Initial Size of Metastatic Lesions Is Best Prognostic Factor in Patients with Metastatic Differentiated Thyroid Carcinoma Confined to the Lung

Automatic prediction of non-iodine-avid status in lung metastases for radioactive I131 treatment in differentiated thyroid cancer patients

Objectives

The growing incidence of differentiated thyroid cancer (DTC) have been linked to insulin resistance and metabolic syndrome. The imperative need for developing effective diagnostic imaging tools to predict the non-iodine-avid status of lung metastasis (LMs) in differentiated thyroid cancer (DTC) patients is underscored to prevent unnecessary radioactive iodine treatment (RAI).

Methods

Primary cohort consisted 1962 pretreated LMs of 496 consecutive DTC patients with pretreated initially diagnosed LMs who underwent chest CT and subsequent post-treatment radioiodine SPECT. After automatic lesion segmentation by SE V-Net, SE Net deep learning was trained to predict non-iodine-avid status of LMs. External validation cohort contained 123 pretreated LMs of 24 consecutive patients from other two hospitals. Stepwise validation was further performed according to the nodule's largest diameter.

Results

The SE-Net deep learning network yielded area under the receiver operating characteristic curve (AUC) values of 0.879 (95% confidence interval: 0.852-0.906) and 0.713 (95% confidence interval: 0.613-0.813) for internal and external validation. With the LM diameter decreasing from ≥10mm to ≤4mm, the AUCs remained relatively stable, for smallest nodules (≤4mm), the model yielded an AUC of 0.783. Decision curve analysis showed that most patients benefited using deep learning to decide radioactive I131 treatment.

Conclusion

This study presents a noninvasive, less radioactive and fully automatic approach that can facilitate suitable DTC patient selection for RAI therapy of LMs. Further prospective multicenter studies with larger study cohorts and related metabolic factors should address the possibility of comprehensive clinical transformation.

The Effect of Radioiodine Therapy on the Prognosis of Differentiated Thyroid Cancer with Lung Metastases

Lung metastasis substantially influences the survival of thyroid cancer (TC) patients. This study sought to investigate factors impacting the survival of differentiated thyroid cancer patients with lung metastases (DTC-LM) undergoing radioiodine therapy (RAI) after thyroid surgery. The retrospective study encompassed 609 TC patients with lung metastases. Survival outcomes-specifically, overall survival (OS) and thyroid cancer-specific survival (TCSS)-were examined through both univariate and multivariate Cox regression analyses. Radioiodine therapy (RAI)'s impact on DTC-LM patient survival was further assessed with the Kaplan-Meier survival curve. Of the 609 TC patients with lung metastases, 434 (71.3%) were found to have undergone thyroid surgery after a median follow-up of 59 months. Anaplastic thyroid cancer (ATC), stage IV, and lung metastases associated with other metastases were identified as risk factors for OS and TCSS in TCLM patients. RAI therapy significantly enhances survival in DTC-LM patients followed by primary site surgery under the age of 55, PTC patients, and those with single organ metastases at lung.

Long-term outcomes and prognostic factors of patients with lung metastases from differentiated thyroid cancer after radioiodine therapy in Japan

Long-term survival in patients with differentiated thyroid cancer (DTC) and lung metastasis remains unexplored in Japan. This study aimed to investigate the long-term survival and prognostic factors of radioiodine therapy (RIT) in a University Hospital setting. This retrospective study included 62 patients with lung metastases from DTC who received RIT between March 2005 and December 2016. According to the ¹³¹I whole-body scan and chest computed tomography results, lung metastases were classified as ¹³¹I-avid or non-¹³¹I-avid, and miliary, micronodular, or macronodular metastases. The 5- and 10-year overall survival (OS) rates from the initial RIT were calculated by the Kaplan-Meier method, and a proportional hazard fit analysis was performed to determine prognostic factors. With a median follow-up of 7.9 years, the 5- and 10-year OS rates from the initial RIT were 93% and 72%, respectively. Univariable and multivariable analyses of patient subgroups revealed that macronodular lung metastases (defined as nodules >1 cm), older age at initial RIT, and high thyroglobulin values (>400 ng/mL) at initial RIT predicted low OS. The 5- and 10-year OS rates of DTC patients with lung metastases were similar to those in previous Japanese reports, which included a smaller sample size compared with ours. Patients with ≤1 cm lung metastases, aged ≤55 years, and a thyroglobulin level of ≤400 ng/mL at the initial RIT had favorable outcomes.

