Providing context for the HIPECT4 results

The recent HIPECT4 and FOxTROT studies provide new options for patients with locally advanced colon cancer. This commentary compares outcomes from these trials and reviews available evidence for hyperthermic intraperitoneal chemotherapy in the setting of colorectal cancer.

Disparities in the Receipt of Systemic Treatment in Metastatic Melanoma

BACKGROUND

In 2011, immunotherapy and targeted therapy revolutionized melanoma treatment. However, inequities in their use may limit the benefits seen by certain patients.

METHODS

We performed a retrospective review of patients in the National Cancer Database for patients with stage IV melanoma from 2 time periods: 2004-2010 and 2016-2020, distinguishing between those who received systemic therapy and those who did not. We investigated the rates and factors associated with treatment omission. We employed Kaplan-Meier analysis to explore the impact of treatment on overall survival.

RESULTS

A total of 19,961 patients met the inclusion criteria: 7621 patients were diagnosed in 2004-2010 and 12,340 patients in 2016-2020, of whom 54.9% and 28.3% did not receive systemic treatment, respectively. The rate of "no treatment" has decreased to a plateau of ∼25% in 2020. Median overall survival was improved with treatment in both time periods (2004-2010: 8.8 vs. 5.6 mo [ P <0.05]; and 2016-2020: 25.9 vs. 4.3 mo [ P <0.05]). Nonmedical factors associated with the omission of treatment in both periods included low socioeconomic status, Medicaid or no health insurance, and treatment at low-volume centers. In the period from 2016 to 2020, patients treated at nonacademic programs were also less likely to receive treatment.

CONCLUSIONS

Systemic therapies significantly improve survival for patients with metastatic melanoma, but significant disparities exist with their receipt. Local efforts are needed to ensure all patients benefit from these revolutionary treatments.

First-line Immunotherapy for Metastatic Merkel Cell Carcinoma: Analysis of Real-world Survival Data and Practice Patterns

BACKGROUND

Immune checkpoint inhibitors are a promising new therapy for advanced Merkel Cell Carcinoma (MCC). We investigated real-world utilization and survival outcomes of first-line immunotherapies in a contemporary cohort.

METHODS

Using the National Cancer Database (NCDB), we identified 759 patients with MCC between 2015 and 2020 with stage IV disease and known status of first-line systemic therapy. Univariable and multivariable analyses were used to determine predictors of immunotherapy usage. Overall survival (OS) was compared for patients receiving immunotherapy, chemotherapy, or no systemic therapies.

RESULTS

We identified 759 patients meeting our inclusion criteria: 329 patients received immunotherapy, 161 received chemotherapy, and 269 received no systemic therapy. Adjusting for demographic, clinical, and facility factors, high facility volume significantly predicted first-line immunotherapy use (OR 1.99; P=0.017). Median OS was 16.2, 12.3, and 8.7 months, among patients who received immunotherapy, chemotherapy, or no systemic therapy, respectively (P<0.001). On Cox multivariable survival analysis, first-line immunotherapy treatment (HR=0.79, P=0.041) and treatment at high-volume centers (HR=0.58, P=0.004) were associated with improved OS.

CONCLUSIONS

Consistent with clinical trial results, first-line immunotherapy associated with improvement in median overall survival for patients with stage IV MCC, significantly outperforming chemotherapy in this real-world cohort. Treatment at high-volume centers associated with first-line immunotherapy utilization suggesting that familiarity with this rare disease is important to achieving optimal outcomes for metastatic MCC.

Neoadjuvant Dual Checkpoint Inhibitors vs Anti-PD1 Therapy in High-Risk Resectable Melanoma: A Pooled Analysis

Importance

Despite the clear potential benefits of neoadjuvant therapy, the optimal neoadjuvant regimen for patients with high-risk resectable melanoma (HRRM) is not known.

Objective

To compare the safety and efficacy of dual checkpoint inhibitors with anti-programmed cell death protein-1 (anti-PD1) therapy in a neoadjuvant setting among patients with HRRM.

Design, Setting, and Participants

In this pooled analysis of clinical trials, studies were selected provided they investigated immune checkpoint inhibitor treatment, were published between January 2018 and March 2023, and were phase 1, 2, or 3 clinical trials. Participant data included in the analysis were derived from trials evaluating the efficacy and safety of anti-PD1 monotherapy and the combination of anti-cytotoxic T lymphocyte-associated protein-4 with anti-PD1 in the neoadjuvant setting, specifically among patients with HRRM.

Interventions

Patients were treated with either anti-PD1 monotherapy; dual checkpoint inhibition (DCPI) with a conventional dose of 3-mg/kg ipilimumab and 1-mg/kg nivolumab; or DCPI with an alternative-dose regimen of 1-mg/kg ipilimumab and 3-mg/kg nivolumab.

Main Outcomes and Measures

The main outcomes were radiologic complete response (rCR), radiologic overall objective response (rOOR), and radiologic progressive disease. Also, pathologic complete response (pCR), the proportion of patients undergoing surgical resection, and occurrence of grade 3 or 4 immune-related adverse events (irAEs) were considered.

Results

Among 573 patients enrolled in 6 clinical trials, neoadjuvant therapy with DCPI was associated with higher odds of achieving pCR compared with anti-PD1 monotherapy (odds ratio [OR], 3.16; P < .001). DCPI was associated with higher odds of grade 3 or 4 irAEs compared with anti-PD1 monotherapy (OR, 3.75; P < .001). When comparing the alternative-dose ipilimumab and nivolumab (IPI-NIVO) regimen with conventional-dose IPI-NIVO, no statistically significant difference in rCR, rOOR, radiologic progressive disease, or pCR was noted. However, the conventional-dose IPI-NIVO regimen was associated with increased grade 3 or 4 irAEs (OR, 4.76; P < .001). Conventional-dose IPI-NIVO was associated with greater odds of achieving improved rOOR (OR, 1.95; P = .046) and pCR (OR, 2.99; P < .001) compared with anti-PD1 monotherapy. The alternative dose of IPI-NIVO also was associated with higher odds of achieving rCR (OR, 2.55; P = .03) and pCR (OR, 3.87; P < .001) compared with anti-PD1 monotherapy. The risk for grade 3 or 4 irAEs is higher with both the conventional-dose (OR, 9.59; P < .001) and alternative-dose IPI-NIVO regimens (OR, 2.02; P = .02) compared with anti-PD1 monotherapy.

Conclusion and Relevance

In this pooled analysis of 6 clinical trials, although DCPI was associated with increased likelihood of achieving pathological and radiologic responses, the associated risk for grade 3 or 4 irAEs was significantly lower with anti-PD1 monotherapy in the neoadjuvant setting for HRRM. Additionally, compared with alternative-dose IPI-NIVO, the conventional dose of IPI-NIVO was associated with increased risk for grade 3 or 4 irAEs, with no significant distinctions in radiologic or pathologic efficacy.

The effect of surgical timing in nonmetastatic melanoma

BACKGROUND AND OBJECTIVES

There is no consensus guidelines on the best timing to perform Sentinel lymph node biopsy (SLNB) in high-risk melanoma patients. We aimed to understand the impact of surgical timing on nodal upstaging in patients with cutaneous melanoma.

METHODS

We queried the National Cancer Database from 2004 to 2018 for patients with T2-T4, N0, M0 melanomas, who underwent melanoma excision and nodal surgery. We included patients who underwent surgery within 2-19 weeks postdiagnosis. We aimed to determine the association of surgical delay (weeks) with nodal positivity.

RESULTS

A total of 53 355 patients were included, of whom 20.9% had positive lymph nodes. Patients underwent surgery at a median of 5 (4-7) weeks after diagnosis. The rate of positive nodes increased with increased weeks to surgery (line of best-fit slope = 0.38). Multivariable regression analysis identified an association between time to surgery and nodal positivity (2.4% increased risk per week, p < 0.05). Our analysis showed significantly increased likelihood of nodal positivity beginning 9 weeks after diagnosis (odds ratio [OR] = 1.3, p < 0.05). Furthermore, patients with T2-3 tumors had a significant increase in nodal positivity with increased time to surgery (OR = 1.03 per week, p < 0.001). However, no significant trend in nodal positivity was identified for patients with T4 melanomas (OR = 1.01 per week, p = 0.596).

CONCLUSION

Surgery within 9 weeks of melanoma diagnosis was not associated with increased likelihood of nodal positivity. These data can guide clinical conversations regarding the importance of surgical timing for melanoma.

Is sentinel lymph node biopsy needed for lentigo maligna melanoma?

BACKGROUND AND OBJECTIVES

Sentinel lymph node biopsy (SLNB) is an area of debate in the management of lentigo maligna melanoma (LMM). The utility of SLNB and its prognostic value in LMM have not yet been studied with large databases.

METHODS

We performed a retrospective review of the National Cancer Database (2012-2020) and the Surveillance, Epidemiology, and End Results (2010-2019) database for patients with cutaneous nonmetastatic LMM with Breslow thickness >1.0 mm. Multivariable logistic regression identified factors associated with SLNB performance and sentinel lymph node (SLN) positivity. Univariable and multivariable analyses assessed overall survival (OS) and melanoma-specific survival (MSS) based on SLNB performance and SLN status.

RESULTS

Compared to other melanoma subtypes, LMM had lower rates of SLNB (66.6% vs. 80.0%-84.0%) and SLN positivity (11.3% vs. 18.6%-34.2%). Compared to patients who did not undergo SLNB, SLN status was significantly associated with improved OS in patients with SLN positive (HR = 0.64 [0.55-0.76]) and SLN negative (HR = 0.68 [0.49-0.94]), and worse MSS only in patients with positive SLN (HR = 3.93, p < 0.05).

