MRI, clinical, and radiomic models for differentiation of uterine leiomyosarcoma and leiomyoma

PURPOSE

To assess the predictive ability of conventional MRI features and MRI texture features in differentiating uterine leiomyoma (LM) from uterine leiomyosarcoma (LMS).

METHODS

This single-center, IRB-approved, HIPAA-compliant retrospective study included 108 patients (69 LM, 39 LMS) who had pathology, preoperative MRI, and clinical data available at our tertiary academic institution. Two radiologists independently evaluated 14 features on preoperative MRI. Texture features based on 3D segmentation were extracted from T2W-weighted MRI (T2WI) using commercially available texture software (TexRAD™, Feedback Medical Ltd., Great Britain). MRI conventional features, and clinical and MRI texture features were compared between LM and LMS groups. Dataset was randomly divided into training (86 cases) and testing (22 cases) cohorts (8:2 ratio); training cohort was further subdivided into training and validation sets using ten-fold cross-validation. Optimal radiomics model was selected out of 90 different machine learning pipelines and five models containing different combinations of MRI, clinical, and radiomics variables.

RESULTS

12/14 MRI conventional features and 2/2 clinical features were significantly different between LM and LMS groups. MRI conventional features had moderate to excellent inter-reader agreement for all but two features. Models combining MRI conventional and clinical features (AUC 0.956) and MRI conventional, clinical, and radiomics features (AUC 0.989) had better performance compared to models containing MRI conventional features alone (AUC 0.846 and 0.890) or radiomics features alone (0.929).

CONCLUSION

While multiple MRI and clinical features differed between LM and LMS groups, the model combining MRI, clinical, and radiomic features had the best predictive ability but was only marginally better than a model utilizing conventional MRI and clinical data alone.

Performance of VI-RADS in predicting muscle-invasive bladder cancer after transurethral resection: a single center retrospective analysis

PURPOSE

To assess VIRADS performance and inter-reader agreement for detecting muscle-invasive bladder cancer (MIBC) following transurethral resection of bladder tumor (TURBT).

METHODS

An IRB-approved, HIPAA-compliant, retrospective study from 2016 to 2020 included patients with bladder urothelial carcinoma who underwent MRI after TURBT, and cystectomy within 3 months without post-MRI treatments. Three radiologists blinded to pathology results independently reviewed MR images and assigned a VI-RADS score. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of VI-RADS were assessed for diagnosing MIBC using VI-RADS scores ≥ 3 and ≥ 4. Inter-reader agreement was assessed using Gwet's agreement coefficient (AC) and percent agreement.

RESULTS

The cohort consisted of 70 patients (mean age, 68 years ± 11 [SD]; range 39-85; 58 men) and included 32/70 (46%) with MIBC at cystectomy. ROC analysis revealed an AUC ranging from 0.67 to 0.77 and no pairwise statistical difference between readers (p-values, 0.06, 0.08, 0.97). Percent sensitivity, specificity, PPV, NPV and accuracy for diagnosing MIBC for the three readers ranged from 81.3-93.8, 36.8-55.3, 55.6-60.5, 77.3-87.5, and 62.9-67.1 respectively for VI-RADS score ≥ 3, and 78.1-81.3, 47.4-68.4, 55.6-67.6, 72.0-78.8 and 61.4-72.9 respectively for VI-RADS score ≥ 4. Gwet's AC was 0.63 [95% confidence interval (CI): 0.49,0.78] for VI-RADS score ≥ 3 with 79% agreement [95% CI 72,87] and 0.54 [95%CI 0.38,0.70] for VI-RADS score ≥ 4 with 76% agreement [95% CI 69,84]. VIRADS performance was not statistically different among 31/70 (44%) patients who received treatments prior to MRI (p ≥ 0.16).

CONCLUSION

VI-RADS had moderate sensitivity and accuracy but low specificity for detection of MIBC following TURBT, with moderate inter-reader agreement.

Development, Implementation, and Assessment of a Quality, Research, Education, and Wellness (QREW) Professional Development Lecture Series for Radiology Faculty

RATIONALE AND OBJECTIVES

Professional development is important to academic radiologists. We developed, implemented, and assessed an internal professional development lecture series focusing on the non-interpretative themes of Quality, Research, Education, and Wellness (QREW).

MATERIALS AND METHODS

The faculty of a 29-member abdominal radiology division at an academic hospital were invited to deliver 1-hour virtual lectures on noninterpretative topics to division colleagues. Topics were curated by division leadership based on the perceived needs of faculty. Anonymous feedback was collected from attendees for quality improvement purposes and analyzed using descriptive statistics and Fisher's exact test.

RESULTS

Over 17 months, 13 QREW lectures were delivered. In total, 91 feedback forms were completed by faculty (mean 7 forms, range 2-12 per session). Of these, 57 responses (63%) were by those <7 years post training ("junior faculty"), 34 responses (37%) by those ≥ 7 years from training ("senior faculty"). Most respondents reported low levels of prior instruction (80/90, 89%) and personal knowledge (49/91, 54%) on topics. Compared to senior faculty, a greater proportion of junior faculty reported less prior instruction (73% vs 98%, P < 0.001) and less personal knowledge (32% vs 65%, P < 0.01). Most respondents agreed or strongly agreed that the topics were important to their clinical practice (87/90, 97%), professional development (86/90, 96%), and personal well-being (82/91, 90%). Faculty identified the QREW program as a major contributor to their professional development.

CONCLUSION

A noninterpretative professional development lecture series delivered by radiology faculty in a virtual, interactive format is feasible and effective, particularly for junior faculty.

Synoptic Reporting for Pretreatment CT Examination in Patients With Advanced Ovarian Cancer: Impact on Documentation of Disease Sites and Physician Satisfaction

BACKGROUND. Imaging reports that consistently document all disease sites with a potential to increase surgical complexity or morbidity can facilitate ovarian cancer treatment planning. OBJECTIVE. The aims of this study were to compare simple structured reports and synoptic reports from pretreatment CT examinations in patients with advanced ovarian cancer in terms of completeness of documenting involvement of clinically relevant anatomic sites as well as to evaluate physician satisfaction with synoptic reports. METHODS. This retrospective study included 205 patients (median age, 65 years) who underwent contrast-enhanced abdominopelvic CT before primary treatment of advanced ovarian cancer from June 1, 2018, to January 31, 2022. A total of 128 reports generated on or before March 31, 2020, used a simple structured report (free text organized into sections); 77 reports generated on or after April 1, 2020, used a synoptic report (a list of 45 anatomic sites relevant to ovarian cancer management, each of which was classified in terms of disease absence versus presence). Reports were reviewed for completeness of documentation of involvement of the 45 sites. For patients who underwent neoadjuvant chemotherapy based on diagnostic laparoscopy findings or underwent primary debulking surgery with suboptimal resection, the EMR was reviewed to identify surgically established sites of disease that were unresectable or challenging to resect. Gynecologic oncology surgeons were electronically surveyed. RESULTS. The mean report turnaround time was 29.8 minutes for simple structured reports versus 54.5 minutes for synoptic reports (p < .001). A mean of 17.6 of 45 sites (range, four to 43 sites) were mentioned by simple structured reports versus 44.5 of 45 sites (range, 39-45) for synoptic reports (p < .001). Forty-three patients had surgically established unresectable or challenging-to-resect disease; involvement of anatomic site(s) with such disease was mentioned in 37% (11/30) of simple structured reports versus 100% (13/13) of synoptic reports (p < .001). All eight surveyed gynecologic oncology surgeons completed the survey. CONCLUSION. A synoptic report improved completeness of pretreatment CT reports in patients with advanced ovarian cancer, including for established sites of unresectable or challenging-to-resect disease. CLINICAL IMPACT. The findings indicate the role of disease-specific synoptic reports in facilitating referrer communication and potentially guiding clinical decision-making.

Current Status of Cancer Genomics and Imaging Phenotypes: What Radiologists Need to Know

Ongoing discoveries in cancer genomics and epigenomics have revolutionized clinical oncology and precision health care. This knowledge provides unprecedented insights into tumor biology and heterogeneity within a single tumor, among primary and metastatic lesions, and among patients with the same histologic type of cancer. Large-scale genomic sequencing studies also sparked the development of new tumor classifications, biomarkers, and targeted therapies. Because of the central role of imaging in cancer diagnosis and therapy, radiologists need to be familiar with the basic concepts of genomics, which are now becoming the new norm in oncologic clinical practice. By incorporating these concepts into clinical practice, radiologists can make their imaging interpretations more meaningful and specific, facilitate multidisciplinary clinical dialogue and interventions, and provide better patient-centric care. This review article highlights basic concepts of genomics and epigenomics, reviews the most common genetic alterations in cancer, and discusses the implications of these concepts on imaging by organ system in a case-based manner. This information will help stimulate new innovations in imaging research, accelerate the development and validation of new imaging biomarkers, and motivate efforts to bring new molecular and functional imaging methods to clinical radiology. Keywords: Oncology, Cancer Genomics, Epignomics, Radiogenomics, Imaging Markers Supplemental material is available for this article. © RSNA, 2023.

