A Novel Sirtuin-3 Inhibitor, LC-0296, Inhibits Cell Survival and Proliferation, and Promotes Apoptosis of Head and Neck Cancer Cells

BACKGROUND

The survival rate of patients with head and neck squamous cell carcinoma (HNSCC) stands at approximately 50% and this has not improved in decades. This study developed a novel sirtuin-3 (SIRT3) inhibitor (LC-0296) and examined its role in altering HNSCC tumorigenesis.

MATERIALS AND METHODS

The effect of the SIRT3 inhibitor, LC-0296, on cell survival, proliferation, and apoptosis, and reactive oxygen species levels in HNSCC cells were studied.

RESULTS

LC-0296 reduces cell proliferation and promotes apoptosis of HNSCC cells but not of normal human oral keratinocytes. This inhibitory effect is mediated, in part, via modulation of reactive oxygen species levels. Additionally, LC-0296 works synergistically to increase the sensitivity of HNSCC cells to radiation and cisplatin treatment.

CONCLUSION

Development of novel SIRT3 inhibitors, such as LC-0296, might enable the development of new targeted therapies to treat and improve the survival rate of patients with head and neck cancer.

Dental amalgam artifact: Adverse impact on tumor visualization and proton beam treatment planning in oral and oropharyngeal cancers

PURPOSE

We evaluated the incidence and impact of dental filling artifacts on the definition of clinical target volume (CTV) for oropharyngeal/oral cavity cancers receiving radiation therapy. We performed phantom proton beam dosimetric analyses using a low-density composite filling to investigate artifact reduction and dose distribution.

METHODS AND MATERIALS

We reviewed oral cavity/oropharynx radiation treatment plans between 2010 and 2012. Plans were evaluated for artifacts and impact on CTV visualization. We constructed a head and neck phantom, obtaining planning computed tomography images at baseline (native tooth) and for each filling (composite and metal amalgam) interchanged into a tooth adjacent to the tumor. We performed uniform scanning proton plans with each filling, evaluating for planning target volume (PTV) coverage and overall dose distribution.

RESULTS

A total of 110 treatment plans were reviewed (71 oropharynx, 39 oral cavity). Artifacts were identified in 81 plans (73.6%), including 53 oropharynx (74.6%) and 28 oral cavity (71.8%). Artifacts obscured the CTV in 77 cases (95%), including 49 of 53 oropharynx cases (92.5%) and all 28 oral cavity cases. On phantom testing, the metal amalgam obscured the tumor while the composite did not. Hounsfield unit (HU) values (range, mean) for the tumor were: baseline (-484.0 to 700.0 HU, 104 HU), composite (-728.5 to 1038.0 HU, 105 HU), metal amalgam (-1023.0 to 807.0 HU, 90.74 HU). The percent of planning target volume receiving 95% of prescription dose of the PTV was baseline (100%), composite (100%), and metal amalgam (92.3%). PTV dose ranges were baseline (98%-106%), composite (98%-107%), and metal amalgam (66%-111%). PTV coverage and dose distributions of the composite and native tooth plans were identical.

CONCLUSIONS

A high incidence of artifacts was found on the planning scans of oral/oropharyngeal cancer patients, adversely impacting CTV visualization. In our phantom model, metal amalgam impacted tumor and tissue density. The PTV was underdosed with the metal amalgam compared with the composite filling. A potential solution involves exchanging metal fillings with composite before proton treatment planning for improved tumor visualization and dosimetry.

Tooth loss prior to radiation in relation to tumor location in patients with head and neck cancer

PURPOSE

This study aimed to investigate the impact of preradiation tooth loss in patients with head and neck cancer.

MATERIALS AND METHODS

Records of 397 (partially) dentate patients who were referred for preradiation oral screening were included. Number and location of teeth lost and occluding pairs lost were determined for different tumor locations.

RESULTS

The majority of patients (54%) were affected by tooth loss. Proportion of teeth lost, their location, and proportion of occluding pairs lost were not evenly distributed across tumor locations. The highest proportions of teeth were removed with oral tumors (maxilla: 25%; mandible: 47%). For preradiation preventive extractions only, ie, not taking into account teeth that were lost due to ablative surgery, tooth loss in the mandible was still not evenly distributed across tumor locations, but tooth loss in the maxilla and occluding pairs lost were.