CONCLUSION

The improved OS associated with SLNB likely implies surgical selection bias. Analysis of MSS confirms appropriate patient selection and suggests important prognostic value associated with SLN status. These results support continued SLNB for LMM patients according to standard guidelines.

Surgical management of 1- to 2-cm neuroendocrine tumors of the appendix: Appendectomy or right hemicolectomy?

BACKGROUND

The surgical management of 1- to 2-cm neuroendocrine tumors of the appendix is an area of debate. We analyzed the clinical outcomes of appendectomy and compared them to right hemicolectomy.

METHODS

We queried the National Cancer Database to identify patients treated for 1- to 2-cm ANETs from 2004 to 2018. Patients were stratified by surgical approach (appendectomy vs. hemicolectomy). Multivariable models were used to identify factors associated with the choice of surgical approach and the association between surgical approach and overall survival.

RESULTS

Of the 3,189 patients we included, 1,573 (49.3%) underwent right hemicolectomy and 1,616 (50.7%) appendectomy. The appendectomy rate increased from 37.7% in 2004 to 58.9% in 2018. On multivariable analysis, patients with grade 2 and 3 tumors were less likely to undergo appendectomy alone (odds ratio = 0.41, 95% confidence interval = 0.26-0.66). Longer travel distance was associated with a higher likelihood of undergoing appendectomy (odds ratio = 2.52, 95% confidence interval = 1.15-5.51). After adjusting for tumor grade, appendectomy alone had similar survival to hemicolectomy (hazard ratio = 1.03, 95% confidence interval = 0.67-1.59).

CONCLUSION

In this updated analysis of the National Cancer Database, right hemicolectomy was not associated with improved overall survival compared to appendectomy alone for 1- to 2-cm neuroendocrine tumors of the appendix. Although patients with grade 2 or 3 tumors are more likely to undergo right hemicolectomy, this procedure may not improve their treatment or overall outcome.

Preoperative therapy in melanoma: Evolving perspectives in clinical trials

We reviewed phase II and III trials beginning after 2010 studying preoperative therapy in melanoma (61 trials). Compared to standard adjuvant treatment, neoadjuvant immune checkpoint inhibitors (ICIs) show improved outcomes with approximately 70-80% recurrence free survival at 2 years. Several biomarkers demonstrate predictive value for pathological response (higher PD-L1 expression) and survival (IFN-γ signatures, CD8 + cell density). A number of 'non-standard' treatment mechanisms are being studied in combination with ICI therapies such as TLR-9 agonists, and anti-LAG3 checkpoint inhibitors, which show promise for alternative therapy options in the neoadjuvant setting. Finally, trials for advanced unresectable melanomas show improved survival compared to definitive systemic treatment when upfront systemic therapies lead to resectability. To conclude, in the preoperative setting for melanoma, ICIs have potential to improve outcomes for patients, and will likely change the standard treatment approach for advanced resectable disease.

Trends in and Prognostic Significance of Time to Treatment in Pancreatic Cancer: A Population-Based Study

INTRODUCTION

The association of time to treatment (TTT) with survival remains unclear in pancreatic adenocarcinoma (PDAC). In this study, we evaluate the recent trends in TTT, causes for delay, and its effect on survival.

METHODS

We included patients with PDAC of all stages from the National Cancer Database (2004-2020) who underwent either surgery or chemotherapy/radiotherapy (CT/RT). TTT was defined as the duration between tissue diagnosis and first treatment. Linear regression (β) was used to study the temporal trends in time delay.

RESULTS

A total of 239,638 patients were included. The median TTT was 25 days. Using multivariable analysis, we found that increasing age (OR 1.48), female gender (OR 1.04), Black race (OR 1.3), lower educational status (OR 1.2), Medicaid, Medicare insurance, and uninsured (OR 1.2, 1.5, and 1.2, respectively), treatment at academic centers (OR 1.3), higher Charlson-Deyo comorbidity index (OR 1.2), and CT/RT (OR 1.5) were associated with increased TTT. There was a steady rise in median TTT from 21 to 28 days between 2004 and 2020 (β = 0.3), suggestive of a worsening trend. Concurrently, there was an increasing trend in utilization of neoadjuvant CT/RT between 2004 and 2020 in early-stage PDAC. On Cox regression, TTT delay was associated with poor overall survival in stage I-IV patients (HR 1.1, 1.1, 1.09, and 1.53, respectively).

CONCLUSIONS

Delayed treatment approaching 2 months was observed in 10% of the population. The rising temporal trend in TTT may be attributed to the increasing shift toward neoadjuvant CT/RT in early-stage PDAC and/or the increasing use of tissue biopsy prior to surgery.

Association of sociodemographic characteristics with utilization of sentinel lymph node biopsy for American Joint Committee on Cancer 8th edition T1b cutaneous melanoma

Sentinel lymph node biopsy (SLNB) is an important staging and prognostic tool for cutaneous melanoma (CM). However, there exists a knowledge gap regarding whether sociodemographic characteristics are associated with receipt of SLNB for T1b CMs, for which there are no definitive recommendations for SLNB per current National Comprehensive Cancer Network guidelines. We performed a retrospective analysis of the 2012-2018 National Cancer Database, identifying patients with American Joint Committee on Cancer staging manual 8th edition stage T1b CM, and used multivariable logistic regression to analyze associations between sociodemographic characteristics and receipt of SLNB. Among 40,458 patients with T1b CM, 23,813 (58.9%) received SLNB. Median age was 62 years, and most patients were male (57%) and non-Hispanic White (95%). In multivariable analyses, patients of Hispanic (aOR 0.67, 95%CI 0.48-0.94) and other (aOR 0.78, 95%CI 0.63-0.97) race/ethnicity, and patients aged > 75 (aOR 0.33, 95%CI 0.29-0.38), were less likely to receive SLNB. Conversely, patients in the highest of seven socioeconomic status levels (aOR 1.37, 95%CI 1.13-1.65) and those treated at higher-volume facilities (aOR 1.29, 95%CI 1.14-1.46) were more likely to receive SLNB. Understanding the underlying drivers of these associations may yield important insights for the management of patients with melanoma.

Predictors of sentinel lymph node metastasis in very thin invasive melanomas

BACKGROUND

Melanomas < 0.8 mm in Breslow depth have less than a 5% risk for nodal positivity. Nonetheless, nodal positivity is prognostic for this group. Early identification of nodal positivity may improve the outcomes for these patients.

OBJECTIVES

To determine the degree to which ulceration and other high-risk features predict sentinel lymph node (SLN) positivity for very thin melanomas.

METHODS

The National Cancer Database was reviewed from 2012 to 2018 for patients with melanoma with Breslow thickness < 0.8 mm. Data were analysed from 7 July 2022 through to 25 February 2023. Patients were excluded if data regarding their ulceration status or SLN biopsy (SLNB) performance were unknown. We analysed patient, tumour and health system factors for their effect on SLN positivity. Data were analysed using χ2 tests and logistic regressions. Overall survival (OS) was compared by Kaplan-Meier analyses.

RESULTS

Positive nodal metastases were seen in 876 (5.0%) patients who underwent SLNB (17 692). Factors significantly associated with nodal positivity on multivariable analysis include lymphovascular invasion [odds ratio (OR) 4.5, P < 0.001], ulceration (OR 2.6, P < 0.001), mitoses (OR 2.1, P < 0.001) and nodular subtype (OR 2.1, P < 0.001). Five-year OS was 75% and 92% for patients with positive and negative SLN, respectively.

CONCLUSIONS

Nodal positivity has prognostic significance for very thin melanomas. In our cohort, the rate of nodal positivity was 5% overall in these patients who underwent SLNB. Specific tumour factors (e.g. lymphovascular invasion, ulceration, mitoses, nodular subtype) were associated with higher rates of SLN metastases and should be used to guide clinicians in choosing which patients will benefit from SLNB.

Patient and provider factors predict non-surgical management for complex upper gastrointestinal cancers

BACKGROUND

Surgery is the only potentially curative treatment for non-metastatic upper gastrointestinal cancers. We analyzed patient and provider characteristics associated with non-surgical management.

METHODS

We queried the National Cancer Database for patients with upper gastrointestinal cancers from 2004 to 2018 who underwent surgery, refused surgery, or for whom surgery was contraindicated. Multivariate logistic regression identified factors associated with surgery being refused or contraindicated, and Kaplan-Meier curves assessed survival.

RESULTS

We identified 249,813 patients based on our selection criteria-86.3% had surgery, 2.4% refused, and for 11.3%, surgery was contraindicated. Median overall survival was 48.2 months for patients who underwent surgery versus 16.3 and 9.4 months for the refusal and contraindicated groups. Medical and non-medical factors predicted both surgery refusals and contraindications, such as increasing age (odds ratio = 1.07 and 1.03, respectively, P < .001), Black race (odds ratio = 1.72 and 1.45, P < .001), comorbidities (Charlson-Deyo score 2+, odds ratio = 1.18 and 1.66, P < .001), low socioeconomic status (odds ratio = 1.70 and 1.40, P < .001), no health insurance (odds ratio = 3.26 and 2.34, P < .001), community cancer programs (odds ratio = 1.43 and 1.40, P < .001), low volume facilities (odds ratio = 1.82 and 1.52, P < .001), and stage 3 disease (odds ratio = 1.51 and 6.50, P < .001). On subset analysis (excluding patients age >70, Charlson-Deyo score 2+, and stage 3 cancer), non-medical predictors of both outcomes were similar.

CONCLUSION

Refusal of and medical contraindications for surgery profoundly impact overall survival. The same factors (ie, race, socioeconomic status, hospital volume, and hospital type) predict these outcomes. These findings suggest variation and potential bias that may exist between physicians and patients discussing cancer surgery.

