| Treatment modality | Typical indication in FTC | Key details / timing | Efficacy data | Important adverse events / limitations | Evidence |
|---|---|---|---|---|---|
| Lobectomy (hemithyroidectomy) | Selected localized, lower-risk differentiated thyroid carcinoma including some FTCs when disease is intrathyroidal and limited | Extent of surgery is determined by preoperative risk assessment; lobectomy may be used for selected lower-risk disease, whereas more extensive surgery is favored for higher-risk tumors. FTC often requires definitive histopathology to demonstrate capsular/vascular invasion because cytology cannot reliably distinguish adenoma from carcinoma | In an FTC meta-analysis, lobectomy itself was **not associated with increased risk of death** compared with more extensive surgery, suggesting appropriateness in carefully selected patients (pqac-00000002) | Limitation: may be insufficient if postoperative pathology shows higher-risk features requiring completion thyroidectomy; preoperative discrimination from follicular adenoma remains difficult (pqac-00000008, pqac-00000012) | (pqac-00000002, pqac-00000008, pqac-00000012) |
| Total thyroidectomy | Standard approach for many DTC/FTC cases with bilateral disease, larger tumors, invasive disease, or when postoperative radioactive iodine (RAI) is planned | Frequently followed by RAI ablation in DTC/FTC; preferred when disease burden or risk profile is higher and when surveillance with thyroglobulin/RAI is needed | Standard treatment for most higher-risk DTC; localized DTC treated with thyroidectomy ± RAI has **10-year survival >90%** in localized disease (broader DTC data) (pqac-00000014) | Risks include hypoparathyroidism and recurrent laryngeal nerve injury; does not prevent later RAI-refractory progression in a minority of patients | (pqac-00000012, pqac-00000014) |
| Completion thyroidectomy / radical resection when indicated | Post-lobectomy high-risk pathology, residual disease, or non-radical initial surgery | Considered when final pathology reveals invasive FTC, multifocality, larger tumor, or features warranting RAI and more complete resection | FTC meta-analysis found **non-radical resection** associated with increased mortality risk, supporting complete oncologic surgery when feasible (pqac-00000002) | Surgical morbidity; decision individualized by tumor extent and patient factors | (pqac-00000002) |
| Radioactive iodine (RAI) therapy | Adjuvant or therapeutic use after thyroidectomy in iodine-avid differentiated thyroid carcinoma, including FTC | Cornerstone of DTC management because thyroid follicular cells retain iodide-handling machinery; best suited to iodine-avid residual, recurrent, or metastatic disease | Standard and often effective in DTC; however, approximately **5–15%** of DTC patients develop RAI-refractory disease with poorer prognosis (pqac-00000014) | Ineffective once tumors lose iodine avidity; repeated ineffective RAI should be avoided in true RAI-refractory disease | (pqac-00000004, pqac-00000012, pqac-00000014) |
| Active surveillance | Indolent, asymptomatic, low-burden RAI-refractory or metastatic differentiated thyroid carcinoma, including selected FTC | Appropriate when tumor growth is slow, burden is low, and there is no threatening location or major symptom burden; local therapies can be used for oligoprogression | No response-rate metric because this is a monitoring strategy; recommended in reviews/guidelines for slowly progressive RAI-refractory disease (pqac-00000014) | Risk of under-treating patients with accelerating disease; requires serial imaging and multidisciplinary reassessment | (pqac-00000014) |
| Indications for systemic therapy in RAI-refractory disease | Progressive, symptomatic, multifocal, or organ-threatening RAI-refractory FTC/DTC | ATA/ESMO-style guidance in reviews recommends systemic treatment for **rapid and/or symptomatic progression involving multiple lesions or organs**, while reserving surveillance for indolent disease (pqac-00000014) | Systemic therapy improves progression-free survival but carries significant toxicity burden; timing should balance disease kinetics and QoL (pqac-00000014) | Hypertension, fatigue, GI toxicity, hand-foot effects, weight loss, dose reductions common with MKIs | (pqac-00000014) |
| Lenvatinib (multikinase inhibitor; first-line) | First-line systemic therapy for advanced progressive RAI-refractory DTC, including FTC | Often favored when disease is clearly progressive/symptomatic and tumor shrinkage is desired; used after thyroidectomy/RAI failure | Real-world multicenter DTC study: **disease control rate 97.7%**, **median PFS 21.8 months**, first objective response at **3.8 months** (pqac-00000014). Reviews identify lenvatinib as standard first-line therapy for RAI-R DTC (pqac-00000014) | In the Korean study, **all patients** had adverse events; **grade 3–4 AEs 23.2%**; common AE was fatigue/asthenia; dose reduction from 20 mg median start to 10 mg sustainable dose was common (pqac-00000014) | (pqac-00000014) |
| Sorafenib (multikinase inhibitor; first-line) | First-line option for advanced progressive RAI-refractory DTC, including FTC | Alternative to lenvatinib; may be selected based on comorbidity, clinician familiarity, and toxicity considerations | Established first-line option from DECISION-era evidence summarized in reviews; improves PFS versus placebo in RAI-R DTC, though no FTC-only metrics were provided in retrieved contexts (pqac-00000014) | Class toxicities include hand-foot skin reaction, diarrhea, fatigue, hypertension, weight loss; may be less tumor-shrinking than lenvatinib in practice | (pqac-00000014) |
