Impact of Tumour Hypoxia on Evofosfamide Sensitivity in Head and Neck Squamous Cell Carcinoma Patient-Derived Xenograft Models

Tumour hypoxia is a marker of poor prognosis and failure of chemoradiotherapy in head and neck squamous cell carcinoma (HNSCC), providing a strategy for therapeutic intervention in this setting. To evaluate the utility of the hypoxia-activated prodrug evofosfamide (TH-302) in HNSCC, we established ten early passage patient-derived xenograft (PDX) models of HNSCC that were characterised by their histopathology, hypoxia status, gene expression, and sensitivity to evofosfamide. All PDX models closely resembled the histology of the patient tumours they were derived from. Pimonidazole-positive tumour hypoxic fractions ranged from 1.7-7.9% in line with reported HNSCC clinical values, while mRNA expression of the Toustrup hypoxia gene signature showed close correlations between PDX and matched patient tumours, together suggesting the PDX models may accurately model clinical tumour hypoxia. Evofosfamide as a single agent (50 mg/kg IP, qd × 5 for three weeks) demonstrated antitumour efficacy that was variable across the PDX models, ranging from complete regressions in one p16-positive PDX model to lack of significant activity in the three most resistant models. Despite all PDX models showing evidence of tumour hypoxia, and hypoxia being essential for activation of evofosfamide, the antitumour activity of evofosfamide only weakly correlated with tumour hypoxia status determined by pimonidazole immunohistochemistry. Other candidate evofosfamide sensitivity genes-MKI67, POR, and SLFN11-did not strongly influence evofosfamide sensitivity in univariate analyses, although a weak significant relationship with MKI67 was observed, while SLFN11 expression was lost in PDX tumours. Overall, these data confirm that evofosfamide has antitumour activity in clinically-relevant PDX tumour models of HNSCC and support further clinical evaluation of this drug in HNSCC patients. Further research is required to identify those factors that, alongside hypoxia, can influence sensitivity to evofosfamide and could act as predictive biomarkers to support its use in precision medicine therapy of HNSCC.

Evofosfamide for the treatment of human papillomavirus-negative head and neck squamous cell carcinoma

Evofosfamide (TH-302) is a clinical-stage hypoxia-activated prodrug of a DNA-crosslinking nitrogen mustard that has potential utility for human papillomavirus (HPV) negative head and neck squamous cell carcinoma (HNSCC), in which tumor hypoxia limits treatment outcome. We report the preclinical efficacy, target engagement, preliminary predictive biomarkers and initial clinical activity of evofosfamide for HPV-negative HNSCC. Evofosfamide was assessed in 22 genomically characterized cell lines and 7 cell line-derived xenograft (CDX), patient-derived xenograft (PDX), orthotopic, and syngeneic tumor models. Biomarker analysis used RNA sequencing, whole-exome sequencing, and whole-genome CRISPR knockout screens. Five advanced/metastatic HNSCC patients received evofosfamide monotherapy (480 mg/m2 qw × 3 each month) in a phase 2 study. Evofosfamide was potent and highly selective for hypoxic HNSCC cells. Proliferative rate was a predominant evofosfamide sensitivity determinant and a proliferation metagene correlated with activity in CDX models. Evofosfamide showed efficacy as monotherapy and with radiotherapy in PDX models, augmented CTLA-4 blockade in syngeneic tumors, and reduced hypoxia in nodes disseminated from an orthotopic model. Of 5 advanced HNSCC patients treated with evofosfamide, 2 showed partial responses while 3 had stable disease. In conclusion, evofosfamide shows promising efficacy in aggressive HPV-negative HNSCC, with predictive biomarkers in development to support further clinical evaluation in this indication.

Acinic cell carcinoma of the parotid gland: Auckland experience and literature review

Acinic cell carcinoma is an uncommon malignancy of the salivary glands and as such it has been difficult to accurately delineate its natural history. The aim of this study is to assess the behaviour of acinic cell salivary cancer of the parotid gland presenting to a single head and neck surgical unit in Auckland. The study is a structured review of cases of acinic cell carcinoma of the parotid gland presenting from 2000 to 2006 to the Head and Neck Unit at Auckland Hospital, those identified from the pathology database and the Otobase head and neck database. Case records and pathology reports were reviewed. Fifteen patients were identified, 9 men and 6 women. The mean age was 67.2 years, with range 50-85 years. The mean follow up was 4.4 years and range 1.1-7 years. There was one case of local recurrence during study period and no deaths. Five of 15 patients received postoperative radiotherapy. Postoperative complications consisted of one wound haematoma and two cases of marginal mandibular weakness (one transient and one permanent). Current management strategies are obtaining appropriate rates of recurrence and postoperative complications within the Auckland population.