CONCLUSIONS

Tumor location affects preradiation tooth loss, though this is primarily a consequence of ablative surgery rather than a consequence of preradiation dental extraction decisions. Since patients with oral cavity tumors are affected most by preradiation tooth loss, treatment planning with regard to functional rehabilitation is desirable for this patient group in particular.

Prognostic Role of Circulating Tumor Cells during Induction Chemotherapy Followed by Curative Surgery Combined with Postoperative Radiotherapy in Patients with Locally Advanced Oral and Oropharyngeal Squamous Cell Cancer

Background

The prognostic role of circulating tumor cells (CTCs) after induction chemotherapy using docetaxel, cisplatin and fluorouracil (TPF) prior to surgery and adjuvant (chemo)radiation in locally advanced oral squamous cell cancer (OSCC) was evaluated.

Methods

In this prospective study, peripheral blood samples from 40 patients of the phase II study TISOC-1 (NCT01108042) with OSCC before, during, and after treatment were taken. CTCs were quantified using laser scanning cytometry of anti– epithelial cell adhesion molecule–stained epithelial cells. Their detection was correlated with clinical risk factors, recurrence-free (RFS) and overall survival (OS).

Results

Before starting the treatment CTCs were detected in 32 of 40 patients (80%). The median number at baseline was 3295 CTCs/ml. The median maximal number of CTCs during treatment was 5005 CTCs/ml. There was a significant increase of CTCs before postoperative radiotherapy compared to baseline before 1^st cycle of IC (p = 0.011), 2^nd cycle of IC (p = 0.001), 3^rd cycle of IC (p = 0.004), and before surgery (p = 0.002), but not compared to end of therapy (p = 0.118). CTCs at baseline >median was also associated to risk of recurrence (p = 0.014). Maximal CTCs during therapy >median was more frequently observed in tumors of the oral cavity (p=0.022) and related to higher risk of death during follow-up (p = 0.028). Patients with CTCs at baseline >median value had significant lower RFS than patients with CTCs at baseline <median value (p = 0.025). Patients with maximal CTCs values >median during the complete course of therapy had a significantly lower OS than patients with values <median (p = 0.049). Finally, the multivariate analysis revealed that OS was significantly lower in patients with maximal CTCs during treatment higher than the median value (HR=6.151; CI: 1.244-30.420).

Conclusions

Baseline CTCs and maximal CTCs during therapy both seem to be good prognostic markers for OSCC when treated by TPF induction chemotherapy, surgery, and postoperative (chemo)radiation.

[Factors for oral infections in patients with oral cancer undergoing radiotherapy]

OBJECTIVE

To investigate the factors associated with oral infections in patients with oral cancer undergoing radiotherapy.

METHODS

Clinical data of 241 patients with oral cancer undergoing radiotherapy between March 2012 and May 2014 in sichuan cancer hospital were reviewed. Univariate and multivariate analyses were performed to determine the factors related to oral infection occurring in the patients. SPSS 17.0 software was used to analyze the data.

RESULTS

Ninety-three (38.59%) of 241 cases had oral infection. Among the 93 cases, 49 (52.69%) cases presented with fungal infections, 44 (47.31%) cases with bacterial infection, and 38 (40.86%) cases with mixed infection. Oral infection occurred since the fifth week after radiotherapy in 55 (59.14%) patients. Multivariate Logistic regression analysis showed that the risk factors for oral infection after radiotherapy were the late stage of cancer, poor oral health habits, the coexistence of multiple treatments, city dwellers and surgical history (all P<0.05).

CONCLUSIONS

Oral infections commonly occur in the late period of radiotherapy. The late stage of cancer, poor oral health habits, the coexistence of multiple treatments, city dwellers and surgical history are key risk factors for oral infection in patients with oral cancer undergoing radiotherapy.

