Topology-based radiomic features for prediction of parotid gland cancer malignancy grade in magnetic resonance images.

PURPOSE: The malignancy grades of parotid gland cancer (PGC) have been assessed for a decision of treatment policies. Therefore, we have investigated the feasibility of topology-based radiomic features for the prediction of parotid gland cancer (PGC) malignancy grade in magnetic resonance (MR) images. MATERIALS AND METHODS: Two-dimensional T1- and T2-weighted MR images of 39 patients with PGC were selected for this study. Imaging properties of PGC can be quantified using the topology, which could be useful for assessing the number of the k-dimensional holes or heterogeneity in PGC regions using invariants of the Betti numbers. Radiomic signatures were constructed from 41,472 features obtained after a harmonization using an elastic net model. PGC patients were stratified using a logistic classification into low/intermediate- and high-grade malignancy groups. The training data were increased by four times to avoid the overfitting problem using a synthetic minority oversampling technique. The proposed approach was assessed using a 4-fold cross-validation test. RESULTS: The highest accuracy of the proposed approach was 0.975 for the validation cases, whereas that of the conventional approach was 0.694. CONCLUSION: This study indicated that topology-based radiomic features could be feasible for the noninvasive prediction of the malignancy grade of PGCs.

Intraparotid node metastasis affects the long-term survival of patients with resectable recurrent parotid gland carcinoma.

PURPOSE: The recurrence rate of parotid gland cancer is high, but research on the prognosis of recurrent parotid gland cancer (RPC) is relatively limited. We aim to determine the potential prognosis factors of RPC. STUDY DESIGN: Retrospective cohort analysis. SETTING: Tertiary cancer center. METHODS: We conducted a retrospective review from 2012 to 2021 on RPC patients treated at the China National Cancer Center (CNCC). To analyze the impact of various variables on overall survival (OS) after recurrence, a univariate and multivariate Cox proportional hazard model was employed. RESULTS: A total of 50/218 (23.0%) patients diagnosed with RPC and underwent surgery. The 5-year OS of all RPC patients in this cohort was 61.9%. 5 of 50 patients (10%) exhibited intraparotid node (IPN) metastasis. By univariate and multivariate analyses, we found that IPN metastasis was one of the prognostic factors of OS (p = 0.039) in RPC patients. The presence of IPN metastasis was also related to poor survival in individuals with negative cervical lymph nodes (CN0) (p = 0.011). In terms of the influence of surgical margins on prognosis, our findings revealed that RPC patients with negative margins exhibited a higher survival result than those with positive margins (p = 0.002). CONCLUSION: According to this study, IPN metastasis indicate a high incidence of mortality in recurrent parotid cancer patients. Particularly, in CN0 patients, the presence of IPN metastasis was associated with poor survival in CN0 patients.

Number of positive lymph nodes combined with the logarithmic ratio of positive lymph nodes predicts long-term survival for patients with node-positive parotid gland carcinoma after surgery: a SEER population-based study.

PURPOSE: To evaluate the prognostic value of the number of positive lymph nodes (NPLN), the ratio of positive lymph nodes (pLNR), and the logarithmic ratio of positive lymph nodes (LODDS) in patients with parotid gland carcinoma. On this basis, establishing and validating an optimal nomogram. METHODS: A total of 895 patients with T1-4N1-3M0 parotid gland carcinoma were included in our study from the Surveillance, Epidemiology, and End Results (SEER) database. Patients' data were randomly assigned to the training cohort and the validation cohort by a ratio of 7:3. Univariate and multivariate COX regression analysis were used to explore the relationship between the study factors and the prognosis of parotid gland carcinoma, including overall survival (OS) and cause-specific survival (CSS). The Akaike Information Criterion (AIC) was used to evaluate model fit. Harrell's concordance index (C-index), integrated discrimination improvement (IDI), and net reclassification index (NRI) were used to evaluate the predictive ability of these models. The decision curve analysis was used to evaluate the clinical benefit of the nomograms compared with the TNM stage. RESULTS: NPLN, pLNR, and LODDS are independent risk factors for the prognostic of PGC. According to the AIC, C index, IDI, and NRI, the models combined with NPLN and LODDS were the best. The decision curves suggested that our nomograms had good predictive abilities for the prognosis of parotid gland carcinoma. CONCLUSION: The two nomograms which contained NPLN and LODDS had the potential to predict OS and CSS in patients with parotid gland carcinoma.

