{"id":2382,"date":"2020-10-09T15:42:16","date_gmt":"2020-10-09T12:42:16","guid":{"rendered":"https:\/\/www.intheranostics.com\/prof\/?page_id=2382"},"modified":"2020-10-09T16:01:59","modified_gmt":"2020-10-09T13:01:59","slug":"radioactive-iodine-therapy","status":"publish","type":"page","link":"https:\/\/www.intheranostics.com\/prof\/en\/radioactive-iodine-therapy\/","title":{"rendered":"Radioactive Iodine Therapy"},"content":{"rendered":"

[et_pb_section fb_built=”1″ fullwidth=”on” _builder_version=”4.4.8″ background_color=”rgba(0,0,0,0)” background_image=”https:\/\/www.intheranostics.com\/wp-content\/uploads\/2020\/06\/metastatik_prostat_kanseri.jpg” custom_padding=”100px||100px||false|false” locked=”off”][et_pb_fullwidth_header title=”Radioactive Iodine Therapy” text_orientation=”center” content_max_width_last_edited=”off|desktop” _builder_version=”4.4.8″ title_font_size=”50px” content_font_size=”41px” subhead_font=”|700|||||||” subhead_font_size=”38px” subhead_line_height=”1.1em” background_enable_color=”off” background_enable_image=”off” custom_margin=”||||false|false” custom_padding=”||||false|false” animation_style=”slide” animation_direction=”bottom”][\/et_pb_fullwidth_header][\/et_pb_section][et_pb_section fb_built=”1″ _builder_version=”4.4.8″ custom_margin=”0px||0px||false|false” custom_padding=”0px|0px|0px|0px|false|false”][et_pb_row _builder_version=”4.4.8″ custom_margin=”0px||||false|false” custom_padding=”0px|0px|0px|0px|false|false”][et_pb_column type=”4_4″ _builder_version=”4.4.8″][et_pb_divider divider_weight=”0px” _builder_version=”4.4.8″ use_background_color_gradient=”on” background_color_gradient_start=”#8dd2e1″ background_color_gradient_end=”#23afca” background_color_gradient_direction=”90deg” width=”50%” module_alignment=”center” height=”10px”][\/et_pb_divider][\/et_pb_column][\/et_pb_row][\/et_pb_section][et_pb_section fb_built=”1″ admin_label=”section” _builder_version=”3.22″][et_pb_row admin_label=”row” _builder_version=”4.4.8″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” custom_margin=”||||false|false” custom_padding=”0px|0px|0px|0px|false|false”][et_pb_column type=”4_4″ _builder_version=”3.25″ custom_padding=”|||” custom_padding__hover=”|||”][et_pb_text _builder_version=”4.4.8″]<\/p>\n

Radioactive Iodine Treatment<\/h3>\n

Indications<\/strong><\/em><\/p>\n

For differentiated thyroid cancer patients, radioactive iodine (I-131 or radioiodine) is indicated for:<\/p>\n

1) Ablation of residual healthy thyroid tissue following total or near total thyroidectomy<\/p>\n

2) Adjuvant treatment of subclinical microscopic disease<\/p>\n

3) Treatment of macroscopic residual\/recurrent or metastatic disease.<\/p>\n

What is Radioactive Iodine Treatment? How Does It Treat?<\/h3>\n

Theranostics is a recently developing field of the medicine. This approach takes body images using a tumor-specific agent to locate the tumor and its metastasis and their potential future locations and it also uses a specific agent with pre-determined therapeutic efficiency for the diseased tissue. This approach enables switching from traditional medicine to contemporary personalized medical procedures.<\/strong><\/p>\n

Administration of low-dose radioactive iodine (I-131 or I-123) to obtain images with high sensitivity and specificity of tumor tissues for diagnostic purposes combined with high-dose radioactive iodine (I-131) for specific and targeted treatment of these tumors is the oldest known example of theranostic practices in differentiated thyroid cancer.<\/p>\n

Radioactive iodine treatment is a standard practice with proven effect on survival in patients with differentiated thyroid cancer, which has been frequently preferred for treatment of benign and malignant (cancer) diseases of thyroid since 1940s.<\/p>\n

