Impact of Surveillance Imaging in Patients with HPV-Associated Oropharyngeal Carcinomas Treated with Definitive Radiation and Chemotherapy

PURPOSE/OBJECTIVE(S)

Post-treatment surveillance imaging for HPV-associated oropharyngeal carcinomas (OPCs) differs among physicians and institutions. Surveillance imaging can detect disease progression earlier, but can also contribute to anxiety and cost, without proven disease-free or survival benefit. We sought to determine the number of surveillance scans needed to detect a recurrence in patients with HPV-associated OPCs.

MATERIALS/METHODS

We included consecutive patients with locally advanced HPV-associated OPC that received definitive concurrent chemoradiotherapy (CRT) with 70 Gy between March 1, 2017 to July 31, 2019. First post-treatment scans were defined as the first scans following the end of CRT. Surveillance scans were defined as body FDG PET/CTs, neck or chest CTs, and neck MRIs taken after the first post-treatment scans showed no evidence of disease. Any scans ordered to follow suspicious lesions on first post-treatment scans were not counted as surveillance scans. Recurrences were classified as detected by first post-treatment scans, surveillance scans, clinical exam, or incidental findings. The number of surveillance scans needed to detect 1 recurrence was determined by dividing the number of surveillance scans by the number of recurrences detected by surveillance scans.

RESULTS

There were a total of 275 patients with median follow-up of 39.8 months (Interquartile Range (IQR), 34.9-47.8). Surveillance scans were first taken at a median of 12.1 months (IQR, 9.2-16) post-CRT. There were 27 (9.8%) patients who had a recurrence: 7 (2.5%) had locoregional recurrence (LR), 19 (6.9%) had distant metastasis (DM), and 1 (0.4%) had both LR and DM. LR was detected at a median of 5.8 months (IQR, 3.4-10.6) post-CRT and DM was detected at a median of 9.5 months (IQR, 4.8-14.3) post-CRT. Of all recurrences, 11/27 (40.7%) were first post-treatment scan detected, 10 (37.0%) were surveillance scan detected, 5 (18.5%) were clinical exam detected, and 1 (3.7%) was incidentally detected on lung cancer screening. Four (50%) LRs were first post-treatment detected (median time to detection, MTD: 4.2 months), 3 (37.5%) were clinical exam detected (MTD: 6.7 months), and 1 (12.5%) was surveillance detected (MTD: 9.0 months). For DM, 9 (45%) were surveillance detected (MTD: 12.7 months), 8 (40%) were first post-treatment detected (MTD: 4.1 months), 2 (10%) were clinical exam detected (MTD: 18.9 months), and 1 (5%) was incidentally detected (MTD: 12.1 months). A total of 702 surveillance scans were taken during the follow-up period. The number of surveillance scans needed to detect 1 LR/DM was 71 overall, 50 within 2 years and 254 beyond 2 years from CRT.

CONCLUSION

First post treatment scans detect most recurrences for HPV-associated OPC. A high burden of surveillance scans is needed to detect one recurrence, especially beyond 2 years from CRT.

Nanoparticles in Drug Delivery: From History to Therapeutic Applications

Current research into the role of engineered nanoparticles in drug delivery systems (DDSs) for medical purposes has developed numerous fascinating nanocarriers. This paper reviews the various conventionally used and current used carriage system to deliver drugs. Due to numerous drawbacks of conventional DDSs, nanocarriers have gained immense interest. Nanocarriers like polymeric nanoparticles, mesoporous nanoparticles, nanomaterials, carbon nanotubes, dendrimers, liposomes, metallic nanoparticles, nanomedicine, and engineered nanomaterials are used as carriage systems for targeted delivery at specific sites of affected areas in the body. Nanomedicine has rapidly grown to treat certain diseases like brain cancer, lung cancer, breast cancer, cardiovascular diseases, and many others. These nanomedicines can improve drug bioavailability and drug absorption time, reduce release time, eliminate drug aggregation, and enhance drug solubility in the blood. Nanomedicine has introduced a new era for drug carriage by refining the therapeutic directories of the energetic pharmaceutical elements engineered within nanoparticles. In this context, the vital information on engineered nanoparticles was reviewed and conferred towards the role in drug carriage systems to treat many ailments. All these nanocarriers were tested in vitro and in vivo. In the coming years, nanomedicines can improve human health more effectively by adding more advanced techniques into the drug delivery system.

