Distant Metastatic Disease Research Articles

Utility of Multiparametric Prostate MRI to Predict Regional or Distant Metastatic Disease Against Conventional Staging Using CT and Bone Scintigraphy or 68Ga-PSMA PET in Intermediate-to-High-Risk Prostate Cancer

Utility of Multiparametric Prostate MRI to Predict Regional or Distant Metastatic Disease Against Conventional Staging Using CT and Bone Scintigraphy or 68Ga-PSMA PET in Intermediate-to-High-Risk Prostate Cancer

A comprehensive approach to defining the cutoff value of oligometastasis in head and neck squamous cell carcinoma.

Patients with limited distant metastatic disease, also known as oligometastasis, show better survival rates than polymetastatic patients, and may be amenable for curative-intent treatment. The definition of oligometastasis, however, is unknown, and no quantitative analyses on the cutoff value for oligometastasis have been performed before. This study aims to derive specific threshold values for the number of metastases and affected locations that defines oligometastatic disease in head and neck squamous cell carcinoma. A retrospective cohort study was conducted including all patients diagnosed with distant metastases between 2006 and 2021. For each patient, the number of distant metastases and affected locations was recorded on the basis of the available imaging at the time of diagnosis. Cox regression analyses and a machine-learning k-means algorithm were used to determine threshold values. A total of 384 patients untreated for their metastatic foci were analyzed. Most patients (n=207; 53.9%) had metastasis to one anatomic location, followed by metastases in two anatomic locations (n=62; 16.1%). The majority of patients had ≥9 metastatic foci (n=174; 45.3%), followed by one focus (n=74; 19.3%) and two foci (n=32; 8.3%). Cox regression and machine-learning k-means models showed that although the number of metastases did not predict survival, the number of affected locations did significantly (p<.001), by identifying a threshold of two locations. Contrary to the prevalent dogma, the definition of oligometastasis should not be defined by the number of metastases but rather by the number of affected locations, with a maximum number of affected locations set at two.

Utilization of miRNAs as Biomarkers for the Diagnosis, Prognosis, and Metastasis in Gynecological Malignancies.

Gynecological cancer is a term referring to malignancies that typically involve ovarian, cervical, uterine, vaginal, and vulvar cancer. Combined, these cancers represent major causes of morbidity and mortality in women with a heavy socioeconomic impact. MiRNAs are small non-coding RNAs that are intensively studied in the field of cancer and changes in them have been linked to a variety of processes involved in cancer that range from tumorigenesis to prognosis and metastatic potential. This review aims to summarize the existing literature that has linked miRNAs with each of the female malignancies as potential biomarkers in diagnosis (circulating miRNAs), in tumor histology and prognosis (as tissue biomarkers), and for local (lymph node) and distant metastatic disease.

Metastatic Melanoma to the Small Bowel and Colon: A Systematic Review of the Global Experience and Institutional Cohort Analysis Detailing a Rare Clinical Entity.

Cutaneous melanoma is among the most common solid tumors to metastasize to the gastrointestinal (GI) tract. Literature summarizing the clinical experience and features of this unique pathology is lacking. A systematic review of the available literature reporting clinically salient features of melanoma metastases to the small and large intestines was conducted. Additionally, we surveyed our institutional experience of surgically treated melanoma metastasis to the small bowel and colon. A descriptive analysis was performed. Kaplan-Meier curves with log-rank tests were used to analyze time-to-event intervals. Univariable and multivariable Cox logistic regression models were generated to identify predictors of survival. Over 100 studies including 1153 patients were included. GI metastases predominantly affected males, were in the small bowel/jejunum, equally presented as solitary and multiple lesions, and were generally not the first site of distant metastatic disease. The median time from primary lesion diagnosis to GI metastasis was 48 months. Analysis of our institutional cohort suggested that survival in patients receiving complete GI-specific surgical resection and immune checkpoint inhibitors (ICIs) was prolonged compared to palliative resection and without ICI therapy. Positive prognostic factors for survival following GI metastasis included fewer GI metastatic lesions, complete resection, and longer duration between primary tumor diagnosis and GI metastasis. GI metastases are a sign of advanced metastatic melanoma. Clinical suspicion of metastatic involvement in patients with a history of melanoma who develop any abdominal symptoms or anemia should remain high. Receipt of complete surgical resection and ICIs may prolong survival in disseminated melanoma.

