Current management of advanced resectable oral cavity squamous cell carcinoma

Photobiomodulation Recovers the Submandibular Gland in Vismodegib-Treated Rats

Objective: The submandibular gland (SMG) produces the most saliva, and factors such as aging and chemotherapy can affect its structure and function. However, there are only temporary treatments available for salivary hypofunction. This study aimed to evaluate the effects of photobiomodulation (PBM) on the function of SMG by using a rat animal model and vismodegib, an antagonist of the sonic hedgehog (SHH) pathway. Methods: Vismodegib (10 mg/kg) drug was gavaged orally for 14 days in rats to significantly decrease the SHH signaling proteins [SHH, protein patched homolog 1 (PTCH1), smoothened protein (SMO), glioma-associated oncogene homolog 1 (GLI1)], induce damage in SMG tissue, and affect salivary functional markers AQP5 and Keratin5. After that, in conjunction with vismodegib administration, PBM was performed using an 850 nm high-power light-emitting diode (LED) device treated daily for 6 days at varying total energy densities of 60, 120, and 180 J/cm2 in at least 3 rats per group. The test results were confirmed by Western blot, immunofluorescence staining, and hematoxylin and eosin staining, and the statistics were t-test or one-way analysis of variance (ANOVA) with Tukey's multiple comparisons tests. Results: Significant decreases in the expression of SHH-related proteins (PTCH1, SMO, GLI1, p < 0.05) with damage of SMG ductal cells were observed with vismodegib administration. However, a significant increase in the expression levels of SHH-related proteins (SHH, SMO, GLI1, p < 0.05) and recovery of SMG ductal cells damaged after vismodegib administration were observed for PBM-treated groups. Salivary functional marker AQP5 also showed the same increase or decrease. Conclusions: This study found that vismodegib damages SMG ductal cells and decreases SHH-related proteins and associated salivary functional markers. Also, 850 nm high-power LED recovered the damaged structure of SMG and increased SHH-related proteins and salivary functional markers. The study results suggest that PBM can restore SMG structure and function through SHH signaling.

Regional Nodal Recurence as a Prognostic Factor in Patients Kept on Observation for cT1-T2 Oral Squamous Cell Carcinomas of Tongue: A Meta-Analysis of 11,973 Patients

The surgical management of the clinically node negative neck in T1-T2 early oral tongue squamous cell carcinoma (OTSCC) has been the topic of debate since few decades. As the occult cervical lymph node metastasis is considered to be the primary prognostic factor in early OTSCC, this meta-analysis has been carried out to find the risk of regional nodal recurrence on patients kept under observation than those who have underwent Elective neck dissection (END). The articles were electronically retrieved from Ovid Medline, PubMed, Cochrane and Scholar for comparison of Observation versus END in early OTSCC. The search strategy identified 35 relevant review articles from April 1979 to April 2020 from different search engines. A total of 11,973 patients from 30 retrospective analyses, 4 prospective and 1 randomized control trials were included in this meta-analysis. Overall test revealed (OR: 13.02 95% CI 1.360-17.154) with t test 2.382 and p value 0.023 which is statistically significant and showed that END significantly reduced the risk of regional nodal recurrence. This meta-analysis finds that there is statistically significant relationship when END was performed which reduced the risk of regional nodal recurrence as seen in patients kept on Observation thereby affecting the Overall survival (OS) rate.

The current status of nanotechnological approaches to therapy and drug delivery in otolaryngology: A contemporary review

Objectives/Hypothesis

To summarize the current standing of nanomedicine-based technology, particularly nanoparticles (NPs), for drug delivery and diagnostic mechanisms in otolaryngology and the otolaryngology subspecialties.

Methods

Literature searches were performed using PubMed and Ovid MEDLINE from 2010 to 2022. The search focused on original articles describing developments and applications of nanotechnology and drug delivery in otology, neurotology, cranial base surgery, head and neck oncology, laryngology, bronchoesophagology, and rhinology. Keyword searches and cross-referencing were also performed. No statistical analysis was performed.