Gynecologic oncology tumor board: the central role of the radiologist

This manuscript is a collaborative, multi-institutional effort by members of the Society of Abdominal Radiology Uterine and Ovarian Cancer Disease Focus Panel and the European Society of Urogenital Radiology Women Pelvic Imaging working group. The manuscript reviews the key role radiologists play at tumor board and highlights key imaging findings that guide management decisions in patients with the most common gynecologic malignancies including ovarian cancer, cervical cancer, and endometrial cancer.

Practical Tips for Reporting Adnexal Lesions Using O-RADS MRI

The Ovarian-Adnexal Reporting and Data System (O-RADS) MRI risk stratification system provides a standardized lexicon and evidence-based risk score for evaluation of adnexal lesions. The goals of the lexicon and risk score are to improve report quality and communication between radiologists and clinicians, reduce variability in the reporting language, and optimize management of adnexal lesions. The O-RADS MRI risk score is based on the presence or absence of specific imaging features, including the lipid content, enhancing solid tissue, number of loculi, and fluid type. The probability of malignancy ranges from less than 0.5% when there are benign features to approximately 90% when there is solid tissue with a high-risk time-intensity curve. This information can aid in optimizing management of patients with adnexal lesions. The authors present an algorithmic approach to the O-RADS MRI risk stratification system and highlight key teaching points and common pitfalls. © RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Adnexal Lesion Imaging: Past, Present, and Future

Currently, imaging is part of the standard of care for patients with adnexal lesions prior to definitive management. Imaging can identify a physiologic finding or classic benign lesion that can be followed up conservatively. When one of these entities is not present, imaging is used to determine the probability of ovarian cancer prior to surgical consultation. Since the inclusion of imaging in the evaluation of adnexal lesions in the 1970s, the rate of surgery for benign lesions has decreased. More recently, data-driven Ovarian-Adnexal Reporting and Data System (O-RADS) scoring systems for US and MRI with standardized lexicons have been developed to allow for assignment of a cancer risk score, with the goal of further decreasing unnecessary interventions while expediting the care of patients with ovarian cancer. US is used as the initial modality for the assessment of adnexal lesions, while MRI is used when there is a clinical need for increased specificity and positive predictive value for the diagnosis of cancer. This article will review how the treatment of adnexal lesions has changed due to imaging over the decades; the current data supporting the use of US, CT, and MRI to determine the likelihood of cancer; and future directions of adnexal imaging for the early detection of ovarian cancer.

The BUMPy road of peritoneal metastases in ovarian cancer

Ovarian cancer is the most common cause of death due to gynecologic malignancies, with more than 70% of patients presenting with advanced stage disease at the time of diagnosis. The extent and distribution of tumor guide primary treatment selection and clinical management. While primary cytoreductive surgery with complete tumor resection improves survival, patients with extensive peritoneal disease may benefit from neoadjuvant chemotherapy first to reduce tumor burden followed by interval cytoreductive surgery. Imaging plays an essential role in triaging patients including selecting patients who may benefit from neoadjuvant chemotherapy before cytoreductive surgery. Interestingly, there are no universally established criteria to predict resectability and local practices depend on local guidelines and surgeon preferences. Nevertheless, certain anatomical tumor locations are known to be difficult to resect and are associated with suboptimal cytoreduction or require special surgical considerations. This review discusses the recent advances in the initial management of patients with ovarian cancer, a practical approach to the assessment and communication of peritoneal metastases locations on CT and MRI. It also explores recent advances in genomics profiling and radiomics that may influence the initial management of these patients.

Interreader Agreement and Intermodality Concordance of O-RADS US and MRI for Assessing Large, Complex Ovarian-Adnexal Cysts

Purpose To assess interreader agreement of the Ovarian-Adnexal Reporting and Data System (O-RADS) and intermodality concordance between US and MRI for characterizing complex adnexal cysts measuring 5 cm or larger. Materials and Methods This retrospective study included 58 "complex cysts" measuring at least 5 cm in size observed at both US and MRI in 54 women (median age, 37 years ± 12 [SD]; seven postmenopausal women) between July 2017 and June 2020, identified from an electronic US database. A separate set of two blinded radiologists independently reviewed the US or MR images to assign the O-RADS category, and an adjudicator resolved discrepancies (a total of six readers). Lesion outcome (49 benign, eight malignant, one lost to follow-up) was recorded. Interreader agreement of O-RADS US and O-RADS MRI and concordance between US and MRI were analyzed. Results Interreader agreement was fair for US (κ = 0.31), moderate for MRI (κ = 0.43), and moderate between US and MRI (κ = 0.58). A significant positive correlation was found between O-RADS US and MRI (τ = 0.72, P < .001). The O-RADS 4 threshold yielded the highest accuracy for both US and MRI (area under the receiver operating characteristic curve = 0.92 and 0.995, respectively). Considering O-RADS US 4 or 5 as potentially malignant and 1-3 as benign, eight lesions that were assessed as potentially malignant at US were correctly downgraded to benign by using findings at MRI. Using findings at MRI, one malignant lesion that was assessed as benign at US was upgraded to potentially malignant. Conclusion O-RADS US and MRI had excellent performance and positive correlation, but significant interobserver variability remains. Keywords: Ovary, MR Imaging, Ultrasonography © RSNA, 2022 See also the commentary by Baumgarten in this issue.

Learning From Experience- Confronting Challenges and Adapting to Change in a Large Academic Abdominal Radiology Practice: Insights From a Faculty Retreat

RATIONALE

Substantial organizational changes, increasing clinical volumes, and the COVID-19 pandemic presented compound stressors to faculty radiologists in our large academic abdominal radiology division and necessitated multiple changes in our practice.

METHODS

To address the challenges and establish group consensus, we conducted a virtual divisional faculty retreat centered on themes of team building, clinical work, trainee education, and faculty mentorship. A pre-retreat survey evaluated satisfaction with aspects of professional life and clinical work practices and invited personal reflections. Survey data were presented in the retreat segments focused on each theme, and subsequent discussion was facilitated in small group breakouts.

RESULTS

Responses to the team-building survey revealed common values and sources of gratitude, including health, family and meaningful work and relationships. Faculty reported a strong sense of personal accomplishment, but with varied emotional exhaustion scores. Faculty were satisfied with remote work assignments but identified opportunities to improve the clinical work schedule including reversion of some remote assignments to in-person and increased interventional radiology shift staggering. Compared to pre-COVID practice, faculty respondents perceived giving lower quality and less frequent feedback to trainees; evolving educational resource needs were identified. A more formal approach to faculty mentoring was sought. A post-retreat survey revealed high participant satisfaction.

OUTCOMES

In the future, we plan to continue divisional retreat activities to respond to evolving challenges and further improve team building, clinical workflow, trainee education, and faculty mentorship.

Multicenter Evaluation of Multiparametric MRI Clear Cell Likelihood Scores in Solid Indeterminate Small Renal Masses

Background Solid small renal masses (SRMs) (≤4 cm) represent benign and malignant tumors. Among SRMs, clear cell renal cell carcinoma (ccRCC) is frequently aggressive. When compared with invasive percutaneous biopsies, the objective of the proposed clear cell likelihood score (ccLS) is to classify ccRCC noninvasively by using multiparametric MRI, but it lacks external validation. Purpose To evaluate the performance of and interobserver agreement for ccLS to diagnose ccRCC among solid SRMs. Materials and Methods This retrospective multicenter cross-sectional study included patients with consecutive solid (≥25% approximate volume enhancement) SRMs undergoing multiparametric MRI between December 2012 and December 2019 at five academic medical centers with histologic confirmation of diagnosis. Masses with macroscopic fat were excluded. After a 1.5-hour training session, two abdominal radiologists per center independently rendered a ccLS for 50 masses. The diagnostic performance for ccRCC was calculated using random-effects logistic regression modeling. The distribution of ccRCC by ccLS was tabulated. Interobserver agreement for ccLS was evaluated with the Fleiss κ statistic. Results A total of 241 patients (mean age, 60 years ± 13 [SD]; 174 men) with 250 solid SRMs were evaluated. The mean size was 25 mm ± 8 (range, 10-39 mm). Of the 250 SRMs, 119 (48%) were ccRCC. The sensitivity, specificity, and positive predictive value for the diagnosis of ccRCC when ccLS was 4 or higher were 75% (95% CI: 68, 81), 78% (72, 84), and 76% (69, 81), respectively. The negative predictive value of a ccLS of 2 or lower was 88% (95% CI: 81, 93). The percentages of ccRCC according to the ccLS were 6% (range, 0%-18%), 38% (range, 0%-100%), 32% (range, 60%-83%), 72% (range, 40%-88%), and 81% (range, 73%-100%) for ccLSs of 1-5, respectively. The mean interobserver agreement was moderate (κ = 0.58; 95% CI: 0.42, 0.75). Conclusion The clear cell likelihood score applied to multiparametric MRI had moderate interobserver agreement and differentiated clear cell renal cell carcinoma from other solid renal masses, with a negative predictive value of 88%. © RSNA, 2022 Online supplemental material is available for this article. See also the editorial by Mileto and Potretzke in this issue.