Acetylcholinesterase inhibitory potential of scorpion venom in Aedes aegypti (Diptera: Culicidae)

Scorpion venom contains a variety of neurotoxins which interact with ion channels and affect their activities. The present study was designed to evaluate the potential of scorpion venom as acetylcholinesterase (AChE) inhibitor by using Aedes aegypti as model organism. Venoms of two species, Hottentota tamulus (Fabricus, 1798) and Androctonus finitimus (Pocock, 1897) were selected for this study. Two peptides (36 kDa from H. tamulus and 54 kDa from A. finitimus) were separated from scorpion venom by using HPLC. Selected peptides caused significantly higher mortality in larvae and adults of Aedes aegypti than control (no mortalities were observed in control groups). Significant acetylcholinesterase (AChE) inhibitory potential of both peptides was recorded by spectrophotometer. The peptide of A. finitimus caused significantly higher mortality (95±1.53% in larvae and 100% in adults) than the peptide of H. tamulus (84.33±2.33% in larvae and 95.37±1.45% in adults). While H. tamulus peptide was more efficient in reducing AChE activity (0.029±0.012 in larvae and 0.03±0.003 in adults) than the peptide of A. finitimus (0.049±0.005 in larvae and 0.047±0.001 in adults). It was concluded that H. tamulus venom peptide was more efficiently reducing AChE activity, thus it could be a potential bio-insecticide which can be synthesized at industrial scale for the control of harmful insects.

COMPARISON OF THE EFFICACY OF ANTIBIOTIC-STEROID AND ICHTHAMMOL GLYCERINE WICK IN TREATMENT OF ACUTE OTITIS EXTERNA

Objective: To compare the efficacy of steroid antibiotic wick with Ichthammol Glycerol wick in the management of Acute Otitis Externa in terms of tenderness and clearance of discharge/debris. Study Design: Quasi-experimental study. Place and Duration of Study: ENT Out Patient department of Combined Military Hospital Peshawar and Hayatabad Medical Complex Peshawar, from May to Nov 2018. Methodology: A total of 250 patients were included and divided into two groups of 125 each. After necessary suction clearance topical Ciprofloxacin/Dexamethasone (Cipotec-D) wick was placed in auditory canal of group A patients and topical Glycerol/Ichthammol wick was placed in group B. Follow up visits were done on 3rd and 7th day of starting the treatment. Results: Group A patients responded better in terms of tenderness (88%) however both groups had similar response in terms of discharge reduction (7.2% vs 6.4%). In terms of efficacy neither of the treatment proved more efficacious compared to the other (p-value 0.058). Conclusion: While steroid antibiotic wick is significantly more efficient in terms reducing tenderness, in terms of overall efficacy and discharge reduction Ichthammol/glycerol is equally effective.

SELF CLEANING OF EARS BY VARIOUS OBJECTS CAUSES MULTIPLE DISEASES OF EXTERNAL EAR

Objective: To find out the association of multiple diseases of external ear with the use of various objects and cotton buds. Study Design: Case control study. Place and Duration of Study: Ear Nose Throat Department, Pakistan Naval Ship Shifa Karachi, from Jan to Oct 2020. Methodology: All the patients having multiple diseases of external ear were included as cases. Controls were selected from the healthy volunteers from general populations. Results: Total number of subjects in this study was 140 with the mean age 25.11 ± 11.21 years (2-55 years of age range). Out of them, 82 were male and 58 were female. Odds ratio was 16.07. Conclusion: There is a solid relationship of illnesses of external ear with the utilization of cotton buds. This detrimental practice should be incapacitated by featuring the notice by brands owners of cotton bud and safety instructions at different instructive levels.