Results

The PubMed search yielded 29 articles, and two Ovid MEDLINE searches both yielded 7 and 26 articles, respectively. Cross-referencing and keyword searches in PubMed and Google Scholar yielded numerous articles. The results indicate that currently, NPs are the most thoroughly studied nanotechnology for drug delivery and therapy in otolaryngology. Organic NPs have been utilized for drug delivery in otology and head and neck oncology due to their high biocompatibility. Inorganic NPs have similarly been utilized for drug delivery. However, inorganic NPs seem to be studied less extensively in these fields, likely due to an increased risk for heavy metal toxicity. Due to their magnetic properties, inorganic NPs have been utilized for magnetic-guided delivery in otology and thermoradiation and magnetic resonance imaging in head and neck oncology. Applications of nanotechnology to the fields of laryngology, bronchoesophagology, and rhinology have been studied less compared with otology and head and neck oncology. However, researchers have primarily employed NPs and other nanotechnologies such as nanofibers and nanoclusters for drug elution at mucosal surfaces to reduce airway and nasal inflammation.

Conclusions

Nanomedicine offers potential benefits in the treatment of patients in the field of otolaryngology due to enhanced control over drug release, cell-specific targeting, and the potential to reduce drug toxicity. Future work is needed to ensure the safety of these therapies to integrate this field of research into human therapies.

Elective Neck Dissection Versus Observation in cT1-T2 Oral Tongue Squamous Cell Carcinoma: A Meta-Analysis of 11,973 Patients

The surgical management of the clinical negative neck node in early oral tongue squamous cell carcinoma (OTSCC) has been the topic of debate since few decades. As the occult cervical lymph node metastasis is considered to be the prime prognostic factor in early OTSCC, this meta-analysis has been carried out to find the risk of regional nodal recurrence, disease specific survival and overall survival rates in outcome of Elective neck dissection (END) versus patients under observation. The articles were electronically retrieved from Ovid Medline, PubMed, Cochrane and Scholar for comparison of END versus Observation in early OTSCC. The search strategy identified 37 relevant review articles from April 1979 to April 2020 from different search engines. A total of 11,973 patients from 32 retrospective analysis, 4 prospective and 1 randomised control trial were included in this meta-analysis. Statistical analysis revealed Overall test (OR: 5.31 95% CI: - 2.132-14.698) with t-test 1.919 and p value 0.113 which is not statistically significant but the readings says that there is always better Disease specific survival with END patients rather than patients kept on observation. Overall test revealed (OR: 13.02 95% CI: 1.360-17.154) with t test 2.382 and p value 0.023 which is statistically significant and showed that End significantly reduced the risk of regional nodal recurrence. Overall test revealed (OR: 7.93 95% CI: - 15.461-4.238) with t test - 1.347 and p value 0.220 which is statistically insignificant and but showed that to some extent Overall survival improves in patient with END than the patients kept on observation. This meta-analysis find that there is statistically significant relationship when Elective neck dissection was performed which reduced the risk of regional nodal recurrence. This analysis didn't statistically find any significance in Disease specific survival and Overall survival with Elective neck dissection patients rather than patients kept on observation but however showed good prognosis when elective neck dissection was performed.

Risk Factors of Microscopically Tumor-Free Surgical Margins for Recurrence and Survival of Oral Squamous Cell Carcinoma Patients

Objectives

The concept of adequate surgical margins remains controversial in oral squamous cell carcinoma (OSCC) surgery. This study aimed to identify surgical margin-related indicators that might impact recurrence and survival of OSCC patients.

Materials and Methods

Histopathological examination was performed using hematoxylin-eosin-stained surgical margin tissue sections in 235 OSCC patients. Axin2 and Snail expression at the surgical margin was detected by immunohistochemistry. The impact of the Axin2-Snail cascade on tumorigenesis of the immortalized human oral keratinocyte (IHOK) line was investigated in vivo.

Results

The width and dysplasia of surgical margins were not significantly associated with the outcome of OSCC patients. In a multivariate analysis using variable clinicopathologic factors and with Axin2 and Snail expression as cofactors, higher age (hazard ratio [HR]:1.050; P=0.047), Axin2 (HR:6.883; P=0.014), and Snail abundance (HR:5.663; P=0.009) had independent impacts on worsened overall survival. Similarly, lesion site in retromolar trigone (HR:4.077; P=0.010), upper (HR:4.332; P=0.005) and lower gingiva (HR:3.545; P=0.012), presence of extranodal extension (HR:9.967; P<0.001), perineural invasion (HR:3.627; P=0.024), and Snail abundance (HR:3.587; P<0.001) had independent impacts on worsened recurrence-free survival. Furthermore, Axin2 knockdown induced decreased Snail expression and attenuated tumorigenesis in the IHOK line.