Assessing the use of Extended Venous Thromboembolism Prophylaxis on the Rates of Venous Thromboembolism and Postpancreatectomy Hemorrhage Following Pancreatectomy for Malignancy

OBJECTIVE

To compare rates of venous thromboembolism (VTE) and postpancreatectomy hemorrhage (PPH) in patients with pancreatic or periampullary malignancy preimplementation and postimplementation of routine extended VTE prophylaxis.

BACKGROUND

Guidelines recommend up to 28 days of VTE prophylaxis following major abdominal cancer operations. There is a paucity of data examining rates of VTE and PPH in patients who receive extended VTE prophylaxis following pancreatectomy.

METHODS

Single-institution analysis of patients who underwent pancreatectomy for malignancy (2004-2021). VTE and PPH rates within 90 days of discharge were compared based on receipt of extended VTE prophylaxis with enoxaparin.

RESULTS

A total of 478 patients were included. Twenty-two (4.6%) patients developed a postoperative VTE, 12 (2.5%) of which occurred postdischarge. Twenty-five (5.2%) patients experienced PPH, 13 (2.7%) of which occurred postdischarge. There was no associated difference in the development of postdischarge VTE between patients who received extended VTE prophylaxis and those who did not (2.3% vs 2.8%, P =0.99). There was no associated difference in the rate of postdischarge PPH between patients who received extended VTE prophylaxis and those who did not (3.4% vs 1.9%, P =0.43). In the subset of patients on antiplatelet agents, the addition of enoxaparin did not appear to be associated with higher VTE (3.9 vs. 0%, P =0.31) or PPH (3.0 vs. 4.5%, P =0.64) rates.

CONCLUSIONS

Extended VTE prophylaxis following pancreatectomy for malignancy was not associated with differences in postdischarge VTE and PPH rates. These data suggest extended VTE prophylaxis is safe but may not be necessary for all patients following pancreatectomy.

An analysis of time to treatment in patients with pancreatic adenocarcinoma

BACKGROUND

Currently, no guidelines exist regarding the appropriate time from diagnosis to treatment among pancreatic adenocarcinoma patients. Herein, we aim to define the median time to treatment in pancreatic adenocarcinoma, factors associated with treatment delay, and prognostic significance.

METHODS

We conducted a retrospective study of pancreatic adenocarcinoma patients, stage I-IV, at a tertiary referral center (2017-2020). We subdivided time to treatment (days) into 4 components: (1) Ti: symptom onset to initial provider evaluation, (2) Tii: initial provider evaluation to diagnosis, (3) Tiii: diagnosis to specialist consultation, (4) Tiv: specialist visit to treatment.

RESULTS

In total, 217 patients met the inclusion criteria. The median Ti, Tii, Tiii, and Tiv were 20, 12, 4, and 14 days, respectively. The total time to treatment was 75 days. Patients with weight loss had longer Ti (β = 108.6). More frequent hospitalizations (β = 19.5) and misdiagnosis (β = 33.4) were associated with longer Tii. Patients with a history of malignancy (β = 15) or active treatment of a second disease (β = 19.4) had longer Tiii. Poor performance status (β = 6.2) or private insurance (β = 50.2) were associated with a longer Tiv. Black patients had longer Ti+ii+iii+iv (β = 100). Time to treatment was not associated with overall survival (P > .05).

CONCLUSION

It takes a median time of less than a month for a patient with pancreatic adenocarcinoma to start treatment, even after they visit a primary provider. The greatest opportunity to shorten the overall time to treatment is by having patients seek medical attention earlier (Ti).

Understanding Factors Leading to Surgical Attrition for "Resectable" Gastric Cancer

OBJECTIVES

We used a novel combined analysis to evaluate various factors associated with failure to surgical resection in non-metastatic gastric cancer.

METHODS

We identified factors associated with the receipt of surgery in publicly available clinical trial data for gastric cancer and in the National Cancer Database (NCDB) for patients with stages I-III gastric adenocarcinoma. Next, we evaluated variable importance in predicting the receipt of surgery in the NCDB.

RESULTS

In published clinical trial data, 10% of patients in surgery-first arms did not undergo surgery, mostly due to disease progression and 15% of patients in neoadjuvant therapy arms failed to reach surgery. Effects related to neoadjuvant administration explained the increased attrition (5%). In the NCDB, 61.7% of patients underwent definitive surgery. In a subset of NCDB patients resembling those enrolled in clinical trials (younger, healthier, and privately insured patients treated at high-volume and academic centers) the rate of surgery was 79.2%. Decreased likelihood of surgery was associated with advanced age (OR 0.97, p < 0.01), Charlson-Deyo score of 2+ (OR 0.90, p < 0.01), T4 tumors (OR 0.39, p < 0.01), N+ disease (OR 0.84, p < 0.01), low socioeconomic status (OR 0.86, p = 0.01), uninsured or on Medicaid (OR 0.58 and 0.69, respectively, p < 0.01), low facility volume (OR 0.64, p < 0.01), and non-academic cancer programs (OR 0.79, p < 0.01).

CONCLUSION

Review of clinical trials shows attrition due to unavoidable tumor and treatment factors (~ 15%). The NCDB indicates non-medical patient and provider characteristics (i.e., age, insurance status, facility volume) associated with attrition. This combined analysis highlights specific opportunities for improving potentially curative surgery rates.

Abstract 4839: Chemotherapy alters mitochondrial metabolism in melanoma

Background: Advanced and metastatic melanoma carries significant mortality despite recent advances. Metabolic plasticity is a hallmark of cancer and an important resistance mechanism in the face of anti-neoplastic therapies. We sought to understand the effect of chemotherapy, Temozolomide (TMZ), on OXPHOS and TCA cycle metabolism in melanoma cell lines. By understanding these metabolic adaptations to chemotherapy, we hope to identify novel combination therapies.

Methods: A375 and SK-MEL-28 cell lines were used for all experiments. Cell viability assays were performed with 1500 cells per well, treated with TMZ and oligomycin or phenformin, and viability was assessed using PicoGreen dsDNA assay. Western blot was used with primary antibodies against TOM20 and Β-actin. LCMS metabolites were assessed by QTRAP triple quadrupole mass spectrometry coupled to a Prominence UFLC HPLC system. This assessed approximately 299 metabolites. Seahorse XFp miniextracellular analyzer was used to obtain OCR with and without TMZ exposure, and after sequential injections of oligomycin, FCCP, and rotenone with antimycin A. Mitochondrial assays included TMRE staining (membrane potential) and Mitotracker Green (mitochondrial mass).

Results: Metabolic profiles of melanoma cell lines change with exposure to chemotherapy. After melanoma cells are exposed to IC30 dose of TMZ, LCMS metabolomics revealed statistically significant increase in TCA cycle metabolites such as succinate, succinyl CoA, malate, oxaloacetate, isocitrate, alpha-ketoglutarate, and fumarate. Melanoma increases OXPHOS in the presence of chemotherapy. Mitochondrial mass, measured by Mitotracker, increased in response to TMZ exposure. We also found increased mitochondrial membrane potential and increased TOM20 expression after cells were treated with TMZ. Seahorse XF Cell Mito Stress Assay demonstrated increased oxygen consumption rate after exposure to TMZ. We then combined TMZ and two mitochondrial inhibitors, phenformin (complex I) and oligomycin (complex V). Combination of phenformin and TMZ was synergistic in cell viability assays as determined by Bliss equation. Oligomycin sensitized both cell lines to TMZ.

Discussion: We have shown that melanoma cells rely on mitochondrial function when exposed to TMZ by increasing levels of TCA cycle intermediates, increasing mitochondrial tropism, and increased expression of mitochondrial enzymes. This demonstrates a metabolic resistance mechanism in response to chemotherapy to promote melanoma cell survival. Finally, we exploit this adaptation by pharmacologic inhibition of mitochondrial electron transport chain (ETC) with phenformin and oligomycin A. This treatment was synergistic with conventional chemotherapy. Our findings point out that the ETC compartment of mitochondria could be a novel and readily available combination treatment strategy for patients with advanced and refractory melanoma.

Citation Format: Alexander W. Loftus, Mehrdad Zarei, Omid Hajihassani, Johnathan J. Hue, Hallie J. Graor, Ali Vaziri-Gohar, Jordan M. Winter, Luke D. Rothermel. Chemotherapy alters mitochondrial metabolism in melanoma. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4839.

Abstract 3701: Targeting wild-type IDH1 enhances chemosensitivity in pancreatic cancer

Introduction: Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer mortality in the United States. The poor prognosis is in part due to development of chemotherapy resistance, despite improvements in multiagent regimens. Our previous work demonstrated that oxidative stress plays an important role in drug resistance. Wild-type isocitrate dehydrogenase 1 (IDH1) is an important enzyme that generates cytosolic NADPH to maintain redox homeostasis and protect cancer cells from oxidative damage. Additionally, we demonstrated that ivosidenib (AG-120), an FDA-approved mutant IDH1 inhibitor, is actually a potent inhibitor of wild-type IDH1, under low magnesium and nutrient levels that are present in the tumor microenvironment.

Methods: We evaluated IDH1 expression in PDAC using The Cancer Genome Atlas (TCGA). Cell viability was assessed by Trypan blue and PicoGreen in drug combination assays. Cellular reactive oxygen species (ROS) levels were determined by the DCFDA method. To further assess the therapeutic potential of AG-120 in combination with chemotherapy, tumor volume analyses were performed using patient-derived xenografts (PDX) in athymic nude mice, and survival studies were performed in C57BL/6J mice transplanted with orthotopic murine pancreatic cancer.

