Systematic Review
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Nov 6, 2019; 7(21): 3474-3485
Published online Nov 6, 2019. doi: 10.12998/wjcc.v7.i21.3474
Characteristics of clear cell renal cell carcinoma metastases to the thyroid gland: A systematic review
Karam Khaddour, Nadiia Marernych, Wendy L Ward, Jerry Liu, Theodora Pappa
Karam Khaddour, Nadiia Marernych, Theodora Pappa, Department of Medicine at Rosalind Franklin University of Medicine and Science, Chicago, IL 60050, United States
Wendy L Ward, Northwestern Medicine McHenry, Chicago, IL 60050, United States
Jerry Liu, Advocate Medical Group Oncology, Crystal Lake, IL 60014, United States
Author contributions: Khaddour K conceptualized and wrote ll the parts of the manuscript. Statistical analysis was provided by a third party and work was reviewed by all authors. Marenych N and Khaddour K collected the data for the systematic review. Ward WL contributed with original pathology pictures from our institution. Pappa T and Liu J contributed to the review of the manuscript. All authors contributed to the final production and overview of the manuscript; all authors reviewed and approved the final manuscript submitted.
Conflict-of-interest statement: Authors declare no conflict of interests for this article.
PRISMA 2009 Checklist statement: Authors revised the manuscript according to the PRISMA 2009 Checklist.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Karam Khaddour, MD, Academic Fellow, Division of Internal Medicine, Rosalind Franklin University of Medicine and Science, 4309 Medical Center Drive, Medical Office Building A, Rosalind Franklin Residency Suite, McHenry, IL 60050, United States. Karam.khaddour@gmail.com
Telephone: +1-314-7286797 Fax: +1-815-7598255
Received: May 8, 2019
Peer-review started: May 10, 2019
First decision: September 9, 2019
Revised: September 25, 2019
Accepted: October 15, 2019
Article in press: October 15, 2019
Published online: November 6, 2019
Abstract
BACKGROUND

Thyroid gland is an uncommon site for metastases from clear cell renal cell carcinoma (CCRCC) and literature is scarce. Due to the variable and often long lag time before development of metastases in patients with CCRCC, thyroid nodules may be misdiagnosed initially as benign. This systematic review aims at a better understanding of the nature of these metastases.

METHODS

A bibliographic search was performed using PubMed (1990-2019), key words being “renal cell carcinoma, thyroid, kidney cancer, clear cell.” 147 cases were analyzed. The patient’s characteristics assessed were: age, sex, stage, size of metastases, lag time, diagnostic modality, initial symptoms, treatment and outcome in last documented follow up. Binary logistic regression, Spearman’s rho and ANOVA were used to identify differences between the existing variables.

RESULTS

The mean age (± SD) was 64 ± (10) years in males and 64 (± 11) in females. The mean lag time to diagnosis of thyroid metastases was 8.7 (± 6.3) years. Gender distribution of the patients was 46.3% male, 52.4% female. There was a weak correlation between lag time and size of metastases, not statistically significant. Size of metastases was significantly higher in symptomatic patients (6.06 ± 3.51 cm) compared to those with painless mass (4.6 ± 0.29 cm) and asymptomatic ones (3.93 ± 1.99 cm) (P = 0.03). Fine Needle Aspiration was diagnostic in 29.4% of cases, 47.1% were non diagnostic. Most patients (80.3%) underwent thyroid surgery. At 1 year follow up, 55.6% of patients operated were alive versus 35.3% who did not have surgery, though this was not statistically significant (P = 0.1).

CONCLUSION

A larger size of thyroid metastasis was more likely to present with symptomatology. A high index of suspicion is warranted when evaluating thyroid nodules in CCRCC patients. There was no significant difference in outcome between patients who underwent surgery and those who did not. With the wider use of immune check-point inhibitors and tyrosine kinase inhibitors in metastatic CCRCC, surgery may eventually be reserved only for palliative purposes.

Keywords: Clear cell renal cell carcinoma, Thyroid, Metastases, Thyroidectomy

Core tip: Thyroid gland is an infrequent site for metastases from clear cell renal cell carcinoma (CCRCC) and literature regarding this topic is scarce. Due to the variable and often long lag time before development of metastases in patients with CCRCC, thyroid nodules may be misdiagnosed initially as benign. This systematic review aims at a better understanding of the nature of these metastases.