Clinical Factors Associated With Suspicious 18F-DCFPyL PSMA PET Activity in Patients Initially Managed With Radical Prostatectomy Including Prostate-Specific Antigen < 0.5 ng/mL.

There are limited data on PSMA PET/CT for workup of recurrence after radical prostatectomy (RP) at low PSA values. We evaluated a PSMA PET/CT cohort of patients with post-RP, focusing on patients with PSA < 0.5 ng/mL. We identified a retrospective cohort who underwent piflufolastat F-18 PSMA PET/CT across an 11 hospital system from July 2021 to February 2023. Prostate-specific membrane antigen (PSMA) positivity was determined by radiology reports. Univariable and multivariable logistic regression identified factors associated with suspicious PSMA activity. Median PSA was 0.37 ng/mL (IQR, 0.15-1.29 ng/mL), with 49% of patients overall having at least 1 suspicious PSMA-avid lesion. Rates of scan positivity among patients with PSA < 0.2 and 0.2 to 0.5 ng/mL were 34% and 38%, respectively. Among all patients, 25% (104/415) had pelvic disease (prostate bed or N1) and 24% (100/415) had M1 disease. Among patients with PSA < 0.5 ng/mL, prior postoperative radiation was associated with suspicious PSMA activity. In the overall cohort, age, PSA at PSMA PET/CT, and RP Gleason grade were associated with PSMA positivity. PSADT, EAU risk, and CAPRA-S were all associated with suspicious PSMA activity. Over one-third of patients with PSAs < 0.2 ng/mL had imaging findings concerning for recurrence. Prior postoperative radiation was associated with higher rates of PSMA positivity among patients with PSA < 0.5 ng/mL, and half of patients with evidence of PSMA avid distant metastatic disease underwent metastasis-directed therapy. PET-PSMA imaging at low PSAs can be considered to inform salvage therapies.

Aggressive Types of Malignant Thyroid Neoplasms.

Differentiated thyroid cancer (DTC) includes many subtypes, which demonstrate favorable to aggressive behavior. During the past decades, efforts have been made to describe aggressive thyroid cancers. Within DTC, aggressive variants constitute rare entities with unique histopathological features and compromised survival, as local and distant metastatic disease is frequent. In recent years, the distinct category of poorly differentiated thyroid cancer was introduced in 2004 and the type of differentiated high-grade thyroid carcinoma was recently added in the 2022 WHO classification of thyroid neoplasms. Finally, anaplastic thyroid cancer exhibits a rapid, resistant to therapy, progression and confers the shortest survival. In this review, we will present the characteristics of these thyroid cancer types and also discuss the treatment, management, and follow-up of these difficult cases. Emphasis was given to recent bibliography of the last decade.

Liver metastases in high-grade neuroendocrine neoplasms: A comparative study of hepatic tumor volume and biochemical findings in NET G3 versus NEC.

Abnormal liver blood tests and liver tumor burden are known prognostic factors in neuroendocrine neoplasms (NEN). However, the relationship between biochemical liver parameters and hepatic tumor load is largely unknown in NEN and in high-grade NEN (G3) specifically. The primary objective of this study was to correlate the biochemical parameters and liver tumor volume of patients with neuroendocrine tumors grade 3 (NET G3) or neuroendocrine carcinomas (NEC). We wanted to investigate whether patients with NET G3 with extensive liver involvement had less severely elevated laboratory liver parameters than NEC patients. In total, 46 patients with NEN were included, 31 had NEC and 15 NET G3. All patients had distant metastatic disease, with liver metastases being the most common (n = 39). Both laboratory results and semiautomatic volumetric measurements of liver tumor burden were obtainable for 34 patients at baseline and 26 patients at follow-up. Alkaline phosphatase (AP), gamma-GT (gGT), and lactate dehydrogenase (LDH) increased significantly between the two time periods (p < .01). In a regression model, liver tumor burden significantly affected several blood parameters, for example, increasing AP, gGT, LDH, and aspartate aminotransferase (ASAT) by a factor of 1.02-1.04 per unit increase (1% tumor burden; all p < .001). AP, gGT, and LDH were significantly lower in NET G3 (factor of 0.43-0.68) than in NEC. Here, we found that liver chemistries changed over the NEN disease course, correlated with hepatic tumor burden, and differed by histologic subtype. The current data can potentially guide treatment decisions, for example, with regard to integration of liver-directed therapies.

