Palot Manzil Fathima Fijula, Kaur Harleen
University of Arkansas for Medical Sciences
University of Arkansas for medical sciences
Thyroid cancer is the most common endocrine cancer and is histologically classified into 5 main types—papillary thyroid, follicular thyroid, oncocytic (Hürthle) cell, medullary thyroid, and anaplastic thyroid carcinoma. Among these malignancies, differentiated thyroid cancers—papillary, follicular, and oncocytic carcinomas—are the most common. Of these tumors, papillary thyroid cancer accounts for 80% to 90% of thyroid malignancies and has the best prognosis. The standard of care for differentiated thyroid cancers typically involves surgery, with or without postoperative radioactive iodine treatment. Radioactive iodine targets and binds to the sodium-iodide symporter on cancer cells, allowing radioactive iodine to enter and accumulate within the cells. The radiation emitted then destroys malignant cells from within. Requirements and doses of radioactive iodine therapy vary based on individual risk factors. The mechanism of action of radioactive iodine includes the following: Selective uptake by thyroid cells: The thyroid gland is unique in its ability to efficiently absorb iodine, which it uses to produce thyroid hormones such as thyroxine (T) and triiodothyronine (T). This selective uptake is used in radioactive iodine therapy. Iodine transporter: Thyroid cells have a specific transporter on their cell membranes called the sodium-iodide symporter, which actively transports iodine into the cells. Radioactive iodine accumulation: During radioactive iodine therapy, patients are typically administered sodium iodide I 131 (I), an isotope chemically identical to stable iodine. Thyroid cells take up this isotope in the same manner as nonradioactive iodine. Local radiation: Once inside the thyroid cells, radioactive iodine emits β-particles, which are high-energy electrons. These β-particles damage the DNA of thyroid cells, leading to cell death. Selective destruction of thyroid tissue: Radioactive iodine primarily targets thyroid tissue because thyroid cells absorb iodine more effectively than other body cells. This targeted approach for thyroid malignancies selectively destroys cancerous thyroid cells while sparing most other body tissues. Systemic effects: Radioactive iodine has both local and systemic effects. A small amount of the unused isotope may be released from the thyroid gland into the bloodstream, where it can be absorbed by distant metastases or residual thyroid tissue not removed by surgery. This mechanism helps eliminate remaining cancer cells outside the thyroid gland. A small amount of the unused isotope can be released from the thyroid gland into the bloodstream, where it may be taken up by distant metastases or residual thyroid tissue that was not removed during surgery. Overall, the mechanism of action of radioactive iodine in treating thyroid malignancy involves exploiting the unique ability of thyroid cells to take up iodine and selectively destroy cancerous thyroid tissue through local and systemic radiation. Thyroid cancer is the most common endocrine cancer, ranking seventhin the world in terms of incidence, with a 5-year survival rate of 98.4%. Papillary (84%), follicular (4%), and oncocytic (2%) thyroid cancers arise from thyroid follicle cells and represent well-differentiated forms. More aggressive types, also derived from follicular cells, include poorly differentiated (5%) and anaplastic (around 1%) thyroid cancers. Medullary thyroid cancer (4%) is a neuroendocrine tumor that originates from the parafollicular cells of the thyroid. Women have nearly 4 times the likelihood of developing early-stage thyroid cancer compared to men, although underlying subclinical prevalence remains the same between sexes. Clinical applications of radioactive iodine therapy fall into 2 main categories—initial treatment (ablation dose) after surgical thyroidectomy, which aims to destroy any thyroid tissue and cancer cells that remain after surgery, and subsequent treatments, which focus solely on residual or recurrent thyroid malignancy. Selecting the appropriate radioactive iodine therapy requires an accurate assessment of postoperative disease status, with serum thyroglobulin levels, neck sonography, and diagnostic iodine scanning as the most commonly used evaluation tools.