Radiation safety consideration during intraoperative radiation therapy

Using in-house-designed phantoms, the authors evaluated radiation exposure rates in the vicinity of a newly acquired intraoperative radiation therapy (IORT) system: Axxent Electronic Brachytherapy System. The authors also investigated the perimeter radiation levels during three different clinical intraoperative treatments (breast, floor of the mouth and bilateral neck cancer patients). Radiation surveys during treatment delivery indicated that IORT using the surface applicator and IORT using balloons inserted into patient body give rise to exposure rates of 200 mR h(-1), 30 cm from a treated area. To reduce the exposure levels, movable lead shields should be used as they reduce the exposure rates by >95%. The authors' measurements suggest that intraoperative treatment using the 50-kVp X-ray source can be administered in any regular operating room without the need for radiation shielding modification as long as the operators utilise lead aprons and/or stand behind lead shields.

Oral cancer malnutrition impacts weight and quality of life

Diet is important for both quality of life (QoL) and survival of patients with oral cancer. Their intake of food is impeded by functional restrictions in chewing and swallowing. In the DÖSAK REHAB STUDY 1652 patients from 38 hospitals within the German-language area of Germany; Austria and Switzerland were examined with regard to functional and psychological variables having an impact on diet. Chewing and swallowing are correlated with mobility of the tongue and the mandible as well as opening of the mouth. Thirty five percent of the patients lost weight; 41% maintained their weight and 24% gained weight. The QoL of patients who were able to maintain their weight and of those who gained weight was significantly better than that of patients who lost weight. A normal diet was important for maintaining weight. Mashed food; liquid food and loss of appetite were closely associated with loss of weight; although it was possible for nutritional counseling and dietary support to be implemented particularly favorably in this respect. Due to problems with eating patients' strength deteriorated; thus restricting activity. Radiotherapy had a negative impact on diet and weight. It influenced sense of taste; dryness of the mouth; swelling and discomfort when ingesting food. Pain and scars in the region of the operation also cause patients to dislike hard; spicy and sour food. Support from a nutritional counselor in implementing a calorie-rich diet remedied this and such support needs to be integrated into patient management. The fact that a poor nutritional status is of such great importance is well-known; but what is often lacking is the systematic implementation of continued professional nutritional counseling over a long period of time; weight control and psycho-social support of the operated patients; particularly those who also have had radiotherapy.

Effect of hyperbaric oxygen treatment on irradiated oral mucosa: microvessel density

The aim of this study was to evaluate the effect of hyperbaric oxygen therapy (HBOT) on microvascular tissue and cell proliferation in the oral mucosa. Twenty patients, aged 51-78 years, were allocated randomly to a treatment or a control group. All had a history of radiotherapy (50-70 Gy) to the orofacial region 2-6 years previously. Tissue samples were taken from the irradiated buccal oral mucosa before HBOT and at 6 months after treatment. In the control group, tissue samples were taken on two occasions, 6 months apart. The samples were subjected to immunohistochemistry staining: double staining with CD31 and D2-40 for microvessels, or Ki-67 for the analysis of cell proliferation. Blood vessel density and area were significantly increased after HBOT (P=0.002-0.041). D2-40-positive lymphatic vessels were significantly increased in number and area in the sub-epithelial area (P=0.002 and P=0.019, respectively). No significant differences were observed in the control group. There were no significant differences in Ki-67-expressing epithelial cells between the two groups. It is concluded that the density and area of blood and lymphatic vessels in the irradiated mucosa are increased by HBOT 6 months after therapy. Epithelial cell proliferation is not affected by HBOT.

Necrotizing fasciitis in oro-maxillo-facial area after radiotherapy for squamous cell carcinoma of the soft palate

The fascia's and subcutaneous adipose tissue's impairment by mono or polymicrobial infection, which also can involve the skin and the muscles, is rarely seen in oro-maxillo-facial area. The present case report is presenting a case of necrotizing fasciitis in a patient who had a history of an invasive squamous cell carcinoma of the soft palate, with surgical treatment and with radiotherapy. He was admitted in our Clinic with malaise and subsequently developed a toxico-septic shock. Clinical symptoms, serological and bacteriological analysis and histopathological examination confirmed the diagnosis of necrotizing fasciitis (NF). The patient subsequently underwent a series of surgical reconstruction and aesthetic treatments because of the complications that had arised in the meantime. Postoperative evolution was favorable towards complete closure of the defect. The prognosis of this disease is generally reserved, the favorable evolution depending on the possibility of wound sterilization and the surgery is required despite its mutilating effect.

