Adjuvant therapy with 131-iodine in patients with elevated serum thyroglobulin after reoperation due to papillary thyroid carcinoma lymph node metastases

Role of adjuvant therapy with radioactive iodine in patients with elevated serum thyroglobulin after neck reoperation due to recurrent papillary thyroid cancer: a monoinstitutional comparative study

BACKGROUND

Most patients with papillary thyroid cancer (PTC) and lymph node metastases (LNM) undergoing reoperation do not show apparent disease after this procedure, but serum thyroglobulin (Tg) continues to be elevated in part of them. This study evaluated adjuvant therapy with ¹³¹I in these patients.

METHODS

Patients with PTC and LNM diagnosed after initial therapy were selected. Patients undergoing reoperation and those without apparent disease after this procedure, but with nonstimulated Tg ≥1 ng/ml 6 months after reoperation, were included. The first 25 patients were submitted to therapy with ¹³¹I (groups A) and the subsequent 30 patients did not receive this therapy (group B).

RESULTS

Groups A and B were similar. During further follow-up, 21 patients developed structural disease and 34 continued without detectable disease (eight achieved complete remission). The outcomes were similar in groups A and B. Patients with Tg reduction >50% after reoperation tended to have a lower risk of recurrence (22.7 versus 48.5%), notably distant metastases (0 versus 15.1%), and were more likely to achieve complete remission (28 versus 3%). Patients with LNM FDG-positive had a higher risk of recurrence (54.5 versus 11.7%) and were less likely to achieve complete remission (3 versus 29.4%) after reoperation.

CONCLUSION

Our results suggest that therapy with ¹³¹I apparently does not prevent recurrences among patients who continue to have elevated Tg after neck reoperation. Further studies involving these patients are necessary, especially those who are at high risk of recurrence.

The role of radioactive iodine in the management of patients with differentiated thyroid cancer - An oncologic surgical perspective

With improved understanding of the biology of differentiated thyroid carcinoma its management is evolving. The approach to surgery for the primary tumour and elective nodal surgery is moving from a "one-size-fits-all" recommendation to a more personalised approach based on risk group stratification. With this selective approach to initial surgery, the indications for adjuvant radioactive iodine (RAI) therapy are also changing. This selective approach to adjuvant therapy requires understanding by the entire treatment team of the rationale for RAI, the potential for benefit, the limitations of the evidence, and the potential for side-effects. This review considers the evidence base for the benefits of using RAI in the primary and recurrent setting as well as the side-effects and risks from RAI treatment. By considering the pros and cons of adjuvant therapy we present an oncologic surgical perspective on selection of treatment for patients, both following pre-operative diagnostic biopsy and in the setting of a post-operative diagnosis of malignancy.

Association of Radioactive Iodine Administration After Reoperation With Outcomes Among Patients With Recurrent or Persistent Papillary Thyroid Cancer

Importance

One-third of patients with papillary thyroid cancer (PTC) develop persistent or recurrent disease after initial therapy. Most patients with persistent or recurrent disease undergo reoperation, but the role of treatment with radioactive iodine (RAI) after reoperation is unclear.

Objective

To determine whether receipt of RAI after reoperation for recurrent PTC is associated with improved outcomes.

Design, Setting, and Participants

This retrospective cohort study included electronic health record data from 102 patients who underwent neck reoperation for persistent or recurrent PTC at a tertiary referral center from April 2006 to January 2016; 50 patients received RAI after reoperation, and 52 did not receive RAI after reoperation. Data analysis was performed from September 1, 2017, to December 1, 2017.

Main Outcomes and Measures

Suppressed thyroglobulin (Tg) levels were compared between patients who underwent reoperation and received RAI and patients who underwent reoperation without receipt of RAI at the following time points: before reoperation (Tg0), after reoperation (Tg1), and after RAI or a comparable time interval among patients whose cases were managed without RAI (Tg2). Outcomes were biochemical response and structural recurrence after reoperation.

Results

The cohort comprised 102 patients who underwent neck reoperation for persistent or recurrent PTC (median age, 44 years [interquartile range, 33-54 years; SD, 14 years]; 67 [66%] female), 50 of whom received treatment with RAI after reoperation. Clinicopathologic characteristics of the patients at the time of the initial surgical procedure were similar between the reoperation with RAI group and the reoperation without RAI group with the exception of tumor (T) stage (T3 and T4, 28 of 50 [56%] vs 19 of 52 [37%]). Although median Tg levels were similar between the reoperation with RAI group and the reoperation without RAI group (Tg0, 3.3 ng/mL vs 2.4 ng/mL; Tg1, 0.6 ng/mL vs 0.2 ng/mL; and Tg2, 0.5 ng/mL vs 0.2 ng/mL; all differences were nonsignificant), the rate of excellent response at Tg1 was lower in the reoperation with RAI group (4 of 33 [12%] vs 24 of 51 [47%]; P = .007). Structural recurrence after reoperation occurred in 18 of 50 patients (36%) in the reoperation with RAI group and 10 of 52 patients (19%) in the reoperation without RAI group. In multivariable analysis accounting for clinicopathologic characteristics and Tg0, receipt of RAI after reoperation was not associated with the rate of a second structural recurrence. In subset analyses limited to patients with incomplete response to reoperation and patients with T3 or T4 tumors, no association between receipt of RAI and the risk of a second recurrence was found.

Conclusions and Relevance

Patients who received RAI after reoperation had outcomes similar to those in patients who underwent reoperation alone. RAI after reoperation was not associated with a significant clinical benefit in this limited series. Larger multicenter studies are required to determine whether receipt of RAI after reoperation improves outcomes among patients with recurrent PTC.