The De Novo Detection of Anti-Thyroglobulin Antibodies and Differentiated Thyroid Cancer Recurrence.

Background: The prevalence and clinical significance of de novo detection of anti-thyroglobulin antibodies (TgAbs) during the follow-up of patients with differentiated thyroid cancer (DTC) is unknown. Methods: We utilized the National Thyroid Cancer Treatment Cooperative Study registry (1987-2012). Patients registered after 1996 (n = 3318) were analyzed. We identified 1545 subjects who had available TgAb status (TgAb cohort) between years 1996 and 2012, of whom 1325 were TgAb negative at first postoperative follow-up testing. From this initial TgAb-negative group, we excluded 513 patients: 423 patients who had less than 3 years of follow-up and/or fewer than three follow-up visits, 86 patients with persistent disease after initial treatment, and 4 patients with data entry errors. The remaining 812 patients were included for analysis, comprising the TgAb persistently negative group (defined as TgAb negative for at least 3 consecutive follow-up visits and at least 3 years of follow-up) (n = 772) and the de novo TgAb-positive group in whom TgAbs became detectable (n = 40). We then assessed whether de novo appearance of TgAb was associated with DTC structural recurrence by using the Kaplan-Meier method. Results: The de novo detection of TgAb occurred in 5% of DTC patients. Recurrence of DTC in the TgAb persistently negative group compared with the de novo TgAb-positive group did not differ significantly (9.6% vs. 15.0%, p = 0.23). Baseline characteristics, histology, history of radiation exposure, staging, and median duration of follow-up were similar between the two groups. Interestingly, in all six patients who suffered a recurrence in the de novo TgAb-positive group, the TgAbs were negative at the time of recurrence detection and became positive at a median of 2.1 (0.7-8.7) years after the structural recurrence. Conclusions: Utilizing a large North American DTC registry, we found the prevalence of de novo TgAb detection to be 5% among initially TgAb-negative patients. We did not find a statistically significant association between de novo TgAb development and DTC structural recurrence. Larger prospective studies are required to confirm these findings and further assess the significance of de novo TgAb detection in the follow-up of DTC.

Reassessing the NTCTCS Staging Systems for Differentiated Thyroid Cancer, Including Age at Diagnosis.

BACKGROUND: Thyroid cancer is unique for having age as a staging variable. Recently, the commonly used age cut-point of 45 years has been questioned. OBJECTIVE: This study assessed alternate staging systems on the outcome of overall survival, and compared these with current National Thyroid Cancer Treatment Cooperative Study (NTCTCS) staging systems for papillary and follicular thyroid cancer. METHODS: A total of 4721 patients with differentiated thyroid cancer were assessed. Five potential alternate staging systems were generated at age cut-points in five-year increments from 35 to 70 years, and tested for model discrimination (Harrell's C-statistic) and calibration (R(2)). The best five models for papillary and follicular cancer were further tested with bootstrap resampling and significance testing for discrimination. RESULTS: The best five alternate papillary cancer systems had age cut-points of 45-50 years, with the highest scoring model using 50 years. No significant difference in C-statistic was found between the best alternate and current NTCTCS systems (p = 0.200). The best five alternate follicular cancer systems had age cut-points of 50-55 years, with the highest scoring model using 50 years. All five best alternate staging systems performed better compared with the current system (p = 0.003-0.035). There was no significant difference in discrimination between the best alternate system (cut-point age 50 years) and the best system of cut-point age 45 years (p = 0.197). CONCLUSIONS: No alternate papillary cancer systems assessed were significantly better than the current system. New alternate staging systems for follicular cancer appear to be better than the current NTCTCS system, although they require external validation.

Long-Term Outcomes Following Therapy in Differentiated Thyroid Carcinoma: NTCTCS Registry Analysis 1987-2012.

