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.

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.

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.

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.

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.

Mobile phone use and trends in the incidence of cancers of the parotid and other salivary glands

BACKGROUND

There has been a significant increase in the use of mobile phones over the last three decades and a possible association with head cancers has been suggested, including cancers of the parotic and other salivary glands. We examined the incidence time trends of parotid and other salivary gland cancers in Australia to ascertain the influence of increased mobile phone use.

METHODS

Analyses of incidence time trends were carried out using Poisson regression to estimate the annual percentage change (APC) in the incidence of salivary gland cancers of all available national registration data from 1982 to 2016, as well as specific time periods (1982-1993, 1994-2005, 2006-2016) representing changes in the prevalence of mobile phone use.

RESULTS

The incidence of parotid gland cancer was stable for the periods 1982-1993 and 1994-2005. During 2006-2016 there was a large decrease in parotid gland cancer for males (APC: -3.71, 95 %CI: -6.66 to -0.67) and a large increase in females (4.80, 1.77-7.91) for adults aged 20-59 years. The incidence for other salivary gland cancers was stable during all the periods.

CONCLUSIONS

The results do not indicate that mobile phone use increased the incidence of parotid or other salivary gland cancers. An increase in parotid gland cancer in females since 2006 may be attributed to other possible risk factors specific to this gender.

Pre-treatment MRI predictor of high-grade malignant parotid gland cancer

OBJECTIVES

We aimed to evaluate pre-treatment MRI predictors of high-grade malignant parotid gland cancer by comparing MRI findings and texture parameters between high-grade and intermediate/low-grade parotid gland cancers.

METHODS

Patients underwent a pre-treatment MRI and had a parotid gland cancer resection with pathological evaluation. Evaluation objectives included attributive factors such as age and gender, several MRI findings of T1- and T2-weighted images, post-contrast fat suppression T1-weighted images, ADC value and 40 texture parameters calculated from T2-weighted axial images. Such objects were compared between high-grade and intermediate/low-grade lesions.

RESULTS

Of the parotid gland cancers surveyed, 39 were included for analysis. Of these, 18 were high-grade lesions, 2 were intermediate-grade lesions, and 19 were low-grade lesions. The high-grade group was significantly older than the low- and intermediate-grade groups (p = 0.01). There were more males in the high-grade group than in the low- and intermediate-grade groups (p = 0.01). There were also significantly more MRI findings of neck lymph node metastases in the high-grade group than in the low- and intermediate-grade groups (p < 0.001). Other MRI findings and texture parameters did not show significant differences between the two groups (p = 0.07-1.00).

CONCLUSIONS

Morphological assessment on MRI and texture parameters alone is not sufficient to estimate the grade of parotid cancer. MRI findings of neck lymph node metastases, as well as patient characteristics such as age (older patients) and gender (male) can be suggestive of high-grade parotid gland cancer in pre-treatment evaluation.

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.

Proton Beam Therapy for Locally Recurrent Parotid Gland Cancer

The aim of this study was to evaluate the efficacy and safety of proton beam therapy for patients with locally recurrent parotid cancer. Between 2009 and 2012, ten patients with locally recurrent parotid gland cancer were treated with proton beam therapy (70.2 Gy equivalents in 32 fractions) with or without intra-arterial infusion chemotherapy of cisplatin (50 mg/body/week, for a total of 5-8 weeks). The median follow-up was 24 months (range 10-49 months). The 1-year overall survival and local control rates were 80 %, and the 3-year overall survival and local control rates were 60 %. None of the patients experienced grade 3-5 toxicities in the treatment or the follow-up periods. These findings suggest that proton beam therapy could be applied effectively and safely for patients with locally recurrent parotid gland cancer.