Results: Analysis of TCGA data indicated that IDH1 is overexpressed in pancreatic cancer tumors. Treatment of MiaPaca2 and Panc1 cancer cells with 5- fluorouracil (5-FU) induced expression of wild-type IDH1 in vitro. Short-term cell viability data demonstrated that targeting IDH1 with AG-120 when combined with DNA-damaging agents (5-FU, oxaliplatin) had a synergistic effect with a positive synergy score and Bliss score greater than 1. Additionally, we assessed long-term cell survival using colony formation assays, which yielded a dramatic reduction in cell survival for both Panc1 and MiaPaCa-2 cells when 5-FU was combined with AG-120, as compared to single-agent controls. Inhibiting IDH1 impairs the ability of pancreatic cancer cells to scavenge ROS levels, enhances chemotherapy-induced apoptosis in pancreatic cancer cells via ROS-mediated damage in vitro. Both PDX tumor volume studies and overall survival analyses revealed that the combination of these AG-120 and chemotherapy synergistically enhanced anti-tumor activity and doubled the survival benefits as compared to single-agent alone.

Conclusion: IDH1 plays a critical role in tumorigenesis and chemoresistance in pancreatic cancer. Our data demonstrate that IDH1 inhibition with AG-120 may enhance chemotherapy efficacy and represents an important area for future investigation in the form of clinical trials.

Citation Format: Mehrdad Zarei, Omid Hajihassani, Jonathan J. Hue, Hallie J. Graor, Arian Hajihassani, Alexander W. Loftus, Luke D. Rothermel, Jordan M. Winter. Targeting wild-type IDH1 enhances chemosensitivity in pancreatic cancer. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3701.

Epidemiology, management, and treatment outcomes of metastatic spinal melanoma

Metastatic spinal melanoma is a rare and aggressive disease process with poor prognosis. We review the literature on metastatic spinal melanoma, focusing on its epidemiology, management, and treatment outcomes. Demographics of metastatic spinal melanoma are similar to those for cutaneous melanoma, and cutaneous primary tumors tend to be most common. Decompressive surgical intervention and radiotherapy have traditionally been considered mainstays of treatment, and stereotactic radiosurgery has emerged as a promising approach in the operative management of metastatic spinal melanoma. While survival outcomes for metastatic spinal melanoma remain poor, they have improved in recent years with the advent of immune checkpoint inhibition, used in conjunction with surgery and radiotherapy. New treatment options remain under investigation, especially for patients with disease refractory to immunotherapy. We additionally explore several of these promising future directions. Nevertheless, further investigation of treatment outcomes, ideally incorporating high-quality prospective data from randomized controlled trials, is needed to identify optimal management of metastatic spinal melanoma.

Targeting wild-type IDH1 enhances chemosensitivity in pancreatic cancer

Pancreatic cancer (PC) is one of the most aggressive types of cancer, with a five-year overall survival rate of 11% among all-comers. Current systemic therapeutic options are limited to cytotoxic chemotherapies which have limited clinical efficacy and are often associated with development of drug resistance. Analysis of The Cancer Genome Atlas showed that wild-type isocitrate dehydrogenase (wtIDH1) is overexpressed in pancreatic tumors. In this study, we focus on the potential roles of wtIDH1 in pancreatic cancer chemoresistance. We found that treatment of pancreatic cancer cells with chemotherapy induced expression of wtIDH1, and this serves as a key resistance factor. The enzyme is protective to cancer cells under chemotherapy-induced oxidative stress by producing NADPH and alpha-ketoglutarate to maintain redox balance and mitochondrial function. An FDA-approved mutant IDH1 inhibitor, ivosidenib (AG-120), is actually a potent wtDH1 inhibitor under a nutrient-deprived microenvironment, reflective of the pancreatic cancer microenvironment. Suppression of wtIDH1 impairs redox balance, results in increased ROS levels, and enhances chemotherapy induced apoptosis in pancreatic cancer vis ROS damage in vitro. In vivo experiments further revealed that inhibiting wtIDH1 enhances chemotherapy anti-tumor effects in patient-derived xenografts and murine models of pancreatic cancer. Pharmacologic wtIDH1 inhibition with ivosidenib represents an attractive option for combination therapies with cytotoxic chemotherapy for patients with pancreatic cancer. Based on these data, we have initiated phase Ib trial combining ivosidenib and multi-agent chemotherapy in patients with pancreatic cancer (NCT05209074).

Severe psychological distress among patients with skin cancer: a population-based study spanning two decades

In this analysis of the National Health Interview Survey, Americans with lower socioeconomic status, who are unmarried and with comorbidities were found to be at higher odds of severe psychological distress. Our findings may inform targeted support-based psycho-oncological interventions, such as shared medical appointments with other at-risk patients who have skin cancer.

Management of adenocarcinoma of the pancreatic tail in the elderly

INTRODUCTION

Elderly patients with adenocarcinoma of the pancreatic head can achieve reasonable survival with multimodal therapy. An analysis specific to cancers of the pancreatic tail has not been published.

METHODS

We identified patients ≥65 years with localized adenocarcinoma of the pancreatic tail in the National Cancer Database (2011-2017). Patients were grouped by age (65-79 and ≥80 years) and categorized by treatment regimen. Postoperative outcomes and survival were analyzed using propensity score matching and multivariable logistical regression.

RESULTS

2168 patients were included: 73.9% were 65-79 years and 26.1% were ≥80 years. 34.1% of octogenarians did not receive any treatment, relative to 15.9% of younger patients (p < 0.001). Thirty-day mortality rates were similar in operatively managed patients; however, the 90-day mortality rate among octogenarians was greater (3.0% vs. 7.8%, p < 0.001; odds ratio [OR] = 1.85, 95% confidence interval [CI] = 1.07-3.19). Age ≥ 80 was not associated with survival on multivariable hazards regression (hazard ratio [HR] = 1.08, 95% CI = 0.95-1.24). After propensity matching, the addition of chemotherapy was not associated with improved survival relative to distal pancreatectomy alone among octogenarians (HR = 1.09, 95% CI = 0.72-1.65).

CONCLUSIONS

Management of adenocarcinoma of the pancreatic tail varies based on patient age. Resection appears to play a key role in management, but there is substantial upfront risk. Shared decision making should be employed to balance the chance for long-term survival with the risk of early mortality.

Average treatment effect of facility hepatopancreatobiliary malignancy case volume on survival of patients with nonoperatively managed hepatobiliary malignancies

BACKGROUND

Surgical volume-outcome relationships have been described for a variety of procedures. There is scant literature on total institutional volume and outcomes in patients who are nonoperatively managed. We examined the average treatment effect of total hepatopancreatobiliary malignancy case volume on survival outcomes of patients with nonresected hepatobiliary malignancies.

METHODS

We identified patients with hepatopancreatobiliary malignancies [pancreatic adenocarcinoma, pancreatic neuroendocrine neoplasms, hepatocellular carcinoma, biliary tract cancers] within the National Cancer Database (2004-2018). We determined percentile thresholds based on the total annual hepatopancreatobiliary malignancy case volume. We then identified nonoperatively managed patients with hepatocellular carcinoma or biliary tract cancers. We used inverse probability-weighted Cox regression to estimate the effect of facility volume on overall survival.

RESULTS

We identified 710,988 patients with hepatopancreatobiliary malignancies. Total annual hepatopancreatobiliary malignancy case volume of 32, 71, and 177 cases/year corresponded to the 25th, 50th, and 75th percentiles. A total of 96,420 with hepatocellular carcinoma and 52,627 patients with biliary tract cancers were managed nonoperatively. In patients with hepatocellular carcinoma or biliary tract cancer, treatment at ≥25th, ≥50th, and ≥75th percentile facilities was associated with improved median, 1-, 2-, and 3-year overall survival compared with treatment at lower-percentile facilities. On inverse probability-weighted Cox analysis, treatment at higher-percentile facilities resulted in a lower hazard of death. Consistent findings were observed in patients with early or intermediate/advanced hepatocellular carcinoma or metastatic biliary tract cancers.

CONCLUSION

Patients with nonoperatively managed hepatocellular carcinoma or biliary tract cancer who receive treatment at higher-volume facilities have improved survival outcomes. These data suggest regionalization of care for patients with hepatocellular carcinoma or biliary tract cancer to high-volume centers may improve survival.

Trends and disparities in the utilization of systemic chemotherapy in patients with metastatic hepato-pancreato-biliary cancers

BACKGROUND

We described trends and disparities in utilization of systemic chemotherapy in metastatic hepato-pancreato-biliary (HPB) cancers.

METHODS

We queried the National Cancer Database for metastatic HPB cancers [hepatocellular carcinoma (HCC), biliary tract cancers (BTC), pancreatic adenocarcinoma (PDAC)]. We used multivariable analysis to examine the factors associated with utilization of systemic chemotherapy. We utilized marginal structural logistic models to estimate the effect of health insurance, facility type, or facility volume on utilization of systemic chemotherapy.

RESULTS

We identified 162,283 patients with metastatic HPB cancers: 23,923 (14.7%) had HCC, 26,766 (16.5%) had BTC, and 111,594 (68.8%) had PDAC. A total of 37.2% patients with HCC, 55.6% with BTC, and 56.4% with PDAC received chemotherapy. Age ≥70 years and Charlson-Deyo score ≥2 were associated with lower likelihood of receiving chemotherapy across all cancers. Patients with private health insurance had higher receipt of chemotherapy. Receiving treatment at academic facilities had no effect on the receipt of chemotherapy. Treatment of patients with HCC or PDAC at high-volume facilities resulted in higher receipt of chemotherapy.

