Democratizing Artificial Intelligence in Anatomic Pathology

CONTEXT.—

Artificial intelligence is a transforming technology for anatomic pathology. Involvement within the workforce will foster support for algorithm development and implementation.

OBJECTIVE.—

To develop a supportive ecosystem that enables pathologists with variable expertise in artificial intelligence to create algorithms in a development environment with seamless transition to a production environment.

DESIGN.—

RESULTS.—

The development team considered internal development and vended solutions. Because of the extended timeline and resource requirements for internal development, a decision was made to use a vended solution. Vendor proposals were solicited and reviewed by pathologists, IT, and security groups. A vendor was selected and pipelines for development and production were established. Proposals for development were solicited from the pathology department. Eighty-four investigators were selected for the initial cohort, receiving training and access to dedicated subject matter experts. A total of 30 of 31 projects progressed through the model development process of annotating, training, and validation. Based on these projects, 15 abstracts were submitted to national meetings.

CONCLUSIONS.—

Democratizing artificial intelligence by creating an ecosystem to support pathologists with varying levels of expertise can break down entry barriers, reduce overall cost of algorithm development, improve algorithm quality, and enhance the speed of adoption.

Creating an atlas of normal tissue for pruning WSI patching through anomaly detection

Patching whole slide images (WSIs) is an important task in computational pathology. While most of them are designed to classify or detect the presence of pathological lesions in a WSI, the confounding role and redundant nature of normal histology are generally overlooked. In this paper, we propose and validate the concept of an "atlas of normal tissue" solely using samples of WSIs obtained from normal biopsies. Such atlases can be employed to eliminate normal fragments of tissue samples and hence increase the representativeness of the remaining patches. We tested our proposed method by establishing a normal atlas using 107 normal skin WSIs and demonstrated how established search engines like Yottixel can be improved. We used 553 WSIs of cutaneous squamous cell carcinoma to demonstrate the advantage. We also validated our method applied to an external dataset of 451 breast WSIs. The number of selected WSI patches was reduced by 30% to 50% after utilizing the proposed normal atlas while maintaining the same indexing and search performance in leave-one-patient-out validation for both datasets. We show that the proposed concept of establishing and using a normal atlas shows promise for unsupervised selection of the most representative patches of the abnormal WSI patches.

Solid-Basaloid Adenoid Cystic Carcinoma of the Breast: An Aggressive Subtype Enriched for Notch Pathway and Chromatin Modifier Mutations With MYB Overexpression

Adenoid cystic carcinoma (AdCC) is a rare triple-negative breast cancer analogous to its extramammary counterparts. Diagnosis of the more aggressive solid-basaloid variant of AdCC (SB-AdCC) can be challenging due to poorly defined histopathologic and molecular features. We characterized 22 invasive and in situ basaloid carcinomas by morphology, immunohistochemistry, genetics, and MYB status using multiple platforms and assessed clinical behavior and neoadjuvant chemotherapy responses. After consensus review, 16/22 cases were classified as SB-AdCC. All SB-AdCC had predominantly solid growth and at least focal myxohyaline stroma and were immune-poor. Eosinophilic squamoid cells (69%, 11/16) and basement membrane-like secretions (69%, 11/16) were common, and intercalated ducts (31%, 5/16) were less frequent. SB-AdCC typically expressed SOX10 (100%, 16/16) and luminal markers (100%, 16/16 CK7; 88%, 14/16 CD117; 93%, 13/14 CAM5.2). SMA (40%, 6/15) expression was less common, and SMM (27%, 3/11), GATA3 (20%, 3/15), and p63 (25%, 4/16) were mostly negative. MYB protein and/or MYB RNA overexpression was universal in evaluable cases (13/13), with RNA in situ hybridization (10/10) more reliable than immunohistochemistry (10/11, plus 4 excisions inconclusive). Fluorescence in situ hybridization and/or next-generation sequencing identified MYB rearrangements (20%, 3/15) and amplifications/copy gains (60%, 9/15) but no MYB::NFIB fusions. SB-AdCC often had aberrations in Notch pathway (60%, including 40% NOTCH1 and 20% NOTCH2) and/or chromatin modifier (60%, including 33% CREBBP) genes, with relatively infrequent TP53 mutations (27%). Unclassified invasive basaloid carcinomas lacking described histologic features of SB-AdCC (n = 4) and basaloid ductal carcinoma in situ (n = 2) showed similar immunoprofiles and genetics as SB-AdCC, including Notch aberrations and MYB overexpression with MYB rearrangements/amplifications. Overall, nodal (22%) and distant (33%) metastases were common, and 23% of patients died of disease (mean follow-up, 35 months; n = 22). Responses were poor in all 7 neoadjuvant chemotherapy-treated patients, without any achieving pathologic complete response. The data highlight the histopathologic spectrum of basaloid carcinomas including SB-AdCC and reveal shared genetics and MYB activation, which can be diagnostically useful. Aggressive behavior and poor treatment responses emphasize a need for additional treatment approaches.

Assessing the capacity of methylated DNA markers of cervical squamous cell carcinoma to discriminate oropharyngeal squamous cell carcinoma in human papillomavirus mediated disease

OBJECTIVE

Early identification of human papillomavirus associated oropharyngeal squamous cell carcinoma (HPV(+)OPSCC) is challenging and novel biomarkers are needed. We hypothesized that a panel of methylated DNA markers (MDMs) found in HPV(+) cervical squamous cell carcinoma (CSCC) will have similar discrimination in HPV(+)OPSCC tissues.

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded tissues were obtained from patients with primary HPV(+)OPSCC or HPV(+)CSCC; control tissues included normal oropharynx palatine tonsil (NOP) and cervix (NCS). Using a methylation-specific polymerase chain reaction, 21 previously validated cervical MDMs were evaluated on tissue-extracted DNA. Discrimination between case and control cervical and oropharynx tissue was assessed using area under the curve (AUC).

RESULTS

34 HPV(+)OPSCC, 36 HPV(+)CSCC, 26 NOP, and 24 NCS patients met inclusion criteria. Within HPV(+)CSCC, 18/21 (86%) of MDMs achieved an AUC ≥ 0.9 and all MDMs exhibited better than chance classifications relative to control cervical tissue (all p < 0.001). In contrast, within HPV(+)OPSCC only 5/21 (24%) MDMs achieved an AUC ≥ 0.90 but 19/21 (90%) exhibited better than chance classifications relative to control tonsil tissue (all p < 0.001). Overall, 13/21 MDMs had statistically significant lower AUCs in the oropharyngeal cohort compared to the cervical cohort, and only 1 MDM exhibited a statistically significant increase in AUC.

CONCLUSIONS

Previously validated MDMs exhibited robust performance in independent HPV(+)CSCC patients. However, most of these MDMs exhibited higher discrimination for HPV(+)CSCC than for HPV(+)OPSCC. This suggests that each SCC subtype requires a unique set of MDMs for optimal discrimination. Future studies are necessary to establish an MDM panel for HPV(+)OPSCC.

Impact of Tumor-Infiltrating Lymphocytes on Disease Progression in Human Papillomavirus-Related Oropharyngeal Carcinoma

OBJECTIVE

We aim to explore the prognostic value of tumor-infiltrating lymphocytes (TILs) in the primary tumor and metastatic lymph nodes of patients with HPV(+)OPSCC. We hypothesize that TILS density at both sites is associated with disease-free survival in HPV(+)OPSCC.

STUDY DESIGN

Matched case-control study among HPV(+)OPSCC patients who underwent intent-to-cure surgery. Cases developed locoregional or distant recurrence. Controls were matched based on age, sex, pathologic T, N, and overall stage, year of surgery, type of adjuvant treatment received, and the Adult Comorbidity Evaluation-27 (ACE-27) score.

SETTING

Single tertiary care center, May 2007 to December 2016.

METHODS

Tumoral TILs (tTILs) density was defined as % TILs; stromal TILs (sTILs) density was defined as absent/sparse or moderate/dense crowding. Associations between TILs and time to disease progression were assessed using Cox regression models.

RESULTS

Forty-four case-control pairs (N = 88) were included: 42 (48%) AJCC pStage I, 39 (44%) pStage II, and 7 (8%) pStage III. tTILs density ≥10% (hazard ratio [HR] 0.41, 95% confidence interval [CI] 0.17-0.99, p = .048) and a moderate/dense sTILs density (HR 0.21, 95% CI 0.06-0.75, p = .016) in the primary tumor were significantly associated with decreased risk of progression. TILs density in the lymph node was associated with decreased risk of progression but did not reach statistical significance. The tTILs and sTILs density correlated strongly between the primary tumor and lymph node. Concordance between the pathologists' was moderate (60%-70%).

CONCLUSIONS

In HPV(+)OPSCC, a higher density of tumoral and stromal TILs in the primary tumor and possibly the lymph node may predict a lower risk of disease progression.

Screening for extranodal extension in HPV-associated oropharyngeal carcinoma: evaluation of a CT-based deep learning algorithm in patient data from a multicentre, randomised de-escalation trial

BACKGROUND

Pretreatment identification of pathological extranodal extension (ENE) would guide therapy de-escalation strategies for in human papillomavirus (HPV)-associated oropharyngeal carcinoma but is diagnostically challenging. ECOG-ACRIN Cancer Research Group E3311 was a multicentre trial wherein patients with HPV-associated oropharyngeal carcinoma were treated surgically and assigned to a pathological risk-based adjuvant strategy of observation, radiation, or concurrent chemoradiation. Despite protocol exclusion of patients with overt radiographic ENE, more than 30% had pathological ENE and required postoperative chemoradiation. We aimed to evaluate a CT-based deep learning algorithm for prediction of ENE in E3311, a diagnostically challenging cohort wherein algorithm use would be impactful in guiding decision-making.