ENDOSCOPIC CARTILAGE TYMPANOPLASTY. OUR TECHNIQUE AND EXPERIENCE OF 157 CASES

Objective: To assess the graft take rate and hearing gain in trans-canal endoscopic tympanoplasty Study Design: Descriptive study. Place and Duration of Study: Pakistan Naval Ship Hafeez, Islamabad Pakistan, form Dec 2015 to Jun 2018 Methodology: All patients with dry central perforations of >3 months history were included in the study. All Patients with perforations of pars tensa were booked for endoscopic cartilage tympanoplasty. All perforations were divided into four types small, medium, large and subtotal or total based on size of the tympanic membrane perforations. Small perforations involving <25% area of Pars Tensa. Medium perforation are Perforations involving 25-50% of Tympanic membrane. Large perforations include Perforations involving 50-75% of pars tensa. Subtotal or total perforations are defined as perforations with >75% perforation of the tympanic membranes. Wet Ears and perforations involving the Pars Flacida were excluded from the study. Preoperative Audiogram was carried out for all patients and A-B Gap were noted for all groups separately so as the demographic data including age and gender. Success was defined as complete closure of Tympanic membrane perforation at 3 months. All patients were operated with 0 Degree 3mm, 14cm rigid endoscope under general anesthesia. Results: Mean age of patients was. 37 years and standard deviation was 12.34 (range 12-58 years). Out of total 157 cases 81 patients male were males (51%) and 76 patients were females (49). Out of 157 ears operated 146 Perforations healed completely an overall success rate of 92%. Patients with small perforations had 100 percent success.....

TOTAL ENDOSCOPIC STAPES SURGERY. OUR TECHNIQUE AND EXPERIENCE OF 45 CASES

Objective: To assess the hearing results of transcanal endoscopic stapedotomy Study Design: Descriptive study. Place and Duration of Study: Pakistan Naval Ship Hafeez Islamabad Pakistan, from Jun 2016 to Jun 2020. Methodology: All patients with surgically confirmed otosclerosis were included in the study. All patients were operated with 0-degree 3mm, 14cm rigid endoscope under general anesthesia. Preoperative and post operative air bone gap was noted along with demographic data, middle ear anomalies (persistent stapedial artery, dehiscent facial nerve, anteriorly placed facial nerve, floating foot plate) and injury to chorda tympani. Postoperative air bone gap (A-B Gap) was documented 12 weeks after surgery. All patients were followed up for 6-12 months Results: Mean age of patients was, 37 years and standard deviation was 12.34 (range 27-52 years). Out of total 45 cases 13 were males (29%) and 32 females (71.%). Four (8.8%) patients had dehiscent facial canal and 1 (2.2%) patient had persistent stapedial artery. Average preoperative A-B gap was 35 db and Average Postoperative A-B Gap was 7 db. Chorda tympani was preserved in all cases. One patient (2.2%) complained of altered taste which resolved after 3 months. Four patients had Postoperative vertigo that lasted 2 days on average. Conclusion: Endoscopic trans canal Stapes surgery is scarless safe effective procedure demonstrable hearing benefits in all patients with minimum complications. The Technique is single handed and has steep learning curve.

ENT SURGEONS AS MASTER TRAINERS OF CRICOTHYROIDOTOMY WILL SAVE PRECIOUS LIVES IN EMERGENCIES

Objective: To train young doctors and paramedical staff on needle cricothyroidotomy and surgical cricothyroidotomy and provision of kits in trauma centers, main operation theatres and medical reception centers of the hospitals. Study Design: Quasi experimental study. Place and Duration of Study: Combined Military Hospital Peshawar and Pakistan Naval Ship Shifa, Karachi Pakistan, from Nov 2017 to Oct 2020. Methodology: Doctors and paramedical staff were selected on volunteer basis. Small groups were trained in 2-3hours. The participants were shown two videos of two procedures in Urdu language first and then were trained on mannequin. Results: A total of 345 participants including 205 males and 140 females were trained with mean age was 28.2667 ± 6.24 (SD) years. Out of 61 residents, 54 medical officers, 143 house officers, 35 nurses and 52 paramedical staff were participants. Conclusion: ENT surgeons must arrange mannequins and conduct training sessions of small groups after every 1 to 2 months.

