Loading…

Postoperative recurrence of papillary thyroid carcinoma with lymph node metastasis

Background and Objectives : The purpose of this study was to retrospectively analyze the features of patients with papillary thyroid carcinoma (PTC) presenting with neck lymph node (LN) metastasis. Methods : The study enrolled 909 patients with PTC who had undergone total thyroidectomy. After a medi...

Full description

Saved in:
Bibliographic Details
Published in:Journal of surgical oncology 2015-08, Vol.112 (2), p.149-154
Main Authors: Liu, Feng-Hsuan, Kuo, Sheng-Fong, Hsueh, Chuen, Chao, Tzu-Chieh, Lin, Jen-Der
Format: Article
Language:English
Subjects:
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
cited_by cdi_FETCH-LOGICAL-c4817-abb3ef05d838f792c7c4ccac4d3d3f88bb4010e6024010821bd01e0f3f61ab933
cites cdi_FETCH-LOGICAL-c4817-abb3ef05d838f792c7c4ccac4d3d3f88bb4010e6024010821bd01e0f3f61ab933
container_end_page 154
container_issue 2
container_start_page 149
container_title Journal of surgical oncology
container_volume 112
creator Liu, Feng-Hsuan
Kuo, Sheng-Fong
Hsueh, Chuen
Chao, Tzu-Chieh
Lin, Jen-Der
description Background and Objectives : The purpose of this study was to retrospectively analyze the features of patients with papillary thyroid carcinoma (PTC) presenting with neck lymph node (LN) metastasis. Methods : The study enrolled 909 patients with PTC who had undergone total thyroidectomy. After a median follow‐up of 14.6 years, 73 (8.0%) patients died of thyroid cancer. A total of 536 patients had the tumor confined to the thyroid (intra‐thyroid), 111 had lymph node (LN) metastasis, 225 showed soft tissue invasion, and 37 had distant metastasis. Results : Compared with the intra‐thyroid group, the group with LN metastases showed larger tumor size, higher postoperative thyroglobulin levels, advanced TNM stage, higher recurrence rates (5.2% vs. 31.5%), and higher disease‐specific mortality (1.3% vs. 12.6%). Of the 111 patients with PTC and LN metastases, 35 (31.5%) were diagnosed with recurrence during a mean follow‐up period of 16.9 ± 0.6 years. Among the 35 patients with recurrent PTC, 14 (40.0%) died of thyroid cancer. The mortality group was characterized by older, mostly male patients who presented with larger initial tumor size compared with survivors. Conclusions : In patients with PTC, the rates of recurrence and cancer mortality were higher in the group with LN metastasis than that in the intra‐thyroid tumor group. J. Surg. Oncol. 2015 111:149–154. © 2015 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals, Inc.
doi_str_mv 10.1002/jso.23967
format article
fullrecord <record><control><sourceid>proquest_pubme</sourceid><recordid>TN_cdi_pubmedcentral_primary_oai_pubmedcentral_nih_gov_5034820</recordid><sourceformat>XML</sourceformat><sourcesystem>PC</sourcesystem><sourcerecordid>3787508471</sourcerecordid><originalsourceid>FETCH-LOGICAL-c4817-abb3ef05d838f792c7c4ccac4d3d3f88bb4010e6024010821bd01e0f3f61ab933</originalsourceid><addsrcrecordid>eNp1kUFv1DAQhS1ERZfCgT-AInGBQ9qxncT2BamqoIBWbQVFcLMcZ8J6SeJgJy3773HZdkUrIY00h_fN0xs9Ql5QOKQA7Ggd_SHjqhKPyIKCqnIFSj4mi6SxvBAK9snTGNcAoFRVPCH7rKKi5LRYkM8XPk5-xGAmd4VZQDuHgIPFzLfZaEbXdSZssmm1Cd41mTXBusH3Jrt20yrrNv24ygbfYNbjZGIaF5-RvdZ0EZ_f7gPy9f27y5MP-fL89OPJ8TK3haQiN3XNsYWykVy2QjErbGGtsUXDG95KWdcFUMAK2M2WjNYNUISWtxU1teL8gLzd-o5z3WNjcZiC6fQYXJ8ia2-cvq8MbqV_-CtdAi8kg2Tw-tYg-F8zxkn3LlpMHw_o56ipYJSXVPIqoa8eoGs_hyG9lyioFAhWyES92VI2-BgDtrswFPRNUzo1pf82ldiX_6bfkXfVJOBoC1y7Djf_d9KfvpzfWebbCxcn_L27MOGnTqoo9bezU30BUl2W35le8j9ze65B</addsrcrecordid><sourcetype>Open