CONCLUSION

A significant proportion of patients with metastatic HPB cancers do not receive systemic chemotherapy. Several disparities in administration of chemotherapy for metastatic HPB cancers exist.

Disparities in treatment and survival for patients with isolated colorectal liver metastases

BACKGROUND

Surgical resection improves survival for patients with isolated colorectal liver metastasis. National studies on the disparities related to this topic are limited; therefore, we investigated factors that affect surgical treatment and survival.

METHODS

We queried the National Cancer Database (2010-2017) for patients with isolated synchronous colorectal liver metastasis. Multivariable logistic regression and Cox proportional hazard regressions were used to identify factors associated with surgical resection, treatment at high-volume facilities, and overall survival.

RESULTS

Of 34,050 patients with isolated colorectal liver metastasis, surgical resection (n = 7,810; 23.0%) was more likely among patients who were of high socioeconomic status (odds ratio = 1.16; 95% confidence interval, 1.04-1.31), traveled long distance for treatment (odds ratio = 1.48; 95% confidence interval, 1.31-1.66), and were treated at high-volume facilities (odds ratio = 4.86; 95% confidence interval, 14.45-5.30). Black patients were less likely to undergo resection (odds ratio = 0.75; 95% confidence interval, 0.69-0.82). Treatment at high-volume facility was more common among patients who were Black (odds ratio = 1.14; 95% confidence interval, 1.07-1.21), were of high socioeconomic status (socioeconomic status index 7: odds ratio = 1.21; 95% confidence interval, 1.11-1.31), and traveled long distance (odds ratio = 4.03; 95% confidence interval, 3.63-4.48) and less likely for nonmetropolitan residents and those of low socioeconomic status (P < .05). Patients of high socioeconomic status and those who traveled long distance, were treated at high-volume facilities, underwent surgical resection, and received perioperative chemotherapy had an associated survival advantage (P < .05 for all), whereas Black race was associated with poorer overall survival (P < .05).

CONCLUSION

Nonmedical patient factors, such as race, socioeconomic status, and geography, are associated with treatment and survival for isolated colorectal liver metastases. Disparities persist after adjusting for surgical resection and treatment facility. These barriers must be addressed to improve care for vulnerable cancer patients.

Average treatment effect of facility hepatopancreatobiliary cancer volume on survival of non-resected pancreatic adenocarcinoma

BACKGROUND

To examine the average treatment effect of hepato-pancreato-biliary (HPB) cancer volume on survival outcomes of patients with non-resected pancreatic adenocarcinoma (PDAC).

METHODS

We queried the National Cancer Database (2004-2018) for patients with HPB malignancies (PDAC, pancreatic neuroendocrine neoplasms, hepatocellular carcinoma, biliary tract cancers). We determined the 25th, 50th, and 75th percentiles based on the total annual HPB volume. We then identified patients with non-resected PDAC. We utilized inverse probability (IP)-weighted Cox regression to estimate the effect of facility volume on overall survival (OS).

RESULTS

We identified 710,988 patients with HPB malignancies. The 25th, 50th, and 75th percentiles of total annual HPB volume were 32, 71, and 177 cases/year, respectively. We included a total of 196,150 patients with non-resected PDAC. Patients treated at ≥25th, ≥50th, and ≥75th percentile facilities had improved median OS compared to those treated at facilities below these thresholds (5.8 vs. 4.2months, 6.5 vs. 4.5months, 7.5 vs. 4.8months, respectively; p < 0.001 for all). Treatment at facilities ≥25th, ≥50th, and ≥75th percentile resulted in lower hazards of death than treatment at lower-percentile facilities (HR: 0.87, 95% CI: 0.84-0.90; HR: 0.87, 95% CI: 0.83-0.91; HR: 0.85, 95% CI: 0.79-0.91, respectively).

CONCLUSION

Our data suggest that consolidation of care of patients with PDAC to high-volume centers may be beneficial even in the nonoperative setting.

Trends in Melanoma Phase 3 Clinical Trials since 2010: Is there Hope for Advanced Melanoma Therapies beyond Approved Treatment Mechanisms?

BACKGROUND

Several drugs and treatment modalities are under investigation to improve current melanoma therapy options. This review profiles the trends in clinical trial investment in late-stage melanoma, and anticipates what changes are expected in melanoma treatment, with a focus on exploratory drug mechanisms.

METHODS

We reviewed nine international clinical trial databases for registered, interventional, and phase 3 cutaneous melanoma clinical trials since 2010.

RESULTS

73 trials studied drug therapies in late-stage (stage III and IV) melanoma. Exploratory mechanisms were investigated in 32% (23/73) of the late-stage melanoma drug therapy trials. Most exploratory drug trials include immunotherapy drug mechanisms (15/23 trials). Two exploratory mechanisms showed promise: the anti-LAG3 antibody, relatlimab, and the hapten modified vaccine, MVax. Many (52%) trials of exploratory mechanisms are ongoing including the use of adoptive cell transfer immunotherapies, dendritic cell vaccine therapy, and histone deacetylase (HDAC) inhibitors, among others.

CONCLUSIONS

Since most clinical trials focus on previously approved drug mechanisms, it is likely that paradigm-changing treatments will involve these therapies being used in new treatment contexts or combinations. Only 2 exploratory drug mechanisms studied since 2010 have achieved promising results in the phase 3 setting, though many other trials are ongoing at this time.

Wild-type IDH1 inhibition enhances chemotherapy response in melanoma

BACKGROUND

Alternative treatment strategies in melanoma beyond immunotherapy and mutation-targeted therapy are urgently needed. Wild-type isocitrate dehydrogenase 1 (wtIDH1) has recently been implicated as a metabolic dependency in cancer. The enzyme protects cancer cells under metabolic stress, including nutrient limited conditions in the tumor microenvironment. Specifically, IDH1 generates NADPH to maintain redox homeostasis and produces α-ketoglutarate to support mitochondrial function through anaplerosis. Herein, the role of wtIDH1 in melanoma is further explored.

METHODS

The expression of wtIDH1 was determined by qRT-PCR, and Western blot in melanoma cell lines and the effect of wtIDH1 on metabolic reprogramming in melanoma was interrogated by LC-MS. The impact of wtIDH1 inhibition alone and in combination with chemotherapy was determined in cell culture and mouse melanoma models.

RESULTS

Melanoma patients express higher levels of the wtIDH1 enzyme compared to normal skin tissue, and elevated wtIDH1 expression portends poor patient survival. Knockdown of IDH1 by RNA interference inhibited cell proliferation and migration under low nutrient levels. Suppression of IDH1 expression in melanoma also decreased NADPH and glutathione levels, resulting in increased reactive oxygen species. An FDA-approved inhibitor of mutant IDH1, ivosidenib (AG-120), exhibited potent anti-wtIDH1 properties under low magnesium and nutrient levels, reflective of the tumor microenvironment in natura. Thus, similar findings were replicated in murine models of melanoma. In light of the impact of wtIDH1 inhibition on oxidative stress, enzyme blockade was synergistic with conventional anti-melanoma chemotherapy in pre-clinical models.

CONCLUSIONS

These results demonstrate the clinical potential of wtIDH1 inhibition as a novel and readily available combination treatment strategy for patients with advanced and refractory melanoma. Schematic shows increased wild-type IDH1 expression and activity as an adaptive response to metabolic stress induced by chemotherapy.

Defining Facility Volume Threshold for Optimization of Short- and Long-Term Outcomes in Patients Undergoing Resection of Perihilar Cholangiocarcinoma

BACKGROUND

We determined the minimum threshold (Tmin) of annual facility case volume to optimize outcomes for patients with resected perihilar cholangiocarcinoma.

METHODS

We identified patients with localized perihilar cholangiocarcinoma who underwent resection within the National Cancer Database (2010-2017). We used marginal structural logistic regression models to estimate the average treatment effect of receiving care in facilities meeting/exceeding Tmin on 90-day mortality and other postoperative outcomes.

RESULTS

A total of 2471 patients underwent resection for perihilar cholangiocarcinoma at 471 facilities. There was no effect of total hepatopancreatobiliary, surgical hepatopancreatobiliary, total hepatobiliary, surgical hepatobiliary, or total perihilar cholangiocarcinoma case volume on 90-day mortality. A Tmin of seven perihilar cholangiocarcinoma resections/year resulted in lower odds of 90-day mortality (IP-weighted OR = 0.49, 95% CI: 0.66-0.87). A total of two facilities met the Tmin. Patients receiving treatment at Tmin facilities had lower odds of length of stay ≥ 7 days (IP-weighted OR = 0.85, 95% CI: 0.75-0.97) and positive surgical resection margins (IP-weighted OR = 0.40, 95% CI: 0.47-0.55). Additionally, undergoing surgery at Tmin facilities resulted in higher (≥ 4 nodes) lymph node yields (IP-weighted OR = 1.94, 95% CI: 1.21-3.11) but no change in the odds of nodal positivity. There was no effect of undergoing surgery at Tmin facilities on 30-day mortality or re-admission.

CONCLUSIONS

Resection of perihilar cholangiocarcinoma is infrequently performed at a high number of facilities. A Tmin of ≥ 7 resections/year resulted in lower 90-day mortality and improved postoperative outcomes. Our data suggest that regionalization of care for patients with perihilar cholangiocarcinoma could potentially improve outcomes in the USA.

Prodromal depression and anxiety are associated with worse treatment compliance and survival among patients with pancreatic cancer

OBJECTIVE

To determine the frequency of depression or anxiety preceding a diagnosis of pancreatic cancer (PC). Further, to examine the association of PC-associated depression or anxiety with treatment compliance and survival.