Macroscopic extranodal extension is an independent predictor of lung metastasis in papillary thyroid cancer

PURPOSE

Lymph node metastasis is common in patients with papillary thyroid cancer (PTC). Some metastatic lymph nodes may present extranodal extension (ENE). The clinical role of ENE in PTC has yet to be clearly identified. We evaluated macroscopic ENE as a potential prognostic indicator of lung metastasis in PTC.

PATIENTS AND METHODS

We identified 1140 consecutive patients who had PTC initially resected at our cancer center. Clinical data and pathological results were reviewed. Univariate and multivariate logistic regression analyses were used to figure out the association between clinicopathological variables and lung metastasis.

RESULTS

In this cohort, 51.7% of PTC patients had lymph node metastasis; 10.4% had macroscopic ENE positive nodes; 2.3% had lung metastasis. In patients with lymph node metastasis, the average number of positive nodes was 5.10 ± 4.91. Multivariable analysis of clinicopathological factors revealed that extrathyroidal extension (odds ratio [OR], 3.57; 95% CI, 1.41-9.04), macroscopic ENE (OR, 7.08; 95% CI, 2.54-19.74), and number of positive nodes were significantly associated with lung metastasis. Compared with 0-3 positive nodes, 7-9 positive nodes denoted a moderate risk of lung metastasis (OR, 4.53; 95% CI, 1.03-19.85). And 10 positive nodes or more indicated a high risk of lung metastasis (OR, 9.63; 95% CI, 2.65-35.02).

CONCLUSION

Macroscopic ENE could serve as a strong independent prognostic factor of lungmetastasis in PTC. More attention should be paid to patients with ENE positive nodes duringfollow-up.

Volumetric burden of metastatic lesions drives outcomes in patients with extracranial oligometastatic disease

Background

We hypothesized that the total volume of metastases at initial oligometastatic (OM) presentation to stereotactic body radiation therapy (SBRT) is an important prognostic factor that can refine the definition of OM disease.

Methods

Patients with extracranial oligometastatic cancer (≤5 lesions) treated with SBRT were included in an international multi‐institutional database. Multivariable Cox and competing risks regression models were used to determine the relationship between distant progression‐free survival (DPFS), widespread progression (WSP), and overall survival (OS) with the total planning target volume (PTV) at initial OM presentation to SBRT. All models were adjusted for histology, pre‐SBRT systemic therapy, osseous‐only lesions, and number of metastases.

Results

In total, 961 patients were included. The median follow‐up was 24.4 months (IQR: 13.8–37.5). Total PTV had a significant effect on DPFS in the first 18 months after SBRT and was most profound in the first 6 months, when each twofold increase in total PTV conferred a 40.6% increased risk of distant progression (p < 0.001). Each twofold increase in total PTV increased the risk of WSP by 45.4% in the first 6 months (p < 0.001). Total PTV had a significant effect on OS in the first 2 years after SBRT, with each twofold PTV change increasing the risk of death by 60.7% during the first 6 months (p < 0.001) and by 34% thereafter (p < 0.001). Exploratory gross tumor volume (GTV) analysis confirmed the PTV‐based observations.

Conclusion

The total volumetric burden of metastases at initial OM presentation to SBRT is strongly and independently prognostic for the risk of distant and widespread progression and survival. We propose that this metric should drive the definition of OM disease and guide treatment decision‐making.

Differentiating pulmonary metastasis from benign lung nodules in thyroid cancer patients using dual-energy CT parameters

OBJECTIVES

To explore the importance of quantitative characteristics of dual-energy CT (DECT) between pulmonary metastasis and benign lung nodules in thyroid cancer.

METHODS

In this retrospective study, we identified 63 patients from our institution's database with pathologically proven thyroid cancer who underwent DECT to assess pulmonary metastasis. Among these patients, 22 had 55 pulmonary metastases, and 41 had 97 benign nodules. If nodules showed increased iodine uptake on I-131 single-photon emission computed tomography-computed tomography or increased size in follow-up CT, they were considered metastatic. We compared the clinical findings and DECT parameters of both groups and performed a receiver operating characteristic analysis to evaluate the optimal cutoff values of the DECT parameters.

RESULTS

Patients with metastases were significantly older than patients with benign nodules (p = 0.048). The DECT parameters of the metastatic nodules were significantly higher than those of the benign nodules (iodine concentration [IC], 5.61 ± 2.02 mg/mL vs. 1.61 ± 0.98 mg/mL; normalized IC [NIC], 0.60 ± 0.20 vs. 0.16 ± 0.11; NIC using pulmonary artery [NIC_PA], 0.60 ± 0.44 vs. 0.15 ± 0.11; slope of the spectral attenuation curves [λHU], 5.18 ± 2.54 vs. 2.12 ± 1.39; and Z-effective value [Z_eff], 10.0 ± 0.94 vs. 8.79 ± 0.75; all p < 0.001). In the subgroup analysis according to nodule size, all DECT parameters of the metastatic nodules in all subgroups were significantly higher than those of the benign nodules (all p < 0.05). The cutoff values for IC, NIC, λHU, NIC_PA, and Z_eff for diagnosing metastases were 3.10, 0.29, 3.57, 0.28, and 9.34, respectively (all p < 0.001).