Parotid and cervical nodal status predict prognosis for patients with head and neck metastatic cutaneous squamous cell carcinoma

BACKGROUND AND OBJECTIVES

The appreciation of parotid involvement being an independent prognostic factor for metastatic cutaneous squamous cell carcinoma (SCC) is relatively new. A more comprehensive clinical staging system that separates parotid (P) from neck (N) disease, and further stratifies the N category has been proposed [O'Brien et al., Head Neck 2002; 24: 417-422]. This paper presents the clinical outcome of patients with head and neck metastatic cutaneous SCC treated at the four major head & neck surgical oncology centers in New Zealand and tests the proposed staging system, with modifications for pathological staging.

METHODS

Patients treated with a curative intent from 1990 to 2005 were identified and re-staged. Survival rates were calculated using the Kaplan-Meier method, and curves were compared with the log-rank test. Multivariate analysis using the Cox regression model was performed to assess the impact of each proposed P and N sub-group, and other parameters.

RESULTS AND CONCLUSIONS

One hundred and seventy patients were identified. The 5-year disease-specific survival rate was 69%, and the loco-regional recurrence rate was 36%. The presence of parotid (P < 0.01) or neck (P = 0.01) disease, immunosuppression (P < 0.01) and the uptake of radiotherapy (P < 0.01) impacted significantly on survival. Increasing P or N category worsened the prognosis significantly.

Effect of immunocompromise on metastatic cutaneous squamous cell carcinoma in the parotid and neck

BACKGROUND

Our aim was to examine the effect of a compromised immune state on the outcomes in patients treated for metastatic cutaneous squamous cell carcinoma (SCC).

METHODS

A retrospective analysis of patients with metastatic cutaneous SCC to the parotid and neck treated at Greenlane Hospital between 1992 and 2002 was conducted. Outcomes were compared between immune-competent and immunocompromised patients. A logistic regression analysis of likely risk factors for poor outcome was done.

RESULTS

Forty-nine patients were identified, nine of whom were immunocompromised. All patients were treated by parotidectomy and/or neck dissection. The facial nerve was sacrificed in 42% of the patients. Thirty-seven patients underwent postoperative radiotherapy (76%). Recurrence was significantly more common in the immunocompromised group (56% vs 28%), with higher rates of local and distant recurrence. Survival at 1 and 2 years was reduced.

CONCLUSION

Immunocompromise has a significant impact on the outcome of metastatic cutaneous SCC to the parotid and neck, affecting recurrence and survival.

Endovascular treatment of epistaxis

AIM

Embolization of external carotid vessels in the treatment of intractable epistaxis is not well documented in Australasia. The aim of the present retrospective study was to audit our experience with the technique, and to compare it with other centres.

METHODS

Retrospective review.

RESULTS

Twenty-nine embolizations were performed in 28 patients. Embolization was successful in 24 out of 28 patients (86%). Three patients required ligation of the anterior ethmoidal arteries, one of whom subsequently underwent successful repeat embolization. There were minor complications in 6/29 procedures (21%), and no major complications.

CONCLUSION

Our outcomes compare favourably with those of larger centres. Embolization is an effective tool in the management of patients with intractable epistaxis.

Comparison of the use of endoscopic and radiologic gastrostomy in a single head and neck cancer unit

BACKGROUND

Head and neck cancer patients frequently require gastrostomy feeding. Different insertion techniques have been described. The aim of the present study was to compare clinical results of percutaneous endoscopic and radiological gastrostomies in patients treated in a regional head and neck cancer unit.

METHODS

The records of patients who received either percutaneous endoscopic gastrostomy (PEG) or percutaneous radiological gastrostomy (PRG) between August 1997 and February 2001 were reviewed retrospectively. Documented complications (leak, infection, nausea and vomiting, ileus, bleeding, peritonitis) were recorded, compared and evaluated.