Current Issues in Treatment of Parotid Gland Cancer and Advanced Surgical Technique of Robotic Parotidectomy.

PURPOSE OF REVIEW: This paper analyzed previous research data to identify the most important issues to be considered during treatment of parotid gland cancer (PGC) and reviewed recent advancements in techniques in parotid surgery. RECENT FINDINGS: For successful treatment of PGC, a preoperative surgical plan should be designed with consideration of the histologic characteristics and anatomical complexity of the tumor, and the functional and anatomical integrity of the facial nerve should be carefully inspected during surgery and damage to the nerve minimized. The need for adjuvant radiotherapy should be determined based on intraoperative findings and pathologic findings of the specimen after surgery. Surgery and radiotherapy are the main treatment options for PGC. To optimize treatment outcomes for PGC, the extent of surgery should be decided according to histologic characteristics and extent of tumor resection, and use of adjuvant radiotherapy should be considered based on risk stratification.

Radiotherapy for cutaneous head and neck cancer and parotid tumours: a prospective investigation of treatment-related acute swallowing and toxicity patterns.

PURPOSE: Reports of acute treatment-related dysphagia and toxicities for patients with parotid tumours or cutaneous head and neck cancer (HNC) are limited. This study aimed to describe the severity and timing of dysphagia and related toxicities experienced during radiotherapy for cutaneous HNC and parotid tumours, to inform the nature of future speech pathology (SP) service models required during treatment. METHODS: Prospective study of 32 patients with parotid tumours and 36 with cutaneous HNC undergoing curative non-surgical management. Dysphagia and acute toxicity data was collected weekly during treatment and at 2, 4 and 12 weeks post-treatment using the Functional Oral Intake Scale, diet descriptors and CTCAE v4.0. RESULTS: In both groups, minimal treatment toxicities (grades 0-1) were observed. Xerostomia and dysgeusia were the most frequently reported grade 2 toxicities. Only 3% of parotid patients and 6% with cutaneous HNC experienced grade 3 dysphagia. Full or soft texture diets were maintained by > 70% of patients in both groups. Symptoms peaked in the final week of treatment and rapidly improved thereafter. Apart from xerostomia < 10% of patients had any grade 2 toxicity at 12 weeks post-treatment. CONCLUSION: Patients in these subgroups of HNC experienced minimal treatment-related toxicity during radiotherapy. As such, the need for supportive symptom management by SP is low. Models that involve interdisciplinary surveillance of symptoms with referral to SP only when required may be best suited for these individuals to ensure issues are identified whilst minimising patient burden created by unnecessary routine SP appointments.

Superselective intra-arterial chemotherapy with concurrent radiotherapy for advanced parotid squamous cell carcinoma: a case report.

A case of advanced parotid cancer in which long-term control was achieved by superselective intra-arterial cisplatin infusion with concomitant radiotherapy is reported. A 63-year-old woman with parotid squamous cell carcinoma was referred to our hospital. Magnetic resonance images revealed extraparotid extension of the tumor, indicating that complete resection would be difficult. Consequently, intra-arterial cisplatin infusion with concomitant radiotherapy was planned as an alternative therapy. Superselective intra-arterial infusion of cisplatin (100 mg/m(2)) was performed six times, at intervals of 7-9 days. The arteries chosen for superselective infusion were the posterior auricular artery, the transverse facial artery and the intrinsic parotid artery originating directly from the external carotid artery. Concurrently, external radiotherapy of a total of 50 Gy in 25 fractions was also performed. The patient achieved a complete response and has remained free of disease recurrence 5 years after treatment. Intra-arterial cisplatin infusion with concomitant radiotherapy can be a practical option for patients with unresectable parotid squamous cell carcinoma.