Ovarian cancer reporting lexicon for computed tomography (CT) and magnetic resonance (MR) imaging developed by the SAR Uterine and Ovarian Cancer Disease-Focused Panel and the ESUR Female Pelvic Imaging Working Group

OBJECTIVES

Imaging evaluation is an essential part of treatment planning for patients with ovarian cancer. Variation in the terminology used for describing ovarian cancer on computed tomography (CT) and magnetic resonance (MR) imaging can lead to ambiguity and inconsistency in clinical radiology reports. The aim of this collaborative project between Society of Abdominal Radiology (SAR) Uterine and Ovarian Cancer (UOC) Disease-focused Panel (DFP) and the European Society of Uroradiology (ESUR) Female Pelvic Imaging (FPI) Working Group was to develop an ovarian cancer reporting lexicon for CT and MR imaging.

METHODS

Twenty-one members of the SAR UOC DFP and ESUR FPI working group, one radiology clinical fellow, and two gynecologic oncology surgeons formed the Ovarian Cancer Reporting Lexicon Committee. Two attending radiologist members of the committee prepared a preliminary list of imaging terms that was sent as an online survey to 173 radiologists and gynecologic oncologic physicians, of whom 67 responded to the survey. The committee reviewed these responses to create a final consensus list of lexicon terms.

RESULTS

An ovarian cancer reporting lexicon was created for CT and MR Imaging. This consensus-based lexicon has 6 major categories of terms: general, adnexal lesion-specific, peritoneal carcinomatosis-specific, lymph node-specific, metastatic disease -specific, and fluid-specific.

CONCLUSIONS

This lexicon for CT and MR imaging evaluation of ovarian cancer patients has the capacity to improve the clarity and consistency of reporting disease sites seen on imaging.

KEY POINTS

• This reporting lexicon for CT and MR imaging provides a list of consensus-based, standardized terms and definitions for reporting sites of ovarian cancer on imaging at initial diagnosis or follow-up. • Use of standardized terms and morphologic imaging descriptors can help improve interdisciplinary communication of disease extent and facilitate optimal patient management. • The radiologists should identify and communicate areas of disease, including difficult to resect or potentially unresectable disease that may limit the ability to achieve optimal resection.

OUP accepted manuscript

Background

Materials and Methods

Results

Conclusion

Robustness and performance of radiomic features in diagnosing cystic renal masses

PURPOSE

We study the inter-reader variability in manual delineation of cystic renal masses (CRMs) presented in computerized tomography (CT) images and its effect on the classification performance of a machine learning algorithm in distinguishing benign from potentially malignant CRMs. In addition, we assessed whether the inclusion of higher-order robust radiomic features improves the classification performance over the use of first-order features.

METHODS

230 CRMs were independently delineated by two radiologists. Through a combination of random fluctuations, dilation, and erosion operations over the original region of interests (ROIs), we generated four additional sets of synthetic ROIs to capture the inter-reader variability realistically, as confirmed by dice coefficient measurements and visual assessment. We then identified the robust features based on the intra-class coefficient (ICC > 0.85) across these datasets. We applied a tenfold stratified cross-validation (CV) to train and test the performance of the random forest model for the classification of CRMs into benign and potentially malignant.

RESULTS

The mean area under the curve (AUC), sensitivity, specificity, positive predictive value, and negative predictive value were 0.87, 0.82, 0.90, 0.85, and 0.93, respectively. With the usage of first-order features alone, the corresponding values were nearly identical.

CONCLUSION

AUC ranged for the robust and uncorrelated features from 0.83 ± 0.09 to 0.93 ± 0.04 and for the first-order features from 0.84 ± 0.09 to 0.91 ± 0.04. Our study indicates that the first-order features alone are sufficient for the classification of CRMs, and that inclusion of higher-order features does not necessarily improve performance.

ACR Appropriateness Criteria® Staging and Follow-up of Primary Vaginal Cancer

Primary vaginal cancer is rare, comprising 1% to 2% of gynecologic malignancies and 20% of all malignancies involving the vagina. More frequently, the vagina is involved secondarily by direct invasion from malignancies originating in adjacent organs or by metastases from other pelvic or extrapelvic primary malignancies. Data on the use of imaging in vaginal cancer are sparse. Insights are derived from the study of imaging in cervical cancer and have reasonable generalizability to vaginal cancer due to similar tumor biology. Given the trend toward definitive chemoradiation for both cancers in all but early stage lesions, principles of postchemoradiation tumor response evaluation are largely analogous. Accordingly, many of the recommendations outlined here are informed by principles translated from the literature on cervical cancer. For pretreatment assessment of local tumor burden and in the case of recurrent vaginal cancer, MRI is the preferred imaging modality. PET/CT has demonstrated utility for the detection of nodal metastatic and unexpected distant metastatic disease. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Multidisciplinary Recommendations Regarding Post-Vaccine Adenopathy and Radiologic Imaging: Radiology Scientific Expert Panel

Vaccination-associated adenopathy is a frequent imaging finding after administration of COVID-19 vaccines that may lead to a diagnostic conundrum in patients with manifest or suspected cancer, in whom it may be indistinguishable from malignant nodal involvement. To help the medical community address this concern in the absence of studies and evidence-based guidelines, this special report offers recommendations developed by a multidisciplinary panel of experts from three of the leading tertiary care cancer centers in the United States. According to these recommendations, some routine imaging examinations, such as those for screening, should be scheduled before or at least 6 weeks after the final vaccination dose to allow for any reactive adenopathy to resolve. However, there should be no delay of other clinically indicated imaging (eg, for acute symptoms, short-interval treatment monitoring, urgent treatment planning or complications) due to prior vaccination. The vaccine should be administered on the side contralateral to the primary or suspected cancer, and both doses should be administered in the same arm. Vaccination information-date(s) administered, injection site(s), laterality, and type of vaccine-should be included in every preimaging patient questionnaire, and this information should be made readily available to interpreting radiologists. Clear and effective communication between patients, radiologists, referring physician teams, and the general public should be considered of the highest priority when managing adenopathy in the setting of COVID-19 vaccination.

Decoding incidental ovarian lesions: use of texture analysis and machine learning for characterization and detection of malignancy

PURPOSE

To compare CT texture features of benign and malignant ovarian lesions and to build a machine learning model to detect malignancy in incidental ovarian lesions.

METHODS

In this IRB-approved, HIPAA-compliant, retrospective study, 427 consecutive patients with incidental ovarian lesions detected on contrast-enhanced CT (348, 81.5% benign and 79, 18.5% malignant) were included. The following CT texture features were analyzed using commercially available software (TexRAD, Feedback Plc, Cambridge, UK): total pixel, mean, standard deviation (SD), entropy, mean value of positive pixels (MPP), skewness, kurtosis and entropy. Three machine learning models were created by combining texture features and patients' age, and performance of these models was assessed using tenfold cross-validation. Receiver operating characteristics (ROC) were constructed to assess sensitivity and specificity. The cutoff value was picked using a cost-weighted method.

RESULTS

Total pixels, mean, SD, entropy, MPP, and skewness were significantly different between benign and malignant groups (p < 0.05). With a selected 10 as a cost factor to optimize cutoff value selection, sensitivity 92%, specificity 60% in the random forest (RF) model, sensitivity 91%, specificity 69% in SVM model, and sensitivity 92%, specificity 61% in the logistic regression, respectively.

CONCLUSION

CT texture analysis could provide objective imaging analysis of incidental ovarian lesions and ML models using CT texture features and age demonstrated high sensitivity and moderate specificity for detection of malignant lesions.