THYROID SURGERY: A COMPARISON OF COMMON COMPLICATIONS BETWEEN EXPERTS AND SURGEONS IN TRAINING

Objective: To determine the frequency of common complications of thyroid surgery by two types of surgeons. Study Design: Comparative cross sectional. Place and Duration of Study: Combined Military Hospital Rawalpindi & Combined Military Hospital Peshawar, from Jan 2013 to Dec 2017. Methodology: This study was conducted to assess the role of surgical skills in complications of thyroid surgery. Surgeons performing surgery for more than 5 years were considered expert and less than 5 years of experience were considered trainee for this specific surgery. Complications by both were analyzed by SPSS-21 and descriptive statistics were applied. Results: A total of 482 surgeries were performed. Out of 407 were female and 75 were males. Mean age was 43.55 ± 10.9 years. Expert surgeons performed 300 cases and 16 (5.3%) experienced some complication in 6 months of follow up.182 cases were performed by surgeons with lesser experience and 14 (7.5%) cases developed complications over the period of follow up. Recurrent laryngeal nerve paralysis occurred in 2 (0.67%) of experienced surgeons cases while 6 cases (3.2%) of less experienced surgeons had the similar complication. Conclusion: While the overall complication rates are not much different between experienced and lesser experienced surgeons, the rate of recurrent laryngeal nerve paralysis is significantly more, though still within the acceptable international complication rate for this particular surgery.

NASOPHARYNGEAL SPECIMEN COLLECTION FROM SUSPECTED COVID-19 CASES, MAKING THE PROCEDURE SAFE

Objective: To comparison was made between standard (control group) nasopharyngeal sample collection technique for RTPCR and modified technique and the outcome was compared in terms of the proportion of positive results of Rt-PCR tests. Study Design: Double blinded randomized clinical trial. Place and Duration of Study: Pakistan Naval Ship Shifa Hospital Karachi Pakistan, from June and July 2020. Methodology: This study was a newly developed modified technique for nasopharyngeal sampling for RT-PCR tests of COVID-19 suspects. Target population included all patients who developed COVID-19 related symptoms and/or also had history of recent travel or closed contact with Covid-19 patients. Total 1500 nasopharyngeal PCR tests were done by a team of trained technicians. Systemetic probability sampling technique was utilized. Subjects were divided into two groups by using even and odd serial numbers. Proportion of positive test results were compared between two groups by using chi square test. Results: Results were collected for 3000 nasopharyngeal swab sample for RT-PCR testing. Mean age was 31.68 ± 11.89 years. In study group with modified technique, 470 tests were found positive for a total of 1500 samples while only 297 out of 1500 samples were detected positive in control group with standard technique. Chi square test applied to assess the difference between this proportion and it proved that the difference was highly statistically significant (p-value <0.00). Conclusion: we interpret that modified samples collection technique is relatively safe for sample collector of Covid-19 PCR which has got potential benefits to get more genuine results of these......

MANAGEMENT OF COTTON BUD INDUCED OTITIS EXTERNA BY UNIQUE METHOD

Objective: To compare the recovery of patients in both groups having acute otitis externa induced by cotton buds/various objects. One group by old method and second group by unique method. Study Design: Quasi-experimental study. Place and Duration of Study: Pakistan Naval Ship Shifa Karachi, from Jan to Dec 2020. Methodology: Non-probability convenience sampling technique was applied. Out of 50 cases were selected for group 1 management. Fifty cases were selected for group 2 management. A chi-square test was applied to compare the recovery of two groups of patients on the 14th day and 42nd day of follow-up. p-value was kept 0.05 as significant. Results: A total of 100 cases were treated in 2 groups. The gender distribution of the study was 54 females and 46 males. The mean age of the study population was 33.09 ± 12.93 years. p-value was calculated on the 14th day and 42nd days. A 2x2 table of 14th follow up day showed recovery by both groups with a p-value of 0.041 which is <0.05. This showed that group 2 management was statistically better than group 1 management. Conclusion: The second group was managed with eardrops containing Betamethasone and Neomycin. This management protocol is unique and better than conventional management as done in the first group.

Oropharyngeal Cancer Early Outcomes and Challenges During the COVID-19 Pandemic

Purpose/Objective(s)

The COVID-19 pandemic triggered a national emergency which drastically affected the practice of medicine. Studies have already shown that delays in cancer screening/diagnosis/treatment have ensued, and some project this will translate into increased mortality. We aimed to evaluate if early oropharyngeal cancer (OPC) outcomes with radiation therapy (RT) were affected.