Access Repository</sourcetype><iscdi>true</iscdi><recordtype>article</recordtype><pqid>1706907248</pqid></control><display><type>article</type><title>Postoperative recurrence of papillary thyroid carcinoma with lymph node metastasis</title><source>Wiley-Blackwell Read &amp; Publish Collection</source><creator>Liu, Feng-Hsuan ; Kuo, Sheng-Fong ; Hsueh, Chuen ; Chao, Tzu-Chieh ; Lin, Jen-Der</creator><creatorcontrib>Liu, Feng-Hsuan ; Kuo, Sheng-Fong ; Hsueh, Chuen ; Chao, Tzu-Chieh ; Lin, Jen-Der</creatorcontrib><description>Background and Objectives : The purpose of this study was to retrospectively analyze the features of patients with papillary thyroid carcinoma (PTC) presenting with neck lymph node (LN) metastasis. Methods : The study enrolled 909 patients with PTC who had undergone total thyroidectomy. After a median follow‐up of 14.6 years, 73 (8.0%) patients died of thyroid cancer. A total of 536 patients had the tumor confined to the thyroid (intra‐thyroid), 111 had lymph node (LN) metastasis, 225 showed soft tissue invasion, and 37 had distant metastasis. Results : Compared with the intra‐thyroid group, the group with LN metastases showed larger tumor size, higher postoperative thyroglobulin levels, advanced TNM stage, higher recurrence rates (5.2% vs. 31.5%), and higher disease‐specific mortality (1.3% vs. 12.6%). Of the 111 patients with PTC and LN metastases, 35 (31.5%) were diagnosed with recurrence during a mean follow‐up period of 16.9 ± 0.6 years. Among the 35 patients with recurrent PTC, 14 (40.0%) died of thyroid cancer. The mortality group was characterized by older, mostly male patients who presented with larger initial tumor size compared with survivors. Conclusions : In patients with PTC, the rates of recurrence and cancer mortality were higher in the group with LN metastasis than that in the intra‐thyroid tumor group. J. Surg. Oncol. 2015 111:149–154. © 2015 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals, Inc.</description><identifier>ISSN: 0022-4790</identifier><identifier>EISSN: 1096-9098</identifier><identifier>DOI: 10.1002/jso.23967</identifier><identifier>PMID: 26175314</identifier><language>eng</language><publisher>United States: Blackwell Publishing Ltd</publisher><subject>Adult ; Aged ; cancer specific survival ; Carcinoma - blood ; Carcinoma - mortality ; Carcinoma - pathology ; Carcinoma - radiotherapy ; Carcinoma - surgery ; Carcinoma, Papillary ; Disease-Free Survival ; Female ; Follow-Up Studies ; Humans ; Iodine Radioisotopes - therapeutic use ; Kaplan-Meier Estimate ; lymph node dissection ; Lymph Nodes - pathology ; Lymph Nodes - surgery ; Lymphatic Metastasis ; Male ; Middle Aged ; Neck Dissection ; Neoplasm Invasiveness ; Neoplasm Recurrence, Local - diagnosis ; Neoplasm Recurrence, Local - radiotherapy ; Neoplasm Staging ; Postoperative Period ; radioactive iodine ; Retrospective Studies ; Risk Factors ; Soft Tissue Neoplasms - diagnosis ; Soft Tissue Neoplasms - radiotherapy ; Soft Tissue Neoplasms - secondary ; thyroglobulin ; Thyroglobulin - blood ; Thyroid Cancer, Papillary ; Thyroid Neoplasms - blood ; Thyroid Neoplasms - mortality ; Thyroid Neoplasms - pathology ; Thyroid Neoplasms - radiotherapy ; Thyroid Neoplasms - surgery ; Thyroidectomy ; total thyroidectomy ; Treatment Outcome</subject><ispartof>Journal of surgical oncology, 2015-08, Vol.112 (2), p.149-154</ispartof><rights>2015 The Authors. Published by Wiley Periodicals, Inc.