ACR Appropriateness Criteria® Staging and Follow-up of Vulvar Cancer

Vulvar cancer is an uncommon gynecologic tumor and one of several human papillomavirus-associated malignancies. Squamous cell carcinoma is the most prevalent histologic subtype of vulvar cancer, accounting for the majority of cases. Imaging plays an important role in managing vulvar cancer. At initial diagnosis, imaging is useful to assess the size and extent of primary tumor and to evaluate the status of inguinofemoral lymph nodes. If recurrent disease is suspected, imaging is essential to demonstrate local extent of tumor and to identify lymph node and distant metastases. In this publication, we summarize the recent literature and describe the panel's recommendations about the appropriate use of imaging for various phases of patient management including initial staging, surveillance, and restaging of vulvar cancer. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

FGFR2 Extracellular Domain In-Frame Deletions are Therapeutically Targetable Genomic Alterations that Function as Oncogenic Drivers in Cholangiocarcinoma

We conducted next generation DNA sequencing on 335 biliary tract cancers and characterized the genomic landscape by anatomic site within the biliary tree. In addition to frequent FGFR2 fusions among patients with intrahepatic cholangiocarcinoma (IHCC), we identified FGFR2 extracellular domain in-frame deletions (EIDs) in 5 of 178 (2.8%) patients with IHCC, including two patients with FGFR2 p.H167_N173del. Expression of this FGFR2 EID in NIH3T3 cells resulted in constitutive FGFR2 activation, oncogenic transformation, and sensitivity to FGFR inhibitors. Three patients with FGFR2 EIDs were treated with Debio 1347, an oral FGFR-1/2/3 inhibitor, and all showed partial responses. One patient developed an acquired L618F FGFR2 kinase domain mutation at disease progression and experienced a further partial response for 17 months to an irreversible FGFR2 inhibitor, futibatinib. Together, these findings reveal FGFR2 EIDs as an alternative mechanism of FGFR2 activation in IHCC that predict sensitivity to FGFR inhibitors in the clinic.

Improving the completeness of structured MRI reports for rectal cancer staging

PURPOSE

Assess the impact of a multifaceted intervention to improve the completeness of structured MRI reports for patients undergoing initial staging for rectal cancer.

METHODS

This Institutional Review Board-approved retrospective study was performed at a large academic hospital. MRI reports for initial staging of rectal cancer in 2017 and 2019 were analyzed pre- and post-implementation of multiple quality improvement interventions in 2018, including harmonizing MRI protocols across the institution, educational conferences and modules, and requiring second opinion consultation for all MRI rectal cancer examinations. The primary outcome measure was the completeness of rectal cancer staging MRI reports, classified as optimal, satisfactory, or unsatisfactory based on the inclusion of 15 quality measures pre-defined by a consensus of abdominal and cancer imaging subspecialists, colorectal surgeons, and radiation oncologists at our institution, based on published recommendations. Fisher's exact test was used to evaluate changes in report quality and documentation of each quality measure.

RESULTS

The study included 138 MRI reports, of which 72 (52%) were completed in 2017 pre-intervention. Post intervention, the proportion of optimal reports increased significantly from 52.8% (38/72) to 71.2% (47/66) (p = 0.035). Documentation of 1 quality measure (N stage) increased post intervention from 91.7% (66/72) to 100% (66/66) (p = 0.029). Documentation of 7 quality measures was 100% post intervention, with a documentation rate of > 95% for all quality measures except radial location of tumor.

CONCLUSION

A combination of educational and system-wide interventions was associated with an improvement in the completeness of structured MRI reports for rectal cancer staging.

Lexicon for renal mass terms at CT and MRI: a consensus of the society of abdominal radiology disease-focused panel on renal cell carcinoma

PURPOSE

There is substantial variation in the radiologic terms used to characterize renal masses, leading to ambiguity and inconsistency in clinical radiology reports and research studies. The purpose of this study was to develop a standardized lexicon to describe renal masses at CT and MRI.

MATERIALS AND METHODS

This multi-institutional, prospective, quality improvement project was exempt from IRB oversight. Thirteen radiologists belonging to the Society of Abdominal Radiology (SAR) disease-focused panel on renal cell carcinoma representing nine academic institutions participated in a modified Delphi process to create a lexicon of terms used to describe imaging features of renal masses at CT and MRI. In the first round, members voted on terms to be included and proposed definitions; subsequent voting rounds and a teleconference established consensus. One non-voting member developed the questionnaire and consolidated responses. Consensus was defined as ≥ 80% agreement.

RESULTS

Of 37 proposed terms, 6 had consensus to be excluded. Consensus for inclusion was reached for 30 of 31 terms (13/14 basic imaging terms, 8/8 CT terms, 6/6 MRI terms and 3/3 miscellaneous terms). Despite substantial initial disagreement about definitions of 'renal mass,' 'necrosis,' 'fat,' and 'restricted diffusion' in the first round, consensus for all was eventually reached. Disagreement remained for the definition of 'solid mass.'

CONCLUSIONS

A modified Delphi method produced a lexicon of preferred terms and definitions to be used in the description of renal masses at CT and MRI. This lexicon should improve clarity and consistency of radiology reports and research related to renal masses.

Molecular Characterization and Therapeutic Targeting of Colorectal Cancers Harboring Receptor Tyrosine Kinase Fusions

PURPOSE

Receptor tyrosine kinase fusions in colorectal cancers are rare, but potentially therapeutically relevant. We describe clinical, molecular, and pathologic attributes of RTK fusion-associated colorectal cancer.

EXPERIMENTAL DESIGN

We identified all cases with RTK fusions in patients with colorectal cancer seen at Dana-Farber Cancer Institute (Boston, MA) who underwent OncoPanel testing between 2013 and 2018. Clinical, histologic, and molecular features were extracted from the patient charts and molecular testing results.

RESULTS

We identified 12 driver oncogenic fusions in various RTKs. These fusions occurred exclusively in BRAF and RAS wild-type tumors and were enriched in right-sided and mismatch repair-deficient (MMR-D) colorectal cancers. All of the MMR-D colorectal cancers with RTK fusions were found in tumors with acquired MMR-D due to MLH1 promoter hypermethylation and one was associated with a sessile serrated polyp. Molecular profiles of MMR-D colorectal cancer with RTK fusions largely resembled BRAF V600E-mutated MMR-D colorectal cancer, rather than those secondary to Lynch syndrome. We describe two patients with fusion-associated microsatellite stable (MSS) colorectal cancer who derived clinical benefit from therapeutic targeting of their translocation. The first harbored an ALK-CAD fusion and received sequential crizotinib and alectinib therapy for a total of 7.5 months until developing an ALK L1196Q gatekeeper mutation. The second patient, whose tumor contained an ROS1-GOPC fusion, continues to benefit from entrectinib after 9 months of therapy.

CONCLUSIONS

RTK fusions in colorectal cancer are a rare, but important disease subgroup that occurs in RAS and BRAF wild-type tumors. Despite enrichment in acquired MMR-D tumors, RTK fusions also occur in MSS colorectal cancer and provide an important therapeutic target.

ACR Appropriateness Criteria® Pretreatment Evaluation and Follow-Up of Endometrial Cancer

To date, there is little consensus on the role of pelvic imaging in assessing local disease extent during initial staging in patients with endometrial carcinoma, with practices differing widely across centers. However, when pretreatment assessment of local tumor extent is indicated, MRI is the preferred imaging modality. Preoperative imaging of endometrial carcinoma can define the extent of disease and indicate the need for subspecialist referral in the presence of deep myometrial invasion, cervical extension, or suspected lymphadenopathy. If distant metastatic disease is clinically suspected, preoperative assessment with cross-sectional imaging or PET/CT may be performed. However, most patients with low-grade disease are at low risk of lymph node and distant metastases. Thus, this group may not require a routine pretreatment evaluation for distant metastases. Recurrence rates in patients with endometrial carcinoma are infrequent. Therefore, radiologic evaluation is typically used only to investigate suspicion of recurrent disease due to symptoms or physical examination and not for routine surveillance after treatment. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

ACR Appropriateness Criteria® Gestational Trophoblastic Disease

Gestational trophoblastic disease (GTD), a rare complication of pregnancy, includes both benign and malignant forms, the latter collectively referred to as gestational trophoblastic neoplasia (GTN). When metastatic, the lungs are the most common site of initial spread. Beta-human chorionic gonadotropin, elaborated to some extent by all forms of GTD, is useful in facilitating disease detection, diagnosis, monitoring treatment response, and follow-up. Imaging evaluation depends on whether GTD manifests in one of its benign forms or whether it has progressed to GTN. Transabdominal and transvaginal ultrasound with duplex Doppler evaluation of the pelvis are usually appropriate diagnostic procedures in either of these circumstances, and in posttreatment surveillance. The appropriateness of more extensive imaging remains dependent on a diagnosis of GTN and on other factors. The use of imaging to assess complications, typically hemorrhagic, should be guided by the location of clinical signs and symptoms. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Abstract 1097: FGFR2 in-frame indels: A novel targetable alteration in intrahepatic cholangiocarcinoma

Biliary cancers include intrahepatic cholangiocarcinoma (IHCC), extrahepatic cholangiocarcinoma (EHCC), and gallbladder cancer (GBC). These cancers are clinically, pathologically, and biologically heterogeneous, but are all aggressive with poor prognosis and few available therapies. Potentially actionable genomic alterations described to date include IDH1 mutations, FGFR2 fusions, BRAF V600E mutations, HER2 amplification/mutation, and BRCA1/2 mutations. FGFR inhibitors have demonstrated encouraging efficacy in patients with FGFR2 oncogenic fusions; however, the efficacy of these inhibitors in patients with other types of FGFR alterations is less clear.