Materials/Methods

On 3/17/2020, in response to the crisis in New York City, telemedicine consultations were implemented at our institution and patients followed prospectively. The Covid cohort (COV) includes new patients through July 2020. They were compared to a contemporary pre-Covid (PC) historical cohort of new patients from November 2019 to 3/16/2020. We reviewed medical records and collected clinicopathologic factors for OPC patients treated with curative intent RT. The Kaplan-Meier method was used to estimate time-to-event outcomes.

Results

Median follow-up was 8.6 [1.0-13.8] months for all (5.8 months COV, 10.1 months PC). Both cohorts encompassed ∼19 weeks, but half as many consults were seen during the pandemic (n = 38 COV, n = 78 PC). The COV cohort included: 74% telehealth, 92% definitive RT (no surgery), and 89% chemoRT. The PC cohort included: 0% telehealth, 88% definitive RT (no surgery), and 94% chemoRT. There was no difference in COV vs. PC median times from consultation to simulation (1.1 [0-6.4] weeks vs. 1.4 [0-10.6] weeks) or simulation to RT start (2.1 [1.3-4.9] weeks vs. 2.0 [1.1-9.9] weeks). There was no difference in 6 month outcomes between COV vs. PC cohorts: local control (100% vs. 100%, P = 0.70), regional control 100% vs. 100%, P = 0.70), distant control (95.2% vs. 97.2%, P = 0.91), cancer-specific survival (100% vs. 98.7%, P = 0.48). There was no difference in outcomes between telemedicine vs. in-person consults. There were numerically more patients with very advanced disease during the pandemic: T4 (13.2% COV vs. 7.7% PC) or N3/M1 (5.2% COV vs. 2.6% PC), but differences were not statistically significant due to limited numbers. More patients treated during the pandemic developed grade 3 dysphagia requiring feeding tubes (10.5% COV vs. 5.1% PC), not significant due to limited numbers. No patients diagnosed with COVID (1 before, 2 during, and 5 after RT) had recurrence at last follow-up.

Conclusion

There was no difference in early 6 month outcomes between COV and PC cohorts, no difference in outcomes with telemedicine, and RT delivery was sustained at pre-pandemic timelines. Several important clinical trends were identified in the COV cohort: about half as many consultations were seen during the pandemic, patients appeared more likely to present with very advanced disease, and more patients required feeding tubes during treatment. These findings may have important post-pandemic healthcare delivery implications related to delays in diagnosis, threats to long-term outcomes, and increased supportive care needs.

COMPLICATIONS OF TRACHEOSTOMY AND LEADING FACTORS AMONG PATIENTS PRESENTING AT A TERTIARY CARE HOSPITAL, KARACHI

Objective: To look for the complications of tracheostomy and factors correlated with presence of these complications at a tertiary care teaching hospital of Pakistan. Study Design: Cross-sectional study. Place and Duration of Study: ENT department, Operation Theater, Emergency department and Critical Care Unit of Pakistan Naval Ship Shifa Hospital, Karachi Pakistan, from Apr to Oct 2019. Methodology: Sixty nine patients who underwent tracheostomy were included in the analysis. Final decision regarding offering the procedure of tracheostomy to the patient was made by consultant ENT specialist in liaison with the primary treating physician. Patients were assessed for the complications during the procedure, immediately after the procedure, 48 hours after the procedure and one week after the procedure. Results: Out of sixty nine patients included in the study, 8 (11.6%) patients underwent emergency tracheostomy while 61 (88.4%) underwent elective tracheostomy. Ten (14.5%) had undergone percutaneous procedure while 59 (85.5%) had undergone open surgical procedure. Hemorrhage was the commonest complication reported followed by dislodgement. With Pearson chi-square test, we found that increasing age (45 years) and emergency tracheostomy had strong association with the presence of complications among the patients undergoing tracheostomy. Conclusion: Tracheostomy emerged as a safe procedure with mostly minor self-limiting complications. Surgeon performing this procedure should be aware of these common complications and should give information care to the patients prior to the procedure. Patients who are elderly or undergoing emergency tracheostomy should be dealt with special care while doing this life saving procedure.

Healing of a large avulsed mandibular bony segment: report of a unique case

This case report puts an emphasis on retaining and re-fixing any avulsed bony segments in the maxillofacial region and maintaining the periosteal layer whenever possible, especially in young patients. Adequate bony fixation and watertight soft tissue closure are vital components for bone healing. The healing potential of facial bones is much higher as compared to the long bones, due to the superior blood supply.