CONTEXT: Initial treatments for patients with differentiated thyroid cancer are supported primarily by single-institution, retrospective studies, with limited follow-up and low event rates. We report updated analyses of long-term outcomes after treatment in patients with differentiated thyroid cancer. OBJECTIVE: The objective was to examine effects of initial therapies on outcomes. DESIGN/SETTING: This was a prospective multi-institutional registry. PATIENTS: A total of 4941 patients, median follow-up, 6 years, participated. INTERVENTION: Interventions included total/near-total thyroidectomy (T/NTT), postoperative radioiodine (RAI), and thyroid hormone suppression therapy (THST). MAIN OUTCOME MEASURE: Main outcome measures were overall survival (OS) and disease-free survival using product limit and proportional hazards analyses. RESULTS: Improved OS was noted in NTCTCS stage III patients who received RAI (risk ratio [RR], 0.66; P = .04) and stage IV patients who received both T/NTT and RAI (RR, 0.66 and 0.70; combined P = .049). In all stages, moderate THST (TSH maintained subnormal-normal) was associated with significantly improved OS (RR stages I-IV: 0.13, 0.09, 0.13, 0.33) and disease-free survival (RR stages I-III: 0.52, 0.40, 0.18); no additional survival benefit was achieved with more aggressive THST (TSH maintained undetectable-subnormal). This remained true, even when distant metastatic disease was diagnosed during follow-up. Lower initial stage and moderate THST were independent predictors of improved OS during follow-up years 1-3. CONCLUSIONS: We confirm previous findings that T/NTT followed by RAI is associated with benefit in high-risk patients, but not in low-risk patients. In contrast with earlier reports, moderate THST is associated with better outcomes across all stages, and aggressive THST may not be warranted even in patients diagnosed with distant metastatic disease during follow-up. Moderate THST continued at least 3 years after diagnosis may be indicated in high-risk patients.

Unique characteristics and outcomes of patients diagnosed with both primary thyroid and primary renal cell carcinoma.

OBJECTIVE: Patients with multiple primary malignancies may exhibit unique clinical characteristics that suggest a common predisposition or lead to different disease management. Given the association of primary thyroid (TC) and renal cell carcinoma (RCC), we characterized the clinicopathologic features of patients treated for both malignancies (TC/RCC). METHODS: TC/RCC patients were identified through the institutional tumor registry and using data compiled by retrospective chart review. To compare with broader institutional and national cohorts, we examined patients admitted with TC or RCC institution-wide and reviewed the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program for these cancers. RESULTS: Overall, 51% of patients developed TC before RCC, 27% developed RCC before TC, and 22% were diagnosed within 1 year of each other. The mean age at TC diagnosis was 52 ± 15 (18-77), which was significantly older than institutional TC patients (45 ± 16.5 years, P≤.0001), and the mean age at RCC diagnosis was 59 ± 12 (32-79). The TC/RCC cohort had a balanced sex distribution (51% female) compared with the institutional TC group (67% female, P = .0003) and the institutional RCC group (31% female, P<.0001). Similar age and sex ratio differences were seen when compared with SEER cohorts. In the TC/RCC cohort, 43% of patients developed other cancers (52% of females, 33% of males; P = .04); among the females, 45% developed breast cancer. CONCLUSION: Individuals who develop both TC and RCC may represent a unique subset of cancer patients. Further prospective research is warranted to explore the unanticipated association with breast cancer in female patients and to investigate a possible common pathogenesis underlying these malignancies.

Recurrence after treatment of micropapillary thyroid cancer.

