Keith Kwan

Early-stage squamous cell carcinoma of the oropharynx: Radiotherapy vs. Trans-Oral Robotic Surgery (ORATOR) – study protocol for a randomized phase II trial

BackgroundThe incidence of oropharyngeal squamous cell carcinoma (OPSCC) has markedly increased over the last three decades due to newly found associations with human papillomavirus (HPV) infection. Primary radiotherapy (RT) is the treatment of choice for OPSCC at most centers, and over the last decade, the addition of concurrent chemotherapy has led to a significant improvement in survival, but at the cost of increased acute and late toxicity. Transoral robotic surgery (TORS) has emerged as a promising alternative treatment, with preliminary case series demonstrating encouraging oncologic, functional, and quality of life (QOL) outcomes. However, comparisons of TORS and RT in a non-randomized fashion are susceptible to bias. The goal of this randomized phase II study is to compare QOL, functional outcomes, toxicity profiles, and survival following primary RT (± chemotherapy) vs. TORS (± adjuvant [chemo] RT) in patients with OPSCC.Methods/DesignThe target patient population comprises OPSCC patients who would be unlikely to require chemotherapy post-resection: Tumor stage T1-T2 with likely negative margins at surgery; Nodal stage N0-2, ≤3 cm in size, with no evidence of extranodal extension on imaging. Participants will be randomized in a 1:1 ratio between Arm 1 (RT ± chemotherapy) and Arm 2 (TORS ± adjuvant [chemo] RT). In Arm 1, patients with N0 disease will receive RT alone, whereas N1-2 patients will receive concurrent chemoradiation. In Arm 2, patients will undergo TORS along with selective neck dissections, which may be staged. Pathologic high-risk features will be used to determine the requirement for adjuvant radiotherapy +/- chemotherapy. The primary endpoint is QOL score using the M.D. Anderson Dysphagia Inventory (MDADI), with secondary endpoints including survival, toxicity, other QOL outcomes, and swallowing function. A sample of 68 patients is required.DiscussionThis study, if successful, will provide a much-needed randomized comparison of the conventional strategy of primary RT vs. the novel strategy of primary TORS. The trial is designed to provide a definitive QOL comparison between the two arms, and to inform the design of an eventual phase III trial for survival outcomes.Trial registrationNCT01590355

The epidemic of human papillomavirus and oropharyngeal cancer in a Canadian population

BACKGROUND Sexually transmitted infection with the human papillomavirus (hpv) is responsible for a significant burden of human cancers involving the cervix, anogenital tract, and oropharynx. Studies in the United States and Europe have demonstrated an alarming increase in the frequency of hpv-positive oropharyngeal cancer, but the same direct evidence does not exist in Canada. METHODS Using the London Health Sciences Centre pathology database, we identified tonsillar cancers diagnosed between 1993 and 2011. Real-time polymerase chain reaction was then used on pre-treatment primary-site biopsy samples to test for dna from the high-risk hpv types 16 and 18. The study cohort was divided into three time periods: 1993-1999, 2000-2005, and 2006-2011. RESULTS Of 160 tumour samples identified, 91 (57%) were positive for hpv 16. The total number of tonsillar cancers significantly increased from 1993-1999 to 2006-2011 (32 vs. 68), and the proportion of cases that were hpv-positive substantially increased (25% vs. 62%, p < 0.002). Those changes were associated with a marked improvement in 5-year overall survival (39% in 1993-1999 vs. 84% in 2006-2011, p < 0.001). When all factors were included in a multivariable model, only hpv status predicted treatment outcome. INTERPRETATION The present study is the first to provide direct evidence that hpv-related oropharyngeal cancer is increasing in incidence in a Canadian population. Given the long lag time between hpv infection and clinically apparent malignancy, oropharyngeal cancer will be a significant clinical problem for the foreseeable future despite vaccination efforts.

High Frequency of Activating PIK3CA Mutations in Human Papillomavirus–Positive Oropharyngeal Cancer