Early preventive exercises versus usual care does not seem to reduce trismus in patients treated with radiotherapy for cancer in the oral cavity or oropharynx: a randomised clinical trial

PURPOSE

In head and neck cancer patients undergoing curative radiotherapy, we investigated the benefits and harms of an early exercise regime on trismus.

MATERIAL AND METHODS

Patients with head and neck cancer undergoing radiotherapy were centrally randomised to exercises 5-6 times for 45 minutes during and after radiotherapy supervised by a physiotherapist in addition to usual care versus usual care alone. The primary outcome was change in maximal interincisor distance (MID) measured at 5 and 12 months. Secondary outcomes were change in cervical ranges of motion, tissue tightness, and health-related quality of life. Mixed model analysis of repeated measures adjusted for tumour size and operation was conducted to assess the effect of early preventive exercises across time periods.

RESULTS

Of the 100 patients included, two patients withdrew and one died before the onset of radiotherapy. The unadjusted mean difference in MID at 12 months after having completed radiotherapy was 0.83 mm (95% confidence interval (CI) -3.64-5.29, p = 0.71) in the exercise intervention group compared with the control group. When adjusted for operation and tumour size, the effect of the exercise intervention on mean MID from baseline to 12-month follow-up was 5.92 mm (95% CI -0.48-12.33, p = 0.07). Of the secondary outcomes, cervical rotation showed a statistically significant deterioration in the exercise group compared with the control group (p = 0.01). No significant effects were observed on the other secondary outcomes.

CONCLUSIONS

In patients with cancer in the oral cavity or oropharynx, early supervised exercises combined with self-care treatment focusing on mobility exercises to reduce trismus do not seem to provide additional beneficial effects compared with usual care during curative radiotherapy.

Assessing advantages of sequential boron neutron capture therapy (BNCT) in an oral cancer model with normalized blood vessels

BACKGROUND

We previously demonstrated the therapeutic success of sequential boron neutron capture therapy (Seq-BNCT) in the hamster cheek pouch oral cancer model. It consists of BPA-BNCT followed by GB-10-BNCT 24 or 48 hours later. Additionally, we proved that tumor blood vessel normalization with thalidomide prior to BPA-BNCT improves tumor control. The aim of the present study was to evaluate the therapeutic efficacy and explore potential boron microdistribution changes in Seq-BNCT preceded by tumor blood vessel normalization.

MATERIAL AND METHODS

Tumor bearing animals were treated with thalidomide for tumor blood vessel normalization, followed by Seq-BNCT (Th+ Seq-BNCT) or Seq-Beam Only (Th+ Seq-BO) in the window of normalization. Boron microdistribution was assessed by neutron autoradiography.

RESULTS

Th+ Seq-BNCT induced overall tumor response of 100%, with 87 (4)% complete tumor response. No cases of severe mucositis in dose-limiting precancerous tissue were observed. Differences in boron homogeneity between tumors pre-treated and not pre-treated with thalidomide were observed.

CONCLUSION

Th+ Seq-BNCT achieved, for the first time, response in all treated tumors. Increased homogeneity in tumor boron microdistribution is associated to an improvement in tumor control.

Application of EPR dosimetry in bone for ex vivo measurements of doses in radiotherapy patients

In the present study, bone samples from three patients treated in radiotherapy facilities in Poland were used for the determination of doses absorbed during radiotherapy. The samples were obtained during surgical treatments of patients performed due to medical indications. For the purpose of retrospective dosimetry, sensitivity of the radiation-induced EPR signal was individually calibrated in the samples by re-irradiation of the samples with known doses. The doses reconstructed in bones extracted within 6 months after irradiation were consistent with those calculated by treatment planning systems. The dose reconstructed in the bone removed 6 y after radiotherapy was ∼14% lower than the calculated one.

