Molecular techniques and genetic alterations in head and neck cancer

It is well known that cellular DNA alterations can lead to the formation of cancer, and there has been much discovery in the pathways involved in the development of head and neck squamous cell carcinoma (HNSCC). With novel genome-wide molecular assays, our ability to detect these abnormalities has increased. We now have a better understanding of the molecular complexity of HNSCC, but there is still much research to be done. In this review, we discuss the well described genetic alterations and touch on the newer findings, as well as some of the future directions of head and neck cancer research.     

Clinical significance of molecular alterations in histologically negative surgical margins of head and neck cancer patients

The development of locoregional recurrence is the main reason for treatment failure in head and neck squamous cell carcinomas (HNSCC) and the remaining of tumor cells in surgical margins is associated with recurrence. Surgical margins are considered negative based on histologic assessment of the pathological specimen. However, this method lacks sensitivity in identifying cells that already started malignant transformation but have not yet developed a pathologic phenotype. We investigated the usefulness of assessing the expression of PTHLH, EPCAM, MMP9, LGALS1 and MET for the detection of molecular alterations in histologically negative surgical margins and determine the correlation of these tumor-related alterations with clinical and prognostic parameters. Differential gene expression was determined by quantitative RT-PCR analyses in normal mucosa, HNSCC and negative margin samples. Thirty-eight percent of the histologically negative surgical margins examined were margin-positive for overexpression of at least one of the genes evaluated. Moreover, MMP9 and PTHLH overexpression in the surgical margins was associated with the development of second primary tumors (p=0.002) and lower rates of local control (log rank test p=0.022; HR=4.186; p=0.035), respectively. These findings demonstrate that the overexpression of tumor-related genes in histologically negative surgical margins is a frequent event. The use of qRT-PCR may be an useful tool in detecting actually negative HNSCC surgical margins and the overexpression of specific genes in these margins could be helpful in the identification of patients with a higher risk of developing second primary tumors and local recurrences, thus aiding the surgeon in the delineation of the HNSCC resection extent and helping in the planning of adjuvant therapy.     

Clinical implications of biomarkers in head and neck cancer

The term biomarker refers to a host of biologic factors found within a tumor or other clinical specimen that can be used to assess the tumor in some way. Biomarkers have many potential clinical applications. Before they are used in actual clinical settings, however, they must be carefully validated. The literature contains many reports of this ongoing work related to head and neck squamous cell carcinoma. Candidate biomarkers for this disease include the p53 gene and its protein; microsatellite regions throughout the genome; human papillomavirus; proteins involved in cellular proliferation, apoptosis, angiogenesis, and intracellular adhesion; epithelial growth factor receptor; and various measures of immune response to cancer. The best new evidence for the validity of each of these candidates is critiqued in this review.     

Persistence of genetically altered fields in head and neck cancer patients: biological and clinical implications.

In 1953, Slaughter et al. [D. P. Slaughter et al., Cancer (Phila.), 6: 963-968, 1953] proposed the concept of field cancerization in patients with squamous cell carcinoma of the head and neck (HNSCC) and discussed its clinical significance for the development of second primary tumors and local recurrences. To define the process of field cancerization and its putative clinical implications, we analyzed genetic aberrations in HNSCC and the accompanying macroscopically normal mucosa. In 28 HNSCC patients, loss of heterozygosity was determined in tumor and five noncontiguous mucosal biopsies using eight microsatellite markers at 9p, 3p, and 17p. For patients who showed loss of heterozygosity in their mucosal biopsies, all margins of the surgical specimen were subsequently analyzed to determine the extension of the field. In these cases, additional markers at 8p, 13q, and 18q as well as p53 mutations were included to determine subclonal differences between field and tumor. Genetically altered fields were detected in 36% (10 of 28) of the HNSCC patients. The field varied in size between patients and consisted of genetically different subclones. In 7 of 10 cases, the field extended into the surgical margins. One particular patient with a genetically altered field in a surgical margin developed a local recurrence after 28 months of follow-up. Microsatellite analysis showed that this recurrence had more molecular markers in common with the nonresected premalignant field than with the original tumor, suggesting that this persistent field has progressed further into a new malignancy. Our data show that genetically altered mucosa remains after treatment in a significant proportion of HNSCC patients, which may explain in part the high frequency of local recurrences and second primary tumors. Adequate identification and risk assessment of these genetically altered fields may have profound implications for future patient management.     