Micropapillary pattern in colorectal cancer: an Australian multicentre experience.

Colorectal cancer is the third most common cancer worldwide. Micropapillary carcinoma (MPC) is increasingly identified as a poor prognostic marker in various cancers, including breast, bladder and lung. It remains an under recognized subtype in colorectal cancer. The aim of this study is to evaluate the prevalence, implications and impact on survival of MPC in colorectal cancer in an Australian cohort. A retrospective review of all colorectal cancer resections in two tertiary centres in Sydney Australia was performed, between 2019 and 2024. MPC was identified on histolopathology as per standard guidelines of the resected specimens. Variables collected included age, sex, TNM, site, lymphovascular invasion (LVI), and lymph node involvement. Of 597 colorectal cancer resections during the study period, 21 cases of MPC were identified (3.5%). Mean age was 60 years (SD 15 years). Twenty patients (95%) had T3-T4 tumours, 19 (90%) had positive lymph node involvement, 18 (86%) had confirmed or suspected LVI, and 4 (19%) had distant metastatic disease. Overall 1-year survival was 90% and 3-year survival was 76%. MPC is associated with high risk features in colorectal adenocarcinoma. Accurate histopathological diagnosis of these more aggressive cancers should guide prognostication, individualized adjuvant treatment and close surveillance.

Emergency admission preceding malignancy diagnosis: Insights from a study at a tertiary care hospital

BACKGROUND: A considerable number of cancer patients are diagnosed following presentation at emergency department with symptoms related to their condition, yet research in this area remains scarce. This study aimed to identify the clinical characteristics and evaluate the health outcomes of patients who presented to the emergency department with symptoms of cancer. MATERIALS AND METHODS: We analyzed data for patients diagnosed with cancer postemergency department presentation at a tertiary care hospital between 2015 to 2021. Data on patient characteristics, clinical features, and health outcomes was abstracted through meticulous review of the patients’ medical record. SPPS was used for data analysis. Wilcoxon rank-sum test and Chi-square or Fisher’s exact test as appropriate, were used to determine statistical significance for continuous and categorical variables, respectively. Regression analysis determined factors associated with treatment and mortality. Kaplein-Meier analysis was performed to determine survival time. RESULTS: During the study period, 108 patients were diagnosed with new malignancies following acute medical admission. The median age of these patients was 67 years (interquartile range [IQR]: 56–75), and 58 (53.7%) of these patients were men. The most common presenting complaints were pain (55.6%), weight loss (44.4%), and poor appetite (36.1%). The median time from the onset of symptoms to hospital presentation was 30 days (IQR 8–62). The most common types of malignancies diagnosed in the study were hepatobiliary (18.5%), gastroesophageal (15.7%), and lung cancer (14.8%). Two-thirds of patients had Stage IV malignancy, and 64.81% presented with distant metastatic disease at the time of diagnosis. Older age (69 vs. 61.5 years; P = 0.04), lower level of general education and higher attainment (11.4% vs. 44.4%; P &lt; 0.01), advanced malignancy stages (P &lt; 0.01), and metastatic disease at diagnosis (75.4% vs. 44.4%; P = 0.01) were associated with higher mortality. CONCLUSION: Emergency presentations for newly diagnosed cancer, often seen in older patients with lower education and multiple comorbidities, were generally associated with poor survival rates owing to advanced disease with distant metastasis. Enhancing awareness of critical symptoms could improve early detection rates.