Dosimetric and NTCP analyses for selecting parotid gland cancer patients for proton therapy.

PURPOSE/OBJECTIVE: To perform a dosimetric and a normal tissue complication probability (NTCP) comparison between intensity modulated proton therapy and photon volumetric modulated arc therapy in a cohort of patients with parotid gland cancers in a post-operative or radical setting. MATERIALS AND METHODS: From May 2011 to September 2021, 37 parotid gland cancers patients treated at two institutions were eligible. Inclusion criteria were as follows: patients aged ⩾ 18 years, diagnosis of parotid gland cancers candidate for postoperative radiotherapy or definitive radiotherapy, presence of written informed consent for the use of anonymous data for research purposes. Organs at risk (OARs) were retrospectively contoured. Target coverage goal was defined as D95 > 98%. Six NTCP models were selected. NTCP profiles were calculated for each patient using an internally-developed Python script in RayStation TPS. Average differences in NTCP between photon and proton plans were tested for significance with a two-sided Wilcoxon signed-rank test. RESULTS: Seventy-four plans were generated. A lower Dmean to the majority of organs at risk (inner ear, cochlea, oral cavity, pharyngeal constrictor muscles, contralateral parotid and submandibular gland) was obtained with intensity modulated proton therapy vs volumetric modulated arc therapy with statistical significance (p < .05). Ten (27%) patients had a difference in NTCP (photon vs proton plans) greater than 10% for hearing loss and tinnitus: among them, seven qualified for both endpoints, two patients for hearing loss only, and one for tinnitus. CONCLUSIONS: In the current study, nearly one-third of patients resulted eligible for proton therapy and they were the most likely to benefit in terms of prevention of hearing loss and tinnitus.

An end-to-end deep convolutional neural network-based dose engine for parotid gland cancer seed implant brachytherapy.

BACKGROUND: Seed implant brachytherapy (SIBT) is a promising treatment modality for parotid gland cancers (PGCs). However, the current clinical standard dose calculation method based on the American Association of Physicists in Medicine (AAPM) Task Group 43 (TG-43) Report oversimplifies patient anatomy as a homogeneous water phantom medium, leading to significant dose calculation errors due to heterogeneity surrounding the parotid gland. Monte Carlo Simulation (MCS) can yield accurate dose distributions but the long computation time hinders its wide application in clinical practice. PURPOSE: This paper aims to develop an end-to-end deep convolutional neural network-based dose engine (DCNN-DE) to achieve fast and accurate dose calculation for PGC SIBT. METHODS: A DCNN model was trained using the patient's CT images and TG-43-based dose maps as inputs, with the corresponding MCS-based dose maps as the ground truth. The DCNN model was enhanced based on our previously proposed model by incorporating attention gates (AGs) and large kernel convolutions. Training and evaluation of the model were performed using a dataset comprising 188 PGC I-125 SIBT patient cases, and its transferability was tested on an additional 16 non-PGC head and neck cancers (HNCs) I-125 SIBT patient cases. Comparison studies were conducted to validate the superiority of the enhanced model over the original one and compare their overall performance. RESULTS: On the PGC testing dataset, the DCNN-DE demonstrated the ability to generate accurate dose maps, with percentage absolute errors (PAEs) of 0.67% ± 0.47% for clinical target volume (CTV) D90 and 1.04% ± 1.33% for skin D0.1cc. The comparison studies revealed that incorporating AGs and large kernel convolutions resulted in 8.2% (p < 0.001) and 3.1% (p < 0.001) accuracy improvement, respectively, as measured by dose mean absolute error. On the non-PGC HNC dataset, the DCNN-DE exhibited good transferability, achieving a CTV D90 PAE of 1.88% ± 1.73%. The DCNN-DE can generate a dose map in less than 10 ms. CONCLUSIONS: We have developed and validated an end-to-end DCNN-DE for PGC SIBT. The proposed DCNN-DE enables fast and accurate dose calculation, making it suitable for application in the plan optimization and evaluation process of PGC SIBT.

