Systemic therapy in the management of metastatic or advanced salivary gland cancers

Salivary gland cancers are very rare tumors. They are characterized by a histologic heterogeneity and a poor outcome. According to this rarity, few prospective data are available to date. No standard recommendations could be held for the use of systemic therapy in these tumors. Several case reports and small studies have investigated the contribution of different agents of chemotherapy. With the extension of molecular biology approach in oncology several signaling pathways have been discovered in different cancers including salivary gland cancers; thus a number of targeted therapies have been investigated. This paper reviewed exhaustively the studies investigating the role of systemic therapies (chemotherapy, targeted therapy, hormone therapy) in salivary gland cancers.     

Systemic therapy in the management of metastatic or advanced salivary gland cancers

ABSTRACT: Salivary gland cancers are very rare tumors. They are characterized by a histologic heterogeneity and a poor outcome. According to this rarity, few prospective data are available to date. No standard recommendations could be held for the use of systemic therapy in these tumors. Several case reports and small studies have investigated the contribution of different agents of chemotherapy. With the extension of molecular biology approach in oncology several signaling pathways have been discovered in different cancers including salivary gland cancers; thus a number of targeted therapies have been investigated. This paper reviewed exhaustively the studies investigating the role of systemic therapies (chemotherapy, targeted therapy, hormone therapy) in salivary gland cancers.     

Fast neutron radiation for inoperable and recurrent salivary gland cancers

The current standard treatment of salivary gland cancers consists of surgical resection, with or without postoperative low linear energy transfer (LET) radiation, resulting in high locoregional control rates. However, tumor control prognosis is poor when conventional radiation is used alone for advanced, inoperable cases. An extensive review of the world's literature on fast neutron irradiation for inoperable, unresectable, or recurrent malignant salivary gland neoplasms is presented and compared with the experience using conventional low LET radiotherapy. The pooled data indicate a locoregional control rate of 67% for fast neutrons versus 25% for photons and/or electrons in the treatment of such advanced disease. The radiobiological rationale supporting this observed increase in tumor control is discussed. The overall significant late complication rate is 19%, but several suboptimal treatment factors were present that contributed substantially to the reported toxicity. With the modern machines and treatment techniques now available, the evidence overwhelmingly supports the role of fast neutron radiation as the treatment of choice for inoperable and recurrent salivary gland cancers.     

Cetuximab in recurrent and/or metastatic salivary gland carcinomas: A phase II study

EGFR overexpression in salivary gland carcinomas provides the rational for the investigation of anti-EGFR treatments in recurrent and/or metastatic salivary gland cancers (RMSGCs). The activity of cetuximab in terms of clinical benefit rate (CBR) defined as the occurrence of objective response (CR or PR) or stable disease (SD) for >or=6months was investigated. From April to December 2005, 30 patients [23 adenoid cystic carcinoma (ACC) and 7 non-ACC] were treated with cetuximab at 400mg/m(2)/week followed by 250mg/m(2)/week until progression, major toxicity or voluntary discontinuation. EGFR expression and gene status were retrospectively analyzed by immunocytochemistry and fluorescence in situ hybridization, respectively. A median of 14 courses of cetuximab (range 5-54) were infused. Skin toxicity was the main adverse event. Cetuximab provides a CBR in 50% (95% CL, 31 to 69%) of cases. None tumor sample showed EGFR gene amplification and an increased EGFR copy number was observed in 12% of samples, all ACC. Skin rash >or=G2, EGFR overexpression and EGFR copy number were not statistically correlated to CB. In RMSGCs further evaluations of EGFR targeting agents are advisable and should take place by appropriate tumor biological selection, differentiating ACC from non-ACC.     