METHODS

For this retrospective evaluation of deep learning algorithm performance, we obtained pretreatment CTs and corresponding surgical pathology reports from the multicentre, randomised de-escalation trial E3311. All enrolled patients on E3311 required pretreatment and diagnostic head and neck imaging; patients with radiographically overt ENE were excluded per study protocol. The lymph node with largest short-axis diameter and up to two additional nodes were segmented on each scan and annotated for ENE per pathology reports. Deep learning algorithm performance for ENE prediction was compared with four board-certified head and neck radiologists. The primary endpoint was the area under the curve (AUC) of the receiver operating characteristic.

FINDINGS

From 178 collected scans, 313 nodes were annotated: 71 (23%) with ENE in general, 39 (13%) with ENE larger than 1 mm ENE. The deep learning algorithm AUC for ENE classification was 0·86 (95% CI 0·82-0·90), outperforming all readers (p<0·0001 for each). Among radiologists, there was high variability in specificity (43-86%) and sensitivity (45-96%) with poor inter-reader agreement (κ 0·32). Matching the algorithm specificity to that of the reader with highest AUC (R2, false positive rate 22%) yielded improved sensitivity to 75% (+ 13%). Setting the algorithm false positive rate to 30% yielded 90% sensitivity. The algorithm showed improved performance compared with radiologists for ENE larger than 1 mm (p<0·0001) and in nodes with short-axis diameter 1 cm or larger.

INTERPRETATION

The deep learning algorithm outperformed experts in predicting pathological ENE on a challenging cohort of patients with HPV-associated oropharyngeal carcinoma from a randomised clinical trial. Deep learning algorithms should be evaluated prospectively as a treatment selection tool.

FUNDING

ECOG-ACRIN Cancer Research Group and the National Cancer Institute of the US National Institutes of Health.

Single patch super-resolution of histopathology whole slide images: a comparative study

Purpose

The latest generation of scanners can digitize histopathology glass slides for computerized image analysis. These images contain valuable information for diagnostic and prognostic purposes. Consequently, the availability of high digital magnifications like 20 × and 40 × is commonly expected in scanning the slides. Thus, the image acquisition typically generates gigapixel high-resolution images, times as large as 100,000 × 100,000    pixels . Naturally, the storage and processing of such huge files may be subject to severe computational bottlenecks. As a result, the need for techniques that can operate on lower magnification levels but produce results on par with outcomes for high magnification levels is becoming urgent.

Approach

Over the past decade, the digital solution of enhancing images resolution has been addressed by the concept of super resolution (SR). In addition, deep learning has offered state-of-the-art results for increasing the image resolution after acquisition. In this study, multiple deep learning networks designed for image SR are trained and assessed for the histopathology domain.

Results

We report quantitative and qualitative comparisons of the results using publicly available cancer images to shed light on the benefits and challenges of deep learning for extrapolating image resolution in histopathology. Three pathologists evaluated the results to assess the quality and diagnostic value of generated SR images.

Conclusions

Pixel-level information, including structures and textures in histopathology images, are learnable by deep networks; hence improving the resolution quantity of scanned slides is possible by training appropriate networks. Different SR networks may perform best for various cancer sites and subtypes.

SARS-CoV-2 RNA detection in Formalin-Fixed Paraffin-Embedded (FFPE) tissue by droplet digital PCR (ddPCR)

BACKGROUND

SARS-CoV-2 is an RNA virus that primarily causes respiratory disease; however, infection of other tissue has been reported. Evaluation of SARS-CoV-2 in tissue specimens may increase understanding of SARS-CoV-2 pathobiology.

MATERIALS AND METHODS

A qualitative test for detection of SARS-CoV-2 in formalin-fixed paraffin-embedded (FFPE) tissues was developed and validated using droplet digital PCR (ddPCR), which has a lower limit of detection than reverse transcription (RT)-qPCR. After extraction of total RNA from unstained FFPE tissue, SARS-CoV-2 nucleocapsid (N1, N2) target sequences were amplified and quantified, along with human RPP30 as a control using the Bio-Rad SARS-CoV-2 ddPCR kit.

RESULTS

SARS-CoV-2 was detected in all 21 known positive samples and none of the 16 negative samples. As few as approximately 5 viral copies were reliably detected. Since January 2021, many tissue types have been clinically tested. Of the 195 clinical specimens, the positivity rate was 35% with placenta and fetal tissue showing the highest percentage of positive cases.

CONCLUSION

This sensitive FFPE-based assay has broad clinical utility with applications as diverse as pregnancy loss and evaluation of liver transplant rejection. This assay will aid in understanding atypical presentations of COVID-19 as well as long-term sequelae.

Outcomes by tobacco history in E3311, a phase II trial of transoral surgery (TOS) followed by pathology-based adjuvant treatment in HPV-associated (HPV+) oropharynx cancer (OPC): A trial of the ECOG-ACRIN Cancer Research Group

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Background: E3311 is a phase II randomized study which showed favorable outcomes among intermediate (INT) risk HPV+ OPC patients (pts) who underwent TOS followed by pathology-guided or adapted, deintensified adjuvant treatment. Among HPV+ pts treated with definitive chemoradiation, survival outcomes are worse among those who smoked > 10 pack years (pk-yrs). Methods: We retrospectively analyzed demographics, pathologic results, and efficacy outcomes from E3311 by smoking group (current (C) vs. former (F) and > 10 vs. ≤10 pk-yrs – the latter a pre-specified stratification factor for INT patients). Binary and categorical variables were compared using a chi-square test (or Fisher’s exact test for small sample sizes). Ordinal variables were compared using a Wilcoxon rank sum test. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method and compared using a log-rank test. Results: Among 359 evaluable pts, performance status (PS) was significantly worse for pts with > 10 pk-yrs vs. ≤10 pk-yrs (15.4% vs. 7.9% with PS of 1, p = 0.034). Primary site, margin status, histologic grade, stage, and extranodal extension were not significantly different between the groups of > 10 vs. ≤10 pk-yrs. Smoking status (F vs. C) was available for 182 pts with a history of smoking. Slightly more C vs. F smokers had tonsil as primary site (79.5% vs. 65.0%, p = 0.09). Positive margins were significantly more frequent among C smokers (10.3% vs. 2.1%; p = 0.029). Overall, there were no significant differences in PFS (p = 0.55) or OS (p = 0.94), comparing those with > 10 vs. ≤10 pk-yrs, or comparing C vs. F smokers (p = 0.76, p = 0.82, respectively). Similarly, no significant differences were observed within the treatment arms. (Table 1) Conclusions: In this analysis of smoking status in E3311, INT risk HPV+ OPC pts who are C smokers or have a history of > 10 pk-yrs had favorable 3-yr PFS and OS rates that were not significantly worse than those with < 10 pk-yrs history. This data represents the first treatment approach for HPV+ OPC in which outcomes were not influenced by smoking status. Clinical trial information: NCT01898494. [Table: see text]

Geochemistry and Provenance of Springs in a Baja California Sur Mountain Catchment

Fractured rock aquifers cover much of Earth's surface and are important mountain sites for groundwater recharge but are poorly understood. To investigate groundwater systematics of a fractured-dominated aquifer in Baja California Sur, Mexico, we examined the spatial patterns of aquifer recharge and connectivity using the geochemistry of springs. We evaluate a range of geochemical data within the context of two endmember hypotheses describing spatial recharge patterns and fracture connectivity. Hypothesis 1 is that the aquifer system is segmented, and springs are fed by local recharge. Hypothesis 2 is that the aquifer system is well connected, with dominant recharge occurring in the higher elevations. The study site is a small <15 km² catchment. Thirty-four distinct springs and two wells were identified in the study area, and 24 of these sites were sampled for geochemical analyses along an elevation gradient and canyon transect. These analyses included major ion composition, trace element and strontium isotopes, δ¹⁸ O and δ² H isotopes, radiocarbon, and tritium. δ¹⁸ O and δ² H isotopes suggest that the precipitation feeding the groundwater system has at least two distinct sources. Carbon isotopes showed a change along the canyon transect, suggesting that shorter flowpaths feed springs in the top of the transect, and longer flowpaths discharge near the bottom. Geochemical interpretations support a combination of the two proposed hypotheses. Understanding of the connectivity and provenance of these springs is significant as they are the primary source of water for the communities that inhabit this region and may be impacted by changes in recharge and use.

Detectable Post-operative Circulating Tumor Human Papillomavirus (HPV) DNA And Association with Recurrence in Patients with HPV-Associated Oropharyngeal Squamous Cell Carcinoma

PURPOSE

  To determine the rate of detectability of ctHPVDNA after surgery but before adjuvant therapy in patients with HPV-associated oropharyngeal squamous cell carcinoma (HPV(+)OPSCC) and to investigate whether detectable ctHPVDNA at this time point may be associated with risk of recurrence.

METHODS AND MATERIALS

 Prospectively collected samples from patients with OPSCC were examined in a blinded fashion using a multi-analyte PCR assay. 45 samples were collected from HPV(+)OPSCC patients pre-op (prior to any treatment), and 159 samples post-op (before or at the start of adjuvant RT). Samples were identified via the radiation oncology biobank or via participation in a clinical trial. RT consisted of 60 Gy +/- cisplatin or de-escalation (30 Gy to 36 Gy in 20 b.i.d. fractions + docetaxel). 32 patients had paired samples available pre and post-op for the primary analysis. Additional exploratory analyses including associations of patient and tumor characteristics with recurrence were assessed using Cox proportional hazards models for all 159 post-op samples.. Detectability of ctHPVDNA was compared across groups utilizing logistic regression. Estimates of recurrence free survival (RFS) were made using Kaplan-Meier (KM).

