure in patients with DTC. The only exception is patients with unifocal papillary
thyroid carcinoma ≤1 cm in diameter who lack: evidence of metastasis, thyroid capsule invasion, history of radiation exposure, and unfavorable histology (tall-cell,
columnar cell or diffuse sclerosing subtypes).
CSE/CSS/CACA/C
SNM 2012
RAI ablation should be considered in selected post-surgical patients. In general, indications for RAI ablation include all patients except those satisfy all the criteria as
follows: all foci are <1cm in diameter, no extrathyroidal extension, N0, M0.
Conclusion
References
1. Revised American Thyroid Association management guidelines for
patients with thyroid nodules and differentiated thyroid cancer.
Thyroid 2009;19:1167-1214.
2. Pacini F, Castagna MG, Brilli L, Pentheroudakis G. Thyroid cancer:
ESMO clinical practice guidelines for diagnosis, treatment and
follow-up. Annals of Oncology 2010;21(S5):v214–v219.
3. British Thyroid Association and Royal College of Physicians.
Guidelines for the management of thyroid cancer. Second Edition.
2007.
4. National Comprehensive Cancer Network (NCCN). Clinical Practice
Guidelines in Oncology. Thyroid Carcinoma. V.3.2011.
5. Silberstein E, Alavi A, Balon H, et al. The SNMMI Practice Guideline
for Therapy of Thyroid Disease with 131I 3.0. J Nucl Med
2012;53:1633-1651.
6. Luster M, Clarke SE, Dietlein M, et al. Guidelines for radioiodine
therapy of differentiated thyroid cancer. Eur J Nucl Med Mol
Imaging 2008;35:1941-1959.
7. The Chinese guideline for management of thyroid nodules and
differentiated thyroid cancer. Chin J Endocrinol Metab
2012;28:779-797.
Although all organizations, except ESMO, clearly define ‘ablation’
as the use of 131I to eliminate the postsurgical thyroid remnant (ATA, BTA,
SNM, EANM, CSE) or destroy residual thyroid function (NCCN), this dose
of 131I actually also serves to treat microscopic tumor deposits (adjuvant
treatment) and metastatic disease (treatment) according to their
indications for postoperative RAI ablation in some guidelines (ATA, BTA,
NCCN, EANM, CSE).
Most guidelines actually incorporate ‘adjuvant treatment’ and
‘treatment’ into ‘ablation’. Although under these circumstances,
remnant ablation may be warranted, the objective of first 131I therapy
is not just remnant ablation, which may affect prescribed activity of
131I administered.
Indications for postoperative 131I ablation vary from one
guideline to another. Controversies exist in the risk stratification, as
well as the management of low risk (and very low risk) patients. More
evidence are needed to standardize these guidelines.
The NCCN’s guideline puts a particular emphasis on that the
indications for ablation be based on suspected or proven RAI uptake
in the thyroid bed, which means a routinely diagnostic imaging before
administration of 131I is necessary.
With improved standardization of terminology and more and
more publications, the guidelines from many countries are becoming
more standardized and consistent for the indications of 131I remnant
ablation.