Patients with metastatic thyroid cancer frequently achieve good long-term outcomes

Patients who had differentiated thyroid cancer with distant metastases who received standard-of-care treatment often attained favorable outcomes, researchers in Israel reported.

Perspective from Constantine A. Stratakis, MD, DMedSci

“Distant metastases are not uncommon in differentiated thyroid carcinoma, with reported prevalence rates ranging widely from 4% to 23%,” Dania Hirsch, MD, of the Endocrine Institute, Rabin Medical Center in Petach Tikva, and colleagues wrote. “Nevertheless, recent series report mortality rates of approximately 3% after total thyroidectomy, indicating that patients with [differentiated thyroid carcinoma] and [distant metastases] may enjoy good outcomes in terms of [OS] and disease-specific survival.”

The researchers evaluated disease-specific survival and OS of 138 patients with differentiated thyroid cancer and distant metastases who were treated at a single medical center, investigating variables that were predictive of long-term good outcomes. Mean follow-up was 12.8 years from diagnosis and 8.2 years from the discovery of metastases.

Patients were mostly women (58.7%) and were aged a mean 54.7 years, with a mean primary tumor size 33.9 mm. The majority of patients had stage T3 or T4 disease (57.7%), the researchers reported, while 48.7% had extrathyroidal extension, and 53.5% had lymph node metastases. Roughly two-thirds (66.7%) had papillary thyroid carcinoma, while 13.8% had follicular thyroid carcinoma and 19.6% had intermediate or poorly differentiated carcinoma, Hirsch and colleagues wrote.

Among the cohort, 136 patients underwent total thyroidectomies, while 133 (96.4%) were treated with radioiodine therapy, the researchers reported. Distant metastases were synchronous in 55.1% of patients. Metastases were most common in patients’ lungs (85.6%), followed by bones (39.9%), brains (5.8%) and liver (3.6%).

By the time of the last follow-up, 24.6% of patients had achieved resolution, while 31.6% showed improvement or stabilization, and 43.4% had structurally progressive disease, the researchers reported. Fewer than half (n = 56; 40.6%) of patients died during the study. The disease-specific mortality rate was 23.2% (n = 32). Younger age, distant metastases limited to the lungs and metastatic radioiodine avidity were all associated with improved OS, the researchers wrote.

“In summary, we found that complete or partial remission might be expected in a significant percentage of patients with [differentiated thyroid cancer] and [distant metastases] treated by standard-of-care approaches,” Hirsch and colleagues wrote. “Our findings indicate that even in the presence of [distant metastases], novel therapies might be needed in only a minority of [differentiated thyroid cancer] patients. The presented data may contribute to the complex process of treatment decision-making in these patients.” – by Andy Polhamus

Disclosure: The researchers report no relevant financial disclosures.

Among those treated for metastatic thyroid cancer, 24.6% achieved resolution, 31.6% showed improvement or stabilization at 43.4% had structurally progressive disease

Perspective

Constantine A. Stratakis, MD, DMedSci

When it comes to treating endocrine tumors, to paraphrase Leo Tolstoy’s statement, non-metastatic tumors are all alike, but every malignant tumor is malignant in its own way. This is especially true for differentiated thyroid cancer and distant metastases: the natural history of this malignancy is predictably hard to predict. Every effort to help patients with differentiated thyroid cancer and their doctors in the proper choice of treatment is welcome. And it was with that goal in mind that Hirsch, et al. reported on a large cohort of patients with differentiated thyroid cancer and distant metastases. They saw 2,018 patients with differentiated thyroid cancer from 1970 to 2014 and identified 138 with distant metastases. Although several patients were seen before several modern approaches were available, the data are very valuable. Patients were mostly in their fifth and sixth decades of life; 58.7% were female. Distant metastases were found in the lungs in most patients (85.6%), and in most the lungs were the sole site of metastasis. Bone metastases occurred in 39.9%, and in few the bones were the sole site. All eight patients with brain metastases also had lung metastases; four had bone metastases. Five patients had liver metastases. Almost all patients (n = 133) received standard diagnostic work-up and treatment, including radioiodine. The site of the distant metastasis was important: None of the patients with brain and only one with liver distant metastases were disease-free at last follow-up. Overall, like other studies have shown, patients with distant metastases at multiple sites had worse prognosis that those with lung lesions only. The data showed 3 main factors for worse prognosis: older age at diagnosis, bone or multiple sites of distant metastases, and absence of radioiodine uptake by the distant metastases. Most patients, therefore those with lung-only lesions, did well: standard therapy led to complete or partial remission. The data show that the new systemic chemotherapies for differentiated thyroid cancer are only needed for a small number of patients. It would have been great if genetics were part of the study, as today the molecular signatures of both the primary tumor and the distant metastases are useful in evaluating prognosis and even response to the chosen chemotherapeutic agent. After all, “you can only predict things after they’ve happened,” as Eugene Ionesco once said – the more data we have from what has happened as these tumors metastasize, the better able we are to predict their behavior. Towards that goal, the report by Hirsch, et al., is a remarkable addition to the literature.

Constantine A. Stratakis, MD, DMedSci

Chief, Section on Genetics & Endocrinology, NICHD, NIH

Disclosures: Stratakis reports no relevant financial disclosures.

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Sources/Disclosures

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Source:

Hirsch D, et al. Endocr Pract. 2017;doi:10.4158/EP171924.OR.