Prevalence and implications of elevated microsatellite alterations at selected tetranucleotides in cancer

Elevated microsatellite alterations at selected tetranucleotides (EMAST), a variation of microsatellite instability (MSI), has been reported in a variety of malignancies (e.g., neoplasias of the lung, head and neck, colorectal region, skin, urinary tract and reproductive organs). EMAST is more prominent at organ sites with potential external exposure to carcinogens (e.g., head, neck, lung, urinary bladder and colon), although the specific molecular mechanisms leading to EMAST remain elusive. Because it is often associated with advanced stages of malignancy, EMAST may be a consequence of rapid cell proliferation and increased mutagenesis. Moreover, defects in DNA mismatch repair enzyme complexes, TP53 mutation status and peritumoural inflammation involving T cells have been described in EMAST tumours. At various tumour sites, EMAST and high-frequency MSI share no clinicopathological features or molecular mechanisms, suggesting their existence as separate entities. Thus EMAST should be explored, because its presence in human cells may reflect both increased risk and the potential for early detection. In particular, the potential use of EMAST in prognosis and prediction may yield novel types of therapeutic intervention, particularly those involving the immune system. This review will summarise the current information concerning EMAST in cancer to highlight the knowledge gaps that require further research.     

头颈部肿瘤组织中PD-L1的表达及临床意义分析

目的 探讨头颈部肿瘤组织中细胞程序性死亡配体-1（PD-L1）的表达情况及临床意义。方法 将2015 年1 月至2016年6月收治的40例头颈部恶性肿瘤组织及20例头颈部囊肿组织的手术标本经包埋制作成蜡块,采用免疫组织化学SP二步法检测以上组织中的PD-L1蛋白表达情况,分析PD-L1表达水平与临床病理参数（年龄、性别、病理分化程度和临床分期）的关系。结果PD-L1在头颈部囊肿组织中不表达,头颈部肿瘤组织中的阳性表达率为65.0%（26/40）,高于头颈部囊肿组织,差异有统计学意义（P<0.05）。PD-L1表达与年龄、性别及病理分化程度无关（P>0.05）,而与患者的临床分期有关（P<0.05）。结论 PD-L1在头颈部恶性肿瘤组织中表达升高,可为头颈部恶性肿瘤的免疫靶向治疗提供参考。     

MRI-guided radiotherapy for head and neck cancer: initial clinical experience

Purpose

To report a single-institutional experience with the use of magnetic resonance imaging (MRI)-guided radiotherapy for cancers of the head and neck.

Materials and methods

Between October 2014 and October 2016, 18 patients with newly diagnosed cancers of the head and neck were prospectively enrolled on an institutional registry trial investigating the feasibility and efficacy of external-beam radiotherapy delivered using on-board MRI. All patients had biopsy-proven evidence of malignancy, measurable disease, and the ability to provide consent. None had previously received any treatment. Median dose was 70 Gy (range 54–70 Gy). MRI scans were obtained as part of an image-guided registration protocol for alignment prior to and during each treatment. Concurrent chemotherapy was administered to 14 patients (78%). Patient-reported outcomes were assessed using the University of Washington quality of life instrument.

Results

Seventeen of 18 patients completed the planned intensity-modulated radiotherapy (IMRT) treatment of which 15 (83%) had a complete response and 2 (11%) had a partial response based on initial post-therapy positron emission tomography (PET) at 3 months. The 1-year estimates of progression-free survival, overall survival, and local–regional control were 95, 96, and 95%, respectively. There were no treatment-related fatalities. The incidence of grade 3+ acute toxicity was 44%. The proportion of patients rating their health-related quality of life as “very good” or “outstanding” at 6 months and 1 year after completion of radiation therapy was 60 and 70%, respectively.