Effects of resveratrol and irradiation upon oral squamous cell carcinoma cells

OBJECTIVE

To evaluate the effects of resveratrol and irradiation on oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

Resveratrol was administered at doses of 5, 10, 25, 50 and 100 µM to PE/CA-PJ15 (OSCC) cultures irradiated with different doses (1, 2.5 and 5 Gy). Effects upon cell viability, apoptosis and migration were evaluated after 24, 48 and 72 h incubation.

RESULTS

After 72 h of incubation, the 100 µM dose of resveratrol induced the greatest decrease in cell viability at all irradiation doses. After 24, 48 and 72 h of incubation, 100 µM of resveratrol induced the greatest cell apoptosis at all irradiation doses. The greatest alterations in the distribution of the G0-G1, G2-M and S phases of the cell cycle were recorded with 50 and 100 µM of resveratrol; after 24, 48 and 72 h of incubation, both these doses resulted in an increase in the S phase, at the expense of the G0-G1 and G2-M phases.

CONCLUSIONS

Resveratrol increases cytotoxic activity in the PE/CA-PJ15 cell line and reduces cell migration capacity, while the combination of resveratrol and irradiation exerts a synergic effect.

TPS-guided interstitial Iodine-125 implantation in patients with oral cavity and maxillofacial carcinomas

OBJECTIVE

To investigate the efficacy as well as the complications involved in the use of interstitial Iodine-125 implantation for the treatment of oral cavity and maxillofacial carcinomas.

PATIENTS AND METHODS

Fifteen patients with oral cavity and maxillofacial carcinomas received treatment planning system (TPS)-guided interstitial Iodine-125 implantation. The apparent activity per particle ranged from 0.6 mCi (2.22MBq) to 0.7 mCi (2.59MBq). The matched peripheral dose delivered by radioactive seeds ranged from 90 to 120 Gy. The efficacy of the treatment and the postoperative complications were evaluated during follow-up.

RESULTS

The seeds were implanted successfully in all 15 patients and median number of seeds implanted was 36.53. CT scans were performed in all patients at 1-6 months postoperatively. During follow-up at 6-27 months, seed migration occurred and a good local tumor control was achieved with an overall response of 86.7%. No severe side effects were observed.

CONCLUSIONS

TPS-guided interstitial Iodine-125 implantation is an effective and safe procedure with minimal invasiveness for the treatment of oral cavity and maxillofacial carcinomas, and it effectively prevents the recurrence of cancer and short-term lymphatic metastasis.

Use of the buccal fat pad in the immediate reconstruction of palatal defects related to cancer surgery with postoperative radiation therapy

PURPOSE

To evaluate the use of the buccal fat pad (BFP) in the immediate reconstruction of oncologic palate defects and the influence of postoperative radiotherapy on reconstruction.

PATIENTS AND METHODS

Patients who were diagnosed with moderate- to high-grade malignancies of the palate underwent partial maxillectomy. The BFP was used as a pedicled flap to reconstruct the defects. All patients received postoperative radiotherapy 4 to 5 weeks after surgery.

RESULTS

Eighteen patients (9 men and 9 women; age range, 37 to 81 yr) underwent surgery and subsequent radiotherapy. The size of all defects ranged from 7.5 to 19.2 cm2. Adequate closure of the defects was achieved during surgery and all flaps were epithelialized within 3 weeks after surgery, with no complications of dehiscence or flap failure. Furthermore, there were no complications derived from postoperative radiotherapy.

CONCLUSIONS

This study suggests that BFP grafting is an effective and reliable method for the reconstruction of small to medium-size palate defects. Furthermore, postoperative radiotherapy does not influence the success of reconstruction.

Do head and neck cancer survivors attend a high street dentist on a regular basis?

Head and neck cancer (HNC) patients face complex oral health issues following treatment. The aims of this study were to determine the proportion of HNC patients attending their dentist regularly and investigate clinicodemographic characteristics associated with attendance. Two surveys asked about patient attendance patterns and dentition. Pre-treatment orthopantomographs were evaluated for those treated between 2007-2009. The response rate was 66% (444/672). 69% (305/444) saw a high street dentist regularly. 28% of edentulous patients attended regularly compared with 84% with natural teeth, p < 0.001. Associations at p < 0.001 with regular attendance were the leaving of formal education (> 16 years) and earlier clinical staging. HNC patients should be encouraged to see a dentist regularly for routine dental care and cancer surveillance in partnership with the cancer service.