RESULTS

There were 74 patients (56 PEG, 18 PRG), most with stage III and IV head and neck malignancy. There was a significantly lower incidence of complications in PEG than PRG (11% vs 44%, P = 0.004). There was a delay of feeding due to tube placement in 4% of PEG and 22% of PRG (P < 0.025). Major complications occurred in 3.6% and 5.6% of PEG and PRG, respectively. Generally the complication rate for either form of gastrostomy was comparable with other studies. No procedure-related deaths occurred.

CONCLUSION

Selection bias, technique and tube type appeared to influence the complication rate in the present review. Percutaneous endoscopic gastrostomy will remain the authors' preferred method while PRG will be reserved for those cases for whom endoscopic placement is deemed to be impractical.

Quality of life after parotid and temporal bone surgery for cancer

OBJECTIVES

The purposes of this study were to examine the quality of life (QL) of patients who received treatment for cancer of the parotid or temporal region, and to identify factors contributing to it. The relationships between clinician-based measures of treatment outcome and the patient-based counterparts were also evaluated.

METHODS

A retrospective, cross-sectional study was conducted on 23 patients who had received either a temporal bone resection or a combination of parotidectomy and radiotherapy. The QL survey involved both global QL and measures of the appearance, communication, hearing, physical, psychological, and social domains. Patients were assessed clinically for their performance status, facial nerve function, disfigurement, and hearing and the results were compared with patient-rated QL. Correlation between the QL variables and global QL was identified using Spearman correlation tests.

RESULTS

Ongoing physical symptoms, communication difficulties, and social disturbances were associated with poorer global QL (P <.05). No correlation was detected between global QL and objective disfigurement, facial function, and measures of hearing loss. With the exception of hearing testing, clinical assessments generally did not correlate well with patient ratings.

CONCLUSION

QL measures provide insight into patients' perceptions of the treatment outcome but do not necessarily correlate with the clinicians' views. The use of a global QL measure overcomes the difficulty of extrapolating the impact of symptom scores or observational measures on patients' overall quality of survival.

Human dural replacement with acellular dermis: clinical results and a review of the literature

BACKGROUND

The search for the ideal dural replacement in the setting where autogenous tissues are unavailable or inadequate still persists. Because of the ability of acellular dermis (AlloDerm, LifeCell Corporation, The Woodlands, TX) to remodel itself into native tissue, this dynamic quality is hypothesized to occur when used as a dural replacement.

METHODS

We report the long-term outcome of a small cohort of patients who, to our knowledge, were the first patients to receive AlloDerm for dural replacement. In addition, to put these current findings in a historical perspective, we present a review of the literature for dural replacement.

RESULTS

Ten patients all successfully underwent duraplasty with AlloDerm with only one postoperative complication that was not related to the acellular dermal dural repair.

CONCLUSIONS

We contend that AlloDerm is a safe and viable option for dural replacement in cases in which autogenous tissues are either unavailable or insufficient for proper reconstruction.

Applications of fast-setting hydroxyapatite cement: cranioplasty

A variety of autogenous and synthetic materials have been used to repair cranial defects resulting from traumatic and iatrogenic causes. In theory, the ideal material should be readily available and safe. It should adequately protect the underlying central nervous system, resist cerebrospinal fluid fistula formation, and be easily contoured. One promising synthetic biomaterial that has been used for cranioplasty is hydroxyapatite cement. This biomaterial has successfully restored cranial contour in most patients in whom it has been used; however, difficulties have arisen because of the material's prolonged water solubility. When exposed to cerebrospinal fluid or blood, inadequate setting of the cement occurs, resulting in loss of its structural integrity. This problem can be alleviated with the use of fast-setting hydroxyapatite cement, which hardens 6 to 12 times faster than the traditional cement. We present, to the best of our knowledge, the first series of the use of this material in 21 patients requiring cranioplasty. The advantages and limitations of fast-setting hydroxyapatite cement will be discussed.

Reconstruction of the pediatric maxilla and mandible

BACKGROUND

The creation of osseous defects in the upper and lower jaws in children is an uncommon occurrence. It is therefore likely that a head and neck reconstructive surgeon will accumulate only limited experience in restoring such defects. We have reviewed 7 pediatric bone-containing microvascular free flap reconstructions in 6 patients for reconstruction of the upper or lower jaws. Three patients were available for long-term follow-up to evaluate the effect of osseous free flap reconstruction on function and growth and development of the donor site.