RESULTS

In a paired analysis of 32 pre and post-op timepoints, 94% of patients had detectable ctHPVDNA pre-op and 41% post-op. RFS at 18 months was 83% (95% CI: 47-95%) for patients with detectable post-op ctHPVDNA compared to 100% for patients with undetectable post-op ctHPVDNA (p=.094).In an exploratory analysis of non-paired post-op samples, ctHPVDNA was detectable in 26% (41 of 159) of patients (median of 22 days post-op). Age (1.06, p=0.025), LVSI (OR 3.17, p=0.011) and ENE (OR=5.67, p=0.001) were associated with detectable ctHPVDNA after surgery. Detectable post-op ctHPVDNA was significantly associated with RFS (p<0.001).

CONCLUSION

Amongst patients with detectable pre-op ctHPVDNA, a significant proportion have detectable post-op ctHPVDNA in paired post-op samples, collected prior to the initiation of adjuvant radiation therapy. Future prospective study is warranted to investigate the association of detectable post-op ctHPVDNA with recurrence, including in comparison to established clinical and pathologic risk factors.

BAP1 Immunostain Status in Intraocular Biopsy Specimens for Uveal Melanoma Highly Correlates with Other Prognostic Markers

Introduction

Loss of BAP1 protein expression emerged as a negative prognostic marker in uveal melanoma (UM) and has primarily been studied in enucleations. Intraocular biopsy is frequently performed prior to UM globe-conserving therapy.

Methods

We retrospectively evaluated BAP1 immunostaining of UM in 16 biopsies and 8 subsequent enucleations, and results were correlated with the UM-specific gene expression profile (GEP; n = 11), chromosome 3 status by FISH and/or chromosomal microarray (n = 12; 9 also had GEP), and clinical outcomes.

Results

UM involved the choroid in 15 (of 16) cases. Biopsy was performed for prognostication (n = 12) or diagnosis (n = 4). Treatment included brachytherapy (n = 13; 5 followed by enucleation) or enucleation only (n = 3). BAP1 nuclear immunostaining was positive in 9, negative in 4, and equivocal in 3 biopsies. For the 3 equivocal biopsies, BAP1 immunostaining was positive in 2 (of 3) subsequent enucleations. BAP1 immunostaining was concordant between all 5 remaining biopsies and enucleations. BAP1-positive biopsies had disomy 3 (n = 6) or 3p loss (n = 1) and class 1 GEP (n = 6). BAP1-negative biopsies had monosomy 3 (n = 3) and class 2 GEP (n = 2). Median follow-up was 62.5 months (range, 17-150). For BAP1-positive UM patients, 8 were alive (7 without metastatic disease) and 3 had died (1 melanoma-related death). Among BAP1-negative UM patients, 2 were alive (1 with metastatic disease) and 3 had melanoma-related deaths.

Conclusion

BAP1 immunostaining in biopsies highly correlates with results in subsequent enucleations and with well-established UM prognostic markers, representing a potential additional prognostic tool for UM biopsies.

The number of radiographically positive lymph nodes further stratifies patient survival among clinical N1 patients with HPV-associated oropharyngeal cancer

Purpose

Human papillomavirus–associated oropharyngeal squamous cell carcinoma (HPV[+]OPSCC) requires further study to optimize the existing clinical staging system and guide treatment selection. We hypothesize that incorporation of the number of radiographically positive lymph nodes will further stratify patients with clinical N1 (cN1) HPV(+)OPSCC.

Methods and Materials

A post hoc analysis from 2 prospective clinical trials at a high-volume referral center was conducted. Patients underwent primary tumor resection and lymphadenectomy, followed by either standard-of-care radiation therapy (60 Gy in 30 fractions) with or without cisplatin (40 mg/m² weekly) or de-escalated radiation therapy (30 Gy in 20 twice-daily fractions) with concomitant 15 mg/m² docetaxel once weekly. Imaging studies were independently reviewed by a blinded neuroradiologist classifying radiographic extranodal extension (rENE) and the number and maximal size of involved lymph nodes. Patients without pathologic data available for assessment were excluded.

Results

A total of 260 patients were included. Of these, 216 (83%) were cN1. Patients had a median of 2 radiographically positive lymph nodes (range, 0-12), and 107 (41%) had rENE. For cN1 patients, stratifying by radiographically positive lymph nodes (1-2 vs 3-4 vs >4) was predictive of progression-free survival (PFS) (P = .017), with 2-year PFS rates of 96%, 88%, and 81%, respectively. More than 2 radiographically positive lymph nodes was identified as a significant threshold for PFS (P = .0055) and overall survival (P = .029). Radiographic ENE and lymph node size were not predictive of PFS among cN1 patients.

Conclusions

The number of radiographically positive lymph nodes is predictive of PFS and overall survival and could be used to meaningfully subcategorize cN1 patients with HPV(+)OPSCC. We recommend further validation of our proposal that cN1 patients with 1 to 2 radiologically positive lymph nodes be categorized as cN1a, patients with 3 to 4 radiologically positive lymph nodes categorized as cN1b, and patients with >4 radiographically positive lymph nodes categorized as cN1c.

Phase II Randomized Trial of Transoral Surgery and Low-Dose Intensity Modulated Radiation Therapy in Resectable p16+ Locally Advanced Oropharynx Cancer: An ECOG-ACRIN Cancer Research Group Trial (E3311)

PURPOSE

Definitive or postoperative chemoradiation (CRT) is curative for human papillomavirus-associated (HPV+) oropharynx cancer (OPC) but induces significant toxicity. As a deintensification strategy, we studied primary transoral surgery (TOS) and reduced postoperative radiation therapy (RT) in intermediate-risk HPV+ OPC.

METHODS

E3311 is a phase II randomized trial of reduced- or standard-dose postoperative RT for resected stage III-IVa (American Joint Committee on Cancer-seventh edition) HPV+ OPC, determined by pathologic parameters. Primary goals were feasibility of prospective multi-institutional study of TOS for HPV+ OPC, and oncologic efficacy (2-year progression-free survival) of TOS and adjuvant therapy in intermediate-risk patients after resection. TOS plus 50 Gy was considered promising if the lower limit of the exact 90% binomial confidence intervals exceeded 85%. Quality of life and swallowing were measured by functional assessment of cancer therapy-head and neck and MD Anderson Dysphagia Index.

RESULTS

Credentialed surgeons performed TOS for 495 patients. Eligible and treated patients were assigned as follows: arm A (low risk, n = 38) enrolled 11%, intermediate risk arms B (50 Gy, n = 100) or C (60 Gy, n = 108) randomly allocated 58%, and arm D (high risk, n = 113) enrolled 31%. With a median 35.2-month follow-up for 359 evaluable (eligible and treated) patients, 2-year progression-free survival Kaplan-Meier estimate is 96.9% (90% CI, 91.9 to 100) for arm A (observation), 94.9% (90% CI, 91.3 to 98.6]) for arm B (50 Gy), 96.0% (90% CI, 92.8 to 99.3) for arm C (60 Gy), and 90.7% (90% CI, 86.2 to 95.4) for arm D (66 Gy plus weekly cisplatin). Treatment arm distribution and oncologic outcome for ineligible or step 2 untreated patients (n = 136) mirrored the 359 evaluable patients. Exploratory comparison of functional assessment of cancer therapy-head and neck total scores between arms B and C is presented.

CONCLUSION

Primary TOS and reduced postoperative RT result in outstanding oncologic outcome and favorable functional outcomes in intermediate-risk HPV+ OPC.

The role of total parotidectomy in high-grade parotid malignancy: A multisurgeon retrospective review

PURPOSE

Determine rates of intra-parotid and neck nodal metastasis, identify risk factors for recurrence, and report outcomes in patients with primary high-grade parotid malignancy who undergo total parotidectomy and neck dissection.

MATERIALS & METHODS

Retrospective review of patients undergoing total parotidectomy and neck dissection for high-grade parotid malignancy between 2005 and 2015. The presence and number of parotid lymph nodes, superficial and deep, as well as cervical lymph nodes involved with metastatic disease were assessed. Risk factors associated with metastatic spread to the parotid deep lobe were identified and recurrence rates reported.

RESULTS

75 patients with median follow-up time of 47 months. 35 patients (46.7%) had parotid lymph node metastasis. Seven patients (9.3%) had deep lobe nodal metastasis without metastasis to the superficial lobe nodes. Nine patients (12%) had positive intra-parotid nodes without positive cervical nodes. Cervical nodal disease was identified in 49.3% patients (37/75). Local, parotid-bed recurrence rate was 5.3% (4/75). Regional lymph node recurrence rate was also 5.3% (4/75). Rate of distant metastasis was 30.6% (23/75). The overall disease free survival rate for all patients at 2 and 5 years were 71% and 60% respectively.

CONCLUSION

Parotid lymph node metastasis occurred at a similar rate to cervical lymph node metastasis (46.7% and 49.3%, respectively). Deep lobe parotid nodal metastasis occurred in nearly a quarter of patients and can occur without superficial parotid nodal metastasis. Rate of recurrence in the parotid bed, which may represent local or regional recurrence, was similar to regional cervical lymph node recurrence. Total parotidectomy and neck dissection should be considered high-grade parotid malignancy regardless of clinical nodal status.