COMPARISON OF OLFACTORY DISTURBANCE IN COVID-19 POSITIVE CASES WITH NON COVID-19 RHINITIS CASES

Objective: To determine association of anosmia as an early symptom of COVID-19 infection. Study Design: Comparative cross sectional study. Place and Duration of Study: ENT department, Combined Military Hospital, Quetta, from Apr to Oct 2020. Methodology: A total of 6411 consenting patients with symptoms of viral upper respiratory tract infection presenting at ENT department, Combined Military Hospital Quetta, from Apr to Oct 2020 were tested for COVID 19 via PCR studies. Results: Out of 6411 individuals 1109 (17.3%) were found to be COVID positive and 5302 (82.7%) were COVID negative. Of the COVID positive cases 611 (55.1%) of COVID positive individuals had anosmia, whereas only 68 (1.2%) of COVID negative individuals had anosmia, this observation was statistically significant (p<0.001 on chi square test). Whereas only 33 (2.9%) patients had nasal obstruction in COVID positive group, and 68 (1.2%) cases in COVID negative group had nasal obstruction, this observation was not statistically significant (p>0.05 on chi square test). Conclusion: Anosmia has a definite association with COVID 19 infection.

POST-OPERATIVE HEMORRHAGE IN SEPTOPLASTY WITH AND WITHOUT NASAL PACKING A COMPARATIVE STUDY AT OTORHINOLARYNGOLOGY DEPARTMENT OF PNS SHIFA HOSPITAL, KARACHI

OBJECTIVE To compare the possibility of Post-operative hemorrhage in septoplasty with and without nasal packing among the patients operated at PNS SHIFA hospital Karachi STUDY DESIGN: Comparative Study  SETTING: PNS SHIFA hospital Karachi DURATION OF STUDY: Six months, 21-04-2019 to 20-10-2019 PATIENTS AND METHODS: Ninety two patients who underwent septoplasty due to deviation of nasal septum at ENT department of PNS SHIFA were included in the analysis. Patients were randomly divided into two groups. Group one did not undergo nasal packing after the surgery and group two underwent nasal packing after the surgical procedure. Chi-square was used to see the difference in post-operative hemorrhage, headache, discomfort and septal perforation between the two groups. RESULTS Out of 92 patients included in the final analysis 61 were male and 31 were female. Pot operative bleeding was found in three patients in group one while thirteen patients in group two had bleeding after the procedure. With Pearson chi-square test, we found that post-operative bleeding, headache and discomfort was significantly more in the patients with nasal packing after the procedure of septoplasty due to deviated nasal septum. CONCLUSION Nasal packing emerged as a procedure linked with more complications rather than benefits among the patients undergoing septoplasty in our study. Not only post-operative hemorrhage but also headache and discomfort were more common among the patients with nasal packing as compared to those without nasal packing. Nasal packing after septoplasty should be discouraged without any obvious indication in the patients undergoing septoplasty. 

ESMO recommendations on microsatellite instability testing for immunotherapy in cancer, and its relationship with PD-1/PD-L1 expression and tumour mutational burden: a systematic review-based approach

BACKGROUND

Cancers with a defective DNA mismatch repair (dMMR) system contain thousands of mutations most frequently located in monomorphic microsatellites and are thereby defined as having microsatellite instability (MSI). Therefore, MSI is a marker of dMMR. MSI/dMMR can be identified using immunohistochemistry to detect loss of MMR proteins and/or molecular tests to show microsatellite alterations. Together with tumour mutational burden (TMB) and PD-1/PD-L1 expression, it plays a role as a predictive biomarker for immunotherapy.

METHODS

To define best practices to implement the detection of dMMR tumours in clinical practice, the ESMO Translational Research and Precision Medicine Working Group launched a collaborative project, based on a systematic review-approach, to generate consensus recommendations on the: (i) definitions related to the concept of MSI/dMMR; (ii) methods of MSI/dMMR testing and (iii) relationships between MSI, TMB and PD-1/PD-L1 expression.

