Ashok Muniappan

Implementing multiplexed genotyping of non-small-cell lung cancers into routine clinical practice

BACKGROUND Personalizing non-small-cell lung cancer (NSCLC) therapy toward oncogene addicted pathway inhibition is effective. Hence, the ability to determine a more comprehensive genotype for each case is becoming essential to optimal cancer care. METHODS We developed a multiplexed PCR-based assay (SNaPshot) to simultaneously identify >50 mutations in several key NSCLC genes. SNaPshot and FISH for ALK translocations were integrated into routine practice as Clinical Laboratory Improvement Amendments-certified tests. Here, we present analyses of the first 589 patients referred for genotyping. RESULTS Pathologic prescreening identified 552 (95%) tumors with sufficient tissue for SNaPshot; 51% had ≥1 mutation identified, most commonly in KRAS (24%), EGFR (13%), PIK3CA (4%) and translocations involving ALK (5%). Unanticipated mutations were observed at lower frequencies in IDH and β-catenin. We observed several associations between genotypes and clinical characteristics, including increased PIK3CA mutations in squamous cell cancers. Genotyping distinguished multiple primary cancers from metastatic disease and steered 78 (22%) of the 353 patients with advanced disease toward a genotype-directed targeted therapy. CONCLUSIONS Broad genotyping can be efficiently incorporated into an NSCLC clinic and has great utility in influencing treatment decisions and directing patients toward relevant clinical trials. As more targeted therapies are developed, such multiplexed molecular testing will become a standard part of practice.

Molecular Mechanisms of Resistance to First- and Second-Generation ALK Inhibitors in ALK-Rearranged Lung Cancer

Advanced, anaplastic lymphoma kinase (ALK)-positive lung cancer is currently treated with the first-generation ALK inhibitor crizotinib followed by more potent, second-generation ALK inhibitors (e.g., ceritinib, alectinib) upon progression. Second-generation inhibitors are generally effective even in the absence of crizotinib-resistant ALK mutations, likely reflecting incomplete inhibition of ALK by crizotinib in many cases. Herein, we analyzed 103 repeat biopsies from ALK-positive patients progressing on various ALK inhibitors. We find that each ALK inhibitor is associated with a distinct spectrum of ALK resistance mutations and that the frequency of one mutation - ALK G1202R - increases significantly after treatment with second-generation agents. To investigate strategies to overcome resistance to second-generation ALK inhibitors, we examine the activity of the third-generation ALK inhibitor lorlatinib in a series of ceritinib-resistant, patient-derived cell lines, and observe that the presence of ALK resistance mutations is highly predictive for sensitivity to lorlatinib, whereas those cell lines without ALK mutations are resistant.

Surgical Treatment of Nonmalignant Tracheoesophageal Fistula: A Thirty-Five Year Experience

BACKGROUND Acquired nonmalignant tracheoesophageal fistula in the adult patient develops in a variety of conditions. We have applied surgical closure with success for 35 years. METHODS From 1975 to 1991, 38 patients underwent surgical repair of a tracheoesophageal fistula. A retrospective study of 36 additional patients undergoing surgical repair from 1992 to 2010 was conducted. RESULTS The most common causes were postintubation injury (n=17, 47%), trauma (n=6, 17%), prior laryngectomy (n=6, 17%), and prior esophagectomy (n=4, 11%). Four patients presented after failing fistula control with an endoluminal stent. The tracheal defect was closed with resection and reconstruction (n=17, 41%), laryngotracheal resection (n=5, 12%), membranous tracheal repair (n=17, 41%), or repair over a tracheal T tube (n=2, 5%), while esophageal repair consisted of 2-layer closure (n=31, 78%), 1-layer closure (n=6, 15%), esophagostomy (n=1, 3%), end-to-end esophageal anastomosis (n=1, 3%), or full thickness skin graft reconstruction (n=1, 3%). The esophageal and tracheal repairs were buttressed by interposing pedicled muscle or omental flaps in all patients. There was 1 postoperative death (3%). Recurrence after repair developed only in fistulas arising after esophagectomy or laryngectomy (n=4, 11%). Fistula closure was ultimately successful in 34 patients (94%). Twenty-nine patients (83%) resumed oral intake and 25 patients (71%) were breathing without a tracheal appliance. CONCLUSIONS Successful closure of benign tracheoesophageal fistula is achieved with several surgical techniques based on buttressed repair and restoration of normal breathing and swallowing. Closure of complex postsurgical fistula may fail. Endoluminal stenting was not found useful.