Abstract B135: Association of residential economic and racial segregation with metastatic disease at diagnosis in pediatric patients with solid tumors

Abstract Background: Disparities in pediatric cancer outcomes by race and ethnicity may be influenced by neighborhood characteristics, particularly residential economic and racial segregation. Prior to a new cancer diagnosis, pediatric patients are vulnerable to structural barriers embedded in their neighborhoods. In particular, residential economic and racial segregation may impede access to initial care for early cancer detection, increasing the likelihood of presenting with distant metastatic disease at diagnosis that can translate to excess morbidity and mortality. This study assesses the association of residential economic and racial segregation as measured by the Index of Concentration at the Extremes (ICE) with the likelihood of presenting with distant metastatic disease (as compared to local or locoregional disease) among children newly diagnosed with cancer. Methods: We studied a cohort of pediatric patients diagnosed with solid tumors at Children’s Healthcare of Atlanta between 2010 and 2016. Patients’ ZIP codes were linked to the ICE, which was constructed at the ZIP code level using American Community Survey 2012-2016 five-year estimates. The ICE was categorized into tertile 1 (most deprived) through tertile 3 (most privileged). Multivariable logistic regression models were used to assess the association between residential economic and racial segregation, defined by tertiles of the ICE, and the likelihood of presenting with distant metastatic disease, as determined by initial cancer staging. All models adjusted for patient- and disease-level covariates, including age, sex at birth, health insurance type, and cancer type. Results: Among 829 patients identified in our analytic sample, 27.6% had distant metastatic disease at diagnosis. Living in the most deprived (ICE tertile 1) versus the most privileged (ICE tertiles 2/3) neighborhoods was significantly associated with a higher likelihood of presenting with distant metastatic disease at diagnosis (adjusted odds ratio [OR] = 1.46; 95% confidence interval [CI] = 1.03 to 2.07; p=0.03). Additionally, non-Hispanic Black patients living in the most deprived neighborhoods were more likely to have distant metastatic disease at diagnosis compared to non-Hispanic White patients living in the most privileged neighborhoods (adjusted OR = 1.83; 95% CI = 1.15 to 2.92; p=0.002). Conclusion: This study provides new insights into how residential economic and racial segregation is associated with metastatic disease at diagnosis among children presenting with a new solid tumor. Our findings highlight the need for geographically targeted interventions to improve community care, resource allocation and investment, and public policies aimed at supporting this vulnerable patient population. Citation Format: Alexandra Cathcart, Sharon M. Castellino, Lu Zhang, Karen Wasilewski-Masker, Andrew L. Hong, Heeju Sohn, Xu Ji. Association of residential economic and racial segregation with metastatic disease at diagnosis in pediatric patients with solid tumors [abstract]. In: Proceedings of the 17th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2024 Sep 21-24; Los Angeles, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2024;33(9 Suppl):Abstract nr B135.

The management of osteosarcoma in children and adolescents in a resource-limited setting: quality improvement considerations to improve treatment outcomes

BackgroundThe survival rates for children and adolescents with osteosarcoma in low-income countries are poor. Insufficient data regarding the challenges of managing osteosarcoma in resource-limited settings has been published. We evaluated the treatment of osteosarcoma in children and adolescents with the aim of improving the health system and management outcomes.MethodsWe sourced data on children under 18 years treated for osteosarcoma at the Uganda Cancer Institute between January 2016 and December 2020. Descriptive statistics and Kaplan-Meier survival analysis were used.ResultsSeventy-four osteosarcoma cases were identified, with a median age of 13 years (IQR 9.8–15). Referrals were made after a median of 28 days (range 1-147). Before appropriate referral, more than a quarter (26%) had undergone invasive procedures that could compromise tumour integrity and outcome. Half (50%) of the patients had metastatic disease at diagnosis, primarily to the lungs (n = 43; 92%). Only 14 (33%) patients received neoadjuvant chemotherapy. Forty-three (58.1%) patients underwent limb amputation surgery, including 25 localized tumours and 18 patients with distant metastatic disease. No metastatectomies were performed. Adjuvant chemotherapy was delayed for longer than 21 days in 26 (61%) patients. No pathology reports described the status of resection margins or the degree of chemotherapy-induced necrosis. Twenty-six (35%) patients abandoned treatment, mainly due to pending radical surgery (n = 18/26; 69%). Only 18% (n = 13) were still alive; 46% (n = 34) had died; and 37% (n = 27) had an unknown status. The median overall survival was 1.1 years, and was significantly negatively affected by disease metastasis, timing of adjuvant therapy, and treatment abandonment.ConclusionsOsteosarcoma outcomes for children and adolescents at the Uganda Cancer Institute are extremely poor. The quality of care can be improved by addressing delayed referrals, high rates of prior manipulative therapy, metastatic disease, treatment abandonment, surgical challenges, and delayed resumption of adjuvant chemotherapy.