</rights><rights>2015 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals, Inc.</rights><rights>2015 Wiley Periodicals, Inc.</rights><lds50>peer_reviewed</lds50><oa>free_for_read</oa><woscitedreferencessubscribed>false</woscitedreferencessubscribed><citedby>FETCH-LOGICAL-c4817-abb3ef05d838f792c7c4ccac4d3d3f88bb4010e6024010821bd01e0f3f61ab933</citedby><cites>FETCH-LOGICAL-c4817-abb3ef05d838f792c7c4ccac4d3d3f88bb4010e6024010821bd01e0f3f61ab933</cites></display><links><openurl>$$Topenurl_article</openurl><openurlfulltext>$$Topenurlfull_article</openurlfulltext><thumbnail>$$Tsyndetics_thumb_exl</thumbnail><link.rule.ids>230,314,780,784,885,27924,27925</link.rule.ids><backlink>$$Uhttps://www.ncbi.nlm.nih.gov/pubmed/26175314$$D View this record in MEDLINE/PubMed$$Hfree_for_read</backlink></links><search><creatorcontrib>Liu, Feng-Hsuan</creatorcontrib><creatorcontrib>Kuo, Sheng-Fong</creatorcontrib><creatorcontrib>Hsueh, Chuen</creatorcontrib><creatorcontrib>Chao, Tzu-Chieh</creatorcontrib><creatorcontrib>Lin, Jen-Der</creatorcontrib><title>Postoperative recurrence of papillary thyroid carcinoma with lymph node metastasis</title><title>Journal of surgical oncology</title><addtitle>J. Surg. Oncol</addtitle><description>Background and Objectives : The purpose of this study was to retrospectively analyze the features of patients with papillary thyroid carcinoma (PTC) presenting with neck lymph node (LN) metastasis. Methods : The study enrolled 909 patients with PTC who had undergone total thyroidectomy. After a median follow‐up of 14.6 years, 73 (8.0%) patients died of thyroid cancer. A total of 536 patients had the tumor confined to the thyroid (intra‐thyroid), 111 had lymph node (LN) metastasis, 225 showed soft tissue invasion, and 37 had distant metastasis. Results : Compared with the intra‐thyroid group, the group with LN metastases showed larger tumor size, higher postoperative thyroglobulin levels, advanced TNM stage, higher recurrence rates (5.2% vs. 31.5%), and higher disease‐specific mortality (1.3% vs. 12.6%). Of the 111 patients with PTC and LN metastases, 35 (31.5%) were diagnosed with recurrence during a mean follow‐up period of 16.9 ± 0.6 years. Among the 35 patients with recurrent PTC, 14 (40.0%) died of thyroid cancer. The mortality group was characterized by older, mostly male patients who presented with larger initial tumor size compared with survivors. Conclusions : In patients with PTC, the rates of recurrence and cancer mortality were higher in the group with LN metastasis than that in the intra‐thyroid tumor group. J. Surg. Oncol. 2015 111:149–154. © 2015 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals, Inc.</description><subject>Adult</subject><subject>Aged</subject><subject>cancer specific survival</subject><subject>Carcinoma - blood</subject><subject>Carcinoma - mortality</subject><subject>Carcinoma - pathology</subject><subject>Carcinoma - radiotherapy</subject><subject>Carcinoma - surgery</subject><subject>Carcinoma, Papillary</subject><subject>Disease-Free Survival</subject><subject>Female</subject><subject>Follow-Up Studies</subject><subject>Humans</subject><subject>Iodine Radioisotopes - therapeutic