Conclusions

MRI-guided radiotherapy achieves clinical outcomes comparable to contemporary series reporting on IMRT for head and neck cancer.

     

Prevalence of head and neck cancers in Ahmedabad,Gujarat

Introduction

Head and neck cancer constitute one of the commonest cancers in India. Use of smokeless tobacco (pan masala, gutka, zarda, etc.) is the maximum in Gujarat, especially in and around Ahmedabad, and it is responsible for a large majority of these cancers.

Aim and objective

The present study was carried out to study the patient’s characteristics, prevalence, treatment modalities and histopathological subtypes of head and neck cancer in and around Ahmedabad.

Methods

A cross-sectional and observational study was carried out at the Head and Neck Services Department of Aastha Oncology Associates, Medi-Surge Hospitals, Ahmedabad, from December 2006 to May 2007. Patients were made to fill up the Case Record Form (CRF) with their informed consent. Proforma of the CRF included patient’s age, gender, income, education, family history, lifestyle, signs and symptoms, various investigations, treatment options and adverse effects during treatment and follow up. Preponderance of cancer was found in males (86%) with maximum prevalence in age group 41–60 years (69%). 58% cases were habitual tobacco chewers. Majority of head and neck cancers constituted the tongue, buccal mucosa and alveolus cancers. Radiotherapy and surgery were major treatment options in 44% patients. Blood parameters profile in all the three treatment groups was found to be lower than the control group.

Conclusion

We conclude that a properly structured and site specific data like this pin points to the magnitude and pattern of head and neck cancer problem in India and it can augment the National Cancer Registry Program.

     

Opportunistic actinomycosis in osteoradionecrosis of the jaws in patients affected by head and neck cancer: incidence and clinical significance

Actinomycosis is occasionally an opportunistic infection occurrence in patients with osteoradionecrosis (ORN). A retrospective study (1992-97) of 50 patients with ORN of the jaws was done to evaluate the incidence and its clinical significance in the management of ORN. Actinomycosis was diagnosed in 12% of ORN cases. In 36 of the 50 patients including five cases of actinomycosis, the ORN was considered to be resolved after treatment. The median treatment duration of ORN was significantly longer (P<0.007) in patients with actinomycosis (29.7 months) than those without the disease (13.4 months). In conclusion, bone biopsy should be considered in cases of ORN with unsatisfactory response to its specific therapies, aiming to identify possible opportunistic actinomycosis infection.     

Prognostic significance of radiologically determined neck node volume in head and neck cancer: a systematic review

This systematic review addresses the prognostic significance of neck node volume in head and neck cancer. Primary tumor volume evolved as an independent significant factor for survival in head and neck cancer patients. Besides primary tumor volume, multiple prognostic features related to the regional lymph nodes were studied in literature. In literature, some authors showed the significance of total tumor volume/nodal volume for survival and loco-regional control. Articles reporting prognosis and survival in nodal tumor volumes were collected by systematically reviewing publications listed in the Pubmed and Embase databases. Publications were included when they at least reported on total tumor volume (TTV) or nodal volume and survival. In this systematic review we studied 21 articles. For measurement of nodal volume different formulas were used. Until now, there's no clear statistical evidence for the use of either TTV or nodal volume versus primary tumor volume to predict the individual loco-regional control or survival after treatment. There is wide variety of tumor measuring systems in the literature. The cut-off value for local tumor response also shows large variation. Firstly consensus should be accomplished on standardization of volume measurements, preferably automatic, and secondly large study groups are needed with identical treatment modalities to further unravel the role of neck node volume as separate staging tool.     