We analyzed somatic alterations in 272 patients with biliary cancers (135 IHCCs, 34 EHCCs, and 59 GBCs) that underwent targeted OncoPanel sequencing at Dana-Farber Cancer Institute. The identified oncogenic alterations were similar to those previously reported in cholangiocarcinoma genomic landscapes. Mutational signature analyses found genomic features of microsatellite instability in 5 cases, APOBEC in 4 cases, and homologous recombination repair deficiency in 7 cases. Clinicopathological and outcome data for these patients are being collected to evaluate for associations with genomic findings.

16 FGFR2 translocations involving intron 17 were identified in the IHCC cohort (14% of evaluable IHCCs). Surprisingly, 5 IHCCs (4% of evaluable cases) harbored extracellular domain FGFR2 indels, of which p.W290_I291delinsC was previously reported to show oncogenic activity in vitro. Two cases harbored an identical FGFR2 p.H167_N173del. In vitro expression of this deletion resulted in oncogenic transformation, and that this growth could be inhibited by FGFR inhibitors. The two patients with FGFR2 p.H167_N173del were treated with an FGFR-1/2/3 inhibitor (Debio-1347), and both achieved durable partial response (PR) of over 11 months. We followed the first patient with tumor sequencing at five timepoints during her care and found that at resistance to Debio-1347, she developed an FGFR2 kinase domain mutation (p.L617F) that was subsequently demonstrated to confer resistance to Debio-1347 in vitro. This patient was then treated with a second FGFR inhibitor and experienced a PR lasting 17 months. At resistance to this second FGFR inhibitor, the tumor was biopsied and found to harbor a previously undetected BRAF p.L597Q mutation. The second patient remains on active treatment.

Our data show that extracellular domain FGFR2 in-frame indels are rare but targetable novel oncogenic alterations in IHCC. An expanded search of AACR Project GENIE data found 18 extracellular FGFR2 in-frame indels in diverse tumor types, supporting further functional evaluation and clinical targeting of these indels across tumor types.

Citation Format: Yvonne Y. Li, James M. Cleary, Srivatsan Raghavan, Liam F. Spurr, Qibiao Wu, Lei Shi, Lauren K. Brais, Maureen Loftus, Lipika Goyal, Anuj K. Patel, Atul B. Shinagare, Thomas E. Clancy, Geoffrey Shapiro, Ethan Cerami, William R. Sellers, William C. Hahn, Matthew Meyerson, Nabeel Bardeesy, Andrew D. Cherniack, Brian M. Wolpin. FGFR2 in-frame indels: A novel targetable alteration in intrahepatic cholangiocarcinoma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1097.

Early Adoption of a Certainty Scale to Improve Diagnostic Certainty Communication

OBJECTIVE

Assess the early voluntary adoption of a certainty scale to improve communicating diagnostic certainty in radiology reports.

METHODS

This institutional review board-approved study was part of a multifaceted initiative to improve radiology report quality at a tertiary academic hospital. A committee comprised of radiology subspecialty division representatives worked to develop recommendations for communicating varying degrees of diagnostic certainty in radiology reports in the form of a certainty scale, made publicly available online, which specified the terms recommended and the terms to be avoided in radiology reports. Twelve radiologists voluntarily piloted the scale; use was not mandatory. We assessed proportion of recommended terms among all diagnostic certainty terms in the Impression section (primary outcome) of all reports generated by the radiologists. Certainty terms were extracted via natural language processing over a 22-week postintervention period (31,399 reports) and compared with the same 22 calendar weeks 1 year pre-intervention (24,244 reports) using Fisher's exact test and statistical process control charts.

RESULTS

Overall, the proportion of recommended terms significantly increased from 8,498 of 10,650 (80.0%) pre-intervention to 9,646 of 11,239 (85.8%) postintervention (P < .0001 and by statistical process control). The proportion of recommended terms significantly increased for 8 of 12 radiologists (P < .0005 each), increased insignificantly for 3 radiologists (P > .05), and decreased without significance for 1 radiologist.

CONCLUSION

Designing and implementing a certainty scale was associated with increased voluntary use of recommended certainty terms in a small radiologist cohort. Larger-scale interventions will be needed for adoption of the scale across a broad range of radiologists.

Muscle-invasive Urothelial Cancer: Association of Mutational Status with Metastatic Pattern and Survival

Background Muscle-invasive urothelial cancer (MIUC) is characterized by substantial genetic heterogeneity and high mutational frequency. Correlation between frequently mutated genes with clinical behavior has been recently demonstrated. Nonetheless, correlation between mutational status of MIUC and metastatic pattern is unknown. Purpose To investigate the association of mutational status of MIUC with metastatic pattern, metastasis-free survival (MFS), and overall survival (OS). Materials and Methods This single-center retrospective study evaluated consecutive patients with biopsy-proven MIUC who underwent serial cross-sectional imaging (CT, MRI, or fluorine 18 fluorodeoxyglucose PET/CT) between April 2010 and December 2018. Mutational status was correlated with location of metastases using the χ² or Fisher exact test. Mutational status and metastatic pattern were correlated with MFS and OS using univariable Cox proportional hazard models. High-risk (presence of TP53, RB1, or KDM6A mutation) and low-risk (presence of ARID1A, FGFR3, PIK3CA, STAG2, and/or TSC1 mutation and absence of TP53, RB1, or KDM6A mutation) groups were determined according to existing literature and were correlated with MFS and OS by using multivariable Cox proportional hazard models. Results One hundred three patients (mean age, 72 years ± 11 [standard deviation]; 81 men) were evaluated. Seventeen of 103 (16%) patients had metastatic disease at diagnosis; 38 of 103 (37%) developed metastatic disease at a median of 5.9 months (interquartile range, 0.8-28 months). TP53 mutation (seen in 58 of 103 patients, 56%) was associated with lymphadenopathy (relative risk [RR]: 1.7; 95% confidence interval [CI]: 1.2, 2.4; P = .002) and osseous metastases (RR: 1.9; 95% CI: 1.6, 2.3; P = .02); RB1 mutation (seen in 19 of 103 patients, 18.4%) was associated with peritoneal carcinomatosis (RR: 5.9; 95% CI: 3.8, 9.2; P = .03). ARID1A mutation was associated with greater OS (hazard ratio [HR]: 3.1; 95% CI: 1.2, 10; P = .01). At multivariable Cox analysis, the high-risk group (TP53, RB1, and/or KDM6A mutations) was independently associated with shorter MFS (HR: 3.5, 95% CI: 1.3, 12; P = .009) and shorter OS (HR: 3.1; 95% CI: 1.2, 10; P = .02). Conclusion Mutational status of muscle-invasive urothelial cancer has implications on metastatic pattern, metastasis-free survival, and overall survival. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Choyke in this issue.

The Safety and Efficacy of Checkpoint Inhibitors in Transplant Recipients: A Case Series and Systematic Review of Literature

Limited data exist on safety and efficacy of immune checkpoint inhibitors (ICIs) among organ transplant recipients. The objective of this study was to report a case series of two patients with renal transplant who received treatment with an ICI and to conduct a pooled analysis of published cases to describe the safety and efficacy of ICIs in organ transplant patients. A systematic search in the Google Scholar and PubMed databases was carried out to include all the published cases of organ transplant patients who received treatment with ICIs including programmed cell death protein 1 (PD-1), programmed death-ligand 1, or cytotoxic lymphocyte antigen-4 inhibitors since their inscription to January 31, 2019. In the present series of two cases with renal allografts who received pembrolizumab, one patient with squamous cell carcinoma of the skin experienced complete response (CR), whereas another patient with melanoma had a mixed response. Both patients experienced allograft rejection, but graft was salvaged. The pooled analysis of 64 patients published in literature showed that overall allograft rejection rate is 41% in organ transplant recipients following ICI therapy. The graft rejection rate was 44% (17/39) for renal, 39% (7/19) for liver, and 20% (1/5) for cardiac allografts. The highest risk was seen among patients who were treated with PD-1 inhibitors, 20/42 (48%)-13/24 (54%) on nivolumab and 7/18 (39%) on pembrolizumab. The risk was lowest with ipilimumab, 23% (3/13). The overall response rate (CR + partial response [PR]) was 20% with ipilimumab, 26% with nivolumab, and 53% with pembrolizumab, whereas disease control rate (CR + PR + stable disease) was 35% with ipilimumab, 37% with nivolumab, and 53% with pembrolizumab. None of the variables including age, gender, type of cancer, type of allograft, type of immunosuppression, time since transplantation to initiation of ICI, and prior history of rejection were significantly associated with the transplant rejection on univariate analysis. The efficacy of ICI among patients with organ transplant appears promising, warranting testing in prospective clinical trials. The risk of rejection and allograft loss is considerable; therefore, the risk and alternative form of therapies should be thoroughly discussed with the transplant patients prior to initiating ICI therapy. IMPLICATIONS FOR PRACTICE: Transplant recipients are at higher risk of developing cancers. Although immune checkpoint inhibitors have been shown to improve the outcome in more than one cancer type, transplant recipients were excluded from these trials. Most of the data on the safety and efficacy of immune checkpoint inhibitors in transplant patients are based upon case series and case reports. The pooled data from these reports suggest that anti-programmed death-ligand 1 inhibitors have reasonable safety and efficacy among organ transplant patients, which warrants testing in clinical trials.