use</subject><subject>Kaplan-Meier Estimate</subject><subject>lymph node dissection</subject><subject>Lymph Nodes - pathology</subject><subject>Lymph Nodes - surgery</subject><subject>Lymphatic Metastasis</subject><subject>Male</subject><subject>Middle Aged</subject><subject>Neck Dissection</subject><subject>Neoplasm Invasiveness</subject><subject>Neoplasm Recurrence, Local - diagnosis</subject><subject>Neoplasm Recurrence, Local - radiotherapy</subject><subject>Neoplasm Staging</subject><subject>Postoperative Period</subject><subject>radioactive iodine</subject><subject>Retrospective Studies</subject><subject>Risk Factors</subject><subject>Soft Tissue Neoplasms - diagnosis</subject><subject>Soft Tissue Neoplasms - radiotherapy</subject><subject>Soft Tissue Neoplasms - secondary</subject><subject>thyroglobulin</subject><subject>Thyroglobulin - blood</subject><subject>Thyroid Cancer, Papillary</subject><subject>Thyroid Neoplasms - blood</subject><subject>Thyroid Neoplasms - mortality</subject><subject>Thyroid Neoplasms - pathology</subject><subject>Thyroid Neoplasms - radiotherapy</subject><subject>Thyroid Neoplasms - surgery</subject><subject>Thyroidectomy</subject><subject>total thyroidectomy</subject><subject>Treatment Outcome</subject><issn>0022-4790</issn><issn>1096-9098</issn><fulltext>true</fulltext><rsrctype>article</rsrctype><creationdate>2015</creationdate><recordtype>article</recordtype><sourceid>24P</sourceid><recordid>eNp1kUFv1DAQhS1ERZfCgT-AInGBQ9qxncT2BamqoIBWbQVFcLMcZ8J6SeJgJy3773HZdkUrIY00h_fN0xs9Ql5QOKQA7Ggd_SHjqhKPyIKCqnIFSj4mi6SxvBAK9snTGNcAoFRVPCH7rKKi5LRYkM8XPk5-xGAmd4VZQDuHgIPFzLfZaEbXdSZssmm1Cd41mTXBusH3Jrt20yrrNv24ygbfYNbjZGIaF5-RvdZ0EZ_f7gPy9f27y5MP-fL89OPJ8TK3haQiN3XNsYWykVy2QjErbGGtsUXDG95KWdcFUMAK2M2WjNYNUISWtxU1teL8gLzd-o5z3WNjcZiC6fQYXJ8ia2-cvq8MbqV_-CtdAi8kg2Tw-tYg-F8zxkn3LlpMHw_o56ipYJSXVPIqoa8eoGs_hyG9lyioFAhWyES92VI2-BgDtrswFPRNUzo1pf82ldiX_6bfkXfVJOBoC1y7Djf_d9KfvpzfWebbCxcn_L27MOGnTqoo9bezU30BUl2W35le8j9ze65B</recordid><startdate>20150801</startdate><enddate>20150801</enddate><creator>Liu, Feng-Hsuan</creator><creator>Kuo, Sheng-Fong</creator><creator>Hsueh, Chuen</creator><creator>Chao, Tzu-Chieh</creator><creator>Lin, Jen-Der</creator><general>Blackwell Publishing Ltd</general><general>Wiley Subscription Services, Inc</general><general>John Wiley and Sons Inc</general><scope>BSCLL</scope><scope>24P</scope><scope>WIN</scope><scope>CGR</scope><scope>CUY</scope><scope>CVF</scope><scope>ECM</scope><scope>EIF</scope><scope>NPM</scope><scope>AAYXX</scope><scope>CITATION</scope><scope>K9.</scope><scope>7X8</scope><scope>5PM</scope></search><sort><creationdate>20150801</creationdate><title>Postoperative recurrence of papillary thyroid carcinoma with lymph node metastasis</title><author>Liu, Feng-Hsuan ; Kuo, Sheng-Fong ; Hsueh, Chuen ; Chao, Tzu-Chieh ; Lin, Jen-Der</author></sort><facets><frbrtype>5</frbrtype><frbrgroupid>cdi_FETCH-LOGICAL-c4817-abb3ef05d838f792c7c4ccac4d3d3f88bb4010e6024010821bd01e0f3f61ab933</frbrgroupid><rsrctype>articles</rsrctype><prefilter>articles</prefilter><language>eng</language><creationdate>2015</creationdate><topic>Adult</topic><topic>Aged</topic><topic>cancer specific survival</topic><topic>Carcinoma - blood</topic><topic>Carcinoma - mortality</topic><topic>Carcinoma - pathology</topic><topic>Carcinoma - radiotherapy</topic><topic>Carcinoma - surgery</topic><topic>Carcinoma, Papillary</topic><topic>Disease-Free