Conclusion

Histopathological examination of surgical margins may not be reliable to predict OSCC patient outcome. Molecular analysis may provide a more accurate risk assessment of surgical margins in OSCC. In particular, Axin2 and Snail are potential predictive biomarkers for the risk assessment of surgical margins in OSCC.

Methods for sentinel lymph node mapping in oral cancer: a literature review

Oral cancers, excluding non-melanoma skin cancer, are the most common cancers of the head and neck. Of these, 90% are squamous cell carcinomas (SCC). Surgery, which consists of dissection of the primary tumor and lymphadenectomy, is considered a radical method of treatment. There are several ranges of cervical lymphadenectomy: selective neck dissection (SND), modified radical neck dissection (MRND), and radical neck dissection (RND). The extension of surgery depends on the stage of clinical advancement, which can be determined by TNM classification, among other methods. The greatest controversy is related to SND in patients with cN0 (no evidence of regional lymph node metastasis), which is currently standard procedure. This approach is dictated by the possibility of hidden or subclinical metastases. The use of the sentinel lymph node (SLN) concept in patients with early stage of oral cancer and appropriate methods of its mapping may lead to a reduction in the extent of the lymphadenectomy procedure, thus reducing postoperative mortality and maintaining the patient’s function and quality of life, with correct oncological results. So far, available methods for SLN mapping are based on use of markers: methylene blue dye (MBD), metastable radioactive isotope Technetium (99mTc), or the fluorescent substance indocyanine green (ICG).

Consistent multimodality approach to oral cavity and high-risk oropharyngeal cancer in veterans

PURPOSE

High-risk oropharyngeal squamous cell carcinoma (OPSCC) associated with tobacco exposure remains difficult to treat due to high rates of locoregional recurrence similar to oral cavity squamous cell carcinoma (OCSCC). Current NCCN guidelines allow for surgical management of this disease, but oncologic and functional data in the modern era remain scarce. We sought to compare and contrast oncologic and functional considerations for surgical management of OPSCC and OCSCC in a cohort of Veterans.

MATERIALS AND METHODS

We conducted a retrospective review of patients treated at the Michael E. DeBakey Veterans Affairs Medical Center between 2017 and 2020, treated using a homogenous, multi-modality algorithm.

RESULTS

OPSCC tumors presented with a higher rate of perineural invasion (p < 0.05) and extranodal extension (p = 0.02) compared to OCSCC tumors. Compliance with NCCN guidelines for adjuvant treatment were lower for OPSCC patients primarily due to a higher rate of previous irradiation; re-irradiation could be delivered in 75% of patients when recommended by NCCN guidelines. Total glossectomy was accompanied by concomitant total laryngectomy in 100% of OPSCC patients and 0% of OCSCC.

CONCLUSION

Surgical resection and free flap reconstruction of high-risk OPSCC generates oncologic outcomes comparable to OCSCC with comparable complication rates but a lower overall functional status. Reconstruction focused on rapid healing allows for high-rates of re-irradiation and minimal treatment delays.

LEVEL OF EVIDENCE

level 4.

Dose escalation in advanced floor of the mouth cancer: a pilot study using a combination of IMRT and stereotactic boost

PURPOSE

We evaluated the efficiency and toxicity of stereotactic hypofractionated boost in combination with conventionally fractionated radiotherapy in the treatment of advanced floor of the mouth cancer.

METHODS

Thirty-seven patients with advanced stage of the floor of the mouth cancer, histologically confirmed squamous cell carcinoma (p16 negative) ineligible for surgical treatment, were indicated for radiochemotherapy or hyperfractionated accelerated radiotherapy (HART). The radiotherapy protocol combined external beam radiotherapy (EBRT) and a stereotactic hypofractionated boost to the primary tumor. The dose delivered from EBRT was 70-72.5 Gy in 35/50 fractions. The hypofractionated boost followed with 10 Gy in two fractions. For the variables-tumor volume, stage and grade a multivariate analysis was performed to find the relationship between overall survival, local progression and metastasis. Toxicity was evaluated according to CTCAE scale version 4.

