Dose-volumetric Parameters for Predicting Hypothyroidism after Radiotherapy for Head and Neck Cancer

Kim, Mi Young; Yu, Tosol; Wu, Hong Gyun

doi:10.1093/jjco/hyt235

Cited by 64 publications

(73 citation statements)

References 18 publications

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“…[3,5,6] In our study, The MRT independent of thyroid volume was 52.2 Gy. Differently, some studies reported that radiation dose-volumetric parameters could be a beneficial for post-RT HT.…”

Section: Discussionsupporting

confidence: 46%

“…Similarly, some studies reported that the median periods for development of HT were between eight and 16 (range, 1-96) months. [3,5,17] For this reason, these findings suggest that post-RT HT should be considered during the entire follow-up period, especially during the first 18 months.…”

Section: Discussionmentioning

confidence: 96%

“…[12] In the present study, the incidence of HT was found as 34.4%, which is within the range of values (17-51%) reported in the literature. [3][4][5][6] This instability of the incidence ratios could be related to multiple variables such as age, sex, irradiation dose, surgery, concurrent chemoradiotherapy, and follow-up periods. Furthermore, subclinical HT (74%) constituted a higher portion of post-RT HT, and that was in agreement with some studies, [6,13] but contra to others [2,14] that found a higher proportion of clinical HT.…”

Section: Discussionmentioning

confidence: 99%

“…Differently, some studies reported that radiation dose-volumetric parameters could be a beneficial for post-RT HT. [3,5] Murthy et al [3] found that only D100 (D100: mean dose to 100% of the thyroid gland) was a significant factor influencing HT in results related with dose-volumetric parameters of the thyroid gland. However, use of dose-volumetric parameters for post-RT HT has not been clearly identified and has inconsistent results.…”

Section: Discussionmentioning

confidence: 99%

“…[2] Hypothyroidism after RT alone or in combination with surgery and/or chemotherapy for HNCs has been well reported between 17% and 51% in the literature. [3][4][5][6] However, thyroid dysfunction after RT for HNC still represents a clinically underestimated problem. [7] Our study is based on the question of "When should we be concerned for post-RT HT?"…”

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confidence: 99%

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Post-radiotherapy hypothyroidism in head and neck cancers: When should we be concerned?

Çelık¹

2017

Kulak Burun Bogaz Ihtis Derg

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Objectives:This study aims to analyze the incidence of hypothyroidism (HT) in patients who underwent radiotherapy (RT) for head and neck cancers (HNC), and to determine risk factors. Patients and Methods:This study was a retrospective analysis of patients who were treated with RT alone or in combination with surgery and/or chemotherapy between January 2005 and May 2012. Patients were grouped according to the primary tumor site, TNM staging system, age, gender, total radiation dose (TRD), mean radiation dose of thyroid gland (MRT), neck dissection, and chemotherapy.Results: A total of 90 patients who were treated with RT were analyzed. The median age was 52±13 (range, 12-87) years. The histopathologic finding of 88 patients was squamous cell carcinoma, others were adenocystic carcinoma and undifferentiated carcinoma. The median follow-up of all patients after RT was 15 (range, 6-72) months. Post-radiotherapy HT was found in 31 patients (34.4%). In this group, clinical and subclinical HT was present in eight (26%) and 23 (74%) patients, respectively. Age younger than 60 years and increased MRT (especially mean thyroid dose 20 Gy<) were significant risk factors for post-radiotherapy HT (p<0.05). Conclusion:Physicians should pay more attention to HT in patients who were treated with RT for HNC during follow-up.Keywords: Head and neck cancers; hypothyroidism; mean radiation dose of thyroid gland; radiotherapy; thyroid gland. Sonuç: Hekimler, takip sırasında HNC için RT ile tedavi edilen hastalarda HT'ye daha fazla dikkat etmelidirler.Anahtar Sözcükler: Baş ve boyun kanserleri; hipotiroidizm; tiroid bezinin ortalama radyasyon dozu; radyoterapi; tiroid bezi.

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“…[3,5,6] In our study, The MRT independent of thyroid volume was 52.2 Gy. Differently, some studies reported that radiation dose-volumetric parameters could be a beneficial for post-RT HT.…”

Section: Discussionsupporting

confidence: 46%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 3 more Smart Citations

Post-radiotherapy hypothyroidism in head and neck cancers: When should we be concerned?