CONCLUSIONS

DECT parameters can help to differentiate metastatic and benign lung nodules in thyroid cancer.

KEY POINTS

• DECT parameters can help to differentiate metastatic and benign lung nodules in patients with thyroid cancer. • DECT parameters showed a significant difference between benign lung nodules and lung metastases, even for nodules with diameters ≥ 3 mm and < 5 mm. • Among the DECT parameters, the highest diagnostic accuracy for differentiating pulmonary metastases from benign lung nodules was achieved with the NIC and IC, followed by the NIC_PA and λHU, and their cutoff values were 0.29, 3.10, 0.28, and 3.57, respectively.

Estimating the Growth Rate of Lung Metastases in Differentiated Thyroid Carcinoma: Response Evaluation Criteria in Solid Tumors or Doubling Time?

Background: Estimating the growth rate of lung metastases for the treatment of patients with metastases of differentiated thyroid carcinoma (DTC) is important. This study aimed to evaluate survival outcomes according to different criteria for estimating the growth rate of lung metastases. Methods: Patients with macronodular (≥1 cm) lung metastases of DTC who underwent total thyroidectomy and high-dose radioactive iodine therapy between 1995 and 2013 were enrolled. The time to progressive disease (PD) by the Response Evaluation Criteria in Solid Tumors (RECIST), average tumor volume doubling time of the two dominant target lung lesions (midDT), and thyroglobulin doubling time (TgDT) were measured in each patient, and their association with disease-specific survival (DSS) was evaluated. Results: Forty-four patients with target lung metastatic nodules with an initial maximal diameter of 1.3 cm (median) were followed-up for a median of 6.8 years after the diagnosis of lung metastases. Based on RECIST, 12 patients (27.3%) showed fast tumor progression, with time to PD <1 year. When assessed by midDT, nine patients (20.5%) had midDT ≤1 year, showing rapid tumor progression. Seven of 33 patients (21.2%) who were negative for thyroglobulin antibody had midDT <1 year. Growth rates assessed by all three criteria were significantly associated with DSS. However, midDT had the highest predictive value for DSS, with a proportion of variation explained of 33.6%. Five-year DSS was 29.6% in patients with midDT ≤1 year, 50.0% in patients with time to PD <1 year, and 42.9% in patients with TgDT <1 year. Conclusions: Among the different criteria for estimating the growth rate of metastases in patients with lung metastases of DTC, midDT was the most powerful for predicting DSS, in comparison with RECIST and TgDT. Performing at least three serial chest computed tomography scans during the first year from the diagnosis of lung metastases can facilitate early detection of patients with rapid tumor progression and provide objective guidance for initiation of systemic therapy.

The Prognosis of Papillary Thyroid Cancer with Initial Distant Metastasis is Strongly Associated with Extensive Extrathyroidal Extension: A Retrospective Cohort Study

BACKGROUND

Extensive extrathyroidal extension (ETE) has a significant role in the prognosis of papillary thyroid cancer (PTC) without distant metastasis, but its role in PTC with initial distant metastasis has never been studied. This study aimed to evaluate the prognostic significance of extensive ETE regarding disease progression, survival, and remission in PTC patients with initial distant metastasis.

METHODS

This retrospective cohort study included PTC patients with initial distant metastasis who underwent total thyroidectomy with a median follow-up period of 6.7 years. The prognostic significance of extensive ETE was assessed in terms of time to tumor progression (TTP), cancer-specific survival (CSS), and cumulative incidence of remission with all-cause death as the competing event.

RESULTS

The study enrolled 64 patients. Of these patients, 21 (32.8%) had extensive ETE, which was associated with a shorter TTP (adjusted hazard ratio [HR], 4.10; p = 0.015) and a lower CSS rate (p = 0.002, log-rank), particularly for patients 55 years of age or older with stage 4b disease (10-year CSS rate: 33.3% in those with and 92.3% in those without extensive ETE; p = 0.017). Additionally, remission was observed only in patients without extensive ETE (10-year cumulative incidence of remission: 0.0% in those with and 29.3% in those without extensive ETE; p = 0.013).