The International Association for the Study of Lung Cancer Mesothelioma Staging Project: Proposals for the M Descriptors in the Forthcoming Ninth Edition of the TNM Classification for Pleural Mesothelioma

IntroductionThe International Association for the Study of Lung Cancer developed a global multicenter database to propose evidence-based revisions for the ninth edition of the TNM classification of pleural mesothelioma (PM). This study analyzes the M category to validate eighth edition M category recommendations. MethodsCases were submitted electronically or by transfer of existing institutional databases for patients with histologically or cytologically confirmed PM. The presence and number of metastases (single versus multiple) in each of eight organ systems were reported for patients with M1 disease at diagnosis. Overall survival (OS) was calculated by the Kaplan-Meier method. Differences in OS were assessed by log-rank test. ResultsOf 7338 submitted cases, 3598 were eligible and 3221 had sufficient data for clinical staging; 228 cases (7%) were M1. Median overall estimated survival was inferior for M1 compared with M0 patients: 10.5 months versus 21.5 months, respectively (p < 0.0001); estimated 1-year survival was 46% versus 71%, respectively. OS differences between M categories were preserved within histologic subgroups. Among 158 patients with organ-specific documentation of M1 disease, there was no statistically significant difference in OS between those with intrathoracic versus more distant metastatic disease (14.4 mo versus 10.9 mo, p = 0.64). No significant survival difference was detected between patients with metastatic disease in a single-organ system versus multiple-organ systems (12.6 mo versus 8.8 mo, p = 0.45). ConclusionsThis evidence-based analysis of the M category for PM conforms with the eighth edition M descriptors. No changes are proposed in the ninth edition of the mesothelioma M category.

Quantitative proteomics reveals serum proteome alterations during metastatic disease progression in breast cancer patients

BackgroundTumor recurrence and metastatic progression remains the leading cause for breast cancer related mortalities. However, the proteomes of patient- matched primary breast cancer (BC) and metastatic lesions have not yet been identified, due to the lack of clinically annotated longitudinal samples. In this study, we evaluated the global-proteomic landscape of BC patients with and without distant metastasis as well as compared the proteome of distant metastatic disease with its corresponding primary BC, within the same patient.MethodsWe performed mass spectrometry-based proteome profiling of 73 serum samples from 51 BC patients. Among the 51 patients with BC, 29 remained metastasis-free (henceforth called non-progressors), and 22 developed metastases (henceforth called progressors). For the 22 progressors, we obtained two samples: one collected within a year of diagnosis, and the other collected within a year before the diagnosis of metastatic disease. MS data were analyzed using intensity-based absolute quantification and normalized before differential expression analysis. Significantly differentially expressed proteins (DEPs; absolute fold-change ≥ 1.5, P-value < 0.05 and 30% abundance per clinical group) were subjected to pathway analyses.ResultsWe identified 967 proteins among 73 serum samples from patients with BC. Among these, 39 proteins were altered in serum samples at diagnosis, between progressors and non-progressors. Among these, 4 proteins were further altered when the progressors developed distant metastasis. In addition, within progressors, 20 proteins were altered in serum collected at diagnosis versus at the onset of metastasis. Pathway analysis showed that these proteins encoded pathways that describe metastasis, including epithelial–mesenchymal transition and focal adhesion that are hallmarks of metastatic cascade.ConclusionsOur results highlight the importance of examining matched samples from distant metastasis with primary BC samples collected at diagnosis to unravel subset of proteins that could be involved in BC progression in serum. This study sets the foundation for additional future investigations that could position these proteins as non-invasive markers for clinically monitoring breast cancer progression in patients.

FDG-PET/MRI in colorectal cancer care: an updated systematic review.