Survival</topic><topic>Female</topic><topic>Follow-Up Studies</topic><topic>Humans</topic><topic>Iodine Radioisotopes - therapeutic use</topic><topic>Kaplan-Meier Estimate</topic><topic>lymph node dissection</topic><topic>Lymph Nodes - pathology</topic><topic>Lymph Nodes - surgery</topic><topic>Lymphatic Metastasis</topic><topic>Male</topic><topic>Middle Aged</topic><topic>Neck Dissection</topic><topic>Neoplasm Invasiveness</topic><topic>Neoplasm Recurrence, Local - diagnosis</topic><topic>Neoplasm Recurrence, Local - radiotherapy</topic><topic>Neoplasm Staging</topic><topic>Postoperative Period</topic><topic>radioactive iodine</topic><topic>Retrospective Studies</topic><topic>Risk Factors</topic><topic>Soft Tissue Neoplasms - diagnosis</topic><topic>Soft Tissue Neoplasms - radiotherapy</topic><topic>Soft Tissue Neoplasms - secondary</topic><topic>thyroglobulin</topic><topic>Thyroglobulin - blood</topic><topic>Thyroid Cancer, Papillary</topic><topic>Thyroid Neoplasms - blood</topic><topic>Thyroid Neoplasms - mortality</topic><topic>Thyroid Neoplasms - pathology</topic><topic>Thyroid Neoplasms - radiotherapy</topic><topic>Thyroid Neoplasms - surgery</topic><topic>Thyroidectomy</topic><topic>total thyroidectomy</topic><topic>Treatment Outcome</topic><toplevel>peer_reviewed</toplevel><toplevel>online_resources</toplevel><creatorcontrib>Liu, Feng-Hsuan</creatorcontrib><creatorcontrib>Kuo, Sheng-Fong</creatorcontrib><creatorcontrib>Hsueh, Chuen</creatorcontrib><creatorcontrib>Chao, Tzu-Chieh</creatorcontrib><creatorcontrib>Lin, Jen-Der</creatorcontrib><collection>Istex</collection><collection>Wiley Online Library Open Access</collection><collection>Wiley-Blackwell Free Backfiles(OpenAccess)</collection><collection>Medline</collection><collection>MEDLINE</collection><collection>MEDLINE (Ovid)</collection><collection>MEDLINE</collection><collection>MEDLINE</collection><collection>PubMed</collection><collection>CrossRef</collection><collection>ProQuest Health &amp; Medical Complete (Alumni)</collection><collection>MEDLINE - Academic</collection><collection>PubMed Central (Full Participant titles)</collection><jtitle>Journal of surgical oncology</jtitle></facets><delivery><delcategory>Remote Search Resource</delcategory><fulltext>fulltext</fulltext></delivery><addata><au>Liu, Feng-Hsuan</au><au>Kuo, Sheng-Fong</au><au>Hsueh, Chuen</au><au>Chao, Tzu-Chieh</au><au>Lin, Jen-Der</au><format>journal</format><genre>article</genre><ristype>JOUR</ristype><atitle>Postoperative recurrence of papillary thyroid carcinoma with lymph node metastasis</atitle><jtitle>Journal of surgical oncology</jtitle><addtitle>J. Surg. Oncol</addtitle><date>2015-08-01</date><risdate>2015</risdate><volume>112</volume><issue>2</issue><spage>149</spage><epage>154</epage><pages>149-154</pages><issn>0022-4790</issn><eissn>1096-9098</eissn><abstract>Background and Objectives : The purpose of this study was to retrospectively analyze the features of patients with papillary thyroid carcinoma (PTC) presenting with neck lymph node (LN) metastasis. Methods : The study enrolled 909 patients with PTC who had undergone total thyroidectomy. After a median follow‐up of 14.6 years, 73 (8.0%) patients died of thyroid cancer. A total of 536 patients had the tumor confined to the thyroid (intra‐thyroid), 111 had lymph node (LN) metastasis, 225 showed soft tissue invasion, and 37 had