Surgical Therapy of Pulmonary Aspergillomas: A 30-Year North American Experience

BACKGROUND Pulmonary aspergilloma is resected to control life-threatening complications such as massive hemoptysis. The role of prophylactic resection in asymptomatic patients is unclear. METHODS A retrospective review was conducted of 60 patients treated at a tertiary center from 1980 to 2010. RESULTS The mean age in 34 (56.7%) men and 26 (43.3%) women was 51 years. Immunosuppression, most commonly from chronic steroid use, was present in 17 (28.3%) patients, and preexisting lung disease was present in 47 (78.3%) patients. Hemoptysis occurred in 33 (55%) patients, whereas 9 (15.0%) patients were asymptomatic. Aspergilloma was simple in 13 (21.7%) patients and complex in 47 (78.3%) patients. Surgical approach was by thoracotomy (n=51 [85.0%]), video-assisted thoracoscopic surgery (n=7 [11.7%]), or a cavernostomy (n=2 [3.3%]). Sublobar resections (n=28 [46.7%]) were most common, followed by lobectomy (n=27 [45%]) and pneumonectomy (n=3 [5%]). Postoperative morbidity occurred in 18 (30%) patients, with prolonged air leak the most frequent complication (n=9 [15%]). Two (3.3%) patients experienced empyema, and 4 (6.7%) patients had bronchopleural fistulas (BPFs). Two patients died within 30 days (3.3%). During a mean follow-up of 54.1±62.2 months, 3 patients had recurrent aspergillomas (5.0%). Actuarial 10-year survival was 62.5% for simple and 68.5% for complex aspergillomas (p=0.858). Comorbid conditions (human immunodeficiency virus [HIV] positivity, malignancy) and male sex were associated with lower survival. CONCLUSIONS Selective surgical treatment favoring lesser pulmonary resection results in fungal eradication and control in most patients. Overall survival is similar after surgical management of simple and complex aspergillomas.

Indirect recognition of MHC class I allopeptides accelerates lung allograft rejection in miniature swine.

The role of indirect allorecognition in graft rejection is examined in two experiments using a swine lung transplantation model. First, two swine received class I mismatched grafts without immunosuppression; another two recipients were treated postoperatively with cyclosporine (CsA). These swine exhibited acute and chronic rejection, respectively. All four recipients developed T‐cell reactivity to donor‐derived class I major histocompatibility complex (MHC) peptides. Second, six swine were immunized with synthetic donor‐derived class I allopeptides prior to transplantation. Control groups consisted of nonimmunized recipients (n = 6) and recipients immunized with an irrelevant peptide (n = 3). These recipients all received a 12‐day course of post‐operative CsA. Swine immunized with allopeptides exhibited accelerated graft rejection, as compared to both control groups (p < 0.01 and p = 0.03, respectively). Within the experimental group, the dominant histologic finding was acute rejection (AR). Obliterative bronchiolitis (OB) was seen in the graft with the longest survival. Both control groups showed a lesser degree of AR, with four out of six nonimmunized swine ultimately developing OB. These studies suggest that indirect allorecognition is operative during lung allograft rejection, and that pre‐transplant sensitization to donor‐derived MHC allopeptides can accelerate graft rejection.

Outcomes With Open and Minimally Invasive Ivor Lewis Esophagectomy After Neoadjuvant Therapy

BACKGROUND Neoadjuvant therapy is integral in the treatment of locally advanced esophageal cancer. Despite increasing acceptance of minimally invasive approaches to esophagectomy, there remain concerns about the safety and oncologic soundness after neoadjuvant therapy. We examined outcomes in patients undergoing open and minimally invasive (MIE) Ivor Lewis esophagectomy after neoadjuvant therapy. METHODS This was a retrospective series of 130 consecutive patients with esophageal cancer undergoing Ivor Lewis esophagectomy with curative intention after neoadjuvant therapy at a tertiary academic center (2008 to 2012). RESULTS An open procedure was performed in 74 patients (56.9%), and 56 (43.1%) underwent MIE after neoadjuvant therapy. MIE patients had shorter median intensive care unit (p = 0.002) and hospital lengths of stay (p < 0.0001). The incidence of postoperative complications was similar (open: 54.8% vs MIE: 41.1%, p = 0.155). However, observed respiratory complications were significantly reduced after MIE (8.9%) compared with open (29.7%; p = 0.004). Anastomotic leak rates were similar (open: 1.4% vs. MIE: 0%, p = 1.00). Mortality at 30 and 90 days was comparable (open: 2.7% and 4.1% vs MIE: 0% and 1.8%, p = 0.506 and p = 0.634, respectively). Complete resection rates and the number of collected lymph nodes was similar. Overall survival rates at 5 years were similar (open: 61% vs MIE: 50%, p = 0.933). MIE was not a significant predictor of overall survival (hazard ratio, 1.07; 95% confidence interval, 0.61 to 1.87; p = 0.810). CONCLUSIONS MIE proves its safety after neoadjuvant therapy because it leads to faster progression during the early postoperative period while reducing pulmonary complications. Open and MIE approaches appear equivalent with regards to perioperative oncologic outcomes after neoadjuvant therapy. Long-term outcomes need further validation.