RESULTS

After a median follow-up of 16 months, 23 patients (62%) achieved complete remission. The median time to local progression and metastasis was 7 months. Local control (LC) at 2 and 5-years was 70% and 62%, respectively. Progression-free survival (PFS) and overall survival (OS) were 57% and 49% at 2 years and 41% and 27% at 5 years, respectively. Statistical analysis revealed that larger tumors had worse overall survival and a greater chance of metastasis. Log-Rank GTV > 44 ccm (HR = 1.96; [95% CI (0.87; 4.38)]; p = 0.11). No boost-related severe acute toxicity was observed. Late osteonecrosis was observed in 3 patients (8%).

CONCLUSION

The combination of EBRT and stereotactic hypofractionated boost is safe and seems to be an effective option for dose escalation in patients with advanced floor of the mouth tumors who are ineligible for surgical treatment and require a non-invasive approach.

The impact of close surgical margins on recurrence in oral squamous cell carcinoma

BACKGROUND

Close margins influence treatment and outcome in patients with oral squamous cell carcinoma (OSCC). This study evaluates 187 cases of surgically treated OSCC regarding the impact of close margins on recurrence-free survival (RFS) and disease-specific survival (DSS).

METHODS

Predictors of worsened outcome were identified using Kaplan-Meier analysis and multivariate Cox regression analysis.

RESULTS

Tumour size [HR:1.70(0.95-3.08)], nodal status [HR:2.15(1.00-4.64)], presence of extracapsular spread (ECS) [HR:6.36(2.41-16.74)] and smoking history [HR:2.87(1.19-6.86)] were associated with worsened RFS. Similar factors were associated with worsened DSS. Close margins did not influence RFS or DSS.

CONCLUSIONS

While most conventional risk factors for OSCC conferred a worsened outcome, close margins did not. One explanation for this would be that close margins (< 5 mm) are equivalent to clear margins and the cutoff definition for a close margin should be re-evaluated. Lack of standardized pathology could also reduce accuracy of reporting of close surgical margins.

A Study on Neck Nodes in Oral Cancers, with Special Reference to Skip Metastasis

To analyse the distribution of Neck metastases (NM) and to study frequency of skip metastases in oral squamous cell carcinoma (SCC) of oral cavity. From September 2012 to April 2013, 30 previously untreated patients with SCC of oral cavity underwent primary surgical treatment in our institution. From pathological report of Neck dissection specimen prevalence and distribution of NM were ascertained. All patients were classified according to American Joint Committee on Cancer 2005 TNM classification. Overall frequency of NM was 36.7%. Frequency of occult metastases was 33.3%. N+ metastases found in 37% cases. The overall frequency of NM in level IV and V was 9.5%. Isolated level III involvement was found in 3.3%. No isolated level IV and V involvement was found. Skip metastases to level III LN was 6.7%. We did not find any skip metastases to level IV in our study. Neck nodes at greater risk for metastases were level I and II (50 and 28.6%). Level III (11.9%), IV (7.14%), V (2.38%). The risk of skip metastases to level IV was nil in our study.

Contemporary Approach to Locally Advanced Oral Cavity Squamous Cell Carcinoma

PURPOSE OF REVIEW

Surgical management of locally advanced oral cavity squamous cell carcinomas (OCSCC) has long been recognized as a primary treatment modality. Technological advances have led to significant improvements in our surgical approach, from improvement in the visualization of tumors to more efficient and precise reconstruction. Here, we review the latest technological advances in surgical extirpation and reconstruction of locally advanced OCSCCs.

RECENT FINDINGS

The focus of technological innovation in surgical extirpation has been on improving visualization, with the use of intraoperative ultrasound for margin delineation, intraoperative navigation, narrow-band imaging, and the use of fluorescence. Though early, these are promising steps to ensuring complete resection of the cancer. Advances in reconstruction have been centered on the incorporation of computer assisted design, manufacturing, and virtual surgical planning, allowing for more complex three-dimensional defects to be expeditiously reconstructed. As these technologies are still under development, their impact on oncologic outcomes are not yet robustly defined; however, as technology continues to advance and become more widely available, new technologies will undoubtedly become integrated into enhancing surgical precision and planning.