RESULTS

The MSI-related definitions, for which a consensus frame-work was used to establish definitions, included: 'microsatellites', 'MSI', 'DNA mismatch repair' and 'features of MSI tumour'. This consensus also provides recommendations on MSI testing; immunohistochemistry for the mismatch repair proteins MLH1, MSH2, MSH6 and PMS2 represents the first action to assess MSI/dMMR (consensus with strong agreement); the second method of MSI/dMMR testing is represented by polymerase chain reaction (PCR)-based assessment of microsatellite alterations using five microsatellite markers including at least BAT-25 and BAT-26 (strong agreement). Next-generation sequencing, coupling MSI and TMB analysis, may represent a decisive tool for selecting patients for immunotherapy, for common or rare cancers not belonging to the spectrum of Lynch syndrome (very strong agreement). The relationships between MSI, TMB and PD-1/PD-L1 expression are complex, and differ according to tumour types.

CONCLUSIONS

This ESMO initiative is a response to the urgent questions raised by the growing success of immunotherapy and provides also important insights on the relationships between MSI, TMB and PD-1/PD-L1.

Identification and validation of novel microenvironment-based immune molecular subgroups of head and neck squamous cell carcinoma: implications for immunotherapy

Background

Targeting the immune checkpoint pathway has demonstrated antitumor cytotoxicity in treatment-refractory head and neck squamous cell carcinoma (HNSC). To understand the molecular mechanisms underpinning its antitumor response, we characterized the immune landscape of HNSC by their tumor and stromal compartments to identify novel immune molecular subgroups.

Patients and methods

A training cohort of 522 HNSC samples from the Cancer Genome Atlas profiled by RNA sequencing was analyzed. We separated gene expression patterns from tumor, stromal, and immune cell gene using a non-negative matrix factorization algorithm. We correlated the expression patterns with a set of immune-related gene signatures, potential immune biomarkers, and clinicopathological features. Six independent datasets containing 838 HNSC samples were used for validation.

Results

Approximately 40% of HNSCs in the cohort (211/522) were identified to show enriched inflammatory response, enhanced cytolytic activity, and active interferon-γ signaling (all, P < 0.001). We named this new molecular class of tumors the Immune Class. Then we found it contained two distinct microenvironment-based subtypes, characterized by markers of active or exhausted immune response. The Exhausted Immune Class was characterized by enrichment of activated stroma and anti-inflammatory M2 macrophage signatures, WNT/transforming growth factor-β signaling pathway activation and poor survival (all, P < 0.05). An enriched proinflammatory M1 macrophage signature, enhanced cytolytic activity, abundant tumor-infiltrating lymphocytes, high human papillomavirus (HPV) infection, and favorable prognosis were associated with Active Immune Class (all, P < 0.05). The robustness of these immune molecular subgroups was verified in the validation cohorts, and Active Immune Class showed potential response to programmed cell death-1 blockade (P = 0.01).

Conclusions

This study revealed a novel Immune Class in HNSC; two subclasses characterized by active or exhausted immune responses were also identified. These findings provide new insights into tailoring immunotherapeutic strategies for different HNSC subgroups.

Poverty-associated emerging infection of Cystic Echinococcosis in population of Northern Pakistan: A hospital based study

Cystic Echinococcosis (CE) is one of the most important zoonotic parasitic diseases in human, livestock, and wildlife globally. The prevalence of CE depends upon human behavioral risk factors, the diversity and ecology of animal host interactions and the genetic diversity within Echinococcus species which differ in their zoonotic potential and pathogenicity. It is a neglected, economic and socio-cultural problem in Pakistan. The available data about the incidence of CE is very limited and no extensive study has been reported in Pakistan. The current study was aimed to analyze the hospital reported cases of CE and the associated risk factors related to the incidence of CE. The hospital-based data of CE for the time period of January 2012-December 2017 was collected from Islamabad, Rawalpindi and Peshawar. The data covered demographic characteristics including age, gender, and cyst localization of infected individuals and socioeconomic determinants. The data was analyzed based upon different risk factors along with the different socioeconomic parameters that has an important impact on the distribution of disease. A total of 228 cases were presented in the selected hospitals of different cities during the study period. Out of total 228 patients, 59.21% were males and 40.78% were females (P<0.001). Most infections have been recorded in young adults (>20-30) showing 22.8% of total infected individuals followed by children (0-10) showing 10.5% (n=24), respectively (P<0.001). Liver was the most vulnerable organ (58.77%, n=134) followed by lungs (14.47%, n=33) (P<0.001). The infection was higher among rural communities (84.2%) than urban (12.8%) (P<0.001). Socioeconomic and demographic factors had an important impact on the intensity of disease (P<0.001). The occurrence of cases in children and young adults was an important finding as it indicated an active transmission of the parasite in Pakistan along with the poverty index. Emergence of echinococcosis in Pakistan showed that emerging health issues in Pakistan could bring the disease to limelight for future research. This finding, together with the fact that 1 hospital reported 214 cases over 6 years 325 underlines the need for a program for prevention/control of this disease in Pakistan. The timely measure needs to be taken to hamper the disease development and establishment. In order to control the disease, complete surveillance should be done which in turn weighs down the disease progress.