Thyroid tissue has a unique ability to collect all iodine from the bloodstream and store it in the gland. Similar to iodine, radioactive iodine is taken up to thyroid gland via sodium-iodine symporter (NIS) membrane proteins and stored in follicular cells of the thyroid gland. NIS membrane proteins are also found in papillary- and follicular-type differentiated thyroid cancers, although their levels are lower compared to healthy thyroid tissues. I-131 is a radionuclide with physical half-life of 8.1 days; it emits 364 KeV energy gamma radiation used in imaging studies and an average of 0.192 MeV energy beta particles used in treatment.<\/p>\n

Anaplastic (undifferentiated) and medullary thyroid cancers as well as other rarer malignant diseases of thyroid gland show no iodine uptake; thus, radioactive iodine is not used for those patients.<\/p>\n

Although majority of patients have a very high chance of prognosis in differentiated thyroid cancers, the risk of relapse or recurrence may be up to 20-30% and relapse may occur even decades after the baseline treatment. Therefore, regular follow-up is necessary for the patients to figure out a relapse and the follow-up should be maintained for the rest of the patient\u2019s life.<\/p>\n

Who is Eligible For Radioactive Iodine Therapy?<\/h3>\n

Radioactive iodine (I-131 or radioiodine) is indicated for ablation of normal residual thyroid tissue following total or near total thyroidectomy for patients with differentiated thyroid cancer and for adjuvant treatment of subclinical microscopic disease as well as treatment of macroscopic residual\/recurrent or metastatic disease.\u00a0<\/p>\n

Postoperative Radioactive Iodine Ablation<\/em><\/h3>\n

It implies radioactive iodine treatment that aims to ablate residual thyroid cancer cells or healthy thyroid tissue several weeks after the surgery. Moreover, ablation is also performed to eliminate thyroid cancer cells, which have already spread to other body parts. Destruction of healthy thyroid tissue residues will facilitate the ability to monitor potential relapse of the disease. In addition to this benefit, it has been demonstrated that radioactive iodine ablation improves survival rates in cases where the cancer has spread to neck or other parts of the body.<\/p>\n

\u00a0<\/strong><\/p>\n

Up-to-date<\/strong> post operative radioactive iodine ablation therapy recommendations according to the American Thyroid Association (ATA) risk classification system and the AJCC\/TNM staging system are as follows:<\/strong><\/p>\n\n\n\n\n\n\n\n\n\n\n\n
\n

ATA risk staging<\/p>\n<\/td>\n

\n

Definition<\/p>\n<\/td>\n

\n

\u00a0Indication of RAI ablation<\/strong><\/p>\n<\/td>\n<\/tr>\n

\n

ATA low risk<\/p>\n

T1a<\/p>\n

N0, Nx<\/p>\n

M0, Mx<\/p>\n<\/td>\n

\n

Tumor size \u22641 cm (unifocal or multifocal)<\/p>\n

 <\/p>\n<\/td>\n

\n

None<\/p>\n<\/td>\n<\/tr>\n

\n

ATA low risk<\/p>\n

T1b, T2<\/p>\n

N0, Nx<\/p>\n

M0, Mx<\/p>\n<\/td>\n

\n

Tumor size > 1-4 cm<\/p>\n<\/td>\n

\n

The procedure might be considered. Not a routine treatment; it might be considered for patients with aggressive histology or vascular invasion<\/p>\n<\/td>\n<\/tr>\n

\n

ATA low to moderate risk<\/p>\n

T3<\/p>\n

N0, Nx<\/p>\n

M0, Mx<\/p>\n<\/td>\n

\n

Tumor size > 4 cm<\/p>\n<\/td>\n

\n

Usually preferred.<\/p>\n<\/td>\n<\/tr>\n

\n

ATA low to moderate risk<\/p>\n

T3<\/p>\n

N0, Nx<\/p>\n

M0, Mx<\/p>\n<\/td>\n

\n

Microscopic extra-thyroidal metastasis, for all tumor sizes.<\/p>\n<\/td>\n

\n

Usually preferred.<\/p>\n<\/td>\n<\/tr>\n

\n

ATA low to moderate risk<\/p>\n

T1 -3<\/p>\n

N1a<\/p>\n

M0, Mx<\/p>\n<\/td>\n

\n

Metastasis of central cervical compartment lymph node<\/p>\n

 <\/p>\n<\/td>\n

\n

Usually preferred.<\/p>\n<\/td>\n<\/tr>\n

\n

ATA low to moderate risk<\/p>\n

T1 -3<\/p>\n

N1b<\/p>\n

M0, Mx<\/p>\n<\/td>\n

\n

Metastasis of lateral cervical compartment or mediastinal cervical lymph node<\/p>\n<\/td>\n