The oncological outcome and influence of neoadjuvant chemotherapy on the surgery in the resectable and locally advanced oral squamous cell carcinoma

Aim

The role of neoadjuvant chemotherapy (NCT) in the treatment of advanced oral squamous cell carcinoma (OSCC) is still controversial. Especially, there are still few studies investigating the influence of NCT on the following surgery. In this retrospective single-center attended cohort study, we investigated the oncological effect of NCT and its influence on the following surgery in patients with resectable locally advanced OSCC.

Method

The clinical data of 88 patients with locally advanced but resectable OSCC (T3/4) were reviewed retrospectively. NCT plus conservative surgery and radical surgery were compared. Five-year disease-specific survival (DSS) was observed as the main endpoint.

Results

Among 88 patients enrolled in this study, 56 patients received upfront radical surgery (non-NCT group) and 32 patients received NCT followed by surgery (NCT group). The patients in the non-NCT group had a statistically better DSS than the patients in the NCT group (P=0.041). Twenty-one out of 32 (65.6%) patients who received NCT were good responders including two patients (6.2%) had a complete response and 19 patients (59.4%) had a partial response. There was no statistical difference between good and poor responders in 5-year DSS (P=0.823). Eleven patients (34.4%) had conservative surgery without flap reconstruction and 21 patients had radical surgery with flap reconstruction after NCT. No statistical difference in surgical margins was found between the two types of surgery (P=0.519). There was also no statistical difference in 5-year DSS between the two types of surgery (P=0.652).

Conclusion

NCT plus surgery could not improve survival compared with upfront surgery. NCT could modify the surgical extent but would not affect the surgical margins. This conclusion should be explained cautiously, and randomized clinical trials with large sample size were needed to further answer the question.

A Unifying Algorithm in Microvascular Reconstruction of Oral Cavity Defects Using the Trilaminar Concept

Although many algorithms exist to classify oral cavity defects, they are limited by either considering a single subsite or failing to provide a concise reconstructive algorithm for the breadth of defects. Based upon our experience as a tertiary referral center, a unifying algorithm is presented that guides free flap selection in this heterogenous population.

A case series on the conservative management of the bony skull in patients with aggressive skin carcinomas of the scalp

Few studies examine techniques of surgical resection for scalp malignancies to ensure clear margins. We present a case series utilizing outer cortex removal in patients without evidence of bony or pericranial invasion. A retrospective casenote review is presented of three cases treated in a tertiary Head and Neck Cancer Centre. An outer table removal approach was utilized based on the absence of bony involvement either on pre-operative imaging or from intra-operative findings. All cases underwent an outer table drilldown procedure. Tumour histology included high grade carcinoma of unknown origin, malignant cylindroma and squamous cell carcinoma. Complete excisions with adequate deep margins were achieved in 100% cases. Overall disease-free survival was 66.6% and local control rate was 100%. This technique allows a high degree of local control, notably at the deep margin. There is little morbidity and it avoids the complications associated with full thickness calvarial resection.

Anatomical locations in the oral cavity where surgical resections of oral squamous cell carcinomas are associated with a close or positive margin-a retrospective study

OBJECTIVES

This study aimed to identify anatomical areas where resections of oral squamous cell carcinomas (OSCC) are significantly associated with close or positive margins.

MATERIALS AND METHODS

This retrospective study included 330 patients with a primary OSCC from 2010 to 2015. Patient and tumour data were categorised into three groups by R-status (R0 [clear], ≥ 5 mm, 185 patients [56.06%]; R1 [positive], < 1 mm, 24 patients [7.27%]; and R0 [close], 1-5 mm, 121 patients [36.67%]).

RESULTS

Areas where resections were significantly associated with close or positive margins were the hard palate (p < 0.001), buccal mucosa (p = 0.03), floor of the mouth (p = 0.004), lower alveolar ridge (p = 0.01), retromolar triangle (p = 0.005), and dorsal tongue (p = 0.02).

CONCLUSIONS

Anatomical areas were identified in the oral cavity where it is challenging to resect OSCCs with an adequate safety margin.

CLINICAL RELEVANCE

These results may enable surgeons to achieve a postulated safe distance during tumour resection, leading to a survival benefit for patients.

