Acinic cell carcinoma of the salivary gland in the adult and paediatric population: a survival analysis

Margins in major salivary gland surgery: clinical and pathological criteria for defining margins and their implications on the choice of multimodal therapies. A systematic review

Objective

Major salivary gland malignancies (MSGM) are a rare and heterogeneous group of tumours accounting for 1-5% of all head and neck cancers. When feasible, surgical removal with negative margins is the preferred treatment, reserving adjuvant radiotherapy for adverse clinicopathological features such as high-grade, advanced-stage, extranodal extension, lympho-vascular invasion, perineural invasion, and positive margins. This systematic review aims to evaluate the current literature on the definition of negative and close margins for MSGM, their impact on loco-regional recurrence (LRR), disease-free (DFS), and overall survival (OS), and their implications in the choice of multimodal therapies.

Methods

An online search of articles published between 2004 and 2024 was carried out using PubMed via a PICO search strategy for qualitative questions and written following the PRISMA statement guidelines. The following parameters were evaluated: definition of free and close margins, and their impact on local control.

Results

The initial search yielded 158 articles. Following the application of inclusion and exclusion criteria, 30 full-text publications were reviewed. All studies were retrospective. A total of 15,985 patients who underwent surgery were considered. Margin involvement ranged widely among the studies from 14.3% to 65.4%. Five out of 30 studies reported no data about association between margins and LRR, DFS, and OS. Twenty of 25 studies reported a significant correlation between positive margins and oncological outcomes regardless of the histological types, while 5 focused on high-stage cancers or more aggressive histotypes and described no association between margin status and oncological outcomes. Nine of 30 studies described close margins in the absence of a univocal definition of threshold for close vs. negative margins. Most studies did not report a significant correlation between close margins and oncological outcomes.

Conclusions

Surgical resection achieving negative margins is recommended for MSGM. Positive margin is widely considered an adverse clinicopathological feature and performing adjuvant radiotherapy has documented survival benefits. A consensus involving a definition of close margin is missing, although further treatment is not recommended, preferring a watch-and-wait approach in presence of close margins.

Cancer-associated stroke from progressive acinic cell carcinoma

Cancer-associated stroke is an evolving subgroup of embolic strokes of undetermined source. A man in his mid-20s with progressive follicular variant acinic cell carcinoma of the parotid was admitted because of new onset left-sided weakness. Neuroimaging confirmed a right middle cerebral artery infarction. After extensive diagnostics, stroke aetiology was deemed from cancer-induced hypercoagulability. Questions which arose regarding his management included (1) What was the best antithrombotic for secondary stroke prevention? (2) What was his risk for intracranial or tumorous bleeding once antithrombotics had been started? (3) How many days post-stroke could the antithrombotic be initiated? and (4) When could he be cleared for palliative chemotherapy and whole brain irradiation? The approach to address the abovementioned questions in the management of a rare cancer complicated by stroke is presented. Although treatments are guided by known pathomechanisms, additional studies are needed to further support current treatment strategies for this subgroup of patients.

Prognostic Assessment and Risk Stratification in Patients With Postoperative Major Salivary Acinar Cell Carcinoma

OBJECTIVE

To investigate the clinicopathological features and prognosis of postoperative major salivary acinar cell carcinoma (MSACC) and develop a prognostic model.

STUDY DESIGN

Retrospective cohort analysis of a public database.

SETTING

Patients with MSACC were identified from the Surveillance, Epidemiology, and End Results database (1975-2019).

METHODS

Overall survival (OS) was evaluated using Kaplan-Meier curves and a log-rank test. Univariate and multivariate Cox analyses were performed to explore independent prognostic factors. The prognostic model was constructed using screened variables and further visualized with a nomogram and web calculator, and assessed by concordance index, the area under the curve, calibration curve, and decision-making curve analysis.

