Subsequent thyroid disorders associated with treatment strategy in head and neck cancer patients: a nationwide cohort study

Latissimus dorsi myocutaneous free flap for the laryngopharyngectomy defect

BACKGROUND

Partial or total laryngopharyngectomy defects have traditionally been reconstructed using the radial forearm, anterolateral thigh, or jejunal free flaps. The latissimus dorsi myocutaneous free flap (LDMFF) is an option for high-risk patients with complex laryngopharyngeal ± cutaneous neck defects.

METHODS

Retrospective single-surgeon case series from 2017 to 2022. Outcomes were assessed at both the back donor site and head and neck.

RESULTS

Twenty-four patients were identified. Flap survival was 100%. There was 1 (4.2%) pharyngocutaneous fistula and 2 (8.3%) tracheo-esophageal peristomal fistulas. At last follow-up, 17 (71%) were sustaining weight on oral intake, and 7 (29%) were G-tube dependent with 4 of these able to do some type of oral intake. Seven (29.2%) had post-operative stricture/stenosis requiring dilation. There were only minor donor site complications, all managed conservatively.

CONCLUSIONS

The LDMFF can be a robust reconstructive option, particularly for radiated high-risk patients with complex pharyngeal defects, including skin.

Development and validation of a machine learning model of radiation-induced hypothyroidism with clinical and dose-volume features

BACKGROUND AND PURPOSE

Radiation-induced hypothyroidism (RIHT) is a common but underestimated late effect in head and neck cancers. However, no consensus exists regarding risk prediction or dose constraints in RIHT. We aimed to develop a machine learning model for the accurate risk prediction of RIHT based on clinical and dose-volume features and to evaluate its performance internally and externally.

MATERIALS AND METHODS

We retrospectively searched two institutions for patients aged >20 years treated with definitive radiotherapy for nasopharyngeal or oropharyngeal cancer, and extracted their clinical information and dose-volume features. One was designated the developmental cohort, the other as the external validation cohort. We compared the performances of machine learning models with those of published normal tissue complication probability (NTCP) models.

RESULTS

The developmental and external validation cohorts consisted of 378 and 49 patients, respectively. The estimated cumulative incidence rates of grade ≥1 hypothyroidism were 53.5% and 61.3% in the developmental and external validation cohorts, respectively. Machine learning models outperformed traditional NTCP models by having lower Brier scores at every time point and a lower integrated Brier score, while demonstrating a comparable calibration index and mean area under the curve. Even simplified machine learning models using only thyroid features performed better than did traditional NTCP algorithms. The machine learning models showed consistent performance between folds. The performance in a previously unseen external validation cohort was comparable to that of the cross-validation.

CONCLUSIONS

Our model outperformed traditional NTCP models, with additional capabilities of predicting the RIHT risk at individual time points. A simplified model using only thyroid dose-volume features still outperforms traditional NTCP models and can be incorporated into future treatment planning systems for biological optimization.

An Analytical Study to Determine Dose-Volume Threshold for Radiation Induced Hypothyroidism

Objective: To determine radiation dose volume threshold in predicting the development of hypothyroidism in cancer patients following neck irradiation. Methods: This is a cross sectional follow up study for patients who had been previously irradiated, prior to enrolment in the study. We have done thyroid dose-volumetric analysis on 120 histologically proven cancer patients in the age group of 18-75 years who received neck irradiation as a part of their definitive or adjuvant radiotherapy with three-dimensional conformal or intensity-modulated radiotherapy technique (3D -CRT or IMRT) and completed at least six months post-radiotherapy. Primary tumor sites included carcinoma or lymphoma of the head and neck, breast, cervical, and upper thoracic esophagus, requiring neck irradiation. Results: The proportion of patients who tested positive for Radiation induced hypothyroidism (RIHT) was found to be 40%, with clinical hypothyroidism and subclinical hypothyroidism being 25.8% and 14.2%, respectively. Time to develop hypothyroidism peaks around two years. Mean thyroid gland dose (Dmean) >28 Gy, thyroid gland volume receiving 40 Gy dose (i.e. V40) >49% and age <50 years were found to be significant risk factors for the development of RIHT on binary logistic regression. RT dose >50 Gy and thyroid gland volume spared from 40 Gy (i.e. VS40) < 2.12cm3 were statistically significant predictors for RIHT on chi-square and (Receiver operating characteristic) ROC curve analysis respectively but not on regression analysis. Conclusion: Dose-volume threshold for the thyroid gland as Dmean <28 Gy and V40 <49% may prevent the development of RIHT.