Transcriptomic and Immunophenotypic Characterization of Tumor Immune Microenvironment in Squamous Cell Carcinoma of the Oral Tongue

The tumor immune microenvironment of oral tongue squamous cell carcinoma may be accountable for differences in clinical behavior, particularly between different age groups. We performed RNA expression profiling and evaluated tumor infiltrating lymphocytes (TILs) and their T-cell subsets in order to assess the functional status of oral tongue squamous cell carcinoma tumor microenvironment and detect potentially clinically useful associations. Archival surgical pathology material from sixteen oral tongue squamous cell carcinoma patients was microscopically evaluated for TIL densities. RNA was extracted from macrodissected whole tumor sections and normal controls and RNA expression profiling was performed by the NanoString PanCancer IO 360 Gene Expression Panel. Immunostains for CD4, CD8 and FOXP3 were evaluated manually and by digital image analysis. Oral tongue squamous cell carcinomas had increased TIL densities, numerically dominated by CD4 + T cells, followed by CD8 + and FOXP3 + T cells. RNA expression profiling of tumors versus normal controls showed tumor signature upregulation in inhibitory immune signaling (CTLA4, TIGIT and PD-L2), followed by inhibitory tumor mechanisms (IDO1, TGF-β, B7-H3 and PD-L1). Patients older than 44 years showed a tumor microenvironment with increased Tregs and CTLA4 expression. Immunohistochemically assessed CD8% correlated well with molecular signatures related to CD8 + cytotoxic T-cell functions. FOXP3% correlated significantly with CTLA4 upregulation. CTLA4 molecular signature could be predicted by FOXP3% assessed by immunohistochemistry (R2 = 0.619, p = 0.026). Oral tongue squamous cell carcinoma hosts a complex inhibitory immune microenvironment, partially reflected in immunohistochemically quantified CD8 + and FOXP3 + T-cell subsets. Immunohistochemistry can be a useful screening tool for detecting tumors with upregulated expression of the targetable molecule CTLA4.

The impact of tumor infiltrating lymphocytes (TILs) on disease progression in human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma

6049

Background: In the head and neck, human papillomavirus-related oropharyngeal squamous cell carcinoma (HPV(+)OPSCC) has a better prognosis and more tumor infiltrating lymphocytes (TILs) compared to its HPV(-) counterpart. Within HPV(+)OPSCC, the prognostic value of TILs in the primary tumor and in metastatic lymph nodes is not well understood. Methods: This is a matched case-control study at a tertiary care center of HPV(+)OPSCC patients who underwent primary surgery between 05/2007–12/2016. Cases developed locoregional recurrence or distant metastases during follow-up, while controls did not during a similar duration of follow-up. Pairs were matched on age, American Joint Committee on Cancer (AJCC) 8th edition pathologic stage, sex, year of surgery, degree of adjuvant treatment, comorbidities, and smoking status. One representative H&E slide of the primary tumor and lymph node (when nodal disease was present) from each patient was independently reviewed by two pathologists (JG, MR) blinded to outcome, for tumor TILs (tTILs) density (defined as % TILs), presence/absence of desmoplastic stroma, and when stroma was present, for stromal TILs (sTILs) density (defined as relative crowding of TILs). The Brandwein-Gensler pattern of invasion (POI) score was used to grade the primary tumor. Interrater agreement was assessed using Cohen’s kappa. Associations between TILs and time to disease progression were assessed using Cox proportional hazards regression models. Results: 41 case-control pairs (N=82) were included in the study: 38 (46%) were AJCC pStage I, 37 (45%) were pStage II, and 7 (9%) were pStage III; 22 (27%) underwent surgery alone, 15 (18%) underwent surgery with adjuvant radiotherapy, and 45 (55%) underwent surgery with adjuvant chemoradiation. Interrater agreement was fair for tTILs density in the primary tumor ( k=0.24) and lymph node ( k=0.23), moderate for desmoplastic stroma in the primary tumor ( k=0.58) and lymph node ( k=0.64), moderate for sTILs density in the primary tumor ( k=0.58) and lymph node ( k=0.48), and fair for the POI score ( k=0.17). tTILs density ≥10% (HR 0.35, 95% CI 0.14-0.90, p=0.028) and a moderate/dense sTILs density (HR 0.15, 95% CI 0.04-0.68, p=0.014) in the primary tumor were significantly associated with decreased risk of disease progression. An aggressive POI score of III or IV was significantly associated with increased risk of disease progression (HR 4.00, 95% CI 1.34-11.96, p=0.013). None of the study measures in the lymph node were significantly associated with disease progression. Conclusions: In HPV(+)OPSCC, a higher density of tumor and stromal TILs and nonaggressive POI in the primary tumor specimen may indicate a lower risk of disease progression. TILs may serve as a powerful prognostic marker for the adaptive immune response to this disease.

EGFR blockade leads to singular oncogene-addiction in ETV6-NTRK3 transformed human epithelial cells and hypersensitization to entrectinib

e18055

Background: Entrectinib, a TRK kinase inhibitor, has been approved for the treatment of tissue agnostic rare tumors positive for TRK fusions. A very low frequency molecular subset of TRK fusion tumors dubbed as secretory carcinoma (SC) are characterized by organ-agnostic epithelial origin, ETV6-NTRK3 (EN) fusion and distinguishable secretory-type tumor cells. These tumors have been frequently miscategorized as acinic cell carcinoma or adenocarcinoma. A previous mouse study identified EGF dependent epithelial progenitors as putative cell-of-origin for SC. Methods: To test the role of EGFR signaling in EN mediated transformation and therapy resistance, we expressed EN, kinase-dead EN-K380M, and drug-resistant EN-G623R in human epithelial MCF10A cells with EGF-dependent primitive function and investigated their ability to grow in the presence and absence of EGF and/or entrectinib. To understand the significance of findings based on our model, we analyzed a total of 22 ‘rare’ patients from Mayo Clinic Tissue Registry and analyzed TCGA PanCan datasets. Results: We report herein that EGF signaling is essential for normal growth but dispensable during EN driven transformation. Our findings suggest that levels equivalent to circulating EGF (0.5-1ng/ml) is sufficient to drive 100% resistance to entrectinib in vitro. Three different strategies to blockade EGF/EGFR axis including depletion of EGF in culture system, genetic depletion of EGFR using shRNA as well as cetuximab antibody-based EGFR neutralization potentiated oncogene-addiction and hypersensitivity to entrectinib in our models. As predicted, models with G623R mutation in EN was refractory to entrectinib under all experimental conditions. Further omics analysis of TCGA PanCan suggested that EN and EGFR mutations are mutually exclusive and entrectinib-resistant G623R mutation were uncommon. Interestingly, nearly all EN tumors from Mayo Clinic Tissue Registry immunostained weakly or strongly for EGFR and showed perfect concordance with pEGFR suggesting pathway activation. Conclusions: Together, these findings raise an important question whether blockade of ‘wildtype’ EGFR signaling could improve medical intervention in SC patients presenting with wildtype EGFR and no drug-resistant mutation in entrectinib, by improving oncogene-addiction and attendant hypersensitization of transformed cells to entrectinib.

Updated report of a phase II randomized trial of transoral surgical resection followed by low-dose or standard postoperative therapy in resectable p16+ locally advanced oropharynx cancer: A trial of the ECOG-ACRIN cancer research group (E3311)

6010

Background: Definitive or postoperative chemoradiation (CRT) is highly curative for human papillomavirus-associated (HPV+) oropharynx cancer (OPC) but induces significant toxicity. As a potential deintensification strategy, we studied primary transoral surgery (TOS) and, in intermediate pathologic risk patients, reduced dose postoperative RT (PORT). Methods: E3311 is a phase II trial with randomization to reduced- or standard-dose PORT for resected stage III-IVa (AJCC7) intermediate pathologic risk HPV+ OPC, stratified by smoking history. Primary endpoints have been reported; we now present updated 3-year PFS and patient-reported outcomes (PRO), including head and neck-cancer specific quality of life (FACT-H&N) and swallowing perception and performance (MDADI). Results: Of 519 enrolled patients, 495 underwent TOS. The primary oncologic endpoint was 2-year PFS for 50 Gy (Arm B) or 60Gy (Arm C). Among 360 eligible and treated patients (ETP), Arm A (observation, N = 38) enrolled 11%, Arms B (N = 100) or C (N = 109) randomized 58%, and Arm D (66Gy + weekly cisplatin, N = 113) enrolled 31%. With 35.1 months median follow-up, 3-year PFS Kaplan-Meier estimate is 96.9% (90% CI [91.9%, 100%]) for Arm A; 94.9% (90% CI [91.3%, 98.6%]) for Arm B; 93.5% (90% CI [89.4%, 97.9%]) for Arm C; and 90.7% (90% CI [86.2%, 95.4%]) for Arm D. Recurrences and death without recurrence were 4 and 1 in Arm B, and 5 and one in Arm C. Smokers ( > 10 pack-years) did not have worse 3-year PFS in Arms B or C. Treatment arm distribution and outcome for ineligible patients who started adjuvant therapy mirrored the 360 ETP. A comparison combining arms B/C versus arm D in the proportion of patients stable/improved in FACT-H&N total score, from baseline to 6 months post-treatment as a pre-specified endpoint, was 56% vs. 38% (p value = 0.011, one-sided Fisher’s exact test); however, underlying differences in treatment and risk may be confounding. An exploratory comparison between Arms B and C revealed improvement in FACT H&N (63% in Arm B vs. 49% in Arm C had a stable/improved score, p-value = 0.056). Conclusions: Primary TOS and reduced PORT retained outstanding oncologic outcome at 35 months follow up, with favorable QOL and functional outcomes, in intermediate risk HPV+ OPC. Clinical trial information: NCT 01898494.