DESIGN

Retrospective review.

SETTING

Academic tertiary referral center for otolaryngology.

PATIENTS AND METHODS

Six pediatric patients ranging in age from 8 to 16 years underwent 2 fibular, 4 scapular, and 1 iliac free flap procedure for restoration of 2 maxillary and 5 mandibular defects from 1992 to 1997. Three of the 6 patients were available for long-term follow-up to assess the postoperative donor site function in an effort to determine the effect of this surgery on long-term donor site morbidity and development.

RESULTS

Two patients were lost to follow-up, and 1 died secondary to complications related to distant metastatic disease. Three of 6 patients were observed for 2 years 6 months, 4 years, and 4 years 2 months, respectively. Two of the 3 patients who were observed long term have undergone full dental rehabilitation and currently maintain a regular diet and deny pain with mastication or deglutition. One patient did not require dental rehabilitation. All 3 patients demonstrate gross facial symmetry and normal dental occlusion. Assessment of the fibular donor site demonstrated normal limb length and circumference. The patients denied pain or restriction to recreational activity. Scapular donor sites demonstrated normal range of motion, strength, and shoulder stability.

CONCLUSIONS

Free flap reconstruction of the pediatric maxilla and mandible requires harvesting bone from actively growing donor sites. We have found no evidence of functional deficit after bone harvest from the fibular or scapular donor sites. Patients demonstrate normal growth at the donor sites, and symmetry of the mandible and maxilla is preserved.

The use of clinical criteria alone in the management of the clinically negative neck among patients with squamous cell carcinoma of the oral cavity and oropharynx

BACKGROUND

Management of the clinically negative neck among patients with oral and oropharyngeal squamous cell carcinoma at the Royal Prince Alfred Hospital, Sydney, Australia has been based on the site and stage of the primary cancer, the likely incidence of microscopic nodal involvement, the treatment modality used for the primary cancer, and whether the neck will be entered during resection or reconstruction. This report analyzes the results of treatment when patients are allocated to either treatment or observation of the neck based on these clinical factors.

METHODS

This is a prospectively documented series of 162 consecutively treated patients with squamous cell carcinoma of the oral cavity and oropharynx and clinically negative necks, treated by 1 surgeon (C.J.O.). There were 128 oral cavity and 34 oropharyngeal cancers clinically staged at T1 for 62 patients, T2 for 61, T3 for 16, and T4 for 23 patients. Management of the neck consisted of elective neck dissection (END) in 96 patients (12 bilateral), elective radiotherapy in 8, and observation in 58. Neck treatment correlated with the T stage in a statistically significant way. Forty-six patients underwent postoperative radiotherapy, which was directed to the neck in 22 patients because of pathological findings following neck dissection. Free-flap reconstruction was used in 90 patients.

RESULTS

Metastatic squamous cell carcinoma was identified in 32 of 108 neck dissections (30%). There was 1 positive node in 15 necks, 2 positive nodes in 11 necks, and 3 or more positive nodes in 6 necks. Extracapsular spread was present in 8 of 32 positive END specimens (25%). Regional control rates in the neck at 3 years were 94% for END, 100% for elective radiotherapy, and 98% for patients initially observed and then treated by therapeutic neck dissection. Death with uncontrolled disease in the neck occurred in 4 of 96 patients (4%) after END and 1 of 58 patients (2%) after neck observation. Overall disease-specific survival was 83%, comprising an 86% rate for patients with pathologically negative necks and 68% if pathologically positive. Disease-specific survival was 86% at 3 years for patients having END, 67% following radiotherapy, and 94% for the observation group.

CONCLUSIONS

Elective neck dissection was performed in most patients, and occult metastatic disease was found in nearly 30% of neck dissections. Observation was most frequently used for patients with early stage disease, and subsequent development of neck metastases was uncommon (9%) in this group. Selective treatment of the clinically negative neck based on the primary tumor site and stage led to a high rate of regional disease control in this series.