Çelık¹

2017

Kulak Burun Bogaz Ihtis Derg

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Effect of dose constraint on the thyroid gland during locoregional intensity‐modulated radiotherapy in breast cancer patients

Haciislamoglu

Canyılmaz

Gedik³

et al. 2019

J Applied Clin Med Phys

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The aim of the present study was to compare radiation dose received by thyroid gland using different radiotherapy (RT) techniques with or without thyroid dose constraint (DC) for breast cancer patients. Computerized tomography (CT) image sets for 10 patients with breast cancer were selected. All patients were treated originally with opposite tangential field‐in field (FinF) for the chest wall and anteroposterior fields for the ipsilateral supraclavicular field. The thyroid gland was not contoured on the CT images at the time of the original scheduled treatment. Four new treatment plans were created for each patient, including intensity‐modulated radiotherapy (IMRT) and helical tomotherapy (HT) plans with thyroid DC exclusion and inclusion (IMRTDC(−), IMRTDC(+), HTDC(−), and HTDC(+), respectively). Thyroid DCs were used to create acceptable dose limits to avoid hypothyroidism as follows: percentage of thyroid volume exceeding 30 Gy less than 50% (V30 < 50%) and mean dose of thyroid (TDmean) ≤ 21 Gy. Dose‐volume histograms (DVHs) for TDmean and percentages of thyroid volume exceeding 10, 20, 30, 40, and 50 Gy (V10, V20, V30, V40, and V50, respectively) were also analyzed. The Dmean of the FinF, IMRTDC(−), HTDC(−), IMRTDC(+) and HTDC(+) plans were 30.56 ± 5.38 Gy, 25.56 ± 6.66 Gy, 27.48 ± 4.16 Gy, 18.57 ± 2.14 Gy, and 17.34 ± 2.70 Gy, respectively. Median V30 values were 55%, 33%, 36%, 18%, and 17%, for FinF, IMRTDC(−), HTDC(−), IMRTDC(+), and HTDC(+), respectively. Differences between treatment plans with or without DC with respect to Dmean and V30 values were statistically significant (P < 0.05). When thyroid DC during breast cancer RT was applied to IMRT and HT, the TDmean and V30 values significantly decreased. Therefore, recognition of the thyroid as an organ at risk (OAR) and the use of DCs during IMRT and HT planning to minimize radiation dose and thyroid volume exposure are recommended.

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Risk factors of early thyroid dysfunction after definitive radiotherapy in nasopharyngeal carcinoma patients

et al. 2023

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BackgroundTo explore the patterns and risk factors of early thyroid dysfunction in nasopharyngeal carcinoma (NPC) patients within 1 year after intensity‐modulated radiation therapy (IMRT).MethodsPatients with NPC who received definitive IMRT between April 2016 and April 2020 were included. All patients had normal thyroid function before definitive IMRT. The chi‐square test, Student's T‐test, Mann–Whitney U test, Kaplan–Meier method, receiver operating characteristics curve, and Cox proportional hazard analysis were used for statistical analysis.ResultsA total of 132 NPC patients were identified. Of these patients, 56 (42.4%) had hypothyroidism and 17 (12.9%) had hyperthyroidism. The median time to hypothyroidism and hyperthyroidism was 9 months (range, 1–12 months) and 1 month (range, 1–6 months) after definitive IMRT, respectively. In patients with hypothyroidism, 41 (73.2%) had subclinical hypothyroidism and 15 (26.8%) had clinical hypothyroidism. In those with hyperthyroidism, 12 patients (70.6%) had subclinical hyperthyroidism, and five patients (29.4%) had clinical hyperthyroidism. Age, clinical stage, thyroid volume, and V45 were independent risk factors for early radiation‐induced hypothyroidism within 1 year after IMRT. Patients aged <47 years, stage III/IV disease, or pre‐irradiation thyroid volume < 14 cm3 had higher risks of developing hypothyroidism.ConclusionPrimary subclinical hypothyroidism was the most common subtype of early thyroid dysfunction in NPC patients within 1 year after IMRT. Age, clinical stage, thyroid volume, and V45 were independent risk factors for early radiation‐induced hypothyroidism in NPC patients.

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Dose-volumetric Parameters for Predicting Hypothyroidism after Radiotherapy for Head and Neck Cancer

Abstract: The V45 may predict risk of developing hypothyroidism after radiotherapy for head and neck cancer, and a V45 of 50% can be a useful dose-volumetric threshold of radiation-induced hypothyroidism.

Cited by 64 publications

References 18 publications

Post-radiotherapy hypothyroidism in head and neck cancers: When should we be concerned?

Post-radiotherapy hypothyroidism in head and neck cancers: When should we be concerned?

Effect of dose constraint on the thyroid gland during locoregional intensity‐modulated radiotherapy in breast cancer patients

Risk factors of early thyroid dysfunction after definitive radiotherapy in nasopharyngeal carcinoma patients

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