Since its introduction in 2011, FDG-PET/MRI has been advocated as a useful adjunct in colorectal cancer care. However, gaps and limitations in current research remain. This systematic review aims to review the current literature to quantify the utility of FDG-PET/MRI in colorectal cancer care. An up-to-date review was performed on the available literature between 2000 and 2023 on PubMed, EMBASE, Medline, databases. All studies reporting on the use of FDG-PET/MRI in colorectal cancer care were analyzed. The main outcome measures were accuracy in initial staging, restaging, and detection of metastatic disease in both rectal as well as colon cancers. The secondary outcome was comparing the performance of FDG-PET/MRI versus Standard of Care Imaging (SCI). Finally, the clinical significance of FDG-PET/MRI was measured in the change in management resulting from imaging findings. A total of 22 observational studies were included, accounting for 988 patients. When individually compared to current Standard of Care Imaging (SCI)-MRI pelvis for rectal cancer and thoraco-abdominal contrast CT, PET/MRI proved superior in terms of distant metastatic disease detection. This led to as much as 21.0% change in management. However, the technological limitations of PET/MRI were once again highlighted, suggesting SCI should retain its place as first-line imaging. FDG-PET/MRI appears to be a promising adjunct in staging and restaging of colorectal cancer in carefully selected patients.

Staging in thick cutaneous malignant melanoma: A sequenced approach

BackgroundPatients with thick cutaneous pT4 malignant melanoma are at high risk for metastatic disease and optimal staging is poorly defined. This study examines the frequency and modality of pre-operative staging to provoke thought on optimal staging. MethodsA retrospective study was performed of patients with clinical T4N0 melanoma diagnosed between 2015-2017. The modality (sentinel lymph node biopsy and/or imaging), timing, and findings of staging investigations were assessed. ResultsOne hundred thirty-six patients with pT4a or pT4b cutaneous melanoma and clinically negative regional lymph nodes were included. Forty patients underwent no staging. Thirty-six patients underwent pre-operative imaging, and of these, regional or distant disease was identified in seven patients (19%). Another 36 patients underwent upfront sentinel lymph node biopsy concurrently with wide local excision. A positive sentinel lymph node biopsy was found in eight (22%) of these patients of which two had regional or distant metastatic disease on post-operative imaging. Of 16 who underwent a sentinel lymph node biopsy after negative pre-operative imaging, three had a positive sentinel lymph node biopsy. ConclusionStaging is non-standardized and underutilized in patients with thick melanoma. With evolving systemic treatment options, a well-defined approach to staging, with consideration for pre-operative imaging in pT4 patients, is essential for high-risk patients.

Melanoma Deaths by Thickness: Most Melanoma Deaths Are Not Attributable to Thin Melanomas

IntroductionPrevious population-based studies have reported that the majority of melanoma mortality is related to patients with thin (≤1 mm Breslow thickness) melanomas. The aim of the present study was to evaluate the relative proportion of melanoma-specific deaths across all stages of melanoma at diagnosis over the past 20 y in the United States. MethodsA review of all cutaneous melanoma cases in the US Surveillance, Epidemiology, and End Results registry from 2004 to 2020 was performed. Breslow thickness was categorized as thin (≤1.0 mm), intermediate (>1-4 mm), or thick (>4 mm). All-cause deaths and melanoma-specific deaths were compared across tumor thickness and stage groups at diagnosis. Survival analysis was performed with nonmelanoma deaths considered as a competing risk to estimate the cumulative incidence of melanoma-specific death. ResultsMost melanoma deaths occurred in patients who initially presented with local disease (53%) compared to regional (36%) or distant (11%) disease (P < 0.001). However, most (66%) of the melanoma-specific deaths in patients who presented with localized disease were in those with intermediate or thick (i.e., Breslow thickness >1.0 mm) primary tumors compared to those with thin melanomas (34%). The cumulative incidence of melanoma-specific death at 10 y in patients with localized thin melanomas at the time of diagnosis was 2.6% (95% confidence intervals 2.5%-2.7%). ConclusionsThe public health burden in terms of melanoma-specific mortality is related to patients with tumors >1 mm Breslow thickness, many of whom have regional and distant metastatic disease at the time of diagnosis, not patients with thin melanomas.

Gastro-Esophageal Cancer: Can Radiomic Parameters from Baseline 18F-FDG-PET/CT Predict the Development of Distant Metastatic Disease?