METHODS

856 patients with PC from a single institution were identified using International Classification of Diseases (ICD) codes. For each case, two non-cancer age- and sex-matched controls were included. Dates of depression or anxiety diagnosis identified using ICD codes were compared to the date of PC diagnosis. The medical record was queried to further explore psychiatric symptoms. Multivariable analyses were performed to examine if prediagnosis depression or anxiety was associated with receipt of treatment or survival.

RESULTS

A greater proportion of patients with PC experienced depression or anxiety in the year preceding diagnosis than the overall frequency in controls (4.6% vs. 2.6%, p = 0.005) based on ICD codes. Patients with PC exhibited signs of prodromal depression or anxiety based on ICD codes, clinical documentation of psychiatric symptoms, or initiation of new psychiatric medications more often than controls (20.7% vs. 6.7%, p < 0.001). Prediagnosis depression or anxiety was associated with a reduced likelihood of receiving chemotherapy (OR = 0.58, p = 0.04). There was an associated decrease in overall survival among patients with metastatic disease who experienced depression or anxiety before PC diagnosis (HR = 1.32, p = 0.04).

CONCLUSIONS

The frequency of depression or anxiety among patients with PC was higher than the general population. Prediagnosis psychiatric symptoms were associated with reduced chemotherapy utilization and worse overall survival. Thus, timely identification and treatment of these symptoms may improve outcomes.

A nationwide analysis of clinical trial participation for common hepato-pancreato-biliary malignancies demonstrates survival advantages for subsets of trial patients but disparities in and infrequency of enrollment

BACKGROUND

We describe factors associated with trial enrollment for patients with hepato-pancreato-biliary (HPB) malignancies. We analyzed the association and effect of trial enrollment on overall survival (OS).

METHODS

The National Cancer Database (2004-2017) was queried for common HPB malignancies (pancreatic adenocarcinoma [PDAC] & neuroendocrine tumors, hepatocellular carcinoma [HCC], biliary tract cancers [BTC]). Multivariable logistic regression was used to identify factors associated with trial enrollment. OS was analyzed by multivariable Cox regression. Inverse-probability-weighted Cox regression was utilized to determine the effect of trial enrollment on OS.

RESULTS

A total of 1573 (0.3%) of 511,639 patients were enrolled in trials; pancreatic malignancy: 1214 (0.4%); HCC: 217 (0.14%); BTC: 106 (0.15%). HCC and BTC were associated with lower likelihood of enrollment compared with pancreatic malignancy. Black and Hispanic patients were less likely to be enrolled compared to White patients. Treatment at academic facilities and metastatic disease were associated with higher likelihood of enrollment. Enrollment was associated with higher OS for PDAC, metastatic HCC, and metastatic BTC. Trial enrollment exhibited an OS advantage for PDAC and metastatic HCC.

CONCLUSION

Nationally, fewer than 1% of patients with HPB malignancies were enrolled in clinical trials. There are racial, sociodemographic, and facility-based disparities in trial enrollment.

Time to Neoadjuvant Chemotherapy Initiation Is not Associated With Survival in Pancreatic Cancer

INTRODUCTION

Not all patients with pancreatic adenocarcinoma (PDAC) tolerate multiagent neoadjuvant chemotherapy (NAC). We utilized institutional data and the National Cancer Database (NCDB) to investigate if time from diagnosis to NAC initiation is associated with survival.

METHODS

Patients who received NAC and underwent pancreatectomy at our institution (2010-2021) or within the NCDB (2010-2016) were identified. Time from diagnosis to NAC was grouped: <21, 21-35, and >35 d. Recurrence-free (RFS) and overall survival (OS) was compared.

RESULTS

At our institution, 122 patients received NAC before pancreatectomy (<21 d: n = 36; 21-35 d: n = 61; >35 d: n = 25). Demographics, performance status, and anatomic resectability were similar. There was no difference in RFS (13.3 versus 12.4 versus 11.9 mo) or OS (26.7 versus 25.8 versus 26.1 mo) based on NAC timing. Patients who received FOLFIRINOX had an improvement in RFS (14.4 versus 12.2 versus 6.8 mo, P = 0.05) and OS (39.2 versus 21.4 versus 17.3 mo, P = 0.01) compared to gemcitabine with nab-paclitaxel or other regimens. Within the NCDB, 6713 patients were included (<21 d: n = 2087; 21-35 d: n = 2656; >35 d: n = 1970). There was no difference in OS (21.6 versus 20.9 versus 22.2 mo). Multiagent NAC was associated with improved OS compared to single-agent (22.6 versus 18.8 mo, P < 0.001).

CONCLUSIONS

Delay in NAC initiation for PDAC is not associated with survival. Patient optimization could be considered with the goal of improving tolerance of multiagent chemotherapy.

A nationwide analysis of pancreatic cancer trial enrollment reveals disparities and participation problems

BACKGROUND

Our research group recently surveyed the clinical trial landscape in pancreatic adenocarcinoma and identified 430 active trials. These represent an opportunity to expand treatment options for patients with pancreatic adenocarcinoma. Our primary objective was to detail clinical trial participation among patients with pancreatic adenocarcinoma. Our secondary objective was to evaluate survival.

METHODS

We queried the National Cancer Database (2004-2016) for patients with pancreatic adenocarcinoma. Patients were stratified by trial participation: clinical trial or non-trial. Multivariable logistic regression was used to identify variables associated with trial participation. The Kaplan-Meier method and multivariable Cox hazards regression were used to analyze survival.

RESULTS

In total, 261,483 patients were included: 1,110 (0.4%) were enrolled in a clinical trial. A total of 57 Black patients participated in a clinical trial (0.19% of Black patients). This was lower compared to White patients (n = 955, 0.49% of White patients, P < .001). After adjusting for demographic and clinical factors, Black patients were less likely to be enrolled in a clinical trial (odds ratio = 0.387, P < .001). Patients treated at nonacademic medical centers were less likely to be in a clinical trial. Trial participation was associated with an increased median survival relative to non-trial patients (stage IV: 9.0 vs 3.8 months, P < .001), and this association remained on multivariable regression (hazard ratio = 0.779, P < .001).

CONCLUSION

Fewer than 1% of patients with pancreatic adenocarcinoma participated in a clinical trial. There are racial and sociodemographic disparities in clinical trial enrollment. An association was observed between clinical trial participants and prolonged survival.

Limited nutrient availability in the tumor microenvironment renders pancreatic tumors sensitive to allosteric IDH1 inhibitors

Nutrient-deprived conditions in the tumor microenvironment (TME) restrain cancer cell viability due to increased free radicals and reduced energy production. In pancreatic cancer cells a cytosolic metabolic enzyme, wild-type isocitrate dehydrogenase 1 (wtIDH1), enables adaptation to these conditions. Under nutrient starvation, wtIDH1 oxidizes isocitrate to generate α-ketoglutarate (αKG) for anaplerosis and NADPH to support antioxidant defense. In this study, we show that allosteric inhibitors of mutant IDH1 (mIDH1) are potent wtIDH1 inhibitors under conditions present in the TME. We demonstrate that low magnesium levels facilitate allosteric inhibition of wtIDH1, which is lethal to cancer cells when nutrients are limited. Furthermore, the Food & Drug Administration (FDA)-approved mIDH1 inhibitor ivosidenib (AG-120) dramatically inhibited tumor growth in preclinical models of pancreatic cancer, highlighting this approach as a potential therapeutic strategy against wild-type IDH1 cancers.

The efficacy of immune checkpoint blockade for melanoma in-transit with or without nodal metastases - A multicenter cohort study

PURPOSE

Guidelines addressing melanoma in-transit metastasis (ITM) recommend immune checkpoint inhibitors (ICI) as a first-line treatment option, despite the fact that there are no efficacy data available from prospective trials for exclusively ITM disease. The study aims to analyze the outcome of patients with ITM treated with ICI based on data from a large cohort of patients treated at international referral clinics.

METHODS

A multicenter retrospective cohort study of patients treated between January 2015 and December 2020 from Australia, Europe, and the USA, evaluating treatment with ICI for ITM with or without nodal involvement (AJCC8 N1c, N2c, and N3c) and without distant disease (M0). Treatment was with PD-1 inhibitor (nivolumab or pembrolizumab) and/or CTLA-4 inhibitor (ipilimumab). The response was evaluated according to the RECIST criteria modified for cutaneous lesions.

RESULTS

A total of 287 patients from 21 institutions in eight countries were included. Immunotherapy was first-line treatment in 64 (22%) patients. PD-1 or CTLA-4 inhibitor monotherapy was given in 233 (81%) and 23 (8%) patients, respectively, while 31 (11%) received both in combination. The overall response rate was 56%, complete response (CR) rate was 36%, and progressive disease (PD) rate was 32%. Median PFS was ten months (95% CI 7.4-12.6 months) with a one-, two-, and five-year PFS rate of 48%, 33%, and 18%, respectively. Median MSS was not reached, and the one-, two-, and five-year MSS rates were 95%, 83%, and 71%, respectively.

CONCLUSION

Systemic immunotherapy is an effective treatment for melanoma ITM. Future studies should evaluate the role of systemic immunotherapy in the context of multimodality therapy, including locoregional treatments such as surgery, intralesional therapy, and regional therapies.

Abstract 3133: Glucose is important for macrophage metabolism and response to immunotherapy in a pancreatic cancer model

Introduction: Pancreatic cancer (PC) is resistant to systemic therapies. This is at least in part due to the characteristically harsh tumor microenvironment which limits the delivery of systemic therapies and is not conducive to anti-tumor immune cell function. Unfortunately, development of novel therapeutics is arduous. Thus, identification of methods to augment the efficacy of existing therapeutics, such as immunotherapies, represents an attractive option. Herein, we attempt to sensitize PC to a colony stimulating factor 1 receptor (CSF1R) inhibitor by augmenting peripheral glucose levels.