Mucoepidermoid carcinoma of the parotid gland: Twenty-year experience in treatment and outcomes

BACKGROUND

Parotid gland mucoepidermoid carcinoma (MEC) has published five-year cancer-specific survival (CSS) rates of 77%-97%, with variance related to grade.

METHODS

Patients receiving primary surgery for parotid gland MEC from 1995 to 2014 at a tertiary medical center underwent clinical review, histopathologic review, and cytogenetic analysis. Survival outcomes were evaluated.

RESULTS

Among 58 patients, T/N/M classification was as follows: T1 in 35 patients, T2 in 14, T4a in 9, N0 in 53, N1 in 2, N2b in 3. Histologic grade was low in 27, intermediate in 17, and high in 12 patients with 98% MAML2 positivity. All patients underwent parotidectomy, and seven patients received adjuvant radiation therapy. CSS was 100% at 5 years and 94.1% at 10 and 15 years. Two patients experienced locoregional recurrence.

CONCLUSIONS

Treatment with adequate surgical resection and adjuvant radiation therapy for high-grade or advanced-stage tumors yields excellent survival, independent of clinical stage or pathologic grade.

Precision Radiotherapy: Reduction in Radiation for Oropharyngeal Cancer in the 30 ROC Trial

BACKGROUND

Patients with human papillomavirus-related oropharyngeal cancers have excellent outcomes but experience clinically significant toxicities when treated with standard chemoradiotherapy (70 Gy). We hypothesized that functional imaging could identify patients who could be safely deescalated to 30 Gy of radiotherapy.

METHODS

In 19 patients, pre- and intratreatment dynamic fluorine-18-labeled fluoromisonidazole positron emission tomography (PET) was used to assess tumor hypoxia. Patients without hypoxia at baseline or intratreatment received 30 Gy; patients with persistent hypoxia received 70 Gy. Neck dissection was performed at 4 months in deescalated patients to assess pathologic response. Magnetic resonance imaging (weekly), circulating plasma cell-free DNA, RNA-sequencing, and whole-genome sequencing (WGS) were performed to identify potential molecular determinants of response. Samples from an independent prospective study were obtained to reproduce molecular findings. All statistical tests were 2-sided.

RESULTS

Fifteen of 19 patients had no hypoxia on baseline PET or resolution on intratreatment PET and were deescalated to 30 Gy. Of these 15 patients, 11 had a pathologic complete response. Two-year locoregional control and overall survival were 94.4% (95% confidence interval = 84.4% to 100%) and 94.7% (95% confidence interval = 85.2% to 100%), respectively. No acute grade 3 radiation-related toxicities were observed. Microenvironmental features on serial imaging correlated better with pathologic response than tumor burden metrics or circulating plasma cell-free DNA. A WGS-based DNA repair defect was associated with response (P = .02) and was reproduced in an independent cohort (P = .03).

CONCLUSIONS

Deescalation of radiotherapy to 30 Gy on the basis of intratreatment hypoxia imaging was feasible, safe, and associated with minimal toxicity. A DNA repair defect identified by WGS was predictive of response. Intratherapy personalization of chemoradiotherapy may facilitate marked deescalation of radiotherapy.

Costs of Definitive Chemoradiation, Surgery, and Adjuvant Radiation Versus De-Escalated Adjuvant Radiation per MC1273 in HPV+ Cancer of the Oropharynx

PURPOSE

De-escalated treatment for human papillomavirus (HPV)+ oropharynx squamous cell carcinoma (OPSCC) has shown promising initial results. Health-care policy is increasingly focusing on high-value care. This analysis compares the cost of care for HPV+ OPSCC treated with definitive chemoradiation (CRT), surgery and adjuvant radiation (RT), and surgery and de-escalated CRT on MC1273.

METHODS AND MATERIALS

MC1273 is a prospective, phase 2 study evaluating adjuvant CRT to 30 to 36 Gy plus docetaxel for HPV+ OPSCC after surgery for high-risk patients. Matched standard-of-care control groups were retrospectively identified for patients treated with definitive CRT or adjuvant RT. Standardized costs were evaluated before radiation, during treatment (during RT), and at short-term (6 month) and long-term (7-24 month) follow-up periods.

RESULTS

A total of 56 definitive CRT, 101 adjuvant RT, and 66 MC1273 patients were included. The CRT arm had more T3-4 disease (63% vs 17-21%) and higher N2c-N3 disease (52% vs 20-24%) vs both other groups. The total treatment costs in the CRT, adjuvant RT, and MC1273 groups were $47,763 (standard deviation [SD], $19,060], $57,845 (SD, $17,480), and $46,007 (SD, $9019), respectively, and the chemotherapy and/or RT costs were $39,936 (SD, $18,480), $26,603 (SD, $12,542), and $17,864 (SD, $3288), respectively. The per-patient, per-month, average short-term follow-up costs were $3860 (SD, $10,525), $1072 (SD, $996), and $972 (SD, $833), respectively, and the long-term costs were $978 (SD, $2294), $485 (SD, $1156), and $653 (SD, $1107), respectively. After adjustment for age, T-stage, and N-stage, treatment costs remained lower for CRT and MC1273 versus adjuvant RT ($45,450 and $47,114 vs $58,590, respectively; P < .001), whereas the total per-patient, per-month follow-up costs were lower in the MC1273 study group and adjuvant RT versus CRT ($853 and $866 vs $2030, respectively; P = .03).

CONCLUSIONS

MC1273 resulted in 10% and 20% reductions in global costs compared with standard-of-care adjuvant RT and definitive CRT treatments. Substantial cost savings may be an added benefit to the already noted low toxicity and maintained quality of life of treatment per MC1273.

Increased ERBB2 Gene Copy Numbers Reveal a Subset of Salivary Duct Carcinomas with High Densities of Tumor Infiltrating Lymphocytes and PD-L1 Expression

Salivary duct carcinoma (SDC) commonly expresses androgen receptor (AR) and HER2, giving rise to treatment implications. SDC may also express programmed-death-ligand-1 (PD-L1), a predictive marker of response to checkpoint inhibitors. PD-L1 can be associated with genomic instability and high density of tumor infiltrating lymphocytes (TILs). Evaluation of HER2 immunohistochemistry (IHC) in SDC is not standardized, and relationships between ERBB2 copy numbers, PD-L1 expression and TILs in SDC are unknown. We evaluated 32 SDCs for HER2, AR and PD-L1 expression (IHC), ERBB2 status (FISH) and TILs (slide review). HER2 was scored with three different systems (breast, gastric, proposed salivary gland). PD-L1 was evaluated with the combined positive score. Most patients were older men, presenting at advanced clinical stage with nodal or distant metastases. During follow-up (mean 5 years, range 6 months to 21 years), 25 of the 32 patients (78%) died of SDC. We propose a HER2 IHC scoring system which accurately predicts underlying ERBB2 amplification or increased copy numbers in SDC. Most tumors had increased ERBB2 copy numbers (19/32 amplification, 6/32 aneusomy), a finding associated with higher TIL densities (p = 0.045) and PD-L1 expression (p = 0.025). Patients with TILs ≥ 40% had better prognoses (Log-Rank p = 0.013), with TILs being favorable prognosticators in univariate analysis (Hazard ratio: 0.18, p = 0.024). A subset of SDCs with increased ERBB2 copy numbers have higher TILs and PD-L1 expression. TILs ≥ 40% are associated with better prognosis.

Human papillomavirus oropharynx carcinoma: Aggressive de-escalation of adjuvant therapy

BACKGROUND

Aggressive dose de-escalated adjuvant radiation therapy (RT) in patients with human papillomavirus-associated oropharyngeal squamous cell carcinoma (HPV(+)OPSCC).

METHODS

Patients with HPV(+)OPSCC on a phase II clinical trial of primary surgery and neck dissection followed by dose de-escalated RT (N = 79) were compared with a cohort of patients who received standard adjuvant therapy (N = 115). Local recurrence-free, regional recurrence-free, distant metastases-free survival, and progression-free survival (PFS) were assessed.

RESULTS

Of 194 patients, 23 experienced progression at a median of 1.1 years following surgery (interquartile range [IQR] 0.7-2.0; range 0.3-5.4); 10 patients in the de-escalated cohort and 13 patients in the standard cohort. The 3-year PFS rate for the de-escalated cohort was 87%, and in the standard cohort was 90% (hazard ratio [HR] 1.18, 95% confidence interval (CI) [0.50-2.75]).

CONCLUSION

Patients with HPV(+)OPSCC who undergo surgical resection and neck dissection and meet criteria for adjuvant therapy can undergo aggressive dose de-escalation of RT without increasing risk of progression locally, regionally or at distant sites.

T cell fraction impacts oncologic outcomes in human papillomavirus associated oropharyngeal squamous cell carcinoma

BACKGROUND

We investigated T cell clonality (TCC) and T cell fraction (TCF) in human papilloma virus associated oropharyngeal squamous cell carcinoma (HPV(+)OPSCC) progressors [cases] vs. non-progressors [controls].