Therapeutic targeting of extracellular FGFR2 activating deletions in intrahepatic cholangiocarcinoma

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Background: Fibroblast growth factor receptor (FGFR) pathway alterations have been identified in approximately 20% of patients (pts) with intrahepatic cholangiocarcinoma (IHCC), most commonly by FGFR2 fusions. Early phase clinical trials have demonstrated encouraging efficacy of FGFR inhibitors in pts with FGFR2-translocated cholangiocarcinoma, but efficacy in pts with other FGFR2 activating alterations is less clear. Methods: Pts with cholangiocarcinoma underwent CLIA-certified next generation DNA sequencing (NGS) to identify actionable alterations. FGFR2 fusions and other FGFR2 genomic events were assessed, with genomic characterization performed before and after treatment with FGFR inhibitors in appropriate pts. Novel extracellular domain in-frame deletions (INDELs) of FGFR2 and apparent resistance mutations were investigated for oncogenic activity and inhibitor resistance in vitro and in vivo. Results: Cholangiocarcinomas from 284 pts (136 male, 148 female; median age, 64 [20-89], including 139 IHCCs, were sequenced. Among the IHCCs, 16 (11.5%) had FGFR2 fusions, with 9 different gene partners. Surprisingly, 5 (3.6%) IHCCs harbored extracellular domain FGFR2 INDELs. Two of these IHCCs harbored an exon 5 deletion FGFR2 p.H167_N173del. Expression of FGFR2 p.H167_N173del in 3T3 cells resulted in oncogenic transformation. In the clinic, two pts with FGFR2 p.H167_N173del were treated with Debio1347, an oral FGFR-1/2/3 inhibitor. Both patients achieved a durable partial response (PR) of 11 months, with one of the pts still on active treatment with Debio-1347. The patient who developed acquired resistance underwent repeat biopsy, and NGS identified a secondary mutation ( FGFR2 p. L617F) in the kinase domain. In vitro studies demonstrated that this mutation confers resistance to Debio1347. This patient was subsequently treated with another FGFR inhibitor and again experienced a PR lasting 17 months. A third biopsy after disease progression demonstrated a previously undetected L597Q BRAF mutation. Conclusions: Extracellular domain FGFR2 in-frame deletions are a novel genomic alteration in IHCC that are transforming and predict clinical sensitivity to FGFR inhibitors.

A model combining clinical and genomic factors to predict response to PD-1/PD-L1 blockade in advanced urothelial carcinoma

Background

In metastatic urothelial carcinoma (mUC), predictive biomarkers that correlate with response to immune checkpoint inhibitors (ICIs) are lacking. Here, we interrogated genomic and clinical features associated with response to ICIs in mUC.

Methods

Sixty two mUC patients treated with ICI who had targeted tumour sequencing were studied. We examined associations between candidate biomarkers and clinical benefit (CB, any objective reduction in tumour size) versus no clinical benefit (NCB, no change or objective increase in tumour size). Both univariable and multivariable analyses for associations were conducted. A comparator cohort of 39 mUC patients treated with taxanes was analysed by using the same methodology.

Results

Nine clinical and seven genomic factors correlated with clinical outcomes in univariable analysis in the ICI cohort. Among the 16 factors, neutrophil-to-lymphocyte ratio (NLR) ≥5 (OR = 0.12, 95% CI, 0.01–1.15), visceral metastasis (OR = 0.05, 95% CI, 0.01–0.43) and single-nucleotide variant (SNV) count < 10 (OR = 0.04, 95% CI, 0.006–0.27) were identified as independent predictors of NCB to ICI in multivariable analysis (c-statistic = 0.90). None of the 16 variables were associated with clinical benefit in the taxane cohort.

Conclusions

This three-factor model includes genomic (SNV count >9) and clinical (NLR <5, lack of visceral metastasis) variables predictive for benefit to ICI but not taxane therapy for mUC. External validation of these hypothesis-generating results is warranted to enable use in routine clinical care.

Preoperative imaging for locoregional staging of bladder cancer

Bladder cancer is the ninth most common cancer, expected to lead to an estimated 17,670 deaths in the United States in 2019. Clinical management and prognosis of bladder cancer mainly depend on the extent of locoregional disease, particularly whether bladder muscle is involved. Therefore, bladder cancer is often divided into superficial, non-muscle-invasive bladder cancer and muscle-invasive bladder cancer; the latter often prompts consideration for cystectomy. While precise staging prior to cystectomy is crucial, the optimal preoperative imaging modality used to stage the disease remains controversial. Transurethral resection of bladder tumor (TURBT) followed by computed tomography (CT) urography is the current recommended approach for staging bladder cancer but suffers from a high rate of understaging. We review the recent literature and compare different imaging modalities for assessing the presence of muscle invasion and lymph node involvement prior to cystectomy and highlight the advantages of each modality.

5-Fluorouracil induced liver toxicity in patients with colorectal cancer: role of computed tomography texture analysis as a potential biomarker

PURPOSE

To assess if CT texture analysis (TA) can serve as a biomarker of liver toxicity in patients with colorectal cancer treated with 5-fluorouracil (5-FU)-based chemotherapy.

METHODS

In this IRB-approved, HIPAA-compliant retrospective study, patients with colorectal cancer treated with 5-FU-based regimens during 2008-2010 were identified from institutional electronic database. Total 43 patients (23 women; mean age 56 years) with normal baseline liver function tests (LFTs), availability of baseline (pre-chemotherapy) and first follow-up CT (median 1.7 months, interquartile range (IQR) 1.5-2.5) performed during chemotherapy were included. Two single-slice ROI of right and left liver lobe were obtained on baseline and first follow-up CT for TA. Texture features [mean, entropy, kurtosis, skewness, mean of positive pixel, standard deviation (SD)] were extracted using a commercially available software (TexRAD; Feedback Medical Ltd, Cambridge, UK). Changes in texture parameters between baseline and follow-up CT were evaluated with Wilcoxon signed-rank test for patients with and without LFT elevation during chemotherapy.

RESULTS

Patients with LFT elevation (n = 34; 79%) showed significantly different mean, entropy, skewness, and SD (p values range 0.007-0.047) between baseline and first follow-up CT. No significant changes in features were observed in patients without LFT elevation (n = 9; 21%). In 19 patients (56%), first follow-up CT was performed before elevation of LFTs was observed.

CONCLUSIONS

This proof-of-concept study shows that there are early changes in liver texture on first follow-up CT in patients with LFT elevation during 5-FU-based chemotherapy for colorectal cancer. In more than 50% of cases, these changes occur before LFT elevation becomes evident on blood tests.

Comparative Effectiveness of Tumor Response Assessment Methods: Standard of Care Versus Computer-Assisted Response Evaluation

PURPOSE

To compare the effectiveness of metastatic tumor response evaluation with computed tomography using computer-assisted versus manual methods.

MATERIALS AND METHODS

In this institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study, 11 readers from 10 different institutions independently categorized tumor response according to three different therapeutic response criteria by using paired baseline and initial post-therapy computed tomography studies from 20 randomly selected patients with metastatic renal cell carcinoma who were treated with sunitinib as part of a completed phase III multi-institutional study. Images were evaluated with a manual tumor response evaluation method (standard of care) and with computer-assisted response evaluation (CARE) that included stepwise guidance, interactive error identification and correction methods, automated tumor metric extraction, calculations, response categorization, and data and image archiving. A crossover design, patient randomization, and 2-week washout period were used to reduce recall bias. Comparative effectiveness metrics included error rate and mean patient evaluation time.

RESULTS

The standard-of-care method, on average, was associated with one or more errors in 30.5% (6.1 of 20) of patients, whereas CARE had a 0.0% (0.0 of 20) error rate ( P < .001). The most common errors were related to data transfer and arithmetic calculation. In patients with errors, the median number of error types was 1 (range, 1 to 3). Mean patient evaluation time with CARE was twice as fast as the standard-of-care method (6.4 minutes v 13.1 minutes; P < .001).

CONCLUSION

CARE reduced errors and time of evaluation, which indicated better overall effectiveness than manual tumor response evaluation methods that are the current standard of care.