Methods Murine PC cells (KPC) and bone marrow derived macrophages were cultured in hypoglycemic (≤2.5mM) or hyperglycemic (25mM) conditions. Phenotypic (western blot, flow cytometry), metabolic (seahorse, LC-MS metabolomics), and cell survival (clonogenic assay) assays were performed. KPC cells were orthotopically injected into the pancreas of immunocompetent mice for survival studies. Mice were randomized to pexidartinib (a CSF1R inhibitor) or vehicle and received either normal water of 30% dextrose (D30).

Results: In a co-culture experiment, tumor-supporting M2 macrophages increased KPC cell growth by 30%, whereas tumor-fighting M1 macrophages decreased KPC growth by 95%. M1 macrophages were poorly suited to survive in hypoglycemic conditions as compared to hyperglycemic conditions (relative survival: 38% vs 100%, p&lt;0.01). M2 macrophage survival was equivalent (93% vs 100%, p=0.39). When cultured in hypoglycemic conditions, M1 macrophages adopted an M2-like metabolic profile (i.e., increased TCA cycle metabolites and decreased glycolytic metabolites) assessed by both seahorse and LC-MS metabolomics. As glucose concentrations decreased in culture media over time, protein levels of an M1 marker (inducible nitric oxide, iNOS) decreased and an M2 marker (arginase) appeared, suggesting a phenotypic switch. Pexidartinib augmented M1 iNOS protein levels and simultaneously decreased M2 arginase levels. On an in vitro flow cytometric analysis, the percentage of M2 macrophages (CD206+, CD301+, F480+, CD11b+) decreased as glucose concentrations were increased (33.7% vs 38.0%), and decreased further when pexidartinib was combined with hyperglycemia (20.5%). Mice treated with pexidartinib and D30 had improved median survival relative to mice receiving pexidartinib alone (median survival: 42 (IQR: 38, 52) vs 34 (IQR: 32, 38) days, p&lt;0.05) in two independent experiments. Of note, pexidartinib alone did not improve survival as compared to vehicle or D30.

Conclusion: Higher glucose conditions promote M1 macrophage survival and function, while preventing the switch to an M2 phenotype. Also, higher peripheral glucose levels appear to sensitize PC to a CSF1R inhibitor. We plan to validate these findings using other immunotherapeutics (e.g., checkpoint inhibitors).

Citation Format: Jonathan J. Hue, Mehrdad Zarei, Hallie J. Graor, Erryk S. Katayama, Omid Hajihassani, Alexander W. Loftus, Luke D. Rothermel, Ali Vaziri-Gohar, Jordan M. Winter. Glucose is important for macrophage metabolism and response to immunotherapy in a pancreatic cancer model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3133.

Abstract 2321: IDO1 is a potential target to combat pancreatic cancer-associated depression

INTRODUCTION: Indolamine 2,3-dioxygenase 1 (IDO1) is upregulated in tumors. It facilitates catabolism of tryptophan to kynurenine and downstream metabolites, which are associated with psychiatric symptoms. To this point, 20% of patients at our institution developed psychiatric symptoms months before pancreatic cancer (PC) diagnosis. This proportion was threefold greater relative to non-cancer controls (6.7%), supplying indirect evidence of a biochemical link. Herein, we investigate IDO1 as a target in pancreatic cancer-associated depression.

METHODS: Human and murine PC cells were used in vitro. Protein levels were assessed using western blotting and cell survival by PicoGreen. For in vivo studies, murine PC cells were injected into the pancreatic tail. Control mice underwent an acellular injection. Mice were treated with epacadostat (an IDO1 inhibitor), escitalopram, or vehicle. To evaluate depressive-like behavior, mice were subjected to the forced swim and tail suspension tests. The open field test was used to monitor mobility. Tumors were analyzed using western blotting and serum metabolites were assessed using LC-MS.

RESULTS: Murine and human PC cells had undetectable basal IDO1 protein levels; however, there was a strong induction with interferon-gamma. There was a further increase in IDO1 with added epacadostat. Escitalopram had no effect on IDO1 levels. Epacadostat and escitalopram did not impact PC cell viability. Physical mobility of PC mice was similar to controls over the study period. PC mice were more immobile relative to controls during the forced swim (percent immobile: 16.0% v 8.2%, p&lt;0.001) and tail suspension (24.1% v 15.4%, p=0.003) tests. There was a 2.3-fold increase in serum kynurenine levels in PC mice relative to controls (p&lt;0.001).PC mice treated with epacadostat were less immobile relative to PC mice receiving vehicle in both the forced swim (3.2% v 6.6%, p=0.002) and tail suspension (25.0% v 39.3%, p=0.002) tests. Metabolomics demonstrated a 95% reduction in serum kynurenine levels in mice receiving epacadostat relative to vehicle (p&lt;0.001). Tumors of mice treated with epacadostat exhibited a compensatory upregulation of IDO1. Mice treated with escitalopram performed similarly to vehicle-treated mice on the forced swim (7.6%, p=0.85) and tail suspension (38.7%, p=0.77) tests, and kynurenine levels were similar. CONCLUSION: Mice with PC exhibit depressive-like behavior relative to control mice with an associated increase in kynurenine. Treatment with epacadostat improved depressive-like behavior and dramatically reduced kynurenine. These data provide evidence to trial epacadostat in patients battling pancreatic cancer-associated depression.

Citation Format: Jonathan J. Hue, Hallie J. Graor, Mehrdad Zarei, Ali Vaziri-Gohar, Erryk S. Katayama, Karen Ji, Omid Hajihassani, Alexander W. Loftus, Luke D. Rothermel, Jordan M. Winter. IDO1 is a potential target to combat pancreatic cancer-associated depression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2321.

Weight Tracking as a Novel Prognostic Marker After Pancreatectomy

BACKGROUND

Objective measures of post-pancreatectomy weight change for pancreatic ductal adenocarcinoma (PDAC) have not been extensively studied for long-term outcomes. We used weight measurements in our institutional medical record to analyze trends in post-pancreatectomy weight and determine the association with disease status.

METHODS

Pancreatectomies for PDAC (n = 315) and benign indications (n = 111) were identified. Preoperative baseline, minimum postoperative (Min #1), and subsequent postoperative maximum (Max) weights were abstracted. Multivariable Cox hazards regression was conducted to analyze the association between weight change and survival.

RESULTS

Median weight loss postoperatively in each group was > 20 lbs. PDAC patients gained 10 lbs after Min #1 compared to 15 lbs in the benign cohort (p < 0.001). Few patients returned to their preoperative weight (29.8% PDAC vs. 40.5% benign, p = 0.04). Patients with early PDAC recurrence (< 13 months) lost more weight (18.0% vs. 13.3% vs. 10.9%, p < 0.001) and gained less weight (2.1% vs. 12.0% vs. 7.9%, p < 0.001) compared with those with late cancer recurrence (≥ 13 months) or no evidence of active disease, respectively. PDAC patients lost 11.2 lbs in the year preceding recurrence diagnosis. Weight loss was not associated with survival; however, weight gain was associated with improved survival.

CONCLUSIONS

Resections for PDAC are complicated by a similar degree of weight loss as patients with benign disease, and there is no association with survival. However, failure to gain weight is especially ominous. Weight loss after weight recovery foreshadows disease recurrence. These data suggest that rigorous weight tracking is an untapped surveillance strategy in patients with PDAC.

Multimodal therapy with or without irreversible electroporation for unresectable locally advanced pancreatic adenocarcinoma: a systematic review and meta-analysis

BACKGROUND

Irreversible electroporation (IRE) is used as a locoregional treatment modality for patients with locally advanced pancreatic cancer (LAPC), but is non-curative and is associated with postoperative morbidity and mortality. We performed a systematic review and meta-analysis comparing survival outcomes of multimodal therapy with or without IRE.

METHODS

Separate searches were performed for multimodal therapy + IRE and multimodal therapy alone given the lack of comparative literature using PubMed, SCOPUS, and Cochrane Library in 3/2021. We determined overall survival (OS) and progression-free survival (PFS) from diagnosis and time of IRE. Treatment-related morbidity and mortality was determined.

RESULTS

Of 585 published articles, 48 met inclusion criteria for IRE (n = 27) and without IRE (n = 21) with data for 1420 (IRE) and 1348 (without IRE) patients. The 6/12/24 months OS with IRE was 99%/84%/28%. The 6/12/24 months OS without IRE was 99%/80%/12%. At 12 months from IRE, OS was 55% and PFS was 12%. The mean major complication and 90-day mortality rates for IRE were 17.95% and 2.65%.

CONCLUSION

Multimodal therapy alone is associated with similar OS to multimodal therapy + IRE in patients with LAPC. Most patients progress and nearly half die within 1 year of the IRE procedure. Given the lack of quality prospective data, IRE should remain experimental and be used with caution in LAPC.

Weight loss during neoadjuvant therapy for pancreatic cancer does not predict poor outcomes

BACKGROUND

Weight changes during neoadjuvant chemotherapy (NAC) for pancreatic cancer (PDAC) are not well studied. We hypothesized that weight loss may predict poor outcomes.

METHODS

Weight change from NAC initiation to pancreatectomy was grouped: gain (≥5%), stable, and loss (≥5%). Pathologic, postoperative, and survival outcomes were compared.