METHODS

This nested case-control study included patients undergoing intent-to-cure surgery ± adjuvant therapy from 6/1/2007-10/3/2016. Patients experiencing local/regional/distant disease (progressors), and a consecutive sample of non-progressors were matched (2 controls: 1 case) on tumor subsite, T-stage and number of metastatic lymph nodes. We performed imunosequencing of the CDR3 regions of human TCRβ chains.

RESULTS

34 progressors and 65 non-progressors were included. There was no statistically significant difference in baseline TCF (range: 0.039-1.084) and TCC (range: 0.007-0.240) (p > 0.05). Female sex was associated with higher TCF (p = 0.03), while extranodal extension (ENE) was associated with lower TCF (p = 0.01). There was a positive correlation between tumor size and clonality (R = 0.34, p < 0.01). The strongest predictor of progression-free survival (PFS) was TCF (HR 0.80, 95%CI 0.66-0.96, p = 0.02). The strongest predictors of cancer specific survival (CSS) were TCF (HR0.69, 95%CI 0.47-1.00, p < 0.05) and Adult Comorbidity Evaluation-27 (ACE-27) score (p < 0.05). Similarly, the strongest predictors of overall survival (OS) were TCF (HR 0.62, 95%CI 0.43-0.91, p = 0.01) and ACE-27 score (p = 0.03). On multivariable modeling, TCF ≥ 0.4 was independently associated with PFS (HR 0.34, 95%CI 0.14-0.85, p = 0.02) while an ACE-27 score of ≥ 2 independently predicted CSS (HR 3.85, 95%CI 1.07-13.85, p = 0.04) and OS (HR 3.51, 95%CI 1.10-11.20, p = 0.03).

CONCLUSIONS

In patients with HPV(+)OPSCC, TCF was higher in female patients and those without ENE, suggesting differential immune responses. Lower TCF was significantly and independently associated with disease progression. Better ACE-27 scores appear to predict improved oncologic control.

A novel surgeon credentialing and quality assurance process using transoral surgery for oropharyngeal cancer in ECOG-ACRIN Cancer Research Group Trial E3311

PURPOSE

Understanding the role of transoral surgery in oropharyngeal cancer (OPC) requires prospective, randomized multi-institutional data. Meticulous evaluation of surgeon expertise and surgical quality assurance (QA) will be critical to the validity of such trials. We describe a novel surgeon credentialing and QA process developed to support the ECOG-ACRIN Cancer Research Group E3311 (E3311) and report outcomes related to QA.

PATIENTS AND METHODS

E3311 was a phase II randomized clinical trial of transoral surgery followed by low- or standard-dose, risk-adjusted post-operative therapy with stage III-IVa (AJCC 7th edition) HPV-associated OPC. In order to be credentialed to accrue to this trial, surgeons were required to demonstrate active hospital credentials and technique-specific surgical expertise with ≥20 cases of transoral resection for OPC. In addition, 10 paired operative and surgical pathology reports from the preceding 24 months were reviewed by an expert panel. Ongoing QA required <10% rate of positive margins, low oropharyngeal bleeding rates, and accrual of at least one patient per 12 months. Otherwise surgeons were placed on hold and not permitted to accrue until re-credentialed using a new series of transoral resections.

RESULTS

120 surgeons trained in transoral minimally invasive surgery applied for credentialing for E3311 and after peer-review, 87 (73%) were approved from 59 centers. During QA on E3311, positive final pathologic margins were reported in 19 (3.8%) patients. Grade III/IV and grade V oropharyngeal bleeding was reported in 29 (5.9%) and 1 (0.2%) of patients.

CONCLUSIONS

We provide proof of concept that a comprehensive credentialing process can support multicenter transoral head and neck surgical oncology trials, with low incidence of positive margins and *grade III/V oropharyngeal bleeding.

Clinicopathologic predictors of survival in buccal squamous cell carcinoma

BACKGROUND

Buccal squamous cell carcinoma (SCC) is a locoregionally aggressive malignancy, representing a small subset of oral cancers in North America. We investigated the prognostic value of several clinicopathologic factors in a cohort of patients diagnosed with buccal SCC.

METHODS

Between years 1992 and 2017, 52 patients were diagnosed with conventional buccal SCC. Archival surgical pathology material was retrospectively reviewed for reportable findings according to the latest reporting guidelines published by the College of American Pathologists. Clinical data were obtained through chart review.

RESULTS

The majority of patients were of older age, current or past smokers, and without specific gender predilection. Most presented at a clinically advanced stage and were treated with surgery alone, or surgery followed by adjuvant radiotherapy. The tumor recurred in about 40% of patients, and almost half of the patients died from the disease by the end of the follow-up period. The worst pattern of invasion (WPOI) was associated with greater depth of invasion (DOI) (P = .031) and perineural invasion (P < .001). In univariate analyses, older age (P = .004), positive nodal status (P = .047), lymphovascular invasion (P = .012), perineural invasion (P = .05), and WPOI-5 (P = .015) were adverse predictors of 5-year overall survival (OS). In multivariate analysis, older age (P = .011), WPOI-5 (P < .001), and perineural invasion (P = .001) remained statistically significant independent prognosticators of worse 5-year OS.

CONCLUSIONS

Older age, WPOI-5, and perineural invasion are significant prognosticators of worse OS. WPOI is associated with DOI, a finding which may have important implications for the pathogenesis and biologic behavior of the disease.

Transoral robotic surgical resection followed by randomization to low- or standard-dose IMRT in resectable p16+ locally advanced oropharynx cancer: A trial of the ECOG-ACRIN Cancer Research Group (E3311)

6500

Background: ECOG-ACRIN 3311 examines reduced postoperative therapy in patients with “intermediate risk” p16+ oropharynx cancer (OPC) undergoing primary transoral surgical management. We report the primary endpoint of 2-year progression free survival (PFS) for patients randomized to 50Gy vs 60Gy without chemotherapy. Methods: Between December 2013 and July 2017, 82 credentialed surgeons performed transoral resection (TOS) for 519 OPC patients (cT1-2 stage III/IV AJCC7 without matted neck nodes); post-operative management was determined by pathologically assessed risk. Among 353 eligible and treated patients, Arm A enrolled 10% (N=37) for clear margins, 0-1 nodes, no extranodal extension (ENE)), Arms B (50Gy, N=102) or C (60Gy, N=104) randomized 58%, for clear/close margins, 2-4 + nodes, or ENE ≤1mm, while Arm D (N=110, 60-66Gy plus weekly cisplatin, 40 mg/m2, positive margin with any T stage, >4 + nodes, or >1mm ENE) enrolled 31%. Arm D assignment was based on >1mm ENE (76%), > 4 nodes (27%), and/or positive margins (11%). Intermediate-risk patients were stratified by smoking history (>10 pk-yr). Of the 80 pts (15%) deemed ineligible, 28 had scans/labs not done per protocol, however treatment arm distribution for all patients mirrored that for the 353 pts eligible and treated. Results: Median follow-up was 31.8 months. 2 yr PFS for Arms A, B and C were 93.9% (90% CI=87.3%, 100%), 95.0% (90% CI=91.4%, 98.6%) and 95.9% (90% CI=92.6%, 99.3%) respectively, while Arm D was 90.5% (90% CI=85.9%, 95.3%). The regimen of TOS + low-dose radiation is considered worthy of further study, since the primary endpoint of the upper bound of the 90% CI (in the intermediate risk group) exceeding 85% was met. Of 17 progression events, 7 were locoregional. There were 10 distant recurrences: Arm A=1, Arm B=2, Arm C=4, Arm D=3. Grade III/IV treatment-related AE rates were 15%/2% during surgery, 13%/2% for Arm B and 25%/0% for Arm C. There were 2 treatment-related deaths (one surgical and one Arm D). Conclusions: Transoral resection of p16+ OPC is safe and results in good oncologic outcome, presenting a promising deintensification approach. For patients with low-risk disease, 2-yr PFS is favorable without post-operative therapy. For those with uninvolved surgical margins, <5 involved nodes, and minimal (<1mm) ENE, reduced dose postoperative RT without chemotherapy appears sufficient. Transoral surgery plus 50Gy should be compared to optimal non-surgical therapy in a phase III trial. Clinical trial information: NCT01898494 .

HISTOLOGIC FINDINGS IN VITREORETINAL LYMPHOMA: Learning From Enucleation Specimens

PURPOSE

We aimed to describe the clinical and histologic findings in a few enucleation cases with intraocular lymphoma.

METHODS

Retrospective review of pathology files from a 22-year period identified cases with intraocular lymphoma among all enucleation specimens. Patient demographics, clinical findings, laboratory results, radiographic studies, and indication for enucleation were abstracted from electronic health records; slides were reviewed.

RESULTS

Four patients (three women and one man; age range, sixth through eighth decades of life) underwent enucleation with a final diagnosis of intraocular lymphoma. Two patients with primary vitreoretinal large B-cell lymphomas had been treated for refractory uveitis. Specimens showed retinal and subretinal infiltrates by atypical large B-lymphocytes and rare neoplastic cells in the vitreous. The remaining two patients had systemic lymphoproliferative disorders. One patient had chronic lymphocytic leukemia and floaters in his eye; vitreoretinal lymphoma developed, consistent with intraocular Richter transformation. The other had diffuse large B-cell lymphoma in remission; however, blurred vision developed, she was treated for panuveitis without improvement, and was later found to have ocular involvement by diffuse large B-cell lymphoma.

CONCLUSION

Our series details the unusual circumstances when an eye is removed for intraocular lymphoma. Different patterns of ocular tissue involvement were observed when we compared primary and secondary lymphomas.