Age and stage as determinants of treatment for oral cavity and oropharyngeal cancers in the elderly

BACKGROUND

We investigate treatment selection for oral cavity and oropharyngeal (OC&OP) cancers to understand factors that influence treatment selection.

METHODS

We studied 7023 patients, ⩾66 years, diagnosed with a first primary OC&OP cancer using SEER-Medicare data. Multinomial logistic regression was to model treatment selection, controlling for other factors.

RESULTS

Most patients with OC cancer were treated with surgery alone (56.5%); most patients with OP cancer were treated with chemotherapy and radiation (28.9%). Age, stage and site were the most important predictors of treatment selection. As age increased from 70 to 81 (the interquartile range), treatment shifted toward surgery alone (OR=1.26; CI: 1.08-1.46) and no treatment (OR=1.5, 95% CI: 1.25-1.80), and away from combined surgery, radiation and treatments involving chemotherapy.

CONCLUSIONS

Age, stage, and site are the most important determinants of treatment selection for patients with OC&OP cancers. Increasing age and stage drive treatment toward non-surgical options and no treatment at all.

Oral squamous cell carcinoma positive for p16/human papilloma virus in post allogeneic stem cell transplantation: 2 cases and review of the literature

Complications of allogeneic hematopoietic stem cell transplantation (allo-HSCT) includes the risk of secondary malignancies. This may be related to mechanisms including radiation and chemotherapy regimens, chronic graft-versus-host disease, inflammation, and prolonged imunosuppression. Oral squamous cell carcinoma (OSCC) is a complication associated with chronic graft-versus-host disease after allo-HSCT. Although human papillomavirus (HPV) is known to be associated with OSCC, the role of HPV in development of OSCC in post-HSCT patients has not been studied. We identified 2 cases of OSCC in allo-HSCT recipients. Both biopsy specimens tested positive for p16(INK4A), a surrogate marker for HPV. We propose that the association of OSCC and HPV in patients after allo-HSCT may not be incidental. Clinical implications of these cases may imply the need for a HPV screening, early intervention, and consideration of anti-HPV vaccination in this population. The effectiveness of such interventions could be validated in a prospective clinical study.

Final results of local-regional control and late toxicity of RTOG 9003: a randomized trial of altered fractionation radiation for locally advanced head and neck cancer

PURPOSE

To test whether altered radiation fractionation schemes (hyperfractionation [HFX], accelerated fractionation, continuous [AFX-C], and accelerated fractionation with split [AFX-S]) improved local-regional control (LRC) rates for patients with squamous cell cancers (SCC) of the head and neck when compared with standard fractionation (SFX) of 70 Gy.

METHODS AND MATERIALS

Patients with stage III or IV (or stage II base of tongue) SCC (n=1076) were randomized to 4 treatment arms: (1) SFX, 70 Gy/35 daily fractions/7 weeks; (2) HFX, 81.6 Gy/68 twice-daily fractions/7 weeks; (3) AFX-S, 67.2 Gy/42 fractions/6 weeks with a 2-week rest after 38.4 Gy; and (4) AFX-C, 72 Gy/42 fractions/6 weeks. The 3 experimental arms were to be compared with SFX.

RESULTS

With patients censored for LRC at 5 years, only the comparison of HFX with SFX was significantly different: HFX, hazard ratio (HR) 0.79 (95% confidence interval 0.62-1.00), P=.05; AFX-C, 0.82 (95% confidence interval 0.65-1.05), P=.11. With patients censored at 5 years, HFX improved overall survival (HR 0.81, P=.05). Prevalence of any grade 3, 4, or 5 toxicity at 5 years; any feeding tube use after 180 days; or feeding tube use at 1 year did not differ significantly when the experimental arms were compared with SFX. When 7-week treatments were compared with 6-week treatments, accelerated fractionation appeared to increase grade 3, 4 or 5 toxicity at 5 years (P=.06). When the worst toxicity per patient was considered by treatment only, the AFX-C arm seemed to trend worse than the SFX arm when grade 0-2 was compared with grade 3-5 toxicity (P=.09).