Parotid Gland Cancer With First Bite Syndrome Detected via CT-Guided Fine Needle Aspiration Cytology.

BACKGROUND/AIM: First bite syndrome (FBS) is a symptom of severe pain at the beginning of a meal that lessens as the meal progresses. It is a common postoperative complication of parapharyngeal space tumors and is rarely reported as the first symptom of parotid carcinoma. The parapharyngeal space is considered a difficult area for approach; hence, preoperative histopathology is often challenging. However, there are hardly any reports on the approach of performing biopsies under computerized tomography (CT) guidance. CASE REPORT: A 28-year-old woman presented to our hospital with the chief complaint of pain in the left parotid region since the past year. Contrast-enhanced magnetic resonance imaging of the parotid gland revealed a 10-mm high-signal area on T2-weighted images extending from the deep lobe of the left parotid gland to the parapharyngeal space, which could not be visualized on ultrasound. She was suspected to have a malignant tumor because of the presence of a parotid tumor with FBS. Therefore, she underwent CT-guided fine-needle aspiration cytology (FNAC) and was diagnosed with adenoid cystic carcinoma. The patient underwent left parotid tumor resection and left cervical dissection, and her pain during feeding improved postoperatively. CONCLUSION: In a patient with parotid tumor extending into the parapharyngeal space with FBS as the initial symptom, CT-guided FNAC was successfully used to diagnose parotid carcinoma. Symptoms of pain, including FBS, should be considered in cases of malignancy. CT-guided FNAC is effective for lesions that cannot be visualized by ultrasound, such as those in the parapharyngeal space.

Differential expression of TRKB tyrosine kinase in the two histological types of parotid salivary duct carcinoma with cancer aggressiveness.

Parotid salivary duct carcinoma (SDC) is a rare and aggressive parotid gland carcinoma (PGC). SDC has two origins: de novo and ex pleomorphic adenoma (SDC ex PA); however, because of its rarity, the clinical and molecular features of the two types of SDC are not sufficiently understood. Here, we studied the differences in their clinicopathological and molecular features using clinical specimens while comparing them to those of adenoid cystic carcinoma (AdCC), an intermediate-grade PGC. Clinicopathological analysis of tissues from patients with PGC revealed significant associations between histological types and malignant phenotypes, including nodal metastasis, recurrence, vascular invasion, and neural invasion, and revealed more malignant phenotypes of de novo SDC than of SDC ex PA. The de novo SDC showed a significantly higher frequency of intra-neural invasion (intra-NI) and vascular invasion than AdCC and SDC ex PA. PGCs with high intra-NI were significantly correlated with malignant phenotypes and survival rates. Recently, we observed the overexpression of tropomyosin receptor kinase B (TRKB), a receptor tyrosine kinase, in PGC cells. Here, immunohistochemical and clinicopathological analyses showed that TRKB was highly expressed in SDC cells, particularly de novo SDC cells, and was significantly associated with poor survival and highly malignant phenotypes, including intra-NI and vascular invasion. Collectively, these data show that TRKB expression is significantly elevated in PGC, particularly in de novo SDC, and can be one of the biomarkers of their aggressiveness.

Irreversible facial nerve palsy as a revelator ofparotid gland cancer.