An Underestimated Toxicity Radiation-Induced Hypothyroidism in Patients Multimodally Treated for Breast Cancer

Radiation therapy is part of the therapeutic arsenal for breast cancer, whether it is adjuvant treatment after lumpectomy or radical mastectomy, or it is used as a palliative option in the case of metastatic or recurrent disease. Significant advances in diagnostic and therapeutic stratification of breast cancers have significantly prolonged survival, even in the metastatic stage. Exposure of patients during the course of the disease in a multidisciplinary therapeutic approach including chemotherapy, hormone therapy, targeted anti-HER therapies or CDK4/6 inhibitors had led to improved survival but with the price of additional toxicity. Among them, hypothyroidism is a well-known consequence of external radiation therapy, especially in the case of cervical region irradiation, including supraclavicular and infra-clavicular nodal levels. In this situation, the thyroid gland is considered as an organ at risk (OAR) and receives a significant dose of radiation. Subclinical hypothyroidism is a common endocrine disorder characterized by elevated TSH levels with normal levels of FT4 (free T4) and FT3 (free T3), and as a late effect, primary hypothyroidism is one of the late effects that significantly affects the quality of life for patients with breast cancer receiving multimodal treatment. Hypothyroidism has a significant impact on quality of life, most often occurring as late clinical toxicity, secondary to thyroid irradiation at doses between 30 and 70 Gy. Dose-volume parameters of irradiation, gland function at the beginning of the treatment and associated systemic therapies may be factors that alter thyroid radio-sensitivity and affect thyroid gland tolerance. In the case of head and neck tumor pathology, in which doses of >50 Gy are routinely used, the thyroid gland is generally considered as an OAR, the rate of radio-induced hypothyroidism being estimated at rates of between 20% and 52%. For breast cancer, the thyroid is often neglected in terms of dosimetry protection, the rate of late dysfunction being 6–21%.

Factors predictive of the development of hypothyroidism after intensity-modulated radiation therapy for pharyngeal cancer

BACKGROUND

Hypothyroidism is a common adverse event after radiotherapy for head and neck tumors and the incidence need to be re-evaluated because of using intensity-modulated radiotherapy (IMRT).

AIMS/OBJECTIVES

Confirm the dose-volume effect of IMRT for pharyngeal cancer on hypothyroidism.

MATERIALS AND METHODS

This was a retrospective analysis of patients underwent IMRT for pharyngeal cancer from June 2011 to May 2018. Patients were classified into group A (thyroid stimulating hormone (TSH) <5μU/ml), group B (5< =TSH < 10), and group C (10< =TSH) based on TSH over 36 months post-radiation. Radiation dose, thyroid volume, and the proportion of the thyroid that received X Gy or greater (Vx) were measured.

RESULTS

Fifty-two patients were included in this work. Hypothyroidism developed in 33/52 (63%) patients, 13 in group B and 20 in group C. The mean radiation dose to the thyroid was 49.4 Gy and the median time until hypothyroidism was 39 months after irradiation. Hypothyroidism was significantly related to neck dissection (ND) and radiation dose to the thyroid. Patients whose thyroid received 45 Gy or more (V45) >67% had a significantly higher incidence of hypothyroidism.

CONCLUSIONS AND SIGNIFICANCE

Patients with pharyngeal cancer who had ND and V45 to the thyroid >67% are at risk of hypothyroidism.

Feature selection and predicting chemotherapy-induced ulcerative mucositis using machine learning methods

OBJECTIVE

Ulcerative mucositis (UM) is a devastating complication of most cancer therapies with less recognized risk factors. Whilst risk predictions are most vital in adverse events, we utilized Machine learning (ML) approaches for predicting chemotherapy-induced UM.

METHODS

We utilized 2017 National Inpatient Sample database to identify discharges with antineoplastic chemotherapy-induced UM among those received chemotherapy as part of their cancer treatment. We used forward selection and backward elimination for feature selection; lasso and Gradient Boosting Method were used for building our linear and non-linear models.

RESULTS

In 2017, there were 253 (unweighted numbers) chemotherapy-induced UM patient discharges from 21,626 (unweighted numbers) adult patients who received antineoplastic chemotherapy as part of their cancer treatment. Our linear model, lasso showed performance (C-statistics) AUC: 0.75 (test dataset), 0.75 (training dataset); the Gradient Boosting Method (GBM) model showed AUC: 0.76 in the training and 0.79 in the test datasets. The feature selection derived from stepwise forward selection and backward elimination methods showed variables of importance--antineoplastic chemotherapy-induced pancytopenia, agranulocytosis due to cancer chemotherapy, fluid and electrolyte imbalance, age, anemia due to chemotherapy, median household income, and depression. Higher importance variable derived from GBM in the order of importance were antineoplastic chemotherapy-induced pancytopenia > co-morbidity score > agranulocytosis due to cancer chemotherapy > age > and fluid and electrolyte imbalance. Further, when the analysis was stratified to females only, the ML models performed better than the unstratified model.