CONCLUSIONS

At 5 years, only HFX improved LRC and overall survival for patients with locally advanced SCC without increasing late toxicity.

Dental implant survival in irradiated oral cancer patients: a systematic review of the literature

PURPOSE

Oral cancer therapy with surgery and radiation is associated with comorbidities; this affects rehabilitation with osseointegrated dental implants. The aim of this systematic review was to evaluate the effect of radiation therapy on osseointegrated dental implant survival in oral cancer patients.

MATERIALS AND METHODS

A review of the literature published between 1990 and June 2012 was conducted. Pertinent studies evaluating the effect of radiation therapy on osseointegration of implants were identified through searches of PubMed, SCIRUS, and Google Scholar. Overall implant survival rates were compared with respect to timing of radiation (prior to or after implantation), site of implant placement (maxilla, mandible, vascularized free flaps, nonvascular bone grafts), radiation dose, time interval between radiation therapy and implant placement, and the effect of hyperbaric oxygen therapy.

RESULTS

Thirty-eight articles were eligible for inclusion in the review. Overall implant survival rates with radiation therapy done pre- and postimplantation were 88.9% and 92.2%, respectively. In preimplantation radiation therapy, the implant survival rate was significantly higher for the mandible (93.3%) than for the maxilla (78.9%) or for grafted bone (87.5%). Similarly, the implant survival rate was higher when implants were placed in free flaps (89.3%) than in nonvascularized bone grafts (81.7%). While a radiation dose above 55 Gy significantly decreased implant survival, no significant relationship between increased implant survival and the remaining variables were found.

CONCLUSION

There, was no significant difference in dental implant survival rates between preimplantation and postimplantation radiation therapy. The anatomical site of implant placement in preimplantation radiation therapy was the most pertinent variable affecting implant survival, with a better survival rate in the mandible compared to the maxilla and grafted bone.

Predicting the severity and prognosis of trismus after intensity-modulated radiation therapy for oral cancer patients by magnetic resonance imaging

To develop magnetic resonance imaging (MRI) indicators to predict trismus outcome for post-operative oral cavity cancer patients who received adjuvant intensity-modulated radiation therapy (IMRT), 22 patients with oral cancer treated with IMRT were studied over a two-year period. Signal abnormality scores (SA scores) were computed from Likert-type ratings of the abnormalities of nine masticator structures and compared with the Mann-Whitney U-test and Kruskal-Wallis one-way ANOVA test between groups. Seventeen patients (77.3%) experienced different degrees of trismus during the two-year follow-up period. The SA score correlated with the trismus grade (r = 0.52, p<0.005). Patients having progressive trismus had higher mean doses of radiation to multiple structures, including the masticator and lateral pterygoid muscles, and the parotid gland (p<0.05). In addition, this group also had higher SA-masticator muscle dose product at 6 months and SA scores at 12 months (p<0.05). At the optimum cut-off points of 0.38 for the propensity score, the sensitivity was 100% and the specificity was 93% for predicting the prognosis of the trismus patients. The SA score, as determined using MRI, can reflect the radiation injury and correlate to trismus severity. Together with the radiation dose, it could serve as a useful biomarker to predict the outcome and guide the management of trismus following radiation therapy.

Ionizing radiation induces autophagy in human oral squamous cell carcinoma

PURPOSE

Irradiation-induced autophagy has been reported in several types of cancers, however, the relationship between irradiation and autophagy in human oral squamous cell carcinoma (OSCC) has not yet been described. In this study we investigated the induction of autophagy in cell lines by exposing them to ionizing irradiation.

METHODS

Human OSCC OC3 and SAS cell lines were used in this study. Cell viability and induction of autophagy were determined under irradiation treatment. The GFP-LC3 puncta formation and the levels of LC3-II as indicators of autophagy were detected by fluorescence microscopy and Western blot method. The signaling pathways involved in irradiation-mediated autophagy were also determined by Western blot method.