Application of prognostic scoring systems in differentiated thyroid carcinoma

BACKGROUND

Total thyroidectomy is widely practised in Australasia for papillary and follicular thyroid carcinoma. Data from large overseas series have demonstrated that patients with these cancers may be separated into risk groups based on clinicopathological prognostic factors. Furthermore, evidence suggests that low-risk patients may be safely treated with less than total thyroidectomy. The aim of the present paper was to determine what proportion of our patients with papillary and follicular thyroid cancer were in the low-risk group in order to select candidates for less aggressive treatment.

METHODS

A prospectively documented series of 175 previously untreated patients with papillary and follicular thyroid carcinoma, treated principally by total thyroidectomy over a 10-year period, was divided into risk groups using the Mayo Clinic, Lahey Clinic and Memorial Hospital prognostic scoring systems. Complication rates for 103 patients treated by total thyroidectomy were also studied and reported.

RESULTS

Women outnumbered men by 2.3:1. There were 128 papillary carcinomas (73%) and 47 follicular cancers (27%). These tumours were < 4 cm in diameter in 81% of patients, and 41% of patients were 40 years of age or younger. Low-risk patients accounted for 75, 81 and 45% of the study group, respectively, when the three prognostic scoring systems were applied to our patient population. The rates for recurrent laryngeal nerve palsy and permanent hypoparathyroidism for patients having total thyroidectomy were 1 and 1.9%, respectively. In the low-risk group there were no permanent complications.

CONCLUSION

Most patients treated at Royal Prince Alfred Hospital during the past 10 years were low-risk patients who may have been eligible for less aggressive surgical treatment.

Use of the peritracheal fold in the dog tracheal transplantation model

OBJECTIVE

To investigate the technical aspects of the canine model of human tracheal transplantation for potential application to reconstruction of extremely long tracheal defects (> 10 cm).

DESIGN

In phase 1, long tracheal segments were skeletonized and pedicled with the thyroid glands, cranial thyroid arteries and veins, and internal jugular vein branches. The segments were elevated completely, attached to the vascular pedicle only, and replaced with primary tracheal anastomoses. In phase 2, long segments were elevated along with a diffuse soft tissue "blanket" that envelops the trachea and thyroid glands. Because this study was designed to primarily address, in situ, tracheal perfusion territories of a cranially located vascular pedicle, microvascular anastomoses were not conducted.

SUBJECTS

Two small-bodied beagles (10-15 kg) and 5 large-bodied mixed-breed dogs (20-30 kg) were humanely killed 2 to 41 days after surgery, and anatomic and histological analyses were conducted.

RESULTS

Unlike that of humans, the thyroid gland complex of dogs is not intimately associated with the trachea but is conjoined with a peritracheal soft tissue "fold." Within this fold, blood is transmitted to the trachea via a diffuse, segmental vascular plexus. In phase 1, pronounced tracheal necrosis occurred within 2 to 5 days. In phase 2, extremely long tracheal segments (10-12 cm), based only on a cranially located pedicle, were still viable at 2 to 6 weeks.

CONCLUSIONS

Preservation of the "peritracheal fold" in the dog model of tracheal transplantation is critical to the onset and maintenance of vascular perfusion in a long tracheal segment. Furthermore, the use of large-bodied dogs is necessary to provide for a usable venous efflux component.

A prospective, longitudinal study of pain in head and neck cancer patients

BACKGROUND

Little is known about the epidemiology of pain in head and neck cancer, the effects of curative treatment on this pain, and the impact that pain experience may have on patients' quality of life (QL).

METHOD

The prevalence and severity of pain was studied in 93 patients who were first seen with a diagnosis of head and neck cancer, were treated, and remained disease free at two years. QL assessment utilised the life-satisfaction scale and the General Health Questionnaire as specific measures. Pain was assessed by a linear analogue scale anchored by words and numbers.

RESULTS

Forty-eight percent had head and neck pain when first seen, whereas only 25% and 26% had such pain at 12 and 24 months. Approximately 8% of patients rated the pain as "severe" when first seen, whereas 3% had severe pain at 12 months and 4% at 2 years. The prevalence of shoulder and arm pain increased from 14% at diagnosis to 37% at a year and 26% at 24 months, but the percentage of patients with severe pain at any stage postoperatively was only 5% and 2%, respectively. Any pain (pain in either in the head and neck or shoulder and arm or both) at 2 years was strongly predicted by earlier posttreatment pain (at 3 months or at 12 months.) Shoulder and arm pain at 2 years was strongly correlated with surgical treatment of the neck, although no difference in pain experience was noted between those who had radical neck dissections and those who had more conservative procedures. There was no correlation between radiotherapy to the neck and subsequent shoulder and arm pain. Pain had an adverse effect on the general well-being and psychological distress of head and neck cancer patients who were free of disease.