Transoral Surgery Alone for Human-Papillomavirus–Associated Oropharyngeal Squamous Cell Carcinoma

The aim of this retrospective study was to describe the oncologic and functional results of treating oropharyngeal squamous cell carcinoma with transoral robotic surgery and neck dissection as monotherapy. A review was performed, including all patients who underwent transoral robotic surgery and neck dissection as the only means of therapy for oropharyngeal carcinoma from March 2007 to July 2009 at a single tertiary care academic medical center. We reviewed all cases with ≥ 24-month follow-up. Functional outcomes included tracheostomy dependence and oral feeding ability. Oncologic outcomes were stratified by human papillomavirus (HPV) status and tobacco use and included local, regional, and distant disease control, as well as disease-specific and recurrence-free survival. Eighteen patients met study criteria. Ten patients (55.6%) were able to eat orally in the immediate postoperative period, and 8 (44.4%) required a temporary nasogastric tube for a mean duration of 13.6 days (range 3 to 24 days) before returning to an oral diet. No patient required placement of a gastrostomy tube, and all patients are tracheostomy-tube–free. Among the HPV-positive nonsmokers (12/18, 66.7%), Kaplan-Meier estimated 3-year local, regional, and distant control rates were 90.9%, 100%, and 100%, respectively. Kaplan-Meier estimated disease-specific survival and recurrence-free survival were 100% and 90.9%, respectively. No complications occurred.

First Line Androgen Deprivation Therapy vs. Chemotherapy for Patients With Androgen Receptor Positive Recurrent or Metastatic Salivary Gland Carcinoma-A Retrospective Study

Objectives: There is a lack of effective therapy for recurrent or metastatic salivary gland carcinoma. Androgen deprivation therapy has demonstrated efficacy in cases of salivary duct carcinoma (SDC) and high-grade adenocarcinoma not otherwise specified (NOS) that express androgen receptor.

Materials and Methods: We conducted a single institution retrospective cohort study examining patients treated for recurrent/metastatic SDC or high-grade adenocarcinoma NOS of the salivary gland. Survival analyses were performed to assess for efficacy of first-line androgen deprivation therapy (ADT) vs. first-line conventional cytotoxic chemotherapy. Efficacy of salvage ADT was also assessed.

Results: Fifty-eight patients were reviewed. Thirty-five patients had recurrent/metastatic disease of which 28 had SDC (80%) and 7 had high-grade adenocarcinoma NOS (20%). Median overall survival for first-line ADT was 25 months compared to 25 months for first-line chemotherapy [RR 0.54 (0.23–1.28, p = 0.16)]. Patients treated with first-line ADT had a response rate of 45% (9/20) and patients treated with first-line chemotherapy had a response rate of 14% (2/14). Six patients received salvage ADT with 1 patient demonstrating complete response and 3 with stable disease as best response (clinical benefit rate 67%).

Conclusion: Overall survival for first line ADT and first line cytotoxic chemotherapy was comparable but response rates to first-line ADT were higher than those with first-line chemotherapy. Salvage ADT is active in recurrent/metastatic salivary gland carcinoma.

Phase II Evaluation of Aggressive Dose De-Escalation for Adjuvant Chemoradiotherapy in Human Papillomavirus-Associated Oropharynx Squamous Cell Carcinoma

PURPOSE

The purpose of this study was to determine if dose de-escalation from 60 to 66 Gy to 30 to 36 Gy of adjuvant radiotherapy (RT) for selected patients with human papillomavirus-associated oropharyngeal squamous cell carcinoma could maintain historical rates for disease control while reducing toxicity and preserving swallow function and quality of life (QOL).

PATIENTS AND METHODS

MC1273 was a single-arm phase II trial testing an aggressive course of RT de-escalation after surgery. Eligibility criteria included patients with p16-positive oropharyngeal squamous cell carcinoma, smoking history of 10 pack-years or less, and negative margins. Cohort A (intermediate risk) received 30 Gy delivered in 1.5-Gy fractions twice per day over 2 weeks along with 15 mg/m² docetaxel once per week. Cohort B included patients with extranodal extension who received the same treatment plus a simultaneous integrated boost to nodal levels with extranodal extension to 36 Gy in 1.8-Gy fractions twice per day. The primary end point was locoregional tumor control at 2 years. Secondary end points included 2-year progression-free survival, overall survival, toxicity, swallow function, and patient-reported QOL.

RESULTS

Accrual was from September 2013 to June 2016 (N = 80; cohort A, n = 37; cohort B, n = 43). Median follow-up was 36 months, with a minimum follow-up of 25 months. The 2-year locoregional tumor control rate was 96.2%, with progression-free survival of 91.1% and overall survival of 98.7%. Rates of grade 3 or worse toxicity at pre-RT and 1 and 2 years post-RT were 2.5%, 0%, and 0%. Swallowing function improved slightly between pre-RT and 12 months post-RT, with one patient requiring temporary feeding tube placement.

CONCLUSION

Aggressive RT de-escalation resulted in locoregional tumor control rates comparable to historical controls, low toxicity, and little decrement in swallowing function or QOL.

Quality assessment of systematic reviews on vertical bone regeneration

The aim of this study was to evaluate and compare the quality of systematic reviews of vertical bone regeneration techniques, using two quality-assessment tools (AMSTAR and ROBIS). An electronic literature search was conducted to identify systematic reviews or meta-analyses that would evaluate at least one of the following outcomes: implant survival, success rates, complications or bone gain after vertical ridge augmentation. Methodological quality assessment was performed by two independent evaluators. Results were compared between reviewers, and reliability measures were calculated using the Holsti's method^® and Cohen's kappa. Seventeen systematic reviews were included, of which seven presented meta-analysis. Mean ±95% confidence interval AMSTAR score was 6.35 [4.74;7.97], with higher scores being correlated with a smaller risk of bias (Pearson's correlation coefficient=-0.84; P<0.01). Cohen's inter-examiner kappa showed substantial agreement for both checklists. From the available evidence, we ascertained that, regardless of the technique used, it is possible to obtain vertical bone gains. Implant success in regenerated areas was similar to implants placed in pristine bone with results equating between 61.5% and 100% with guided bone regeneration being considered the most predictable technique regarding bone stability, while distraction osteogenesis achieved the biggest bone gains with the highest risk of possible complications.

Ewing sarcoma of the head and neck: The Mayo Clinic experience

BACKGROUND

Treatment options of Ewing sarcoma of the head and neck include surgery, radiotherapy (RT), and chemoradiotherapy. However, local control can be challenging.

METHODS

We conducted a retrospective review of all patients with head and neck Ewing sarcoma treated from 1972 to 2015 at a single tertiary care hospital.

RESULTS

Seventeen patients met criteria (median 21 years, range 5-58 years; 5 women). Mean follow-up was 10.4 years (range 2.2-39 years). Tumors occurred commonly in the cervical spine (5/17), the skull (3/17), and the paranasal sinuses (3/17). A total of 14 of 17 patients underwent surgical resection, 9 with gross total resection. After multimodality therapy, the 5-year overall survival (OS) and recurrence-free survival (RFS) was 87% and 75%, respectively.

CONCLUSION

Combined multimodal treatment resulted in a 5-year OS and RFS of 87% and 75%, respectively. Aggressive surgical resection with adjuvant chemoradiotherapy should be considered. Although negative margin surgery is the goal, subtotal resection may be acceptable in the setting of adjuvant treatment.

Transforming Laboratory Utilization Review into Laboratory Stewardship: Guidelines by the PLUGS National Committee for Laboratory Stewardship

Appropriate utilization of clinical laboratory services is important for patient care and requires institutional stewardship. Clinical laboratory stewardship programs are dedicated to improving the ordering, retrieval, and interpretation of appropriate laboratory tests. In addition, these programs focus on developing, maintaining, and improving systems to provide proper financial coverage for medically necessary testing. Overall, clinical laboratory stewardship programs help clinicians improve the quality of patient care while reducing costs to patients, hospitals, and health systems. This document, which was created by a new multiinstitutional committee interested in promoting and formalizing laboratory stewardship, summarizes core elements of successful hospital-based clinical laboratory stewardship programs. The core elements will also be helpful for independent commercial clinical laboratories.

Characteristics and outcomes of head and neck cancer in solid organ transplant recipients

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Background: The immune system plays a major role in anti-tumor surveillance in healthy individuals. Immunosuppression after solid organ transplant prevents graft rejection, but leads to increased incidence of various malignancies including head and neck squamous cell carcinoma (HNSCC). Outcomes of patients (pts) with post-transplant HNSCC are unknown. Methods: After Institutional Review Board approval, we retrospectively identified pts who developed HNSCC after solid organ transplant between 1995 and 2010. Adults with pathology-proven HNSCC and good follow up were included. Cutaneous cancers were excluded. Median overall survival (mOS) and progression free survival (mPFS) were analyzed using the Kaplan–Meier method. The prognostic effect of variables was studied with Cox proportional hazards models. Results: 33 pts met study inclusion criteria. The median time to HNSCC after transplant was 5.9 years. The primary site was the oral cavity in 15 pts, the oropharynx in 10, the larynx in 3, the hypopharynx in 2, the parotid in 2 and unknown in 1 pt. 58% of pts presented with locally advanced disease, 39% with localized disease and one pt with metastatic disease. 87% underwent upfront surgical resection. Of those, 66% received adjuvant therapy (38% radiation alone and 28% chemoradiation). 6% of pts had definitive chemoradiation. After a median follow up of 10.5 years, the 5-year OS rate was 45% and 37% for localized and locally advanced disease respectively. 75% of pts with oropharyngeal tumors were HPV-positive and they had better outcomes (5-year OS rate of 67%). The mPFS for the cohort was 22.8 months (95% CI; 11.6-50.1) with a median time to relapse of 15.2 months. The pattern of relapse was local in 69% of pts, distant in 25% and local plus distant in 6%. In a multivariate analysis, age > 60 years was a negative predictor of survival (HR 2.7; 95% CI, 1.1 to 6.5; P = 0.03). Conclusions: This retrospective study evaluated the clinical course and outcomes of pts with non-cutaneous HNSCC after solid organ transplant. Pts had inferior survival compared to historical controls. older pts had poor prognosis. The risk of local and distant recurrence was high. HPV-positive oropharyngeal tumors continue to have better outcomes in this population.