A novel classification system for the evaluation and reconstruction of oral defects following oncological surgery

Accurate evaluation of oral tissue defects following oncological surgery is necessary for the subsequent reconstruction. However, there is currently no effective classification system for oral defects in the clinical setting. The present study therefore developed a clinical classification system for the evaluation and reconstruction of oral defects. A retrospective cohort study was performed. A two-dimensional classification system based on coronal computed tomography/magnetic resonance imaging was developed and validated by 145 cases with oral defects. Oral defects could be classified into 6 types (I–VI) horizontally and 2 classes (a and b) vertically. The proportion of the various types was as follows: Type I, 35.9%; type II, 21.4%; type III, 23.4%; type IV, 4.8%; type V, 2.1%; and type VI, 12.4%. Among them, 91 cases (62.8%) were class a and 54 cases (37.2%) were class b. Type Ia-Va represented the unilateral 1–5 subsites involving superficial oral defects without mandibular continuity destruction (88 cases, 60.7%). Type Ib-Vb (+M) represented the unilateral 1–5 subsites involving deep oral defects with segmental mandibular continuity destruction (38 cases, 26.2%). Type I–V (+S) represented the unilateral through and through oral defects with cheek skin involvement (10 cases, 6.9%). Type VI represented bilateral oral defects (18 cases, 12.4%). The present classification system for the evaluation of the oral defects was simple and practical, and could identify the common types of oral defects and guide the reconstruction.

The effectiveness of elective neck dissection on early (stage I, II) squamous cell carcinoma of the oral tongue

Objectives

The purpose of this study was to evaluate and compare the treatment outcomes of partial glossectomy with or without elective neck dissection in patients with tongue squamous cell carcinoma (SCCa).

Materials and Methods

A total of 98 patients who were diagnosed with tongue SCCa and underwent partial glossectomy between 2005 and 2014 were evaluated. Only 14 patients received elective neck dissection, and 84 patients received only partial glossectomy.

Results

There were 56 men and 42 women with a mean age of 57 years and mean follow-up period of 33.7 months. There were 70 patients graded as T1 and 28 as T2. The total occult metastasis rate was 17.3%. The 5-year overall survival rate was 83.3% with elective neck dissection and 92.4% with observation. The 5-year disease-free survival rate was in 70.7% in the elective neck dissection group and 65.3% in the observation group.

Conclusion

We retrospectively reviewed the records of 98 patients with tongue SCCa. These patients were divided into two groups, those who underwent elective neck dissection and those who did not. There was no statistically significant difference between the groups undergoing partial glossectomy with or without elective neck dissection.

Temporal trends in outcome of oral squamous cell cancer in a resource-limited setting

AIMS AND BACKGROUND

Improving survival has been documented for oral squamous cell carcinoma in recent years. It is a common malignancy in Pakistan but survival outcomes have not been reported. The objective of this study was to determine survival and identify independent predictors in patients with oral squamous cell cancer in 2 different time periods.

METHODS

A retrospective review of patients who received treatment between 2003 and 2012 was performed. Patients were divided into two 5 year groups: group 1 (2003-2007) (n = 628) and group 2 (2008-2012) (n = 920). Demographics, risk factors, treatment approaches, and outcomes were compared. Disease-free and overall survival were calculated. Cox proportional hazard model was used to determine independent predictors of survival.

RESULTS

A significant difference was present for ethnicity and grade and clinical T and N stage of tumors, with earlier presentation in group 2. More patients underwent surgery (p = 0.001) and had radical treatment intent (p<0.0001) in recent years. Induction chemotherapy (p<0.0001) and palliative chemotherapy (p<0.0001) were used more frequently. No significant difference in disease-free survival was observed but overall 5-year survival improved significantly (23% vs 42%) (p<0.0001). Use of palliative chemotherapy reduced risk of death significantly (hazard ratio [HR] 0.1, confidence interval [CI] 0.02-0.4, p = 0.003), while pathologic nodal positivity significantly increased the risk (HR 2.5, CI 1-5.9, p = 0.03).

CONCLUSIONS

These results from a single cancer hospital demonstrate improvement in overall survival secondary to early detection, better patient selection, and use of palliative chemotherapy in the later period.