<br><b>Introduction:</b> Bell's palsy is still the diagnosis of exclusion. In most patients it does not progress, it is unilateral, and selflimiting. Additionally, the majority of patients recover spontaneously within 3 weeks. It is well known that all patients with irreversible facial nerve paresis (FNP) need further examinations to exclude the organic, infectious, metabolic, and autoimmunological causes of the palsy. The goal of the study was to assess the frequency of malignancies hidden under the diagnosis of "Bell's palsy".</br> <br><b>Aim:</b> We aimed to create a diagnostic algorithm to avoid failures concerning patients whose only symptom of parotid gland cancer was irreversible FNP.</br> <br><b>Material and methods:</b> We analyzed 253 consecutive patients with FNP treated in our department in the last 5 years. The subject of the study was "Bell's palsy" cases. All patients with irreversible FNP were reassessed in 6-12 months. We underlined all shortcomings in the diagnostics of those in whom malignancies were found in MRI of the neck and presented the proposal for a diagnostic algorithm to avoid missing such an entity.</br> <br><b>Results:</b> Bell's palsy was observed in 157/253 patients (62.06%), in 36/157 (22.92%) it remained permanent. In 4/36 patients (11.11%) with irreversible FNP, which constituted 2.54% of all "Bell's palsy" cases, parotid gland deep lobe mass was found in MRI. In one patient, infiltration of the skull base was diagnosed. Adenoid cystic carcinoma was confirmed in final histopathology in all cases.</br> <br><b>Conclusions:</b> Our experience has shown that irreversible FNP can be a revelator of the malignant tumor located in the deep lobe of the parotid gland. Contrast-enhanced MRI covering intra- and extracranial segments of the facial nerve should be ordered in all cases of FNP without recovery after 4 months. Repeated imaging should be considered in undiagnosed cases. The main point of our study is to underline that the assessment of the deep lobe of the parotid gland with MRI should be included in the standard diagnostic protocol in all irreversible "Bell's palsy" cases.</br>.

A Rare Case of Extraosseous Osteosarcoma (EOS) of Parotid Gland.

Extraosseous osteosarcoma is a rare malignant soft tissue neoplasm, and extraosseous osteosarcoma of the parotid gland is very rare. It has a very aggressive course, and there are no standardized treatment guidelines. We report the case of a 20 year old male patient who presented with history of right neck swelling since 6 years for which he had undergone right parotid surgery 5 years ago. The final histopathological report indicated that the mass was a pleomorphic adenoma. One year after the first surgery, the patient experienced recurrence of swelling over the operated site, and the size of the swelling has been increasing gradually since then. He was evaluated clinically, and a large mass was noted over the upper aspect of the right upper neck, extending to the occipital and parotid regions. An MRI scan was done which showed a 12 × 10 × 8 cm lesion centred in the right parotid gland, involving paraspinal muscles, C1-C2 vertebrae and extending into the parapharyngeal space. FNAC of the lesion showed features of pleomorphic adenoma. The patient underwent a complete excision of the tumour. The patient's post-operative period was uneventful. The final histopathological report of the patient was extraosseous osteosarcoma of the parotid gland. The patient was referred for adjuvant radiotherapy. He has been on regular follow-up for the past 6 months and has shown no sign of recurrence. EOS is an extremely rare tumour of the head and neck region which often requires extensive surgical resection with or without adjuvant radiotherapy. It has a high rate of local recurrence and a very low disease free survival. Such patients should be kept on a close follow-up.

Adjuvant radiotherapy in node-negative salivary malignancies of the parotid gland: A multi-institutional analysis.