RESULTS

95 patients were included: 31.6% lost weight, 58.9% maintained weight, and 9.5% gained weight. There were no differences in chemotherapeutic regimens. Median recurrence-free survival (RFS) and overall survival (OS) were similar between patients with stable weight and those who lost weight (RFS: 9.6vs14.0months; OS: 25.8vs26.7months). Among those who gained weight, RFS (29.5months) and OS (38.4months) were greater relative to the other weight categories. On multivariable regression, weight gain was associated with improved RFS compared to loss (HR = 0.16).

CONCLUSION

Most patients maintain or lose weight during NAC, and weight loss does not predict poor outcomes. Weight gain may predict improved RFS.

Combined multiagent chemotherapy and radiotherapy is associated with prolonged overall survival in patients with non-operatively managed stage II-III pancreatic adenocarcinoma

BACKGROUND

Most patients with pancreatic adenocarcinoma (PDAC) do not undergo surgical resection. The role of radiotherapy (RT) in non-operatively managed localized pancreatic adenocarcinoma is unclear.

METHODS

The National Cancer Database (2010-2016) was queried for patients with clinical stage II-III PDAC treated with multiagent systemic chemotherapy (CT) +/- RT but not surgery. Factors associated with the receipt of RT and overall survival were compared after adjusting for patient demographics and clinical characteristics.

RESULTS

A total of 14,921 patients were included, of whom 9279 received CT and 5382 received CT + RT. Patients treated with CT + RT were more likely to be younger (65vs66yrs), treated at non-academic facilities (48.8%vs46.7%), have private insurance (40.3%vs36.5%), and have clinical T4 tumors (53.6%vs48.7%). Most patients who were treated with RT received external beam radiotherapy (89.3%), and the median dose was 5,000 cGy. Median time to start of RT was 129 days. CT + RT was associated with longer overall survival (15.9vs11.8mos,p < 0.001), and remained associated with survival on multivariable analysis (HR 0.74, 95%CI 0.70-0.78). On a 4-month conditional survival analysis, combined CT + RT remained associated with improved survival compared to CT alone (16.0vs13.1mos,p < 0.001).

CONCLUSIONS

In patients with non-operatively managed localized pancreatic adenocarcinoma, combined radiotherapy and multiagent systemic chemotherapy is associated with improved overall survival compared to chemotherapy alone.

Assessing the Role of Operative Intervention in Elderly Patients With Nonfunctional Pancreatic Neuroendocrine Neoplasms

OBJECTIVES

Resection of locoregional pancreatic neuroendocrine neoplasms (PanNENs) is typically recommended, but there is a paucity of data on the management of elderly patients.

METHODS

The National Cancer Database (2004-2016) was queried for patients 80 years or older with localized PanNENs. Patients were grouped as nonoperative or operative management. Postoperative outcomes and survival were compared.

RESULTS

In total, 591 patients were included: 202 underwent resection, and 389 did not. Increasing age and pancreatic head tumors were associated with lower likelihood of resection. The overall 90-day mortality rate was 6.4%, which was higher for pancreatoduodenectomy than distal pancreatectomy (13.6% vs 5.1%, respectively). Operatively managed patients had longer median survival (80.8 vs 45.0 months, P < 0.001), and this association was independent of tumor location. On multivariable Cox regression, resection remained associated with longer survival (hazard ratio, 0.69; 95% confidence interval, 0.50-0.95). Among operatively managed patients, age and tumor location were not associated with survival; however, greater comorbidity and high-risk tumor-specific features were associated with worse survival.

CONCLUSIONS

Resection of nonfunctional PanNENs in elderly patients is associated with improved survival compared with nonoperative management. Resection could be considered in appropriate operative candidates, regardless of tumor location, but the perioperative mortality rate must be considered.

Facility type and size-stratified analysis of management patterns and outcomes of patients with localized non-functional pancreatic neuroendocrine tumors

BACKGROUND

Non-functional neuroendocrine tumors of the pancreas (NF-pNETs) are uncommon. Consensus guidelines have conflicting recommendations. We performed a nationwide analysis of patterns in management and outcomes based on facility type and tumor size.

METHODS

The National Cancer Database (2004-2016) was queried for patients with localized NF-pNETs (<1 cm, 1-2 cm, >2 cm) stratified by facility type. Management decisions, operative outcomes, and survival were compared.

RESULTS

A total of 7170 patients were included in the analysis (<1 cm = 916; 1-2 cm = 2180; >2 cm = 4074). Most patients were treated at academic facilities (62.8%). Over 67% of patients with tumors <1 cm underwent resection, independent of facility type (p = 0.443). There was no association between facility type and operative vs non-operative management of patients with NF-pNETs 1-2 cm in size. Patients treated at academic facilities were more likely to undergo resection for tumors >2 cm compared to other facility types. Resection was associated with improved survival among patients with tumors 1-2 cm (HR = 0.43,p < 0.001) and >2 cm (HR = 0.32,p < 0.001), but not <1 cm (HR = 0.64,p = 0.054), as compared to non-operative management.

CONCLUSION

There is heterogeneity in management of NF-pNETs across facility types. Treatment at academic facilities appears to be associated with higher resection rates for tumors >2 cm. There appears to be an independent association between operative management and improved survival for tumors ≥1 cm in size.

Abstract PD7-08: Less is not necessarily more: A propensity matched national analysis on effect and outcome of sentinel lymph node biopsy omission

Background: Routine sentinel lymph node biopsy (SLNB) has been recommended against by Choosing Wisely© Foundation due to its low value in clinical node negative, hormone receptor positive breast cancer patients age≥70 years old. We used the National Cancer Database (NCDB) to examine the effect of SLNB omission and outcomes in this population. We hypothesized that SLNB would be beneficial in this population.Methods: The National Cancer Database was queried for women diagnosed with primary unilateral invasive clinical stage T1N0M0 hormone receptor positive, HER-2 negative breast cancer from 2012-2017. Patients age ≥ 70 years old with Charlson Score ≥1 who underwent partial mastectomy and received hormonal therapy were included in the study cohort. Patients received neoadjuvant therapy or underwent upfront axillary lymph node dissection (ALND) were excluded. A 1:3 propensity match with replacement was performed to compare SLNB omission vs. SLNB group controlling age, race, comorbidities, insurance and facility. Overall survival was analyzed using stratified multivariable Cox proportional hazard regression analysis.Results: Of 14,150 patients, 1,928 (13.6%) omitted SLNB and 12,222 (86.4%) underwent SLNB, including 1,545/12,222 (12.6%) who proceeded to ALND. Central portion tumor location (OR=1.77, P=0.001), clinical T1c (OR= 2.49, P&lt;0.001) and lymph-vascular invasion (OR=7.46, P&lt;0.001) were significant associated with positive pathological lymph node involvement in SLNB group. Among the 1,397 patients of positive nodal status with SLNB, 87.7% received radiation therapy and 19.3% received chemotherapy. Propensity matching reduced bias between the groups, generating 1,903 SLNB omission and 5,703 SLNB patients for analysis. After match, the SLNB omission group was less likely to receive chemotherapy (1.1% vs. 3.0%, p&lt;0.001) or radiation therapy (28.9% vs. 60.8%, p&lt;0.001). Omitting SLNB was associated with inferior overall survival (3-year 83.7% vs. 90.6%, 5-year 66.4% vs. 76.1%, p&lt;0.001). Omitting SLNB was also associated with inferior survival in multivariate cox regression (HR=1.64, p&lt;0.001). Chemotherapy (OR=0.51, p=0.020) and radiation therapy (OR=0.85, P=0.007) were associated with superior overall survival.Conclusions: SLNB remains to be of importance in cT1N0M0 HR+HER2- patients of age 70 years. Pathologic staging affects decisions on adjuvant treatment and SLNB omission is associated with inferior survival. In this population, SLNB might need to be re-implemented, especially in patients with high likelihood of nodal involvement.

Citation Format: Lifen Cao, Megan E Miller, Luke D Rothermel, Alberto J Montero, Christopher W Towe, Robert Shenk. Less is not necessarily more: A propensity matched national analysis on effect and outcome of sentinel lymph node biopsy omission [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD7-08.

Black race is independently associated with underutilization of preoperative chemotherapy in clinical stage T2 or higher gastric adenocarcinoma

BACKGROUND

Consensus guidelines recommend for perioperative chemotherapy and surgery for patients with clinical stage (cT) T2 or greater gastric adenocarcinoma. We compared adherence to guidelines in these patients stratified by race.

METHODS

Non-Hispanic White and Black patients with resected ≥cT2 gastric adenocarcinoma were identified within the National Cancer Database (2008-2017). We compared administration of preoperative chemotherapy by race, adjusting for clinicodemographic variables. We performed marginal standardization of logistic regression to calculate adjusted probabilities of administration of preoperative chemotherapy in patients under the age of 80 years with insurance.

RESULTS

A total of 13,850 patients were identified (White = 12,161; Black = 1,689). Black race was associated with lower likelihood of receiving preoperative chemotherapy than White race (odds ratio = 0.46, 95% confidence interval: 0.39-0.54). Other factors associated with lower likelihood of preoperative chemotherapy included age ≥70 years, female sex, treatment at community facilities, non-private or no health insurance, and cT4 disease. Factors associated with higher likelihood of preoperative chemotherapy included treatment at high-volume facilities, longer distance to facility, higher education and income levels, cT3 disease, and cN+ disease. In patients <80 years with insurance, marginal standardization models demonstrated that Black race was associated with a lower adjusted probability of receiving preoperative chemotherapy regardless of age, insurance payor, facility type/volume, distance to facility, cT stage, cN stage, sex, and education/income levels.

CONCLUSION

Black race was associated with underutilization of preoperative chemotherapy for cT2 or greater gastric cancer, in discordance to published guidelines. The etiology of these disparities is multifactorial, and correcting the root causes represents a critical area for improvement.