Salivary glands adenoid cystic carcinoma: a molecular profile update and potential implications

Adenoid Cystic carcinoma of minor salivary glands (AdCCmSG): a multidisciplinary update

INTRODUCTION

Adenoid cystic carcinoma of minor salivary glands (AdCCmSG) represents a 'rarity in the rarity,' posing a clinical challenge in lack of standardized, evidence-based recommendations. At present, AdCCmSG management is mostly translated from major salivary gland cancers (MSGCs). Ideally, AdCCmSG diagnostic-therapeutic workup should be discussed and carried out within a multidisciplinary, high-expertise setting, including pathologists, surgeons, radiation oncologists and medical oncologists.

AREAS COVERED

The present review provides an overview of epidemiology and pathologic classification. Moreover, the most recent, clinically relevant updates in the treatment of AdCCmSG (Pubmed searches, specific guidelines) are critically discussed, aiming to a better understanding of this rare pathologic entity, potentially optimizing the care process, and offering a starting point for reflection on future therapeutic developments.

EXPERT OPINION

The management of rare cancers is often hindered by limited data and clinical trials, lack of evidence-based guidelines, and hardly represented disease heterogeneity, which cannot be successfully tackled with a 'one-size-fits-all' approach. Our goal is to address these potential pitfalls, providing an easy-to-use, updated, multidisciplinary collection of expert opinions concerning AdCCmSG management as of today's clinical practice. We will also cover the most promising future perspectives, based on the potential therapeutic targets highlighted within AdCCmSG's molecular background.

Treatment of lacrimal gland adenoid cystic carcinoma: a systematic review and Meta-analysis

AIM

To evaluate lacrimal gland adenoid cystic carcinoma (LGACC) of prognosis in patients who underwent different treatment regimens.

METHODS

We searched PubMed, EMBASE, and the Cochrane Library for studies done on the treatment of LGACC, between January 1987 and April 2022. A Meta-analysis was conducted to pool the 5-year overall survival rate (OR), and the 5-year recurrence rate (RR) and 5-year metastasis rate (MR) were assessed.

RESULTS

The 30 studies involved 585 patients were included in the Meta-analysis. The pooled 5-year OR with surgery alone was 50%, the 5-year RR was 63%, and the 5-year MR was 34%. The pooled 5-year OR with surgery and adjuvant radiotherapy combined was 67% (95%CI 61%,73%), the 5-year RR was 41%, and the 5-year MR was 35%. The pooled 5-year OR with surgery and adjuvant chemoradiotherapy combined was 72% (95%CI 59%, 84%), the 5-year RR was 48%, and the 5-year MR was 36%. The pooled 5-year OR with surgery, intra-arterial cytoreductive chemotherapy, and adjuvant chemoradiotherapy combined was 78% (95%CI 68%, 89%), the 5-year RR was 15%, and the 5-year MR was 27%.

CONCLUSION

Comprehensive treatment is more effective than surgery alone. Surgery combined with intra-arterial chemotherapy and adjuvant chemoradiotherapy seems to add value to the therapeutic effect of comprehensive treatment of LGACC but further high-quality research is required to validate this.

PTEN Deregulation Mechanisms in Salivary Gland Carcinomas

Among the tumour suppressor genes that affect critically cell functions and homeostasis, phosphatase and tensin homolog deleted in chromosome 10 (PTEN- gene locus: 10q21) regulates the PI3K/Akt/mTOR signalling pathway. PTEN is deleted, mutated or epigenetically hyper-methylated in a variety of human solid malignancies. Salivary gland carcinomas (SGCs) belong to the head and neck carcinomas (HNCs) super category of solid malignancies. Histo-pathologically, they demonstrate a significant diversity due to a variety of distinct and mixed subtypes. Genetically, they are characterized by a broad spectrum of gene and chromosomal imbalances. Referring specifically to suppressor genes, PTEN deregulation plays a critical role in signaling transduction in the corresponding SGC pre- and malignant epithelia modifying the response rates to potential targeted therapeutic strategies. In the current review, we explored the role of PTEN deregulation mechanisms that are involved in the onset and progression of SGCs.

Molecular Biology and Therapeutic Targets of Primitive Tracheal Tumors: Focus on Tumors Derived by Salivary Glands and Squamous Cell Carcinoma

Primary tracheal tumors are rare, constituting approximately 0.1-0.4% of malignant diseases. Squamous cell carcinoma (SCC) and adenoid cystic carcinoma (ACC) account for about two-thirds of these tumors. Despite most primary tracheal cancers being eligible for surgery and/or radiotherapy, unresectable, recurrent and metastatic tumors may require systemic treatments. Unfortunately, the poor response to available chemotherapy as well as the lack of other real therapeutic alternatives affects the quality of life and outcome of patients suffering from more advanced disease. In this condition, target therapy against driver mutations could constitute an alternative to chemotherapy, and may help in disease control. The past two decades have seen extraordinary progress in developing novel target treatment options, shifting the treatment paradigm for several cancers such as lung cancer. The improvement of knowledge regarding the genetic and biological alterations, of major primary tracheal tumors, has opened up new treatment perspectives, suggesting the possible role of biological targeted therapies for the treatment of these rare tumors. The purpose of this review is to outline the state of knowledge regarding the molecular biology, and the preliminary data on target treatments of the main primary tracheal tumors, focusing on salivary-gland-derived cancers and squamous cell carcinoma.