BACKGROUND AND PURPOSE: To determine the role of adjuvant radiotherapy (ART) in parotid gland cancer without nodal metastasis, we evaluated the survival outcomes, prognostic factors, and dose-response relationships in patients with node-negative parotid gland cancer patients. MATERIALS AND METHODS: Patients who underwent curative parotidectomy and were pathologically diagnosed with parotid gland cancer without regional or distant metastases between 2004 and 2019 were reviewed. The benefit of ART in terms of locoregional control (LRC) and progression-free survival (PFS) were evaluated. RESULTS: In total, 261 patients were included in the analysis. Of them, 45.2 % received ART. The median follow-up period was 66.8 months. Multivariate analysis revealed that histological grade and ART were independent prognostic factors for LRC and PFS (all p <.05). For patients with high-grade histology, ART was associated with a significant improvement in 5-year LRC (p =.005) and PFS (p =.009). Among patients with high-grade histology who completed RT, higher biologic effective dose (≥77 Gy10) significantly increased PFS (adjusted hazard ratio [HR], 0.10 per 1-Gy increase; 95 % confidence interval [CI], 0.02-0.58; p =.010). ART significantly improved LRC (p =.039) in patients with low-to-intermediate histological grade as well per multivariate analysis, and subgroup analyses revealed patients with T3-4 stage and close/positive resection margins (<1 mm) would benefit from ART. CONCLUSION: ART should be strongly recommended for patients with node-negative parotid gland cancer with high-grade histology in terms of disease control and survival. In patients with low-to-intermediate-grade disease, those with high T stage and incomplete resection margin benefit with ART.

Diagnosis and Management of Parotid Gland Cancer with Focus on the Role of Preoperative Fine-Needle Aspiration Cytology: A 10-Year-Long Retrospective Study with 5-Year Follow-Up.

Introduction: Salivary gland cancers represent a rare heterogeneous group of neoplasms with complex clinicopathological characteristics and distinct biological behaviour. The appropriate diagnosis and management of parotid gland cancer are challenging and should be based on the clinical, imaging, cytological, and histological features. The present study analysed the use of preoperative fine-needle aspiration cytology (FNAC) and intraoperative frozen section (FS) to guide the appropriate surgical and postoperative treatment of parotid gland cancers. Materials and Methods: We selected 48 patients with primary malignancy of the parotid gland surgically treated between 1 January 2008 and 30 June 2017 at the Maxillo-Facial Surgery Division, University Hospital of Parma, Italy. The patients had postoperative histological diagnosis of malignant parotid cancer and were followed up for longer than 5 years. Results: The 48 patients included in this study had a mean age of 56.7 years. The most frequent type of parotid gland cancer was carcinoma ex pleomorphic adenoma (22.9%), followed by mucoepidermoid carcinoma (16.7%) and acinic cell carcinoma (14.6%). All 48 patients underwent preoperative FNAC: 29 (60.4%) and 19 (39.6%) were suggestive of malignant and benign lesions, respectively. In 31 patients, intraoperative FS was performed. Discussion: Compared to previous studies, the present study showed significantly lower diagnostic sensitivity of FNAC for parotid gland cancers. The preoperative diagnostic accuracy for suspected malignant cases may be improved by repeat analysis of the cytological specimen by experts, preoperative core needle biopsy, and/or intraoperative FS analysis of the suspected mass.

Case Report: A case of complete response to entrectinib in NTRK fusion gene-positive parotid gland cancer.

Introduction: Expression of the NTRK gene is rare in solid tumors but is highly prevalent in salivary gland secretory carcinomas. Here, we report a case of a complete response to entrectinib in a patient with NTRK fusion gene-positive parotid carcinoma. Case description: The patient was a 44-year-old man who underwent total left parotidectomy and left cervical lymph node dissection for a left parotid tumor at 24 years of age. The histopathological diagnosis was mammary analog secretory carcinoma. Postoperatively, the patient received only radiation therapy. Sixteen years after the surgery, the patient became aware of a mass in the left parotid region. A close examination revealed local recurrence and multiple cervical lymph node metastases. S-1 monotherapy was started as chemotherapy but was discontinued 3 years later because of disease progression. As there was no standard treatment, a comprehensive genomic profiling test using a next-generation sequencer was performed, and the ETV6-NTRK3 fusion gene was identified. Entrectinib, an NTRK inhibitor, was immediately administered at a dose of 600 mg/day. The local recurrence rapidly shrank grossly from the beginning of treatment, and a complete response was observed 6 months later. However, creatinine levels exhibited an increase at week 68 of treatment; consequently, entrectinib dosage was lowered to 400 mg/day, leading to an immediate improvement in creatinine levels. Entrectinib was associated with additional side effects, including dysgeusia, fatigue, dizziness, and weight gain, all of which were also alleviated by the reduction in entrectinib dose. Thirty months after treatment initiation, the patient maintained a complete response and continued to receive entrectinib. Conclusion: The NTRK fusion gene should always be checked in the presence of salivary gland secretory carcinoma.