\n

Usually preferred.<\/p>\n<\/td>\n<\/tr>\n

\n

ATA high risk<\/p>\n

T4<\/p>\n

Any N<\/p>\n

Any M<\/p>\n<\/td>\n

\n

Large extra-thyroidal metastasis, for all tumor sizes.<\/p>\n<\/td>\n

\n

Yes<\/p>\n<\/td>\n<\/tr>\n

\n

ATA high risk<\/p>\n

M1<\/p>\n

Any T<\/p>\n

Any N<\/p>\n<\/td>\n

\n

Distant metastasis<\/p>\n<\/td>\n

\n

Yes<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n

American Thyroid Association (ATA) risk classification system:<\/strong><\/p>\n\n\n\n\n\n
\n

Low risk<\/strong><\/p>\n<\/td>\n

\n

No local or distant metastasis is present.<\/p>\n

Macroscopic tumor is totally removed.<\/p>\n

There is no tumor invasion in peripheral tissues and structures.<\/p>\n

There is no aggressive tumor histology (such as tall cell variant, hobnail variant, columnar cell carcinoma).<\/p>\n

No uptake excluding thyroid bed in screening after the treatment, if RAI is administered.<\/p>\n

There is no vascular invasion.<\/p>\n

Clinically N0 or \u22645, pathologically N1 micrometastases (maximum diameter <0.2 cm)<\/p>\n

Intra-thyroidal, encapsulated follicular variant papillary thyroid cancer<\/p>\n

Intra-thyroidal, well differentiated follicular thyroid cancer, with capsule invasion and without vascular invasion or minimum vascular invasion (<4 foci)<\/p>\n

Intra-thyroidal papillary microcarcinoma, uni- or multi-focal, V600E BRAF mutation (if known)<\/p>\n<\/td>\n<\/tr>\n

\n

Moderate risk<\/p>\n<\/td>\n

\n

Microscopic tumor invasion to perithyroidal soft tissues.<\/p>\n

Papillary thyroid cancer with vascular invasion.<\/p>\n

Uptake in neck excluding thyroid bed on the first total body scan following radioactive iodine therapy.<\/p>\n

Aggressive tumor histology (such as tall cell variant, hobnail variant, columnar cell carcinoma).<\/p>\n

Clinically N1 or >5 pathologic N1 with maximum diameter <3 cm<\/p>\n

Intra-thyroidal papillary thyroid cancer, primary tumor 1-4 cm, B600E BRAF mutation (if known)<\/p>\n

Multifocal papillary microcarcinoma, extra-thyroidal metastasis and V600E BRAF mutation (if known)<\/p>\n<\/td>\n<\/tr>\n

\n

High risk<\/p>\n<\/td>\n

\n

Macroscopic tumor invasion to perithyroidal soft tissues (Large extra-thyroidal metastasis)<\/p>\n

Incomplete tumor resection<\/p>\n

Distant metastasis<\/p>\n

Postoperative elevated serum Tg levels suggestive of distant metastasis<\/p>\n

Pathologically N1 metastatic lymph node which measures larger than 3 cm in any of them<\/p>\n

Follicular thyroid cancer with diffuse vascular invasion (>4 foci)<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

 <\/p>\n

Treatment of Recurrent or Residual Differentiated Thyroid Cancer with Radioactive Iodine<\/em><\/strong><\/p>\n

Surgery is usually the first-line option if the cancer tissue is operable. Radioactive iodine treatment can be performed alone or in combination with surgery. Presence of differentiated thyroid cancer, which is refractory to radioactive iodine should be suspected if cancer foci that do not show significant uptake in radioactive iodine scan are identified in other imaging methods such as MRI or 18F-FDG-PET scan.<\/p>\n

Treatment of Differentiated Thyroid Cancer Refractory to Radioactive Iodine <\/em><\/strong><\/p>\n

Definition: <\/em><\/strong><\/p>\n