Systemic therapy in metastatic or recurrent endometrial cancer

Endometrial cancer is one of the most common gynecologic malignancies. In patients with advanced or recurrent endometrial cancer survival is greatly diminished. Hormonal therapy and chemotherapy play a major role in the management of advanced or recurrent endometrial cancer. Endocrine therapy provides a 10-20% response rate (RR) and survival of less than 1 year. Combination chemotherapy offers a RR of 40-60%, but the survival is still less than 1 year. The combination of cisplatin plus doxorubicin is the most commonly used regimen, but carboplatin plus paclitaxel represents an efficacious, low toxicity regimen in advanced or recurrent endometrial cancer. The addition of paclitaxel to cisplatin plus doxorubicin appears to improve response rates, progression-free survival and overall survival, but to worsen toxicity profile. At this time the focus of future research should be on the use of novel targeted agents, since it is unlikely that further significant advances could be made with chemotherapy and endocrine therapy. mTOR inhibitors represent a promising therapeutic strategy for endometrial cancer. Anti-HER-2/neu targeted therapy might be a novel and attractive therapeutic option in patients with biologically aggressive variants (uterine serous papillary carcinoma, clear cell carcinoma) of endometrial cancer. Research in better understanding the signal transduction pathways in endometrial carcinogenesis will allow the development of specific and selective molecularly targeted inhibitors.     

Systemic therapy in the management of recurrent or metastatic salivary duct carcinoma: A systematic review

BackgroundSalivary duct carcinoma (SDC) is an aggressive subtype of salivary gland cancer. Approximately half of SDC patients will develop recurrences or metastases. Therapeutic palliative therapy is therefore often needed. The majority of SDC tumors expresses the androgen receptor (AR) and one-third expresses human epidermal growth factor receptor 2 (HER2), both are potential therapeutic targets. The aim of this paper is to systematically review and summarize the evidence on systemic palliative therapy for SDC and to provide treatment recommendations.Materials and methodsElectronic libraries were systematically searched with a broad search strategy to identify studies where SDC patients received systemic therapy. Due to the rarity of SDC no restrictions were placed on study designs.ResultsThe search resulted in 2014 articles of which 153 were full-text analyzed. Forty-five studies were included in the analysis, which included in total 256 SDC patients receiving systemic therapy. Two phase 2 trials primarily including SDC patients were identified. The majority of the studies were case series or case reports, resulting in an overall low quality of available evidence. Based on studies including ≥ 5 SDC patients, objective responses to HER2 targeting agents were observed in 60–70%, to AR pathway agents in 18–53% and to chemotherapy in 10–50%.ConclusionFor AR or HER2 positive SDC, agents targeting these pathways are the cornerstone for palliative treatment. Regarding chemotherapy, the combination of carboplatin combined with a taxane is best studied. Regarding other targeted agents and immunotherapy evidence is anecdotal, limiting formulation of treatment recommendations for these antineoplastic agents.     

Chemoreirradiation for recurrent salivary gland malignancies

Background and purpose

To report our experience in treating recurrent salivary gland malignancies using concurrent chemotherapy and reirradiation.

Materials and methods

Between 1986 and 2007, 14 patients with locoregionally recurrent salivary gland cancer underwent maximal surgical resection followed by adjuvant 5-fluorouracil and hydroxyurea-based chemotherapy concurrently with 1.5 Gy twice daily or 2 Gy daily reirradiation. Each cycle consisted of chemoreirradiation for 5 consecutive days followed by a 9-day break. The median reirradiation dose was 66 Gy (R 30-72 Gy) after a mean radiation treatment interval of 48 months.

Results

The median follow-up for all patients was 18 months (R 2-125 months) and 41 months for survivors. The parotid gland (n = 6) and minor salivary glands (n = 6) were involved more commonly than the submandibular gland (n = 2). Locoregional control at 1 and 3 years was 72.2% and 51.6%, respectively. Actuarial overall survival at 3 and 5 years was 35.7% and 26.8%, respectively. Tracheostomies and feeding tubes were placed in 2 and 8 patients, respectively. Six patients had feeding tubes at last follow-up or death.