Deep learning-based two-step organs at risk auto-segmentation model for brachytherapy planning in parotid gland carcinoma.

Purpose: Delineation of organs at risk (OARs) represents a crucial step for both tailored delivery of radiation doses and prevention of radiation-induced toxicity in brachytherapy. Due to lack of studies on auto-segmentation methods in head and neck cancers, our study proposed a deep learning-based two-step approach for auto-segmentation of organs at risk in parotid carcinoma brachytherapy. Material and methods: Computed tomography images of 200 patients with parotid gland carcinoma were used to train and evaluate our in-house developed two-step 3D nnU-Net-based model for OARs auto-segmentation. OARs during brachytherapy were defined as the auricula, condyle process, skin, mastoid process, external auditory canal, and mandibular ramus. Auto-segmentation results were compared to those of manual segmentation by expert oncologists. Accuracy was quantitatively evaluated in terms of dice similarity coefficient (DSC), Jaccard index, 95th-percentile Hausdorff distance (95HD), and precision and recall. Qualitative evaluation of auto-segmentation results was also performed. Results: The mean DSC values of each OAR were 0.88, 0.91, 0.75, 0.89, 0.74, and 0.93, respectively, indicating close resemblance of auto-segmentation results to those of manual contouring. In addition, auto-segmentation could be completed within a minute, as compared with manual segmentation, which required over 20 minutes. All generated results were deemed clinically acceptable. Conclusions: Our proposed deep learning-based two-step OARs auto-segmentation model demonstrated high efficiency and good agreement with gold standard manual contours. Thereby, this novel approach carries the potential in expediting the treatment planning process of brachytherapy for parotid gland cancers, while allowing for more accurate radiation delivery to minimize toxicity.

Prediction of Long-Term Survival Outcome by Lymph Node Ratio in Patients of Parotid Gland Cancer: A Retrospective study.

Background: Lymph node ratio (LNR) has been reported to reliably predict cancer-specific survival (CSS) in parotid gland cancer (PGC). Our study was designed to validate the significance of LNR in patients with PGC. Methods: Patients diagnosed with stage I-IV PGC were enrolled from Surveillance Epidemiology and End Results database (SEER, N = 3529), which is the training group, and Sun Yat-sen University Cancer Center database (SYSUCC, N = 99), the validation group. We used X-tile software to choose the optimal cutoff value of LNR; then, univariable and multivariable analyses were performed, assessing the association between LNR and CSS. Results: The optimal cutoff value of LNR was 0.32 by X-tile based on 3529 patients from SEER. Cox proportional hazard regression analysis revealed better CSS for patients with LNR ≤ 0.32 (adjusted hazard ratio [HR] 1.612, 95% confidence interval [95% CI] 1.286-2.019; p < 0.001) compared with patients with LNR > 0.32 in SEER. In the SYSUCC cohort, patients with LNR ≤ 0.32 also had better CSS over patients with LNR > 0.32 (p < 0.001). In N2 and N3 stage groups, patients with LNR ≤ 0.32 had superior CSS outcomes over those with the LNR > 0.32 group, but this benefit was absent in the N1 stage group. Conclusions: In conclusion, the lymph node ratio turned out to be an independent prognostic factor for cancer-specific survival of PGC in this study. This valuable information could help clinicians to evaluate the prognosis of PGC and suggest that adequate lymph node dissection is necessary.