distant metastasis. Results : Compared with the intra‐thyroid group, the group with LN metastases showed larger tumor size, higher postoperative thyroglobulin levels, advanced TNM stage, higher recurrence rates (5.2% vs. 31.5%), and higher disease‐specific mortality (1.3% vs. 12.6%). Of the 111 patients with PTC and LN metastases, 35 (31.5%) were diagnosed with recurrence during a mean follow‐up period of 16.9 ± 0.6 years. Among the 35 patients with recurrent PTC, 14 (40.0%) died of thyroid cancer. The mortality group was characterized by older, mostly male patients who presented with larger initial tumor size compared with survivors. Conclusions : In patients with PTC, the rates of recurrence and cancer mortality were higher in the group with LN metastasis than that in the intra‐thyroid tumor group. J. Surg. Oncol. 2015 111:149–154. © 2015 The Authors. Journal of Surgical Oncology Published by Wiley Periodicals, Inc.</abstract><cop>United States</cop><pub>Blackwell Publishing Ltd</pub><pmid>26175314</pmid><doi>10.1002/jso.23967</doi><tpages>6</tpages><oa>free_for_read</oa></addata></record>
fulltext fulltext
identifier ISSN: 0022-4790
ispartof Journal of surgical oncology, 2015-08, Vol.112 (2), p.149-154
issn 0022-4790
1096-9098
language eng
recordid cdi_pubmedcentral_primary_oai_pubmedcentral_nih_gov_5034820
source Wiley-Blackwell Read & Publish Collection
subjects Adult
Aged
cancer specific survival
Carcinoma - blood
Carcinoma - mortality
Carcinoma - pathology
Carcinoma - radiotherapy
Carcinoma - surgery
Carcinoma, Papillary
Disease-Free Survival
Female
Follow-Up Studies
Humans
Iodine Radioisotopes - therapeutic use
Kaplan-Meier Estimate
lymph node dissection
Lymph Nodes - pathology
Lymph Nodes - surgery
Lymphatic Metastasis
Male
Middle Aged
Neck Dissection
Neoplasm Invasiveness
Neoplasm Recurrence, Local - diagnosis
Neoplasm Recurrence, Local - radiotherapy
Neoplasm Staging
Postoperative Period
radioactive iodine
Retrospective Studies
Risk Factors
Soft Tissue Neoplasms - diagnosis
Soft Tissue Neoplasms - radiotherapy
Soft Tissue Neoplasms - secondary
thyroglobulin
Thyroglobulin - blood
Thyroid Cancer, Papillary
Thyroid Neoplasms - blood
Thyroid Neoplasms - mortality
Thyroid Neoplasms - pathology
Thyroid Neoplasms - radiotherapy
Thyroid Neoplasms - surgery
Thyroidectomy
total thyroidectomy
Treatment Outcome
title Postoperative recurrence of papillary thyroid carcinoma with lymph node metastasis
url http://sfxeu10.hosted.exlibrisgroup.com/loughborough?ctx_ver=Z39.88-2004&ctx_enc=info:ofi/enc:UTF-8&ctx_tim=2025-01-01T05%3A25%3A08IST&url_ver=Z39.88-2004&url_ctx_fmt=infofi/fmt:kev:mtx:ctx&rfr_id=info:sid/primo.exlibrisgroup.com:primo3-Article-proquest_pubme&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.genre=article&rft.atitle=Postoperative%20recurrence%20of%20papillary%20thyroid%20carcinoma%20with%20lymph%20node%20metastasis&rft.jtitle=Journal%20of%20surgical%20oncology&rft.au=Liu,%20Feng-Hsuan&rft.date=2015-08-01&rft.volume=112&rft.issue=2&rft.spage=149&rft.epage=154&rft.pages=149-154&rft.issn=0022-4790&rft.eissn=1096-9098&rft_id=info:doi/10.1002/jso.23967&rft_dat=%3Cproquest_pubme%3E3787508471%3C/proquest_pubme%3E%3Cgrp_id%3Ecdi_FETCH-LOGICAL-c4817-abb3ef05d838f792c7c4ccac4d3d3f88bb4010e6024010821bd01e0f3f61ab933%3C/grp_id%3E%3Coa%3E%3C/oa%3E%3Curl%3E%3C/url%3E&rft_id=info:oai/&rft_pqid=1706907248&rft_id=info:pmid/26175314&rfr_iscdi=true