| Cabozantinib (multikinase inhibitor; second-line) | Second-line therapy for RAI-refractory DTC/FTC after progression on VEGFR-targeted MKIs such as lenvatinib and/or sorafenib | Used after failure of first-line MKIs; now recognized as standard resistant-case option in reviews | Reviews state cabozantinib is the **standard second-line treatment** for RAI-R thyroid carcinoma after prior VEGFR-targeted therapy; specific ORR/PFS values were not provided in retrieved contexts (pqac-00000014) | Significant TKI toxicities; careful monitoring required | (pqac-00000014) |
| RET inhibitor: Selpercatinib | RET fusion-positive advanced thyroid cancer, including rare follicular-cell derived tumors with RET fusions | Requires molecular testing; suited for patients with actionable RET fusion, especially after RAI-refractory progression | In previously treated **RET fusion-positive thyroid cancer**, **ORR 78.9%** (2 CR, 13 PR); in treatment-naive RET-altered thyroid cancer, **ORR 100%** in a very small cohort (1 CR, 7 PR) (pqac-00000013) | **94%** experienced at least one treatment-related AE; **28% grade 3** and **2% grade 4** treatment-related AEs in cited study summary (pqac-00000013) | (pqac-00000012, pqac-00000013) |
| RET inhibitor: Pralsetinib | Advanced/metastatic RET fusion-positive thyroid cancer requiring systemic therapy; also RET-mutant MTC | Requires identification of RET fusion; another selective RET-targeted option | In PTC cohort summarized in review, **ORR 89%** (all PRs) for RET-altered thyroid cancer subgroup (pqac-00000013) | **15%** experienced serious treatment-related adverse events in cited summary (pqac-00000013) | (pqac-00000012, pqac-00000013) |
| NTRK inhibitor: Larotrectinib | NTRK fusion-positive advanced thyroid cancer including FTC | Requires molecular testing for NTRK1/2/3 fusion; tumor-agnostic targeted option | In **29 patients** with TRK fusion thyroid cancer (**FTC n=2**), among 28 evaluable patients **ORR 71%**; response rate **86% in DTC** and **29% in ATC** (pqac-00000013) | Favorable safety profile; **7% grade 3** treatment-related AE in cited study summary (pqac-00000013) | (pqac-00000012, pqac-00000013) |
| NTRK inhibitor: Entrectinib | NTRK fusion-positive advanced thyroid cancer | Alternative TRK inhibitor after fusion detection | In thyroid cancer cohort summarized in review, **ORR 53.8%** and median duration of response **13.2 months** (subtypes not fully specified) (pqac-00000013) | Multi-target kinase profile may broaden off-target toxicities relative to highly selective TRK inhibition | (pqac-00000012, pqac-00000013) |
| BRAF/MEK-targeted therapy (dabrafenib + trametinib) | Primarily BRAF V600E-mutated ATC; relevance to FTC is limited because classic FTC is usually RAS-like rather than BRAF-driven | Important mainly for thyroid cancers with BRAF V600E; may also inform redifferentiation strategies in selected follicular-cell derived cancers | Review table reports high activity in BRAF V600E ATC (**ORR 69%**) and activity in PTC, but FTC-specific evidence was not provided in retrieved contexts (pqac-00000013) | Not a standard FTC treatment absent a targetable BRAF alteration; molecular matching required | (pqac-00000012, pqac-00000013) |
| Redifferentiation therapy (e.g., sorafenib or trametinib plus RAI concepts) | Investigational strategy for RAI-refractory follicular-cell derived thyroid cancers that may regain iodine uptake | Intended to re-sensitize dedifferentiated tumors to RAI; discussed as promising but not yet definitive | Reviews note **promising, but not excellent** results, with sorafenib and trametinib included in redifferentiation protocols (pqac-00000014) | Experimental/selected-center use; benefit inconsistent and not yet routine standard of care | (pqac-00000014) |
| Immunotherapy / ICI-based approaches | Investigational or selected advanced RAI-refractory disease, often in combination strategies | Under study, especially combined with TKIs or in more aggressive dedifferentiated disease | Reviews describe ICIs as **promising** and under investigation rather than established standard therapy for FTC (pqac-00000014) | Response predictors and optimal combinations remain uncertain; immune toxicities apply | (pqac-00000004, pqac-00000014) |
| Local therapies in metastatic/RAI-refractory disease | Oligoprogression, symptomatic focal lesions, bone metastases, lesions threatening function | Surgery, radiotherapy, or other local ablative approaches may be used before or during systemic therapy; antiresorptives may be added for bone metastases | Useful for disease control in limited progressing sites; no pooled response metrics in retrieved contexts | Not a substitute for systemic therapy in diffuse rapid progression | (pqac-00000014) |


*Table: This table summarizes current treatment strategies for follicular thyroid carcinoma, emphasizing surgery, radioactive iodine, systemic therapy for RAI-refractory disease, and biomarker-matched targeted treatments. It highlights when each modality is used, what efficacy has been reported, and the main safety or practical limitations.*