RESULTS

Irradiation decreased cell viability only in OC3 cells, while autophagic machinery and related signaling pathways were found to be elevated after irradiation in OC3 and SAS cells. However, autophagic degradation determined by the reduction of p62 levels was only found in OC3 cells, suggesting autophagosome accumulation took place in SAS cells. In addition, irradiation accompanied with rapamycin treatment elevated autophagy formation and induced death of OC3 cells.

CONCLUSIONS

These results suggested that induction of autophagy might provide an advantageous strategy to increase the anticancer effects of radiotherapy in patients with OSCCs.

Clinical effectiveness of 125I-seed implantation in combination with nimotuzumab therapy for the advanced oral carcinoma: preliminary results

OBJECTIVE

This study determines the short-term efficacy and toxicity of combined 125I-seed implantation and nimotuzumab in treating the advanced oral carcinoma. 125I-seed implantation is safe and has shown good short-term efficacy in clinical practice. Nimotuzumab is a useful biological agent for targeted therapy. Effect of 125I-seed implantation with nimotuzumab in treating oral carcinomas remains unclear.

PATIENTS AND METHODS

From November 2011 to December 2012, 11 patients with advanced oral carcinoma (pathologic types: 7 cases of squamous cell carcinoma and 4 cases of poorly differentiated adenocarcinoma) were enrolled in our hospital. The patients did not receive surgery due to systemic disease or locally advanced cancer. All of them underwent 125I-seed implantation with the matched peripheral doses (MPD) ranging from 90-100 Gy. The apparent activity per seed ranged from 0.6 mCi (2.22 MBq) to 0.7 mCi (2.59 MBq). Later, all patients were given nimotuzumab (200 mg, intravenous drip, weekly, for 6 weeks). The patients were then followed up and the response rate, acute/chronic radiation-induced injury, and safety of the induction treatment were analyzed.

RESULTS

Three patients achieved complete while 6 patients had partial response; yielding a response rate of 81.8%. Major adverse events included radiation-induced oral mucositis, local hemorrhage, bone marrow suppression, nausea/vomiting, and alopecia. Adverse reaction was not significantly different between the group of patients under 65 years of age and over 65 years of age (p > 0.05). Nimotuzumab enhanced the tumor sensitivity to brachytherapy without increasing AEs and improved the patients' life quality.

CONCLUSIONS

125I-seed implantation combined with nimotuzumab is effective and safe for patients with unresectable oral carcinoma.

Survivin silencing enhances radiosensitivity in oral squamous cell carcinoma cell

OBJECTIVE

Survivin is a member of the inhibitor of apoptosis protein (IAP) family. It is overexpressed in most cancer tissues and induces resistance to radiation therapy. In this study, we investigated whether knockdown of survivin by siRNA could induce apoptosis and enhance radiosensitivity in oral squamous cell carcinoma cells (OSCC).

MATERIALS AND METHODS

Oral squamous cell carcinoma cell lines KB was subjected to radiotherapy, small interfering RNA (siRNA) targeting survivin was transfected into KB cells in vitro, then subjected to radiotherapy. After irradiation or/and siRNA transfection, viable and dead cells were counted to determine radiation sensitivity by MTT assay, proliferation by colony-forming ability and apoptosis was analyzed by flow cytometry. Tumor-bearing mice were irradiated with 6 Gy of 60 Co-γ radiator.

RESULTS

The results showed knockdown of survivin in KB cells showed reduced cell proliferation and increased number of radiation-induced apoptosis. Apoptosis was increased by survivin silencing alone and increased further in combination with irradiation. Colony formation was significantly reduced by survivin silencing in combination with irradiation.

CONCLUSIONS

Survivin silencing sensitizes KB cells toward irradiation. Survivin silencing in combination with radiation inhibits cell proliferation and colony formation significantly and increases apoptosis more than each single treatment alone. In addition, survivin silencing significantly enhanced inhibition of tumor growth and potentiated cell apoptosis by irradiation in KB xenografts. In conclusion, survivin silencing could enhance sensitivity of human KB cells to radiotherapy in vitro and in vivo.