Abstract P4-04-01: The landscape of somatic genetic alterations in breast cancers from CHEK2 germline mutation carriers

Introduction: Checkpoint kinase 2 (CHEK2) is a tumor suppressor gene, which regulates cell cycle in response to DNA damage response. Selected CHEK2 germline mutations have been shown to confer an increased risk of breast cancer development. Multiple founder mutations in CHEK2 have been identified, and meta analyses have shown that CHEK2 truncating variants confer a higher breast cancer risk than missense variants. Here, we assessed the phenotype and repertoire of genetic alterations of breast cancers from 33 patients with CHEK2 pathogenic germline variants.

Materials and methods: We performed targeted capture massively parallel sequencing (≥410 genes) of tumor and normal samples from 13 patients with CHEK2 pathogenic germline variants, and retrieved whole exome sequencing (WES) data (BAM files) of tumor and normal samples from 20 patients with CHEK2 germline pathogenic variants included in the TCGA breast cancer study. In addition, we retrieved WES data of BRCA1, BRCA2 and ATM associated breast cancers from TCGA and Weigelt et al. (JNCI 2018). Somatic mutations, copy number alterations, mutational signatures and large-scale transitions (LSTs) were defined using state-of-the-art bioinformatics algorithms.

Results: Of the 33 CHEK2-associated breast cancers included in this study, 21 had missense and 12 had loss-of-function (LoF) germline mutations, and 81% were ER-positive and 12% HER2-positive. CHEK2-associated breast cancers statistically significantly less frequently displayed an ER-negative/HER2-negative phenotype (0%) than BRCA1- (80%) or BRCA2-associated (33%) breast cancers (BRCA1, p&lt;0.0001 for both comparisons), but were similar to ATM-associated breast cancers. Biallelic inactivation of CHEK2 through loss of heterozygosity (LOH) of the wild-type allele was present in 17 of 33 samples (52%). LOH of the CHEK2 wild-type allele was significantly more frequent in tumors with LOF mutations than in those with missense mutations (78% vs 36%, respectively; p=0.0394). PIK3CA (36%) and GATA3 (33%) were the two most recurrently mutated genes in these samples. TP53 somatic mutations were detected in five cases, four of which harbored missense CHEK2 germline mutations. Unlike BRCA1- and BRCA2-associated breast cancers, but akin to ATM-associated breast cancers, CHEK2-associated breast cancers lacked the mutational signature associated with homologous recombination (HR) DNA repair defects (i.e. signature 3) and only five cases displayed high LST scores.

Conclusion:CHEK2-associated breast cancers are phenotypically and genetically distinct from BRCA1- and BRCA2-associated breast cancers, but similar to ATM-associated breast cancers. Akin to ATM-associated breast cancers, CHEK2-associated breast cancers are preferentially ER-positive, lack genomics features consistent with defective HR, and have a repertoire of somatic genetic alterations similar to those of non-BRCA1/2 ER-positive breast cancers. Our results suggest that either CHEK2 germline mutations contribute to an increased risk of breast cancer independently of the HR DNA repair defects or that the mutational signatures caused by CHEK2 pathogenic germline mutations differ from those caused by pathogenic germline mutations affecting bona fide HR-related genes (e.g. BRCA1, BRCA2 and PALB2).

Citation Format: Kumar R, Pei X, Selenica P, Wen HY, Powell S, Robson M, Riaz N, Reis-Filho JS, Weigelt B, Mandelker D. The landscape of somatic genetic alterations in breast cancers from CHEK2 germline mutation carriers [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-04-01.