Current surgical treatment of intermediate risk differentiated thyroid cancer: a systematic review

ABSTRACT

Introduction: Surgical treatment of thyroid cancer has become less aggressive but for many patients, the threshold for performing total thyroidectomy (TT), as opposed to thyroid lobectomy (TL), has remained unclear. Current American Thyroid Association (ATA) guidelines encourage more individualization of treatment options, which necessitates explicit review of the pros and cons of the different options with patients.

Areas covered: This review focuses on the extent of surgery for treatment of intermediate-risk differentiated thyroid cancer, restricted to relevant literature available after publication of the 2015 ATA guidelines.

Expert opinion: Dynamic risk-stratification facilitates a tailored approach when deciding on the extent of surgery for thyroid cancer. Treatment with TT allows for a lower recurrence risk, a simpler follow-up regimen, and treatment with adjuvant post-operative radioactive iodine. Treatment with TL has a lower associated risk of complications and avoidance of lifelong thyroid hormone replacement but has a significant risk of requiring a completion thyroid lobectomy (CT). Overall, treatment with TL and TT have comparable survival outcomes, but TL is the more cost-effective option. Larger cancer size is correlated with worse clinical outcomes, and numerous subgroup analyses have shown poorer outcomes for cancers with a diameter that is 2–4 cm compared to 1–2 cm.

KEYWORDS:

• American thyroid association
• guidelines
• lobectomy
• thyroid cancer
• thyroid surgery
• thyroidectomy
• tumor burden

Article highlights

• The ideal extent of surgical resection for treatment of ATA intermediate-risk DTC is an area of controversy, with more recent evidence shifting management towards less aggressive options. Discussion points surgeons must cover with their patients when reviewing total thyroidectomy (TT) versus thyroid lobectomy (TL) for intermediate-risk DTC treatment should include: long-term survival outcomes, risk of cancer recurrence, risk of surgical complications, need for life long thyroid hormone suppression, risk of requiring further surgical and medical treatment and implications for surveillance.

• When compared to TL, treatment of intermediate-risk DTC with TT allows for a lower recurrence risk, a more straightforward postoperative cancer surveillance regimen and permits treatment with adjuvant postoperative RAI if required. Conversely, when compared to TT treatment of intermediate risk DTC with TL has a lower risk of complications, and potential avoidance of lifelong thyroid hormone replacement, but does have a significant risk of requiring a CT. Both options have a similar long-term survival, although TL has been shown to be more cost-effective.

• Increasing cancer size is correlated with the presence of high-risk pathological characteristics, increased burden of disease, and worse response to therapy. Cancer size has continued to be a key prognostic characteristic of DTC.

• Higher quality, prospective studies evaluating different surgical approaches for intermediate-risk DTC treatment are required. Future RCTs comparing outcomes of TT versus TL for this subset of patients will help to better characterize which individuals will benefit from more extensive operations. We also foresee increased emphasis on patient-centered discussions regarding extent of surgical treatment, and an evolution of current guidelines so more patients will be eligible for TL. There is also an increasing need for improved pre-operative prediction of DTC aggressiveness, an important area of research that includes the study of molecular prognosticators and novel imaging approaches and techniques.

Data availability statement

The authors confirm that the data supporting the findings of this study are available within the article.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Geolocation information

The study reviewed English language articles from around the world.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose

Additional information

Funding

This paper received no funding.