甲状腺癌是最常见的内分泌系统癌症，组织学上可分为5种主要类型——乳头状甲状腺癌、滤泡状甲状腺癌、嗜酸性（许特莱）细胞癌、髓样甲状腺癌和未分化甲状腺癌。在这些恶性肿瘤中，分化型甲状腺癌——乳头状癌、滤泡状癌和嗜酸性细胞癌——最为常见。在这些肿瘤中，乳头状甲状腺癌占甲状腺恶性肿瘤的80%至90%，预后最佳。分化型甲状腺癌的标准治疗通常包括手术，术后可进行或不进行放射性碘治疗。放射性碘靶向并结合癌细胞上的钠碘同向转运体，使放射性碘进入细胞并在细胞内积聚。然后发出的辐射从内部破坏恶性细胞。放射性碘治疗的要求和剂量因个体风险因素而异。放射性碘的作用机制如下：甲状腺细胞的选择性摄取：甲状腺具有高效吸收碘的独特能力，它利用碘来产生甲状腺激素，如甲状腺素（T）和三碘甲状腺原氨酸（T）。这种选择性摄取被用于放射性碘治疗。碘转运体：甲状腺细胞在其细胞膜上有一个特定的转运体，称为钠碘同向转运体，它将碘主动转运到细胞内。放射性碘积聚：在放射性碘治疗期间，患者通常会服用碘化钠I 131（I），这是一种与稳定碘化学性质相同的同位素。甲状腺细胞以与非放射性碘相同的方式摄取这种同位素。局部辐射：一旦进入甲状腺细胞，放射性碘会发出β粒子，即高能电子。这些β粒子会损伤甲状腺细胞的DNA，导致细胞死亡。甲状腺组织的选择性破坏：放射性碘主要靶向甲状腺组织，因为甲状腺细胞比其他身体细胞更有效地吸收碘。这种针对甲状腺恶性肿瘤的靶向方法选择性地破坏甲状腺癌细胞，同时 sparing most other body tissues. Systemic effects: Radioactive iodine has both local and systemic effects. A small amount of the unused isotope may be released from the thyroid gland into the bloodstream, where it can be absorbed by distant metastases or residual thyroid tissue not removed by surgery. This mechanism helps eliminate remaining cancer cells outside the thyroid gland. A small amount of the unused isotope can be released from the thyroid gland into the bloodstream, where it may be taken up by distant metastases or residual thyroid tissue that was not removed during surgery. Overall, the mechanism of action of radioactive iodine in treating thyroid malignancy involves exploiting the unique ability of thyroid cells to take up iodine and selectively destroy cancerous thyroid tissue through local and systemic radiation. 甲状腺癌是最常见的内分泌系统癌症，在全球发病率排名第七，5年生存率为98.4%。乳头状（84%）、滤泡状（4%）和嗜酸性（2%）甲状腺癌起源于甲状腺滤泡细胞，是分化良好的类型。更具侵袭性的类型，也源自滤泡细胞，包括低分化（5%）和未分化（约1%）甲状腺癌。髓样甲状腺癌（4%）是一种神经内分泌肿瘤，起源于甲状腺的滤泡旁细胞。女性患早期甲状腺癌的可能性几乎是男性的4倍，尽管两性潜在的亚临床患病率相同。放射性碘治疗的临床应用主要分为两大类——手术甲状腺切除术后的初始治疗（消融剂量），旨在破坏手术后残留的任何甲状腺组织和癌细胞，以及后续治疗，其仅专注于残留或复发性甲状腺恶性肿瘤。选择合适的放射性碘治疗需要准确评估术后疾病状态，血清甲状腺球蛋白水平、颈部超声检查和诊断性碘扫描是最常用的评估工具。 保留大多数其他身体组织。全身效应：放射性碘具有局部和全身效应。少量未使用的同位素可能从甲状腺释放到血液中，在那里它可以被远处转移灶或手术未切除的残留甲状腺组织吸收。这种机制有助于清除甲状腺外剩余的癌细胞。少量未使用的同位素可以从甲状腺释放到血液中，在那里它可能被远处转移灶或手术中未切除的残留甲状腺组织摄取。总体而言，放射性碘治疗甲状腺恶性肿瘤的作用机制包括利用甲状腺细胞摄取碘的独特能力，并通过局部和全身辐射选择性地破坏甲状腺癌组织。甲状腺癌是最常见的内分泌系统癌症，在全球发病率排名第七，5年生存率为98.4%。乳头状（84%）、滤泡状（4%）和嗜酸性（2%）甲状腺癌起源于甲状腺滤泡细胞，是分化良好的类型。更具侵袭性的类型，也源自滤泡细胞，包括低分化（5%）和未分化（约1%）甲状腺癌。髓样甲状腺癌（4%）是一种神经内分泌肿瘤，起源于甲状腺的滤泡旁细胞。女性患早期甲状腺癌的可能性几乎是男性的4倍，尽管两性潜在的亚临床患病率相同。放射性碘治疗的临床应用主要分为两大类——手术甲状腺切除术后的初始治疗（消融剂量），旨在破坏手术后残留的任何甲状腺组织和癌细胞，以及后续治疗，其仅专注于残留或复发性甲状腺恶性肿瘤。选择合适的放射性碘治疗需要准确评估术后疾病状态，血清甲状腺球蛋白水平、颈部超声检查和诊断性碘扫描是最常用的评估工具。
原文中“sparing most other body tissues”部分翻译时出现重复，疑原文有误，已按正确理解翻译，但保留了重复部分供你参考。