CONCLUSION

Our study showed ML methods performed well in predicting the chemotherapy-induced UM. Predictors identified through ML approach matched to the clinically meaningful and previously discussed predictors of the chemotherapy-induced UM.

Real-world safety and effectiveness of nivolumab for recurrent or metastatic head and neck cancer in Japan: a post-marketing surveillance

Background

On the basis of phase III CheckMate 141 results, nivolumab was approved for recurrent or metastatic head and neck cancer after undergoing platinum-containing chemotherapy in Japan. This post-marketing surveillance aimed to evaluate the safety and effectiveness of nivolumab for head and neck cancer in the real-world setting.

Methods

All patients with head and neck cancer who planned to receive nivolumab were centrally registered. This study monitored 607 patients for 6 months to assess nivolumab’s safety, especially treatment-related adverse events (TRAEs) of special interest, and effectiveness.

Results

TRAEs occurred in 36.1% patients, with no new safety signals. The most common TRAEs with grade ≥ 3 were interstitial lung disease (1.2%), diarrhea (0.8%), and hepatic function abnormal (0.7%). Meanwhile, thyroid dysfunction (10.2%), hepatic dysfunction (5.3%), and interstitial lung disease (4.1%) were the most common TRAE categories of special interest. Although the median time to the onset of each TRAE category of special interest was mostly 1–2 months, most of them occurred throughout the observation period; nonetheless, the majority of patients recovered or remitted. The 6-month survival rate was 55.9%.

Conclusion

Japanese patients with head and neck cancer treated with nivolumab in the real-world setting manifested no new safety signals.

Clinical Trial Registration

clinicaltrials.jp: JapicCTI-184071.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10147-021-01949-1.

Research progress of radiation-induced hypothyroidism in head and neck cancer

This paper reviews the factors related to hypothyroidism after radiotherapy in patients with head and neck cancer to facilitate the prevention of radiation-induced hypothyroidism and reduce its incidence. Hypothyroidism is a common complication after radiotherapy in patients with head and neck cancer, wherein the higher the radiation dose to the thyroid and pituitary gland, the higher the incidence of hypothyroidism. With prolonged follow-up time, the incidence of hypothyroidism gradually increases. Intensity modulated radiotherapy should limit the dose to the thyroid, which would reduce the incidence of hypothyroidism. In addition, the risk factors for hypothyroidism include small thyroid volume size, female sex, and previous neck surgery. The incidence of radiation-induced hypothyroidism in head and neck cancer is related to the radiation dose, radiotherapy technique, thyroid volume, sex, and age. A prospective, large sample and long-term follow-up study should be carried out to establish a model of normal tissue complications that are likely to be related to radiation-induced hypothyroidism.

A Study on Nonthermal Irreversible Electroporation of the Thyroid

Background:

Nonthermal irreversible electroporation is a minimally invasive surgery technology that employs high and brief electric fields to ablate undesirable tissues. Nonthermal irreversible electroporation can ablate only cells while preserving intact functional properties of the extracellular structures. Therefore, nonthermal irreversible electroporation can be used to ablate tissues safely near large blood vessels, the esophagus, or nerves. This suggests that it could be used for thyroid ablation abutting the esophagus. This study examines the feasibility of using nonthermal irreversible electroporation for thyroid ablation.

Methods:

Rats were used to evaluate the effects of nonthermal irreversible electroporation on the thyroid. The procedure entails the delivery of high electric field pulses (1-3 kV/cm, 100 microseconds) between 2 surface electrodes bracing the thyroid. The right lobe was treated with various nonthermal irreversible electroporation pulse sequences, and the left was the control. After 24 hours of the nonthermal irreversible electroporation treatment, the thyroid was examined with hemotoxylin and eosin histological analysis. Mathematical models of electric fields and the Joule heating-induced temperature raise in the thyroid were developed to examine the experimental results.

Results:

Treatment with nonthermal irreversible electroporation leads to follicular cells damage, associated with cell swelling, inflammatory cell infiltration, and cell ablation. Nonthermal irreversible electroporation spares the trachea structure. Unusually high electric fields, for these types of tissue, 3000 V/cm, are needed for thyroid ablation. The mathematical model suggests that this may be related to the heterogeneous structure of the thyroid-induced distortion of local electric fields. Moreover, most of the tissue does not experience thermal damage inducing temperature elevation. However, the heterogeneous structure of the thyroid may cause local hot spots with the potential for local thermal damage.

Conclusion:

Nonthermal irreversible electroporation with 3000 V/cm can be used for thyroid ablation. Possible applications are treatment of hyperthyroidism and thyroid cancer. The highly heterogeneous structure of the thyroid distorts the electric fields and temperature distribution in the thyroid must be considered when designing treatment protocols for this tissue type.