IMPORTANCE Large-scale whole-exome sequencing studies of head and neck squamous cell carcinoma (HNSCC) have established that the disease is dominated by frequent mutations in tumor suppressor genes with rare activating mutations in oncogenes that would be easily targetable with molecular agents. There was evidence in these reports, however, that activating mutations in phosphoinositide 3-kinase catalytic subunit p110α (PIK3CA) were common in patients with human papillomavirus (HPV)-positive tumors. We set out to test this prediction in oropharyngeal patient samples from our institution. OBJECTIVE To confirm whether activating mutations in PIK3CA are frequent in HPV-positive HNSCC because this mutated oncogene represents a potential therapeutic target. DESIGN, SETTING, AND PARTICIPANTS A retrospective search of the London Health Sciences Centre pathology database was performed to identify oropharyngeal cancer samples. DNA from pretreatment primary site biopsy samples from 87 patients were tested for high-risk HPV types 16 and 18 by real-time polymerase chain reaction. MAIN OUTCOMES AND MEASURES Samples were tested for activating mutations at the 3 mutational hot spots (codons 542, 545, and 1047) by polymerase chain reaction followed by Sanger sequencing using forward and reverse primers. RESULTS Only 4 of 41 HPV-negative tumors (10%) demonstrated PIK3CA hot spot mutations, including 3 at codon 1047 and 1 at codon 542. Of 46 HPV-positive tumors, 13 (28%) demonstrated activating PIK3CA mutations, including 7 at codon 542, 5 at codon 545, and 1 at codon 1047. The difference in PIK3CA mutation frequency was significantly different between HPV-positive and HPV-negative cancers (P = .03). CONCLUSIONS AND RELEVANCE Although there has been a suggestion that activating PIK3CA mutations are common in HPV-positive HNSCC, to our knowledge, this is the first study to clearly identify this phenomenon. Targeting PIK3CA with molecular agents in HPV-positive patients may be a mechanism to improve cure rates and decrease treatment toxic effects in this rapidly growing cohort of patients.

Does HPV type affect outcome in oropharyngeal cancer

BackgroundAn epidemic of human papillomavirus (HPV)-related oropharyngeal squamous cell cancer (OPSCC) has been reported worldwide largely due to oral infection with HPV type-16, which is responsible for approximately 90% of HPV-positive cases. The purpose of this study was to determine the rate of HPV-positive oropharyngeal cancer in Southwestern Ontario, Canada.MethodsA retrospective search identified ninety-five patients diagnosed with OPSCC. Pre-treatment biopsy specimens were tested for p16 expression using immunohistochemistry and for HPV-16, HPV-18 and other high-risk subtypes, including 31,33,35,39,45,51,52,56,58,59,67,68, by real-time qPCR.ResultsFifty-nine tumours (62%) were positive for p16 expression and fifty (53%) were positive for known high-risk HPV types. Of the latter, 45 tumors (90%) were identified as HPV-16 positive, and five tumors (10%) were positive for other high-risk HPV types (HPV-18 (2), HPV-67 (2), HPV-33 (1)). HPV status by qPCR and p16 expression were extremely tightly correlated (p < 0.001, Fishers exact test). Patients with HPV-positive tumors had improved 3-year overall (OS) and disease-free survival (DFS) compared to patients with HPV-negative tumors (90% vs 65%, p = 0.001; and 85% vs 49%, p = 0.005; respectively). HPV-16 related OPSCC presented with cervical metastases more frequently than other high-risk HPV types (p = 0.005) and poorer disease-free survival was observed, although this was not statistically significant.ConclusionHPV-16 infection is responsible for a significant proportion of OPSCC in Southwestern Ontario. Other high-risk subtypes are responsible for a smaller subset of OPSCC that present less frequently with cervical metastases and may have a different prognosis.

A Pilot Study Comparing HPV-Positive and HPV-Negative Head and Neck Squamous Cell Carcinomas by Whole Exome Sequencing

Background. Next-generation sequencing of cancers has identified important therapeutic targets and biomarkers. The goal of this pilot study was to compare the genetic changes in a human papillomavirus- (HPV-)positive and an HPV-negative head and neck tumor. Methods. DNA was extracted from the blood and primary tumor of a patient with an HPV-positive tonsillar cancer and those of a patient with an HPV-negative oral tongue tumor. Exome enrichment was performed using the Agilent SureSelect All Exon Kit, followed by sequencing on the ABI SOLiD platform. Results. Exome sequencing revealed slightly more mutations in the HPV-negative tumor (73) in contrast to the HPV-positive tumor (58). Multiple mutations were noted in zinc finger genes (ZNF3, 10, 229, 470, 543, 616, 664, 638, 716, and 799) and mucin genes (MUC4, 6, 12, and 16). Mutations were noted in MUC12 in both tumors. Conclusions. HPV-positive HNSCC is distinct from HPV-negative disease in terms of evidence of viral infection, p16 status, and frequency of mutations. Next-generation sequencing has the potential to identify novel therapeutic targets and biomarkers in HNSCC.