Bosniak Classification of Cystic Renal Masses, Version 2019: An Update Proposal and Needs Assessment

Cystic renal cell carcinoma (RCC) is almost certainly overdiagnosed and overtreated. Efforts to diagnose and treat RCC at a curable stage result in many benign neoplasms and indolent cancers being resected without clear benefit. This is especially true for cystic masses, which compared with solid masses are more likely to be benign and, when malignant, less aggressive. For more than 30 years, the Bosniak classification has been used to stratify the risk of malignancy in cystic renal masses. Although it is widely used and still effective, the classification does not formally incorporate masses identified at MRI or US or masses that are incompletely characterized but are highly likely to be benign, and it is affected by interreader variability and variable reported malignancy rates. The Bosniak classification system cannot fully differentiate aggressive from indolent cancers and results in many benign masses being resected. This proposed update to the Bosniak classification addresses some of these shortcomings. The primary modifications incorporate MRI, establish definitions for previously vague imaging terms, and enable a greater proportion of masses to enter lower-risk classes. Although the update will require validation, it aims to expand the number of cystic masses to which the Bosniak classification can be applied while improving its precision and accuracy for the likelihood of cancer in each class.

Radiogenomics in renal cell carcinoma

Radiogenomics, a field of radiology investigating the association between the imaging features of a disease and its gene expression pattern, has expanded considerably in the last few years. Recent advances in whole-genome sequencing of clear cell renal cell carcinoma (ccRCC) and the identification of mutations with prognostic significance have led to increased interest in the relationship between imaging and genomic data. ccRCC is particularly suitable for radiogenomic analysis as the relative paucity of mutated genes allows for more straightforward genomic-imaging associations. The ultimate aim of radiogenomics of ccRCC is to retrieve additional data for accurate diagnosis, prognostic stratification, and optimization of therapy. In this review article, we will present the state-of-the-art of radiogenomics of ccRCC, and after briefly reviewing updates in genomics, we will discuss imaging-genomic associations for diagnosis and staging, prognosis, and for assessment of optimal therapy in ccRCC.

Radiologic imaging utilization of small cell lung cancer staging and treatment

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Background: Over the past several decades, first line therapy recommendations for small cell lung cancer (SCLC) have remained relatively unchanged. Additionally, the National Comprehensive Cancer Network (NCCN) guidelines regarding initial evaluation, staging, response assessment, and surveillance of SCLC have also remained relatively static. To evaluate radiologic imaging utilization for SCLC, we reviewed patients imaging data and assessed their association with staging, metastatic sites at presentation, overall survival, and other clinical factors. Methods: Retrospective analysis of patients with a diagnosis of SCLC that received treatment and follow up from 2003 through 2018 was completed. Cross-sectional radiology imaging data including computed tomography of the chest abdomen and pelvis (CT CAP), magnetic resonance imaging (MRI), and positron-emission tomography (PET) was obtained from the picture archiving and communication system (PACS) and clinical data including age, sex, race, smoking history, extensive/limited stage, and metastatic sites at presentation was obtained from the electronic medical record. Results: The average age at diagnosis for all SCLC patients (n = 518) from 2003 to 2018 was 66 with a male to female ratio of 0.89. The mean overall survival of all SCLC patients was 410.2 days with extensive (n = 371) stage = 312.5 days and limited (n = 147) stage = 718.8 days. We found a significantly increased number of patients less than age 66 presented with brain metastasis compared to those greater than age 66 ( P< 0.01). The absolute total number of CT CAP and PET studies was significantly increased in limited stage patients compared to extensive stage ( P< 0.001). However, when accounting for mean overall survival, extensive stage patients received a significantly increased number of CT Brain ( P< 0.05), PET ( P< 0.01), CT CAP, and MRI Brain ( P< 0.001) studies compared to limited stage per year. Conclusions: Overall radiology imaging utilization is significantly different between limited and extensive stage SCLC patients over the past 15 years.

Frequency and imaging features of abdominal immune-related adverse events in metastatic lung cancer patients treated with PD-1 inhibitor

PURPOSE

To investigate the frequency and imaging features of radiographically evident abdominal immune-related adverse events (irAEs) in patients with metastatic non-small-cell lung cancer (NSCLC) treated with PD-1 inhibitors.

METHODS

This retrospective study included 137 patients with metastatic NSCLC treated with PD-1 inhibitor nivolumab monotherapy (75 women; median age: 65 years), who had a baseline CT and at least one follow-up abdomen CT during therapy. Baseline and all follow-up abdominal CTs performed for monitoring of nivolumab therapy were reviewed to identify the organ-specific abdominal irAEs including colitis/enteritis, hepatitis, biliary toxicity, pancreatitis, nephritis, sarcoid-like reaction, and pancreatic and adrenal atrophy. Their frequency and imaging features were described.

RESULTS

Eighteen (13%) patients had radiologically identified abdominal irAEs (median 2.1 months after starting nivolumab; interquartile range 1.17-5.83 months); 16 patients developed enteritis/colitis (12 pancolitis, two segmental colitis, one enterocolitis, one enteritis), two hepatitis, one adrenalitis. One patient with hepatitis also developed colitis/enteritis. Radiographic abdominal irAE occurred after nivolumab therapy was discontinued in six patients before any subsequent therapy was started. IrAEs prompted nivolumab interruption and treatment with steroids in four patients (three colitis/enteritis, one hepatitis). Most common CT features of colitis/enteritis included mesenteric hyperemia (n = 15), bowel wall thickening (n = 13), mucosal hyperenhancement (n = 10), and fluid-filled colon (n = 9).

CONCLUSION

Abdominal irAEs were detected on CT in 13% of NSCLC patients treated with nivolumab, and colitis, in the pancolitis form, was the most common irAE. Given the expanding role of immunotherapy, radiologists should be aware of the frequency and imaging manifestations of abdominal irAEs and the impact on patient management.

Standardized report template for indeterminate renal masses at CT and MRI: a collaborative product of the SAR Disease-Focused Panel on Renal Cell Carcinoma

PURPOSE

To create a succinct yet comprehensive evidence-based structured report template for indeterminate renal masses characterized at CT and MRI.

METHODS

This IRB-exempt, iterative, multi-institutional quality improvement project was informed by published data derived from a multi-institutional survey and a multi-institutional review of CT and MRI radiology reports. A two-stage blinded Delphi process by the 16-member 12-institution Society of Abdominal Radiology Disease-Focused Panel on Renal Cell Carcinoma was conducted to create a structured report template for indeterminate renal masses evaluated at CT and MRI. Individual reporting characteristics were scored by members as 'core,' 'optional,' or 'exclude.' Threshold for inclusion was ≥ 80% support. If < 80% members considered a characteristic a 'core' feature, but ≥ 80% considered it either 'core' or 'optional,' it was considered an 'optional' feature. If neither was the case, the characteristic was excluded. Free-text comments were permitted. Characteristics considered 'core' by 50-99% of respondents in Round 1 (i.e., nonunanimous support) and uninvestigated free-text comments were assessed in Round 2. Core and optional structured reporting templates were derived.

RESULTS

The response rate was 100% in Round 1 (16/16) and Round 2 (16/16). In Round 1, 5 characteristics had unanimous support as 'core' features. Following Round 2, 13 characteristics had ≥ 80% support as 'core' features, and 10 characteristics had ≥ 80% support as 'optional' features. Structured report templates were derived.

DISCUSSION

Structured 'core' and 'optional' templates for indeterminate renal masses at CT and MRI were derived, which may improve compliance with reporting preferred and essential imaging characteristics.

Predictive Role of Computed Tomography Texture Analysis in Patients with Metastatic Urothelial Cancer Treated with Programmed Death-1 and Programmed Death-ligand 1 Inhibitors

BACKGROUND

Reliable biomarkers to predict the response of metastatic urothelial cancer (mUC) to programmed death-1 and programmed death-ligand 1 (PD-1/PD-L1) inhibitors are being investigated. Texture analysis represents tumor heterogeneity and may serve as a predictor of response in mUC.

OBJECTIVE

To assess the predictive ability of computed tomography (CT) texture analysis for progression-free survival (PFS) in patients with mUC treated with PD-1/PD-L1 inhibitors.

DESIGN, SETTING, AND PARTICIPANTS

Forty-two postplatinum patients with mUC treated with PD-1/PD-L1 inhibitors from 2013 to 2018, including those with measurable disease per RECIST 1.1 who had contrast-enhanced baseline or first follow-up CT within 3mo after starting treatment, were included. PFS was calculated based on serial follow-up CT scans. Eleven patients with follow-up of <12mo without progression were excluded. Texture features of measurable lesions on baseline and first follow-up CT were extracted using commercially available software (TexRAD; Feedback Plc, Cambridge, UK) using different spatial scaling factors (0, 2-6).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Stepwise logistic regression analysis was conducted to identify patients with PFS <12mo, and performance was assessed using receiver operator characteristic curves.