We aimed to determine if clinical parameters and radiomics combined with sarcopenia status derived from baseline 18F-FDG-PET/CT could predict developing metastatic disease and overall survival (OS) in gastroesophageal cancer (GEC). Patients referred for primary staging who underwent 18F-FDG-PET/CT from 2008 to 2019 were evaluated retrospectively. Overall, 243 GEC patients (mean age = 64) were enrolled. Clinical, histopathology, and sarcopenia data were obtained, and primary tumor radiomics features were extracted. For classification (early-stage vs. advanced disease), the association of the studied parameters was evaluated. Various clinical and radiomics models were developed and assessed. Accuracy and area under the curve (AUC) were calculated. For OS prediction, univariable and multivariable Cox analyses were performed. The best model included PET/CT radiomics features, clinical data, and sarcopenia score (accuracy = 80%; AUC = 88%). For OS prediction, various clinical, CT, and PET features entered the multivariable analysis. Three clinical factors (advanced disease, age ≥ 70 and ECOG ≥ 2), along with one CT-derived and one PET-derived radiomics feature, retained their significance. Overall, 18F-FDG PET/CT radiomics seems to have a potential added value in identifying GEC patients with advanced disease and may enhance the performance of baseline clinical parameters. These features may also have a prognostic value for OS, improving the decision-making for GEC patients.

Perineural invasion as a predictor of local recurrence in cats with squamous cell carcinoma treated with electrochemotherapy.

Squamous cell carcinoma (SCC) is a malignant neoplasm that accounts for approximately 15-25% and 70-80% of all feline cutaneous and oral tumors, respectively. Similar to that in humans, feline SCC can be highly invasive locally; however, its metastasis rate is low. Thus, effective local treatment may be curative for most patients, and includes surgery, electrochemotherapy (ECT), cryosurgery, or a combination of these. However, this neoplasia can manifest more aggressively in some patients, leading to higher recurrence rates. In humans, perineural invasion (PNI) has been described as a relevant tumor dissemination pathway associated with high-risk SCC, resulting in higher recurrence rates, resistance to local treatments, and short survival. However, PNI and its prognostic value have not been described in feline SCC. This study aimed to evaluate the PNI in a feline population with SCC treated with ECT and correlate its presence with the occurrence of local recurrence and other clinical variables. Twenty-four cats histopathologically diagnosed with SCC between 2013 and 2021 were retrospectively selected from the medical records of the Oncological Center Vet Cancer (São Paulo, SP, Brazil). The inclusion criteria were ECT as the sole therapy, histopathological evaluation of PNI, and absence of distant metastatic disease. The complete response rate was 96% (23/24), and PNI was identified in 33% of the cats (8/24, PNI-positive group), whereas 67% were free of this invasion (16/24, PNI-negative group). All PNI-positive cats developed local recurrence, whereas only five PNI-negative cats experienced recurrence. Local recurrence was significantly associated with PNI (p = 0.03). The results of this study are preliminary but promising. The data obtained are the first regarding PNI occurrence in feline SCC and pave the way for further studies, mainly to correlate the PNI with survival data and better define its prognostic value.

Cobimetinib plus atezolizumab for RAS and NF1/2-mutated poorly differentiated thyroid carcinoma.