Human Adipose-Derived Mesenchymal Stem Cells for Osseous Rehabilitation of Induced Osteoradionecrosis: A Rodent Model

Objective Human adipose-derived mesenchymal stem cells (ADSCs) were used to rehabilitate bone damaged by osteoradionecrosis (ORN) in an established animal model. Study Design Prospective animal study. Setting Academic department laboratory. Subjects and Methods After institutional review board and Institutional Animal Care and Use Committee approval, 24 athymic nude rats were divided into 5 groups: 4 groups irradiated (20 Gy) by brachytherapy catheter placed at the left hemimandible and 1 mock irradiation control (n = 4). For all groups, ORN was initiated by extraction of the central molar 1 week later. After 28 days, animals (n = 5/group) received injection at the extraction site with saline (SAL), ADSCs, platelet-rich plasma and collagen (PRP/COL), or ADSCs + PRP/COL. Rats were sacrificed 28 days later and their mandibles harvested for histopathology analysis (osteoblasts, osteoclasts, and fibrosis) and bone volume measurement using 3-dimensional micro-computed tomography. Results All but 1 rat survived the experiment period (23/24). Radiographic and histological analysis revealed 60% bone loss in the SAL group compared with the nonirradiated control. Injection of ADSCs increased jaw region bone volume by up to 36% ( P < .01). All experimental groups (ADSC, PRP/COL, and ADSC + PRP/COL) showed dramatically decreased osteoclast counts ( P < .001) while injection of PRP/COL with or without ADSCs increased osteoblasts. Increased fibrosis was observed after ADSC injection ( P < .05). Conclusion The application of human ADSCs to an induced mandibular osteoradionecrosis model in athymic rats results in increased deposition or preservation of bone, demonstrated both histologically and radiographically. This offers an encouraging possible treatment option for translational research in this difficult disease.

[Cervical ischaemic neuronopathy and cardioembolism: another cause of man-in-the-barrel syndrome]

INTRODUCTION

Spinal infarction accounts for 1% of all strokes. Cardioembolism is a rare cause. Common areas of ischemic spinal damage are watershed in the dorsal or lumbar regions; however cervical spinal cord infarction has been reported previously.

CASE REPORT

We present a new case of a man-in-the-barrel syndrome produced by cardiac embolization associated with atrial fibrillation during an acute myocardial infarction, which caused cervical ischemic neuronopathy (infarction of the anterior horn).

CONCLUSIONS

Classic features of cervical spinal cord ischemia are acute tetraplegia, bladder, bowel and cardiovascular dysfunction and dissociate sensory loss. Incomplete collateralization and anatomical characteristics of the circulation of the anterior spinal artery in the cervical spinal cord, makes of the portion C3 to C5, the most vulnerable portion to ischemic damage, since the radicular arteries supply begins bellow C5 and the pathophysiology of a fast fresh clot lysis produced unique bilateral neuronal horn cells damage.

Abstract CT227: MC1273: Phase II evaluation of aggressive dose de-escalation for adjuvant chemoradiation in HPV associated oropharynx cancer

Background: Traditional adjuvant therapy for oropharyngeal squamous cell carcinoma (OPSCC) consists of 60-66 Gy of radiation therapy (XRT) given in 2 Gy daily fractions along with high dose cisplatin if the patient has high risk factors. Despite the excellent cure rates for HPV+ OPSCC, one in three patients treated with conventional treatment will develop grade &gt;3 long-term sequelae from therapy. There is intense interest in de-intensifying adjuvant therapy for this patient population in order to maximize quality of life while maintaining excellent historical rates of disease control.

Methods: MC1273 is a phase II non-randomized trial open at Mayo Clinic Rochester testing a novel course of aggressive therapy de-escalation following surgery for HPV+ OPSCC. The primary endpoint is local/regional control at 2 years while secondary endpoints include toxicity and quality of life (QOL). The eligibility criteria include all patients with p16-positive OPSCC with less than a ten pack-year smoking history who have had a complete surgical resection. Exclusion criteria include positive surgical margins, prior history of malignancy, and history of connective tissue disorders. Patients are divided into two prospective cohorts depending upon risk factors found at surgery. Patients with intermediate risk disease (≥T3, ≥N2, lymphovascular invasion, or perineural invasion) are enrolled in MC1273A while patients with extracapsular extension (ECE) are enrolled in MC1273B. Patients on MC1273A receive 30 Gy of radiation delivered in 1.5 Gy twice-daily fractions over the course of two weeks along with weekly docetaxel (15 mg/m2) given on day 1 and day 8. Patients on MC1273B receive a similar treatment regimen but also have the nodal level with positive ECE concurrently boosted to 36 Gy in 1.8 Gy twice-daily fractions. In addition to standard of care follow-up, patients receive a swallowing assessment with speech therapy immediately before XRT, one month post-XRT, and one year post-XRT. Patients also have QOL assessment consisting of the XeQOLS, Eq-5D, FACT H&N (Vers 4) and Dermatology Life Quality Index assessed at pre-XRT and 3, 12, and 24 months post-XRT.

Results: Each cohort of MC1273 is powered to detect a 10% local/regional failure rate with 85% confidence. Each cohort will accrue 35 evaluable patients and 5 additional patients to account for ineligibilities and violations (40 patients total per cohort.) MC1273A began accrual in September 2013. The first five patients were monitored for grade ≥4 acute toxicities before proceeding to open accrual. MC1273B began accrual in May 2014 and has also proceeded to open accrual. Accrual will also begin in Mayo Clinic Scottsdale in the first quarter of 2015.

Conclusions: MC1273 is meeting its accrual targets and should finish accrual by 2016. We anticipate that preliminary results for toxicity will be available by 2017 and local/regional data will be available by 2018.

Citation Format: Daniel J. Ma, Katharine A. Price, Eric J. Moore, Joaquin J. Garcia, Scott H. Okuno, Daniel L. Price, Jeff A. Sloan, Nathan R. Foster, Robert L. Foote. MC1273: Phase II evaluation of aggressive dose de-escalation for adjuvant chemoradiation in HPV associated oropharynx cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr CT227. doi:10.1158/1538-7445.AM2015-CT227

Targeted deep sequencing of mucinous ovarian tumors reveals multiple overlapping RAS-pathway activating mutations in borderline and cancerous neoplasms

BACKGROUND

Mucinous ovarian tumors represent a distinct histotype of epithelial ovarian cancer. The rarest (2-4 % of ovarian carcinomas) of the five major histotypes, their genomic landscape remains poorly described. We undertook hotspot sequencing of 50 genes commonly mutated in human cancer across 69 mucinous ovarian tumors. Our goals were to establish the overall frequency of cancer-hotspot mutations across a large cohort, especially those tumors previously thought to be "RAS-pathway alteration negative", using highly-sensitive next-generation sequencing as well as further explore a small number of cases with apparent heterogeneity in RAS-pathway activating alterations.

METHODS

Using the Ion Torrent PGM platform, we performed next generation sequencing analysis using the v2 Cancer Hotspot Panel. Regions of disparate ERBB2-amplification status were sequenced independently for two mucinous carcinoma (MC) cases, previously established as showing ERBB2 amplification/overexpression heterogeneity, to assess the hypothesis of subclonal populations containing either KRAS mutation or ERBB2 amplification independently or simultaneously.

RESULTS

We detected mutations in KRAS, TP53, CDKN2A, PIK3CA, PTEN, BRAF, FGFR2, STK11, CTNNB1, SRC, SMAD4, GNA11 and ERBB2. KRAS mutations remain the most frequently observed alteration among MC (64.9 %) and mucinous borderline tumors (MBOT) (92.3 %). TP53 mutation occurred more frequently in carcinomas than borderline tumors (56.8 % and 11.5 %, respectively), and combined IHC and mutation data suggest alterations occur in approximately 68 % of MC and as many as 20 % of MBOT. Proven and potential RAS-pathway activating changes were observed in all but one MC. Concurrent ERBB2 amplification and KRAS mutation were observed in a substantial number of cases (7/63 total), as was co-occurrence of KRAS and BRAF mutations (one case). Microdissection of ERBB2-amplified regions of tumors harboring KRAS mutation suggests these alterations are occurring in the same cell populations, while consistency of KRAS allelic frequency in both ERBB2 amplified and non-amplified regions suggests this mutation occurred in advance of the amplification event.

CONCLUSIONS

Overall, the prevalence of RAS-alteration and striking co-occurrence of pathway "double-hits" supports a critical role for tumor progression in this ovarian malignancy. Given the spectrum of RAS-activating mutations, it is clear that targeting this pathway may be a viable therapeutic option for patients with recurrent or advanced stage mucinous ovarian carcinoma, however caution should be exercised in selecting one or more personalized therapeutics given the frequency of non-redundant RAS-activating alterations.