CONCLUSIONS

Extensive ETE of the primary lesion results in poorer prognoses for PTC patients with initial distant metastasis. The high CSS rate for patients with stage 4b PTC but no extensive ETE indicates that the prognosis of this patient population should be distinguished from that of other stage 4 cases.

Lung Metastases From Papillary Thyroid Cancer With Persistently Negative Thyroglobulin and Elevated Thyroglobulin Antibody Levels During Radioactive Iodine Treatment and Follow-Up: Long-Term Outcomes and Prognostic Indicators

Background: The lung is the most frequent site of distant metastasis from differentiated thyroid cancer (DTC). However, lung metastasis from papillary thyroid cancer (PTC) with persistently negative thyroglobulin (Tg) and elevated Tg antibody (TgAb) levels is an extremely rare entity, and the prognosis is therefore elusive. We investigated the clinical characteristics, long-term outcomes, and prognostic factors of lung metastases in PTC patients with persistently negative thyroglobulin (Tg) and elevated Tg antibody (TgAb) levels during radioactive iodine (¹³¹I) treatment and follow-up. Methods: We retrospectively reviewed 10,482 patients with DTC who underwent postoperative ¹³¹I treatment from 2007 to 2017 at Shanghai Sixth's People's Hospital. The relationships between progression-free survival (PFS) and several variables were assessed by univariate and multivariate analyses using the Kaplan-Meier method and a Cox proportional hazards model, respectively. Results: Forty-seven patients with PTC were enrolled in this study (4.48‰ of all patients with DTC). The median age at the initial diagnosis of lung metastasis was 39.6 ± 15.4 years, and the patients comprised 14 male and 33 female patients (male: female ratio = 1.00:2.36). Twenty-five patients had ¹³¹I avidity and 22 had non-¹³¹I avidity. At the end of the 5-years follow-up, 12 patients exhibited progressive disease (PD), and 2 patients had died. At the end of the 10-years follow-up, 21 patients showed PD and five patients had died. The 5- and 10-year PFS rates were 74.47 and 53.32%, respectively; the 5- and 10-years overall survival (OS) rates were 95.74 and 89.36%, respectively. The timing of diagnosis of lung metastases, maximal size of lung metastases, and ¹³¹I avidity were significantly associated with the 5-years PFS rate (P = 0.035, P = 0.030, and P<0.001, respectively). Only ¹³¹I avidity was associated with the 10-years PFS rate (P < 0.001). The multivariate analyses also showed that non-¹³¹I avidity were the independent poor prognostic factors for 10-years PFS at the end of follow-up (P < 0.001). Conclusions: Lung metastases from PTC in patients with persistently negative Tg and elevated TgAb levels had an excellent prognosis and survival rate during ¹³¹I treatment and follow-up. The loss of ¹³¹I avidity remained the strongest independent predictor of a poor prognosis and survival in these patients.

Prognostic Implication of N1b Classification in the Eighth Edition of the Tumor-Node-Metastasis Staging System of Differentiated Thyroid Cancer

BACKGROUND

Regional lymph node metastases (LNM) have prognostic significance in differentiated thyroid cancer (DTC). However, there was no distinction between N1a and N1b in the final staging classification in the eighth edition of the tumor-node-metastasis (TNM) staging system. This study aimed to evaluate the prognostic implication of N1b classification for predicting disease-specific survival (DSS) in DTC patients with stage I/II disease.

METHODS

A total of 3089 patients with stage I/II DTC who underwent thyroid surgery between 1996 and 2005 were included. DSS was evaluated according to N classification and number of LNM. A modification of the TNM was assessed that classified N1b cases in patients aged ≥55 years as stage IIB and the remaining cases as stage IIA.

RESULTS

The mean patient age was 45.6 years, and the median follow-up period was 10.0 years. In patients aged ≥55 years, patients with N1b had significantly poorer DSS compared to those with N0 (hazard ratio [HR] = 11.0; p < 0.001) and N1a (HR = 4.2; p = 0.013). The large-volume LNM group had significantly poorer DSS compared to the N0 (HR = 10.1; p < 0.001) and small-volume LNM (HR = 3.9; p = 0.019) groups. When patients were reclassified using the modified TNM staging system, DSS was significantly poorer in stage IIB patients than in stage IIA patients (HR = 2.9; p = 0.030).

CONCLUSIONS

N1b classification has a significant prognostic implication in patients with stage I/II DTC, especially in older patients. Modified TNM staging employing N1b classification could be more useful for the prediction of DSS.

Prognostic indicators of outcomes in patients with lung metastases from differentiated thyroid carcinoma during long-term follow-up

BACKGROUND

Distant metastases, although uncommon, represent maximum disease-related mortality in differentiated thyroid carcinoma (DTC). Lungs are the most frequent sites of metastases. We aimed to evaluate long-term outcomes and identify prognostic factors in metastatic DTC limited to the lungs.