Image fusion technique for target volume delineation in 125I seed implant brachytherapy for parotid gland cancers.

Purpose: Variability in volume delineation is a possible error source in brachytherapy. This study assessed the interobserver variations in clinical target volume (CTV) delineation in postoperative adjuvant 125I seed implant brachytherapy after parotid gland cancer surgical resection and evaluated the image fusion technique for target volume delineation. Material and Methods: Five radiation oncologists delineated gross tumor volume (GTV) and CTV in 20 patients using conventional delineation and image fusion methods. The consistency in target volume delineation was determined on the basis of differences between the oncologists. Variability was determined using Kendall's W-test, the mean conformity index (CI), the mean distance to conformity (MDC), and the center of gravity distance (CGD). Results: There were significant variations in the delineated target volumes among radiation oncologists, but the CTV consistency was significantly enhanced using the image fusion technique, based on Kendall's W, mean CI, average MDC, and average CGD, which were 0.752, 0.41, 2.75, and 4.997, respectively, using the conventional method, and 0.987, 0.86, 0.55, and 1.27, respectively, using the image fusion method. Conclusions: The interobserver variation in the delineation of the postoperative parotid target volume is large, but it can be considerably decreased using image fusion technology, which resulted in a noticeable improvement in the delineation precision of the target volume for parotid gland cancer. Thus, this technology can enhance the efficacy of 125I seed implant brachytherapy and decrease any adverse effects induced by errors in target delineation.

Is elective neck dissection necessary for patients with cT3-4N0 parotid gland cancer?

OBJECTIVE: Management of the cervical lymph nodes in patients with cT3-4N0 parotid gland cancer (PGC) has been controversial. This study investigated the need for elective neck dissection (END) in patients with cT3-4N0 PGC. METHODS: We retrospectively examined cervical lymph node metastasis, overall survival (OS), and disease-free survival (DFS) rates in 40 patients with cT3-4N0 PGC according to whether or not END was performed. RESULTS: Cervical lymph node metastasis occurred in 27.5% of patients and level II was the most common area. Recurrence could be treated by salvage neck dissection. There was no significant difference in OS (P=0.581) or DFS (P=0.728) between the group that underwent END and the group that did not. CONCLUSION: END at level II is worth performing because of the occult lymph node metastasis rate. The area of neck dissection should be limited because there is no evidence that END improves the prognosis of cT3-4N0 PGC.

Clinico-Epidemiological Analysis of Most Prevalent Parotid Gland Carcinomas in Poland over a 20-Year Period.

(1) Background: Malignant tumours of the salivary glands have different clinical and histopathological characteristics. They most commonly involve the parotid gland. Histopathologically, the most common are mucoepidermoid carcinoma (MEC), adenoid cystic carcinoma (AdCC), acinic cell carcinoma (AcCC), adenocarcinoma, carcinoma in pleomorphic adenoma (CPA), and squamous cell carcinoma (SCC). (2) Methods: We analysed 2318 patients with malignant parotid gland tumours reported to the National Cancer Registry (NCR) in Poland over 20 years (1999-2018). The demographic characteristics of patients, clinical factors, and overall survival (OS) were analysed. (3) Results: The average age was 61.33 ± 16.1 years. The majority were males (55%) and urban citizens (64%). High percentage of carcinomas was diagnosed in locoregional (33.7%) and systemic (10.4%) stadium. The most prevalent diagnoses were SCC (33.3%) and adenocarcinoma (19.6%). Surgical resection with adjuvant RT (42.1%) was the most common treatment. The OS analysis showed a median survival time of 5.6 years. The most favorable median OS was found in patients with AcCC (18.30 years), the worst for SCC (1.58 years). (4) Conclusion: AcCC has the best prognosis and SCC the worst. Tumour stadium, treatment, and demographic factors affect prognosis. Improvements in diagnosis and re-evaluation of treatment standards are necessary to enhance the outcome of patients with parotid gland cancers in Poland.