6106 Background: Poorly differentiated thyroid carcinomas (PDTC) are a subset of thyroid cancers characterized by high-grade pathologic features. They hold an intermediate position on the spectrum of follicular-derived thyroid cancers. Due to their more aggressive clinical behavior, PDTCs typically exhibit shorter responses to the usual kinase inhibitors (KIs) used in advanced differentiated thyroid cancers and develop resistance earlier on. In fact, median progression free survival (PFS) with single-agent lenvatinib in patients with PDTC in the SELECT trial (n=28) was 14.8 months. Although there are increasing data to support the use of immunotherapy plus KI combinations in anaplastic thyroid cancer, evidence demonstrating the efficacy of this strategy in PDTC is sparse. We aimed to study the safety and efficacy of atezolizumab combined with KIs in PDTC. Methods: We enrolledpatientswith PDTC in a single-center phase II prospective trial of atezolizumab plus mutation-determined targeted therapy (NCT03181100). Patients with RAS or NF- mutated tumors were treated with atezolizumab plus the MEK inhibitor (MEKi) cobimetinib. Primary outcome was median overall survival (mOS). Best response to therapy was assessed per RECIST v1.1; survival by the Kaplan-Meier method. Results: Eight patients with RAS/NF-mutated PDTC were enrolled. Median age at treatment start was 68.5 years. All patients had distant metastatic disease at time of enrollment. Prior to study entrance, 7/8 patients (88%) had surgical resection of the primary tumor, 6/8 (75%) radioactive iodine, 2/8 (25%) external beam radiation to the neck, and 3/8 (38%) bridging cytotoxic chemotherapy. All patients were naïve to KIs. Six (75%) patients had RAS mutations (1 HRAS, 3 KRAS, 2 NRAS) and 3 (38%) had NF mutations (2 NF1, 1 NF2). One patient’s tumor harbored both KRAS and NF2 mutations at baseline. PD-L1 score was positive in 3/4 evaluable specimens. Median duration of follow-up was 65 months. Best response to therapy was stable disease in 6/8 (75%), partial response in 1/8 (12.5%) and progressive disease in 1/8 (12.5%). mOS was 23 months (95% CI, 12.8 – 33.2) and median PFS was 7 months (95% CI, 2.4 – 11.6). 4/8 patients received radioactive iodine (RAI) while on systemic therapy. Median dose of RAI was 149 millicuries (range, 108 – 153). mOS was significantly longer in patients who received RAI (32 vs 16 months; p= 0.034). The combination of cobimetinib + atezolizumab was overall well tolerated, with an expected adverse event profile. Conclusions: In patients with metastatic PDTC driven by RAS or NFmutations, combination of the anti-PD-L1 atezolizumab with MEKi cobimetinib showed some clinical efficacy, although PFS was shorter than with single-agent lenvatinib. However, SELECT trial did not delineate responses by driver mutations. This combination could thus be considered in selected patients at high risk of complications with antiangiogenic KIs. Clinical trial information: NCT03181100 .

Evaluating the utility of routine survivorship exams in breast cancer: Modality of detection of recurrence in a prospective cohort study.

1629 Background: National Comprehensive Cancer Network surveillance guidelines for invasive breast cancer recommend a history and physical exam every 3-12 months for the first 5 years, followed by annually, and mammography every 12 months. However, frequent in-office visits create time toxicity for breast cancer survivors, may have low utility in recurrence detection, and can create false reassurance. This study evaluates the modality of breast cancer recurrence in an integrated health system with access to primary and specialty care. Methods: We investigated mode of detection of recurrent breast cancer in the Pathways Study, a prospective cohort study of adult women diagnosed with and treated for invasive breast cancer in Kaiser Permanente Northern California, with enrollment from 2006 to 2013, and follow-up through December 2021. In this analysis, we included 4,431 women diagnosed at Stages I-III. Cohort members were followed for recurrences, deaths, and other outcomes. Of primary interest was modality of detection of recurrence, categorized as patient-driven symptoms, surveillance mammogram, diagnostic testing (i.e., other surveillance imaging for recurrence such as PET CT or MRI), routine clinical breast exam, or incidental finding. Results: A total of 617 (13.9%) women were identified as having breast cancer recurrence. Patients with recurrence shared similar demographic characteristics to those without recurrence. The recurrence population had median age of 59.2 years, BMI of 28.2 kg/m2, and racial/ethnic composition of 63% white,13% Hispanic,12% Asian, and 10% black. The median time from diagnosis to recurrence was 4 years. Seventy percent of recurrences were found to have distant metastatic disease, of which only 6.7% had concurrent local nodal and/or breast involvement. For those without metastases, 17.7% had recurrence localized in the ipsilateral breast, 2.8% in both the breast and locoregional nodes, and 9.3% only in locoregional nodes. Most recurrences were detected by patient driven symptoms (69.4%). Among the total cases, 8.1% of patients were diagnosed by routine mammogram, 10.9% with diagnostic testing and 4.5% by incidental finding. Recurrences in 6.8% of patients were detected by routine physician exam. Overall survival for those with recurrence was 31.1% and most deaths were attributed to breast cancer (89%). Conclusions: Our study, the largest investigation of breast cancer recurrence modality of detection in a US community oncology setting with comprehensive care, revealed the majority of recurrences were identified through patient self-detection with only 6.8% detected by physician exam. Most recurrences were distant, underscoring the need for alternative screening modalities to detect metastatic recurrences earlier, especially in the context of emerging treatments and improved survival rates for oligometastatic disease.