Conclusions

Concurrent chemotherapy and reirradiation for recurrent salivary malignancies result in promising locoregional control for patients with recurrent salivary gland malignancies.     

A phase II study of sorafenib in recurrent and/or metastatic salivary gland carcinomas: Translational analyses and clinical impact

BackgroundPre-clinical and clinical evidence suggests a rationale for the use of anti-angiogenic agents, including sorafenib, in recurrent and/or metastatic salivary gland carcinomas (RMSGCs). This study evaluates the activity of sorafenib in patients with RMSGCs and also investigates whether the activity of sorafenib could be related to its main tailored targets (i.e. BRAF, vascular endothelial growth factor receptor 2 [VEGFR2], platelet-derived growth factor receptor α [PDGFRα] and β, RET, KIT).Patients and methodsPatients received sorafenib at 400 mg BID. The primary end-point was response rate (RR) including complete response or partial response (PR); secondary end-points included RR according to Choi criteria, disease control rate (DCR), overall survival (OS), and progression-free survival (PFS).ResultsThirty-seven patients (19 adenoid cystic cancers, ACC) were enrolled. Six PRs were recorded. RR was 16% (95% confidence interval [CI]: 6–32; 11% in ACC and 22% in non-ACC). Choi criteria could be applied in 30 out of 37 cases with a RR of 50% (95% CI: 31–69%); DCR was 76% (95% CI: 59–88%). Incidence of ≥G3 adverse events was 29.7%. Median PFS and OS for the entire population were 5.9 months and 23.4 months, respectively. Median PFS and OS were 8.9 and 26.4 months for ACC versus 4.2 and 12.3 months for non-ACC patients.All the cases showed expression of PDGFRβ in the stroma and VEGFR2 in endothelial cells; PDGFRα positivity was found in the stroma of four (27%) cases. All except for two cases showed no PDGFRβ, VEGFR2 and PDGFRα expression in the tumour cells. KIT expression was restricted to ACC and a weak RET expression was limited to one adenocarcinoma, not otherwise specified (NOS). No BRAF mutation was found. No correlation was observed between the sorafenib activity and the expression of its markers although all six responders (two ACC, one adenocarcinoma, NOS, one salivary duct cancer [SDC], one high-grade mucoepidermoid [HG-MEC] and one poorly-differentiated cancer) are enriched in the stromal component showing a PDGFRβ immunodecoration. In ACCs, immunohistochemistry revealed MYB protein expression in 15/16 cases (94%) and the MYB-NFIB fusion oncogene was observed in 9/14 (64%).ConclusionsSorafenib is the first anti-angiogenic agent to demonstrate activity in RMSGC patients, particularly in some histotypes such as HG-MEC, SDC and adenocarcinoma, NOS. The PDGFRβ-positive rich stromal component characterising these histotypes and the lack of correlation between the activity of sorafenib and its targets suggests anti-angiogenic effect as the prevalent mechanism of action of sorafenib in SGCs.     

Biology and management of salivary gland cancers

The salivary gland cancers are uncommon neoplasms of the head and neck, which exhibit considerable pathologic, biological, and clinical diversity. Surgical resection, often with postoperative radiation, is the standard therapeutic approach, and the results after treatment vary widely depending on the tumor histology. Chemotherapy has been of only limited palliative benefit in patients with advanced disease, and there has been little exploration of its use in definitive management. Recent investigation has focused on identification of the characteristic molecular signatures and genomic alterations of the specific histologic subtypes. These efforts have suggested the potential for molecularly targeted therapies, and clinical trials exploring this approach are currently underway.     