RESULTS AND LIMITATIONS

Of 31 included patients, 18 had PFS <12mo. Twenty-five baseline CT and 29 first follow-up CT scans met the inclusion criteria. In patients with PFS <12mo, entropy and mean were higher on first follow-up CT (p=0.02 and p=0.005, respectively). A predictive model including mean and entropy on first follow-up CT yielded 95% sensitivity, 80% specificity, 90% positive predictive value, 89% negative predictive value, and 90% accuracy (area under the curve=0.963) to identify patients with PFS <12mo. Limitations include retrospective nature and small sample size.

CONCLUSIONS

CT texture analysis can help predict early progression with high accuracy soon after starting PD-1/PD-L1 inhibitors. Studies investigating the correlation of texture analysis with survival endpoints may help validate texture analysis as a biomarker of PD-1/PD-L1 inhibitors' treatment response.

PATIENT SUMMARY

Computed tomography texture analysis can help predict durability of response in patients with metastatic urothelial cancer early during treatment with programmed death-1 and programmed death-ligand 1 (PD-1/PD-L1) inhibitors.

Predictive role of CT texture analysis in patients with metastatic urothelial cancer treated with PD-1/PD-L1 inhibitors

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Background: Reliable biomarkers to predict response of urothelial cancer to PD-1/PD-L1 inhibitors are still being investigated. Texture analysis represents underlying tumor heterogeneity and may serve as a predictor of response in urothelial cancer. The purpose of this study was to assess predictive ability of CT texture analysis for disease progression in patients with metastatic urothelial cancer treated with PD-1/PD-L1 inhibitor. Methods: In this IRB-approved HIPAA-compliant retrospective study, from total 93 consecutive patients with metastatic urothelial cancer treated with PD-1/PD-L1 inhibitors from 2013-2018, 43 patients with measurable disease per RECIST 1.1 criteria who had contrast-enhanced CT performed within three months after starting treatment were included. Progression-free survival was calculated based on serial follow-up CTs, and 11 patients without progression who did not reach 1 year follow-up were excluded. Texture features of measurable lesions on first follow-up CT were extracted (TexRAD Ltd, Feedback Plc, Cambridge, UK). Stepwise logistic regression analysis to identify patients who had progressive disease (PD) at 12 months was performed and performance assessed using receiver operator curves. Results: Of 32 included patients (24 men, 8 women; median age: 65 years) who had total 80 measurable lesions, 22 progressed by 12 months. On first follow-up CT, the entropy and mean of the lesions were higher (p = 0.04, p = 0.02) for patients with PD by 12 months. Calculated specificity and sensitivity of entropy (AUC = 0.79) were 90%, and 63%; of mean (AUC = 0.81) were 90%, and 50%. A predictive model including mean and entropy yielded 95% sensitivity, 80% specificity, 91% PPV, 89% NPV and 91% accuracy (AUC = 0.863) to identify patients with PD at 12 months. Conclusions: Texture analysis of CT performed within three months after starting PD-1/PD-L1 can help predict patients who progress by 12 months with high accuracy. Further studies investigating the correlation of texture analysis with survival endpoints may help validate the role of texture analysis as a biomarker to predict response to PD1/PD-L1 inhibitors.

Lobular breast cancer: patterns of intraabdominal metastatic spread on imaging and prognostic significance

OBJECTIVE

To retrospectively review the frequency, patterns and intra-abdominal sites of metastatic invasive lobular breast cancer, and to correlate the findings with overall survival.

MATERIALS AND METHODS

From a pathology database search revealing 327 patients with metastatic lobular breast cancer at our institution from January 2004 through August 2014, imaging was available in 116 patients (age range, 31-87 years, mean age, 55). Simple descriptive statistics were performed to record and tabulate the abdominal metastatic spread. Prognostic significance of abdominal metastases and individual abdominal metastatic sites was studied using the Log-rank test and construction of Kaplan-Meier curves.

RESULTS

The most frequent sites of intra-abdominal metastatic invasive lobular breast cancer were peritoneum (55 patients, 47%), followed by liver (37 patients, 32%), bowel (34 patients, 29%), ovary (33 patients, 28%), retroperitoneum (16 patients, 14%), ureter (16 patients, 14%), and lymph nodes (15 patients, 13%). Bowel obstruction was noted in 15 patients (13%) and hydronephrosis in 25 patients (22%). The median abdominal metastasis-free survival was 76 months (interquartile range: 17-191). The overall survival (OS) was 86 months (interquartile range: 49-188). Patients with abdominal metastases had shorter OS. Patients with hepatic metastases had shorter overall survival than those patients without hepatic metastases (p = 0.02, Log-Rank test).

CONCLUSION

Invasive lobular breast cancer has a predilection for metastasizing to both typical (liver) and atypical intra-abdominal sites (peritoneum, GI tract, and adnexa). Presence of intra-abdominal disease and hepatic metastases in patients with ILC negatively affects overall survival.

Multi-institutional analysis of CT and MRI reports evaluating indeterminate renal masses: comparison to a national survey investigating desired report elements

PURPOSE

To determine the need for a standardized renal mass reporting template by analyzing reports of indeterminate renal masses and comparing their contents to stated preferences of radiologists and urologists.

METHODS

The host IRB waived regulatory oversight for this multi-institutional HIPAA-compliant quality improvement effort. CT and MRI reports created to characterize an indeterminate renal mass were analyzed from 6 community (median: 17 reports/site) and 6 academic (median: 23 reports/site) United States practices. Report contents were compared to a published national survey of stated preferences by academic radiologists and urologists from 9 institutions. Descriptive statistics and Chi-square tests were calculated.

RESULTS

Of 319 reports, 85% (271; 192 CT, 79 MRI) reported a possibly malignant mass (236 solid, 35 cystic). Some essential elements were commonly described: size (99% [269/271]), mass type (solid vs. cystic; 99% [268/271]), enhancement (presence vs. absence; 92% [248/271]). Other essential elements had incomplete penetrance: the presence or absence of fat in solid masses (14% [34/236]), size comparisons when available (79% [111/140]), Bosniak classification for cystic masses (54% [19/35]). Preferred but non-essential elements generally were described in less than half of reports. Nephrometry scores usually were not included for local therapy candidates (12% [30/257]). Academic practices were significantly more likely than community practices to include mass characterization details, probability of malignancy, and staging. Community practices were significantly more likely to include management recommendations.

CONCLUSIONS

Renal mass reporting elements considered essential or preferred often are omitted in radiology reports. Variation exists across radiologists and practice settings. A standardized template may mitigate these inconsistencies.

Correction to: Multi-institutional analysis of CT and MRI reports evaluating indeterminate renal masses: comparison to a national survey investigating desired report elements

The original version of this article contained an error in author name. The co-author's name was published as Ivan M. Pedrosa, instead it should be Ivan Pedrosa. The original article has been corrected.

Optimal Phase of Dynamic Computed Tomography for Reliable Size Measurement of Metastatic Neuroendocrine Tumors of the Liver: Comparison between Pre- and Post-Contrast Phases

Objective

The reliability of size measurements of liver metastases from neuroendocrine tumors (NETs) on contrast-enhanced computed tomography (CT) phases made by different readers may be hampered due to transient, variable rim enhancement in arterial phase (AP) or portal venous phase (PVP) images. We aimed to assess the reliability of tumor size measurements in pre- and post-contrast scans.

Materials and Methods

The study coordinator selected target lesions according to Response Evaluation Criteria in Solid Tumors 1.1 guidelines in 44 consecutive patients with pathologically confirmed NET liver metastases. Two blinded readers measured the longest diameters of target lesions on pre-contrast, AP, and PVP images twice with a 4-week interval. Inter- and intra-observer agreements were evaluated using Bland-Altman plots and 95% limit of agreement (LOA) calculations.

Results

Of the 79 target lesions (approximate mean size of 3 cm), 45 showed rim enhancement. Inter-observer agreement assessed based on LOA was highest in pre-contrast CT images (−6.1–5.7 mm), followed by PVP (−7.9–7.1 mm) and AP (−8.5–7.4 mm) images. Intra-observer agreement showed the same trend: −2.8–2.9 mm and −2.9–2.9 mm for readers 1 and 2, respectively, on pre-contrast CT, −2.8–2.9 mm and −3.0–3.2 mm, respectively, on PVP, and −3.2–4.2 mm and −3.4–3.2 mm, respectively, on AP images. Mean tumor diameters differed significantly among the phases in the following increasing order: pre-contrast CT, PVP, and AP images.

Conclusion

There was better inter- and intra-observer agreement in size measurements of NET liver metastases on precontrast scans than on AP and PVP scans. Pre-contrast CT may be the optimal for measuring NET liver metastases if its accuracy is proven.