METHODS

This retrospective study included 89 patients with DTC and metastases limited to the lungs, who were treated between 1996 and 2012 at Samsung Medical Center. Progression-free survival (PFS) and cancer-specific survival (CSS) rates were evaluated according to clinicopathologic factors. Cox regression analysis was used to identify independent factors associated with structural progressive disease (PD) and cancer-specific death.

RESULTS

With a median follow-up of 84 months, the 5- and 10-year CSS rates were 78% and 73%, respectively. Older age at diagnosis (≥55 years), radioactive iodine (RAI) nonavidity, preoperative or late diagnosis of metastasis and macro-nodular metastasis (≥1 cm) were predictive of decreased PFS and CSS. Multivariate analysis identified older age (P = .002), RAI nonavidity (P = .045) and preoperative (P = .030) or late diagnosis (P = .026) as independent predictors of structural PD. RAI avidity was also independent predictor of cancer-specific death (P = .025).

CONCLUSION

Patients with DTC and metastatic disease limited to the lungs had favourable long-term outcomes. Age, RAI avidity and timing of metastasis were found to be major factors for predicting prognosis.

Comparison of the Seventh and Eighth Editions of the American Joint Committee on Cancer/Union for International Cancer Control Tumor-Node-Metastasis Staging System for Differentiated Thyroid Cancer

OBJECTIVE

To evaluate the efficacy and prognostic validity for disease-specific survival (DSS) of the eighth edition American Joint Committee on Cancer/Union for International Cancer Control tumor-node-metastasis (TNM) staging system (TNM-8) compared to the seventh edition (TNM-7) in patients with differentiated thyroid carcinoma (DTC).

METHODS

The seventh and eighth editions of the TNM staging system were applied to 1613 DTC patients who underwent thyroid surgery between 1996 and 2003. The proportion of variation explained and Harrell's c-index were evaluated to compare the predictive capability of DSS.

RESULTS

The mean age of the patients was 44.7 years, and the median follow-up period was 11.2 years. When TNM-8 was applied, 63% of T3 and 3% of N1b DTCs were downgraded to T1/T2 and N1a, respectively. About 38% of patients were downstaged according to TNM-8. The 10-year DSS rates in TNM-7 stages I, II, III, and IV were 99.7%, 98.2%, 98.8%, and 83.2%, respectively. Those in TNM-8 stages I, II, III, and IV were 99.6%, 95.4%, 72.3%, and 48.6%, respectively. The proportion of variation explained values of TNM-7 and TNM-8 were 6.0% and 7.0%, respectively. The Harrell's c-index of TNM-7 was 0.86 and that of TNM-8 was 0.88.

CONCLUSIONS

A significant number of patients were reclassified to lower stages with the application of TNM-8 compared to TNM-7. Applying TNM-8 could improve the accuracy of the staging system for predicting DSS in patients with DTC.

Growth Kinetics of Macronodular Lung Metastases and Survival in Differentiated Thyroid Carcinoma

BACKGROUND

The clinical course of patients with lung metastases of differentiated thyroid carcinoma (DTC) vary, and cancer-specific survival (CSS) can be associated with tumor burden. This study evaluated the growth kinetics of lung metastases from DTC using serial chest computed tomography for Response Evaluation Criteria in Solid Tumors assessment and its prognostic implications.

METHODS

Forty-four patients with macronodular lung metastases (≥1 cm) of DTC were included. The time intervals to disease progression of lung metastases were measured and compared to CSS rates.

RESULTS

On the basis of the time to progression, 15 (34%), 17 (39%), and 12 (27%) patients were classified into the slow (≥3 years), moderate (1-3 years), and rapid groups (<1 year), respectively. The growth kinetics of lung metastases exhibited a linear pattern in the three groups. The doubling time of tumor burden was 1.8 years (R² = 0.973, p = 0.013) in the rapid group, and the estimated doubling time of the tumor burden in the moderate and slow groups was 5.9 years and 19.3 years, respectively. No independent variable predicted the growth kinetics of lung metastases. In multivariate analysis, disease progression within the first year was an independent predictor of CSS (hazard ratio = 8.6; p = 0.003).

CONCLUSIONS

This is the first study to demonstrate objectively that tumor growth kinetics within the first year are an independent predictor of CSS in patients with macronodular lung metastases. Performing chest computed tomography at least twice a year in the early phase of the disease in patients with macronodular lung metastases may be helpful for identifying high-risk patients who are eligible for treatment with tyrosine kinase inhibitors.