Molecular events in relapsed oral squamous cell carcinoma: Recurrence vs. secondary primary tumor

Relapses have a great impact on both the morbidity and mortality rates of oral squamous cell carcinoma (OSCC) patients. Current classification criteria are imprecise and need improvements. Recent advances in understanding of OSCC relapses on a molecular level provide new possibilities to better classify true recurrences and second primary tumors. This review discusses the limitations of the current OSCC relapse classification method and presents possible alternatives to improve this classification based on molecular techniques. Moreover, these molecular techniques add to the further understanding of these lesions and may provide tools for clinical management.

The promoting effect of carbamide peroxide teeth bleaching gel in a preclinical model of head and neck cancer in hamster buccal pouch

Objectives

The aim of this study was to verify the promoting effect of carbamide peroxide on dimethylbenzanthracene (DMBA)-induced carcinogenesis in the hamster buccal pouch, in order to reduce the period of latency for tumor formation.

Methods

Sixteen hamsters were randomized into two groups of eight animals each. The hamsters of the group I had their right buccal pouches treated with 0.5% DMBA and 10% carbamide peroxide teeth bleaching gel for 55 days. The animals of the group II had their right pouches treated only with DMBA. After, six animals of each group had their pouches prepared for light microscopy. Histomorphometry was performed to assess the presence of keratinization, nuclear polymorphism, pattern of invasion, number of blood vessels, and inflammatory infiltrate in the tumor front. Furthermore, the newly formed lesions were graded according the Bryne's grading system. The remaining animals had the vascular system of the pouches casted by Mercox and qualitatively analyzed by scanning electron microscopy.

Results

Histopathological analysis of the buccal pouches treated with DMBA and carbamide peroxide exhibited formation of squamous cell carcinoma well-differentiated with a high degree of malignancy in all pouches. The development of this neoplasm was associated with a significant increase in the number of blood vessels, presence of keratin pearls, and inflammatory infiltrate. The pouches of the group II showed inflammation, epithelial hyperplasia, dysplasia, and squamous cell carcinoma in only three right pouches. The analysis of the electron micrographs of the pouches chemically inducted with DBMA and carbamide peroxide reveled formation of a new vascular network characteristic of squamous cell carcinoma.

Conclusion

The protocol presented here, using DMBA associated with carbamide peroxide, shortens the period of latency to produce squamous cell carcinoma in the hamster buccal pouch, decreasing the time and costs of the experiments.

Effects of postoperative chemotherapy and radiotherapy on patients with squamous cell carcinoma of the oral cavity and multiple regional lymph node metastases

Nodal metastasis in oral squamous cell carcinoma (OSCC) is considered to be a predictor of a poor prognosis. The aim of this study was to investigate the relationship between the number of positive lymph nodes and the prognosis in OSCC patients with nodal metastases and to assess the effects of postoperative radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) on this patient group. A retrospective investigation of 98 patients with OSCC who underwent radical neck dissection and had at least three pathologically positive lymph nodes was performed. The 5-year disease-specific survival rate was 66.7% for patients with 3 positive nodes, while it was significantly lower for those with 4 positive nodes and those with ≥ 5 positive nodes (21.5% and 46.1%, respectively; P < 0.01). The loco-regional control and disease-specific survival rates for the surgery alone, surgery plus RT, and surgery plus CCRT groups were 46.2% and 40.5%, 66.3% and 54.4%, and 81.7% and 52.4%, respectively. For patients with ≥ 4 positive nodes, the loco-regional control rate after surgery plus CCRT was better than that observed after surgery alone (77.5% vs. 32.6%, P = 0.01). Postoperative RT and CCRT have positive impacts on the prognosis of OSCC patients with advanced stage neck disease.

Thymoquinone induces apoptosis in oral cancer cells through p38β inhibition

Oral cancer is a common malignancy associated with high morbidity and mortality. While p38 MAPK is reported to be involved in different cellular activities such as proliferation and differentiation, reports rarely define the roles of the individual members of the p38 MAPK family in cancer. We used two unique cell lines developed by our lab representing chemically induced oral cancer cells (T28) and non-tumor cells (N28) obtained from tissues surrounding the induced cancer as a model to screen out whether p38 MAPK is involved in the malignant transformation processes. The results suggest an association between p38β not p38α and oral cancer development. Additionally, the anti-cancer activity of thymoquinone (TQ) was screened out and we found evidences suggesting that the anti-tumor activity of TQ may be attributed to the downregulation of p38β MAPK.