Genetic alterations in salivary gland cancers

Salivary gland cancers are an incredibly heterogeneous group of tumors that include 24 histologically distinct tumor types. The use of new genetic methods has paved the way for promising advancements in our understanding of the molecular biology underlying each type of tumor. The objective of this review was to highlight common oncogenes, tumor suppressor genes, and cytogenetic and epigenetic changes associated with the most common tumor types: mucoepidermoid carcinoma, adenoid cystic carcinoma, salivary duct carcinoma, mammary analogue secretory carcinoma, hyalinizing clear cell carcinoma, carcinoma ex pleomorphic adenoma, and acinic cell carcinoma. Recent insights into the pathogenesis of each cancer subtype have helped better define and classify these tumors. Further research in salivary gland cancers should focus on determining the key genes involved in the tumorigenesis of each distinct malignancy and identifying individualized chemotherapies directed at these targets. Cancer 2016;122:1822–31 . © 2016 American Cancer Society.     

Second primary malignancies following salivary gland cancers

Four hundred and fifteen males and 367 females who had invasive malignant tumours of the salivary glands as their first cancer diagnosed in Connecticut between 1935 and 1978 were identified and followed 2342 and 2868 person-years respectively. Overall a slight excess of second primary cancers (relative risk 1.35) was observed. Significant excesses were noted for respiratory cancers in males (relative risk 2.8) and for ovarian cancer (relative risk 5.3) but not breast cancer (relative risk 1.3) in women. Possible reasons for excesses at these sites are discussed, but it seems most likely they are related to small number variation.     

Systemic therapy in the management of metastatic or locally recurrent adenoid cystic carcinoma of the salivary glands: a systematic review

Adenoid cystic carcinomas (ACC) are rare cancers usually arising in the salivary glands. Once metastatic, the natural history can vary; some patients with indolent cancer remain asymptomatic for long periods, whereas others have rapidly progressive disease. Chemotherapy is generally reserved for the palliative treatment of symptomatic locally recurrent or metastatic disease that is not amenable to further surgery or radiation. Prospective trials of chemotherapy in advanced ACC are limited, and the optimum regimen is unclear. The aim of this systematic review is to summarise and rate the quality of trials assessing chemotherapy for treatment of ACC, by use of the European Lung Cancer Working Party scoring system. Endpoints evaluated include tumour response and rates of symptomatic improvement. 34 trials involving 441 patients are included. We give evidence-based recommendations for management of ACC with chemotherapy, along with considerations for the design of future clinical trials in this disease.     

Upfront submandibular salivary gland transfer in pharyngeal cancers

Head and neck irradiation results in salivary dysfunction and subsequent xerostomia. Twenty two patients with squamous cancer of oropharynx or hypopharynx underwent contralateral submandibular salivary gland transfer (SMSGT) to submental triangle to shield it from subsequent radiotherapy. Resting salivary outputs of transferred and untransferred gland (control) were measured before and after SMSGT and following radiotherapy, by cannulating individual submandibular duct. They were compared by paired samples t-test. Following radiation therapy transferred gland retained 73% and untransferred gland (control) retained 27% of baseline salivary output. This significant difference in post-radiation salivary outputs suggests preservation of function of transferred salivary gland.     

Management of salivary gland malignancies: current and developing therapies

Salivary gland tumors are rare, clinically diverse neoplasms that represent less than 1% of all malignancies. In locoregional recurrent or metastatic disease, systemic therapy is the standard approach. While numerous small phase II studies have evaluated the activity of cytotoxic agents, either alone or in combination, the response rates are generally modest with objective response rates ranging from 15%–50%. Duration of response is cited in the range of 6–9 months. Given this, further evaluation of novel therapies is mandatory in these diseases. With the emergence of molecular targeted therapy, these tumors become optimal candidates for trials of investigational drugs and established drugs for new indications. Of note, given the often indolent nature of disease, only patients with progressive disease should be enrolled and treated on these clinical trials. Study designs must incorporate stringent inclusion criteria to enable accurate reporting of disease response and stabilization. With dedication and co-operation, patients with these rare neoplasms can be accrued to clinical trials and the establishment of new treatment guidelines will be forthcoming.