Nutritional implications of dental and swallowing issues in head and neck cancer

Tumors of the head and neck account for 4% of cancers in the United States. Both the disease process itself and side effects of cancer treatment, such as xerostomia, dysphagia, and malnutrition, compromise oral health, swallowing ability, and nutritional status. Optimal treatment of dental, swallowing, and nutritional problems of head and neck cancer patients requires practical strategies that address these problems. These strategies should include appropriate referrals to the dentist, speech/language pathologist, and registered dietitian to enhance patient comfort, prevent secondary malnutrition and dental disease, and improve treatment outcomes. Since dental, swallowing, and nutritional issues are interrelated, appropriate therapeutic strategies hinge on timely, integrated input from each discipline. A better understanding of the dental and swallowing therapies used in patients with head and neck cancer by health professionals will help promote the comprehensive care of these patients.     

Comparative clinical studies for head and neck cancer in Japan

Very few large multi-institutional comparative clinical studies for head and neck cancer are reported in Japan. Many studies for organ-preservation with better QOL have been reported around the world, and comparative clinical studies are also necessary in Japan to evaluate organ-preservation treatment. I reviewed comparative clinical studies for head and neck cancer in Japan. Inuyama et al. reported a multi-institutional randomized clinical trial (RCT) that compared the efficacy of CBDCA + PEP and CDDP + PEP. Comparative clinical studies for combination chemotherapy, CDDP + PEP + MTX (PPM) vs. CDDP + PEP + 5-FU (PPF), and PPM vs. CDDP + PEP (PP) are reported. Effects and toxicity are different with each regimen, but the differences are not statistically significant. An RCT of neoadjuvant chemotherapy (NAC) for nasopharyngeal cancer with a small sample size was reported. Three-year survival was significantly better for the NAC group. An RCT of concurrent chemo-radiotherapy with CDDP vs. CBDCA was also reported. CBDCA with radiation was significantly better in terms of 2- and 5-year survival. This result is interesting but the low-dose CDDP with radiation 4 times per week is not standard. A large nationwide RCT with 560 cases investigating adjuvant chemotherapy with UFT was conducted in 1987. The differences in 3-year survival and 3-year disease-free survival with or without UFT adjuvant were not statistically significant, but the incidence of distant metastasis was significantly lower in the UFT adjuvant group. Comparative clinical studies of 5-HT3 antagonists for chemotherapy including CDDP are reported. We conducted a crossover comparative clinical study on the combination of azasetron and dexamethasone. The combination with dexamethasone significantly prevented acute emesis induced by CDDP. Comparative clinical studies of head and neck cancer have not provided good evidence, with the exception of an RCT of adjuvant chemotherapy with UFT, in the past. Well-designed comparative clinical studies with the cooperation of head and neck surgeons, radio-oncologists, and medical oncologists should be considered in order to acquire high-level evidence.     

Genetic alterations in head and neck cancer: interactions among environmental carcinogens, cell cycle control, and host DNA repair

Head and neck squamous cell carcinomas (HNSCC) arise as a consequence of cumulative genetic changes brought about by continued exposure to carcinogens associated with tobacco and alcohol use, influenced by viral agents such as human papillomaviruses, in a background of acquired or heritable genetic susceptibility. The presence of widespread genomic instability in HNSCC, such as cytogenetic aberrations, allelic imbalance/loss of heterozygosity, and microsatellite instability, suggests that there is an imperfection in the host DNA repair machinery. Genomic instability with progressive accumulation of detrimental genetic alterations appears to be dependent upon a circuitous interaction between the environmental genotoxic insults and the host DNA repair machinery, the functional integrity of which is governed by the proper cell cycle control and host DNA repair capacity. Thus, it can be hypothesized that continued exposure to environmental carcinogens (ie, longstanding history of smoking and drinking), loss of proper cell cycle control (eg, inactivation of p53 or p16 tumor suppressor genes or amplification of the proto-oncongene cyclin D1), and impaired DNA repair capacity (both inherited and acquired) are prerequisites in head and neck carcinogenesis.