Kallikrein-related peptidase 10 expression in salivary gland tissues and tumours

Objectives Kallikrein-related peptidase 10 (KLK10) has been implicated in the development of several types of cancer. The purpose of this study was to analyze the expression of KLK10 in 3 types of salivary gland tumour and normal salivary glands. Materials and methods: A standard immunoperoxidase staining technique was used to assess the Immunoexpression profile of KLK10 in normal salivary glands and 3 types of salivary gland tumour: pleomorphic adenoma, adenoid cystic carcinoma and mucoepidermoid carcinoma. Results Pleomorphic adenomas showed significantly lower KLK10 levels than control tissues. Neither of the malignant tumours (adenoid cystic carcinoma and mucoepidermoid carcinoma) showed a significant alteration in the immunoreactive scores of KLK10 in comparison with the normal salivary gland tissues. KLK10 immunoreactive scores were comparable in adenoid cystic carcinoma and mucoepidermoid carcinoma. Pleomorphic adenoma had significantly lower levels of KLK10 than mucoepidermoid carcinoma. Conclusions The finding of lower KLK10 levels in pleomorphic adenoma suggests aberrant expression in a tumour that develops primarily from myoepithelial cells. A kallikrein cascade may play a role in the development and/or outcome of some salivary gland tumours.

3D human lung histology reconstruction and registration to in vivo imaging.

Stereotactic ablative radiotherapy (SABR) delivers high-dose-per-fraction radiotherapy to tumours and spares surrounding tissue. It is effective for early-stage non-small cell lung cancer. However, SABR causes radiationinduced lung injuries that mimic recurring cancer, confounding detection of recurrences and early salvage therapy. We have previously developed radiomics-based recurrence detection. However, our radiomics system needs to be validated against histologic markers of viable tumour post-SABR. In this paper, our goals were to develop semiautomatic (1) 2D reconstruction of pseudo whole-mount (PWM) tissue sections from scanned slides, (2) 3D reconstruction and registration of PWM sections to pre-surgery computed tomography (CT), and (3) quantitative registration error measurement. Lobectomy tissue sections on standard 1” × 3” slides were obtained from patients who underwent SABR. Our graphical user interface allows interactive stitching of the sections into PWMs. Using our developed 3D Slicer-based thin-plate spline warping tool, we performed 3D PWM reconstruction and registered them to CT via correspondence of homologous intrinsic landmarks. The target registration error for 229 fiducial pairs defining vessels and airways was calculated for 56 PWMs reconstructed from 9 patients. We measured a mean of 7.33 mm, standard deviation of 4.59 mm and root mean square of 8.65 mm. This proof-of-principle study demonstrates for the first time that it is feasible to register in vivo human lung CT images with histology, with no modifications to the clinical pathology workflow other than videography to document gross dissection. Ongoing work to automate this process will yield a tool for histologic lung imaging and radiomics validation.

Using quantitative tissue phenotype to assess the margins of surgical samples from a pan-Canadian surgery study

The purpose of this study was to use quantitative tissue phenotype (QTP) to assess the surgical margins to examine if a fluorescence visualization‐guided surgical approach produces a shift in the surgical field by sparing normal tissue while catching high‐risk tissue.

Successful Treatment of Fibrosing Organising Pneumonia Causing Respiratory Failure with Mycophenolic Acid.

Organising pneumonia (OP) is usually promptly responsive to corticosteroid treatment. We describe a series of 3 cases of severe, progressive, biopsy-proven fibrosing OP causing respiratory failure. All cases presented with peribronchial and subpleural consolidations, had a fibro-inflammatory infiltrative component in the alveolar septa, and only had a partial and unsatisfactory response to corticosteroids. However, they responded to mycophenolic acid (MPA) treatment with resolution of respiratory failure as well as clinical and functional improvement. MPA as an additional treatment option for aggressive forms of fibrosing OP and interstitial lung disease needs to be further explored.

Endobronchial Carcinoid Tumour with Extensive Ossification: An Unusual Case Presentation

Carcinoid tumour is a well-known primary endobronchial lung neoplasm. Although calcifications may be seen in up to 30% of pulmonary carcinoid tumours, near complete ossification of these tumours is an unusual finding. Such lesions can prove diagnostically challenging at the time of intraoperative frozen section as the latter technique requires thin sectioning of the lesion for microscopic assessment. We present an unusual case of endobronchial carcinoid tumour with extensive ossification in a 45-year-old male. Preliminary intraoperative diagnosis was achieved through the alternative use of cytology scrape smears. The final diagnosis was confirmed after decalcification of the tumour. The prognostic implications of heavily ossified carcinoid tumours remain elusive. Long-term clinical follow-up of these patients is recommended.