CONCLUSIONS

Pain is common among those presenting with curable head and neck cancer. Pain can be reduced by curative treatment but neck dissection may cause increased shoulder and arm pain. Ongoing pain is predictable and impacts adversely on patients QL.

Use of an acellular dermal allograft for dural replacement: an experimental study

OBJECTIVE

In this study, a nonimmunogenic, acellular, dermal collagen matrix termed XenoDerm (LifeCell Corp., The Woodlands, TX) was examined for use as a dural replacement material in a porcine model. This model was used to investigate whether AlloDerm (LifeCell), an almost identical material made from human dermis, could be safely used in neurological surgery.

METHODS

Bilateral temporoparietal dural defects were surgically created in 12 Yucatan minipigs. One side was repaired with autologous pericranium, and the other was repaired with XenoDerm. The pigs were killed after 1, 3, or 6 months, and the areas of dural repair were collected and examined macroscopically and histologically. XenoDerm is derived from porcine skin collected in thin sheets. It is processed so that the epidermis and all dermal cells are removed without disruption of the collagen matrix, rendering the material immunogenically inert and resistant to calcification. It is packaged as a freeze-dried sheet and is easily rehydrated at the time of surgery.

RESULTS

There were no postoperative complications, and all pigs survived. Both grafts performed well as dural replacements in all cases. There was no macroscopic evidence of inflammation or cerebrospinal fluid leakage. The XenoDerm grafts were intact, retained their original dimensions, and resembled the surrounding dura. The autologous pericranial grafts, in contrast, were thicker than when implanted and had bony excrescences firmly adhering to their surfaces. Again, however, there was no evidence of cerebrospinal fluid fistulae. There was no gross adherence to the underlying meninges or brain tissue in any specimen. Repopulation by fibroblasts and neovascularization were evident in the XenoDerm grafts as early as 1 month after surgery; by 3 months, the XenoDerm had been remodeled to assume the connective tissue appearance of the surrounding dura.

CONCLUSION

In this porcine model, an allograft of acellular dermis is a nearly ideal dural replacement. AlloDerm, the human equivalent of XenoDerm, would be an allograft of acellular dermis after implantation in human subjects. On the basis of this study and previous work with AlloDerm in other reconstructive applications, it is proposed that this material could be similarly used for duraplasty in human subjects.

The prevalence of exostoses in the external auditory meatus of surfers

Fifty-four surfers and 38 surf life savers were examined and questioned in order to determine the prevalence of exostoses. Seventy-three per cent had evidence of body exostoses in the external auditory meatus. Forty per cent had their ear canals narrowed by 50% or more. The relationship between the number of years spent surfing or life saving and the extent of canal stenosis was highly significant (P < 0.00001). Left and right ears were affected equally in this series and the obstruction appears to begin after approximately 7 years and is further aggravated by continued surfing. Over 90% of subjects who had participated for longer than 10 years had some evidence of exostoses. There was no significant association between the number of days per year or the number of hours per day spent surfing and the development of surfer's ear in this sample. Those who participated in their water sport over winter had significantly more exostoses than those who did not (P < 0.0001). Those who lived in the South Island (colder water) had more surfer's ear than those in the North Island (warmer water).

Use of surgical stapling device in excision of pharyngeal diverticulum

Pharyngeal diverticulum (Zenker's diverticulum, hypopharyngeal pouch) is an outpouching of pharyngeal mucosa through a triangular area of weakness between the lower oblique fibres of the inferior constrictor muscle and cricopharyngeus called Killian's dehiscence. Prescribed treatment in large pouches is excision of the diverticulum with or without cricopharyngeal myotomy. Experience of closure of the oesophageal defect with an automatic stapling device is presented in nine cases of pharyngeal diverticula. Previous reports describing this technique have included substantial delays in the resumption of oral intake and prolonged hospitalization. It is shown that these delays are unnecessary.