RESULTS

An upward trend in the incidence of MSACC was observed throughout the study period. A total of 1398 patients were enrolled (training cohort: 978; validation cohort: 420), and the 5- and 10-year OS rates were 97.7% and 81.6%, respectively. Age, marital status, sex, histological grade, T stage, and lymph node status were identified as prognostic factors for OS. A novel nomogram was developed and showed excellent discrimination and clinical applicability. Additionally, a web calculator was designed to dynamically predict patient survival. Based on the nomogram-based score, a risk stratification system was constructed to distinguish patients with different risks. The OS of high-risk patients was significantly lower than that of the low-risk subgroup.

CONCLUSION

Long-term survival in postoperative MSACC was influenced by 6 prognostic factors. The proposed model enables individualized survival prediction and risk stratification, prompting us to be vigilant in high-risk subgroups and consider timely adjustment of subsequent treatment.

Acinic cell carcinoma of the parotid gland: Timeo Danaos et dona ferentes? A multicenter retrospective analysis focusing on survival outcome

OBJECTIVES

To analyze the demographic data, surgical and adjuvant treatment data and the survival outcomes in adult patients affected by acinic cell carcinoma of the parotid gland (AciCC).

METHODS

A retrospective multicenter analysis of patients treated for AciCC of the parotid gland from 2000 to 2021 was performed. Exclusion criteria were pediatric (0-18 years) patients, the absence of follow-up and patients with secondary metastatic disease to the parotid gland. Multivariable logistic regression was used to determine factors associated with survival.

RESULTS

The study included 81 adult patients with AciCC of the parotid gland. The median age was 46.3 years (SD 15.81, range 19-84 years), with a gender female prevalence (F = 48, M = 33). The mean follow-up was 77.7 months (min 4-max 361, SD 72.46). The 5 years overall survival (OS) was 97.5%. The 5 years disease-free survival (DFS) was 60%. No statistical differences have been found in prognosis for age (< 65 or ≥ 65 years), sex, surgery type (superficial vs profound parotid surgery), radicality (R0 vs R1 + Rclose), neck dissection, early pathologic T and N stages and adjuvant therapy (p > 0.05).

CONCLUSION

This study did not find prognostic factor for poorest outcome. In contrast with the existing literature, our results showed how also high-grade tumours cannot be considered predictive of recurrence or aggressive behaviour.

Head and Neck Acinic Cell Carcinoma: A New Grading System Proposal and Diagnostic Utility of NR4A3 Immunohistochemistry

Acinic cell carcinoma (AciCC) is traditionally considered as a low-grade salivary gland carcinoma. However, a subset demonstrates high-grade features with a higher mortality rate and distant metastasis. In this large retrospective study of 117 cases, we aimed to establish a histologic grading scheme for AciCC. Adverse independent prognostic factors identified on the multivariate analysis included older age, tumor necrosis, nuclear anaplasia, lymphovascular invasion, absence of tumor-associated lymphoid stroma, and high American Joint Committee on Cancer (AJCC) pT and pN stages. A 3-tiered grading scheme using 4 pathologic parameters (mitotic index, necrosis, tumor border, and fibrosis at the frankly invasive front) was subsequently applied. Compared with low/intermediate-grade, high-grade AciCC defined as a mitotic index ≥5/10 HPFs and/or necrosis was an independently adverse prognostic factor. The 5-year overall survival was 50% in high-grade AciCCs, and 100% in low-grade or intermediate-grade AciCCs. Compared with low-grade or intermediate-grade AciCC, high-grade tumors were associated with older age, larger tumor size, focal rather than diffuse zymogen granules, solid architecture, infiltrative tumor border, fibrosis at the frankly invasive front, lymphovascular invasion, perineural invasion, positive margin, high pT, and pN stages. NR4A3 was a highly sensitive and specific immunohistochemical stain for diagnosing AciCC with a sensitivity and specificity of 96% and 93%, respectively. In conclusion, although we proposed a 2-tiered grading system for AciCC with high-grade tumors defined by a mitotic count ≥5/10 HPFs and/or necrosis, more studies are needed to assess the prognostic value of intermediate grade. NR4A3 immunohistochemical stain is a useful diagnostic marker for AciCC.