Hyperbaric oxygen therapy for the treatment of anastomotic complications after tracheal resection and reconstruction

OBJECTIVE Failure of anastomotic healing is a rare but serious complication of laryngotracheal resection. Treatment options include reoperation, tracheostomy, or T-tube placement. Hyperbaric oxygen therapy (HBOT) is the delivery of 100% O2 at pressures greater than 1 atm, and has been shown to enhance wound healing after tracheal resection in animal models. To date, there have been no reports describing its usefulness in humans after tracheal resection. METHODS Five consecutive patients with varying degrees of failed anastomotic healing, from necrotic cartilage to partial separation identified by bronchoscopy were treated with HBOT. HBOT was administered for 90 minutes via a hyperbaric chamber pressurized to 2 atm with 100% oxygen. Patients were treated with daily or twice daily HBOT. Four of 5 patients had buttressing of the anastomosis by strap muscle at the initial surgery. RESULTS All patients had evidence of anastomotic healing on bronchoscopy. None of the patients in this series required tracheostomy, T-tube, or reoperation after initiation of HBOT. On average it took 9.6 days for healing to occur (5-14 days). The size of the anastomotic defect ranged between 3 and 13 mm. One patient required bilateral tympanostomy tubes for inner ear discomfort and experienced blurry vision as complications of HBOT. One patient developed tracheal stenosis from granulation tissue that required bronchoscopic debridement. CONCLUSIONS In select patients with anastomotic complications after tracheal resection, HBOT may aid in healing and avoid tracheostomy. Future investigations are necessary to further define the benefits of HBOT in the management of airway anastomotic complications.

Pulmonary Artery Pseudoaneurysms: Clinical Features and CT Findings

OBJECTIVE The purpose of this study was to analyze the clinical and CT features of pulmonary artery pseudoaneurysms (PAPs). MATERIALS AND METHODS A database search of chest CT examinations performed from January 1, 2000 to December 31, 2014 identified 24 patients with findings consistent with PAPs. A CT finding consistent with a PAP was defined as a focal saccular outpouching of a pulmonary artery. Medical records were reviewed to determine clinical presentations, treatments, and outcomes. CT scans were reviewed by two board-certified fellowship-trained chest radiologists. RESULTS A total of 35 PAPs were identified in 24 patients. Hemoptysis and shortness of breath were the most common presenting symptoms. The most commonly identified causes of PAPs were infection (33%), neoplasms (13%), and trauma (17%). Of the 35 PAPs, 29 (83%) were located in segmental or subsegmental pulmonary arteries. A solitary PAP was identified in 20 (83%) patients, and multiple PAPs were identified in three patients with endocarditis and one patient with pulmonary metastases. Only three of 35 (9%) PAPs were associated with a ground-glass halo. Endovascular treatment was successfully performed in 12 patients, and only one patient had immediate recurrent hemoptysis after treatment. PAP was clinically suspected by the referring clinicians in only three patients. Sixteen of the 35 (46%) PAPs were not reported on the initial CT studies. CONCLUSION PAPs showed a strong predilection for the peripheral pulmonary arteries. Multiplicity of PAPs can be seen in the settings of endocarditis and pulmonary metastatic disease. Most PAPs were not associated with a ground-glass halo. PAPs can be lethal but were often not suspected clinically and were underreported by radiologists.

Tracheo-Esophageal Fistula

Tracheoesophageal fistula (TEF) is a rare complication after postintubation tracheal injury or esophagectomy. It is associated with significant morbidity and the risk of mortality. Contrast esophagography and direct endoscopic examination are the keys to prompt diagnosis, in addition to a high index of suspicion. While conservative and endoscopic management are essential initially, operative management is the only definitive treatment available. Direct surgical repair of the fistula, which on occasion requires tracheal reconstruction, and buttressing of the repair with muscle is effective. Most patients are able to resume oral alimentation and are free from tracheal appliances.

Surgical resection of an intravascular superior vena cava primary lipoma.

CLINICAL SUMMARY A 55-year-old woman was referred to our surgical department for enlargement of the superior mediastinum found on a routine chest radiograph. Her medical history and physical examination were unremarkable. Thoracic computed tomography (CT) with intravenous contrast showed an intraluminal nonenhancing tumor occluding the distal right subclavian vein, the right brachiocephalic vein, and the SVC up to the right atrium (Figure 1, A and B). A superior