BACKGROUND: Despite very low mortality associated with micropapillary thyroid cancer, locoregional recurrence is common and controversy exists regarding optimal surgical treatment and the role of adjunctive radioiodine. METHODS: The National Thyroid Cancer Treatment Cooperative Study Group Registry was analyzed for recurrences in patients with unifocal versus multifocal micropapillary cancer, with or without nodal disease, depending upon the extent of surgery and the use of adjunctive radioiodine. Six hundred eleven patients considered disease-free after initial therapy were followed for 2572 person-years. RESULTS: Thirty patients (6.2%) had recurrences detected at a mean 2.8 years after primary treatment. Recurrences did not differ between patients with unifocal and multifocal disease overall; however, among patients who received less than a near-total thyroidectomy (NTT), those with multifocal disease had more recurrences than those with unifocal disease (18% vs. 4%, p = 0.01). Patients with multifocal disease who had a total (T) or NTT trended toward fewer recurrences than those undergoing less than an NTT (6% vs. 18%, p = 0.058). In patients who did not receive radioiodine therapy, recurrence was more common in patients with multifocal disease versus unifocal disease (7% vs. 2%, p = 0.02). However, radioiodine did not reduce recurrences in patients with multifocal disease or patients with positive nodes. Patients with positive nodes had more recurrences than node-negative patients regardless of surgical extent or use of radioiodine. CONCLUSIONS: Patients with micropapillary multifocal disease have a reduced risk of recurrence after a T/NTT compared with less surgery. A randomized, controlled trial is necessary and feasible to determine if radioiodine ablation of thyroid remnants is advantageous in patients with intrathyroidal micropapillary cancer.

Outcomes of patients with differentiated thyroid carcinoma following initial therapy.

This analysis was performed to determine the effect of initial therapy on the outcomes of thyroid cancer patients. The study setting was a prospectively followed multi-institutional registry. Patients were stratified as low risk (stages I and II) or high risk (stages III and IV). Treatments employed included near-total thyroidectomy, administration of radioactive iodine, and thyroid hormone suppression therapy. Outcome measures were overall survival, disease-specific survival, and disease-free survival. Near-total thyroidectomy, radioactive iodine, and aggressive thyroid hormone suppression therapy were each independently associated with longer overall survival in high-risk patients. Near-total thyroidectomy followed by radioactive iodine therapy, and moderate thyroid hormone suppression therapy, both predicted improved overall survival in stage II patients. No treatment modality, including lack of radioactive iodine, was associated with altered survival in stage I patients. Based on our overall survival data, we confirm that near-total thyroidectomy is indicated in high-risk patients. We also conclude that radioactive iodine therapy is beneficial for stage II, III, and IV patients. Importantly, we show for the first time that superior outcomes are associated with aggressive thyroid hormone suppression therapy in high-risk patients, but are achieved with modest suppression in stage II patients. We were unable to show any impact, positive or negative, of specific therapies in stage I patients.

Socioeconomic factors and the presentation, management, and outcome of patients with differentiated thyroid carcinoma.

To determine whether patients from disadvantaged socioeconomic groups present with more advanced thyroid carcinoma or experience differing management and clinical outcomes, we retrospectively reviewed the charts of 292 patients seen at MD Anderson Cancer Center and Ben Taub General Hospital between 1987 and 1994. At diagnosis, the mean age was 42 +/- 16 years, 78% of patients were female, 76% of patients were low risk (TNM stage I or II), and 22% high risk (stage III or IV). Neighborhood income (+/- standard error of the mean [SEM]) (1990 census data) was lower in the high-risk group compared with the low-risk group (US dollars 26200 +/- 1670 vs. US dollars 30900 +/- 870, p = 0.012). Men were more likely than women to present at an older age (47.5 +/- 16.7 vs. 40.2 +/- 16.0, p = 0.0014) and in the high-risk group (46% vs. 15%, p < 0.0001). No socioeconomic factor (ethnicity, marital status, occupation prestige, neighborhood income, insurance type) influenced initial diagnostic assessment. Similarly, no socioeconomic factor influenced initial disease management or the type of follow-up received over the 12-year period. Married patients had a lower 5-year recurrence rate than those unmarried (18% vs. 32%, p = 0.03); however, this did not affect overall or disease-specific survival. Similarly, ethnicity, marital status, occupation prestige, and insurance type did not influence overall or disease-specific survival. Although 10-year overall survival rates were lower in patients in the lowest income quartile (57% vs. 70% for upper, p = 0.0024) and in men compared with women (39% vs. 76%, p < 0.0001), gender alone influenced 10-year disease-specific survival (80% for men, 89% for women, p = 0.047). In summary, no socioeconomic factor appears to affect initial treatment or follow-up pattern in patients with differentiated thyroid cancer. Income and gender may affect stage at initial disease presentation and may be risk factors affecting eventual clinical outcomes.