Therapeutic effect of oncolytic adenovirus expressing relaxin in radioresistant oral squamous cell carcinoma

Radioresistance is one of the main determinants of treatment outcome in oral squamous cell carcinoma (OSCC), and treatment of radioresistant OSCC is difficult due to cross resistance to other conventional treatments. We aimed to identify whether genetically modified oncolytic adenovirus expressing relaxin (RLX), which affects collagen metabolism, can effectively inhibit growth of the radioresistant OSCC. Therapeutic effect of oncolytic adenovirus was compared between radiosensitive and radioresistant OSCC cell lines in vitro and in vivo, and spread of adenovirus throughout the tumor mass was verified by immunohistochemistry (IHC). Oncolytic adenovirus effectively killed cancer cells and there was no significant difference in the cytotoxic effect between radiosensitive and radioresistant OSCC cell lines. In animal experiments, the adenovirus significantly reduced the size of tumor, and there was no significant difference between radiosensitive and radioresistant OSCC. In IHC, RLX expressing adenovirus showed better proliferation and eliminated collagens more effectively compared to RLX nonexpressing adenovirus. These findings suggested that genetically modified oncolytic adenovirus can effectively inhibit growth of the radioresistant OSCC and might be a new therapeutic option in radioresistant OSCC.

Buccinator Myomucosal Flap for Reconstruction of Glossectomy Defects

Objective

The use of the myomucosal flap from the buccinator muscle is a valuable reconstruction method for intraoral defects. We report the clinical advantages and pitfalls of using the buccinator myomucosal flap for tongue reconstruction after intraoral resection of tongue cancer.

Study Design

Prospective study.

Setting

University hospital.

Subjects and Methods

We used buccal artery–based buccinator myomucosal flaps for tongue reconstruction in 11 partial or total edentulous patients who underwent resection of tongue cancer. The size and site of the tongue defect ranged from one-third to one-half of the tongue in the lateral border. We analyzed the clinical features and oncologic and functional outcomes to define adequate indications.

Results

All flaps were successfully harvested and transposed, and the donor sites were primarily closed. The pedicles were safely divided 2 to 3 weeks postoperatively. In 8 of 11 patients, concurrent upper neck dissection was performed without compromising blood supply to the flap. The range of tongue motion and the volume of the reconstructed tongue were satisfactory, and the patients experienced no difficulties in swallowing or speech.

Conclusion

Particularly in edentulous patients, the buccal myomucosal flap can be a good option for reconstructing partial tongue defects after cancer surgery.

An unlikely role for the NAT2 genotypes and haplotypes in the oral cancer of south Indians

The arylamine N-acetyltransferase 2 (NAT2) enzyme detoxifies a wide spectrum of naturally occurring xenobiotics including carcinogens and drugs. Acetylation catalysed by the NAT2 is an important process in metabolic activation of arylamines to electrophilic intermediates that initiate carcinogenesis. Polymorphism in N-acetyltransferase 2 gene was reported to be associated with the susceptibility of various cancers.

OBJECTIVE

The aim of our study was to determine whether there is any association between the susceptibility to oral cancer amongst the variations of NAT2 genotypes.

DESIGN

This study was carried out in 157 patients with oral cancer. The control group consisted of 132 healthy volunteers. The most common polymorphisms rs1799929, rs1799930 and rs1799931 on the NAT2 gene were screened for the genotypes using TaqMan allelic discrimination.

RESULTS

All the three SNPs were polymorphic with minor allele frequency of 0.339, 0.372 and 0.061 for rs1799929, rs1799930 and rs1799931, respectively. None of the polymorphic site deviated from HWE in controls. There were no significant differences in genotype or allele frequencies of three SNPs between controls and cases with oral cancer. Risk of oral cancer development for the carriers of the individual deduced phenotypes was also not statistically significant. Of the 3 studied polymorphisms, 2 were in strong LD and form one haplotype block. None of the haplotype had shown significant association with the oral cancer.

CONCLUSIONS

Our study concludes that the NAT2 genotypes, phenotypes and haplotypes are not involved in the susceptibility to oral cancer in South Indian subjects.