Serum Tumor Markers and Outcomes in Patients With Appendiceal Adenocarcinoma

Importance

Serum tumor markers carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and cancer antigen 125 (CA125) have been useful in the management of gastrointestinal and gynecological cancers; however, there is limited information regarding their utility in patients with appendiceal adenocarcinoma.

Objective

To assess the association of serum tumor markers (CEA, CA19-9, and CA125) with clinical outcomes and pathologic and molecular features in patients with appendiceal adenocarcinoma.

Design, Setting, and Participants

This is a retrospective cohort study at a single tertiary care comprehensive cancer center. The median (IQR) follow-up time was 52 (21-101) months. Software was used to query the MD Anderson internal patient database to identify patients with a diagnosis of appendiceal adenocarcinoma and at least 1 tumor marker measured at MD Anderson between March 2016 and May 2023. Data were analyzed from January to December 2023.

Main Outcomes and Measures

Association of serum tumor markers with survival in patients with appendiceal adenocarcinoma. Cox proportional hazards regression analyses were also performed to assess associations between clinical factors (serum tumor marker levels, demographics, and patient and disease characteristics) and patient outcomes (overall survival).

Results

A total of 1338 patients with appendiceal adenocarcinoma were included, with a median (range) age at diagnosis of 56.5 (22.3-89.6) years. The majority of the patients had metastatic disease (1080 patients [80.7%]). CEA was elevated in 742 of the patients tested (56%), while CA19-9 and CA125 were elevated in 381 patients (34%) and 312 patients (27%), respectively. Individually, elevation of CEA, CA19-9, or CA125 were associated with worse 5-year survival; elevated vs normal was 81% vs 95% for CEA (hazard ratio [HR], 4.0; 95% CI, 2.9-5.6), 84% vs 92% for CA19-9 (HR, 2.2; 95% CI, 1.4-3.4), and 69% vs 93% for CA125 (HR, 4.6; 95% CI, 2.7-7.8) (P < .001 for all). Quantitative evaluation of tumor markers was associated with outcomes. Patients with highly elevated (top 10th percentile) CEA, CA19-9, or CA125 had markedly worse survival, with 5-year survival rates of 59% for CEA (HR, 9.8; 95% CI, 5.3-18.0), 64% for CA19-9 (HR, 6.0; 95% CI, 3.0-11.7), and 57% for CA125 (HR, 7.6; 95% CI, 3.5-16.5) (P < .001 for all). Although metastatic tumors had higher levels of all tumor markers, when restricting survival analysis to 1080 patients with metastatic disease, elevated CEA, CA19-9, or CA125 were all still associated worse survival (HR for CEA, 3.4; 95% CI, 2.5-4.8; P < .001; HR for CA19-9, 1.8; 95% CI, 1.2-2.7; P = .002; and HR for CA125, 3.9; 95% CI, 2.4-6.4; P < .001). Interestingly, tumor grade was not associated with CEA or CA19-9 level, while CA-125 was slightly higher in high-grade tumors relative to low-grade tumors (mean value, 18.3 vs 15.0; difference, 3.3; 95% CI, 0.9-3.7; P < .001). Multivariable analysis identified an incremental increase in the risk of death with an increase in the number of elevated tumor markers, with an 11-fold increased risk of death in patients with all 3 tumor markers elevated relative to those with none elevated. Somatic mutations in KRAS and GNAS were associated with significantly higher levels of CEA and CA19-9.

Conclusions and Relevance

In this retrospective study of serum tumor markers in patients with appendiceal adenocarcinoma, CEA, CA19-9, and CA125 were associated with overall survival in appendiceal adenocarcinoma. Given their value, all 3 biomarkers should be included in the initial workup of patients with a diagnosis of appendiceal adenocarcinoma.

Repeat Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy for Recurrent Mucinous Appendiceal Adenocarcinoma: A Viable Treatment Strategy with Demonstrable Benefit

INTRODUCTION

Many patients with mucinous appendiceal adenocarcinoma experience peritoneal recurrence despite complete cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Prior work has demonstrated that repeat CRS/HIPEC can prolong survival in select patients. We sought to validate these findings using outcomes from a high-volume center.

PATIENTS AND METHODS

Patients with mucinous appendiceal adenocarcinoma who underwent CRS/HIPEC at MD Anderson Cancer Center between 2004 and 2021 were stratified by whether they underwent CRS/HIPEC for recurrent disease or as part of initial treatment. Only patients who underwent complete CRS/HIPEC were included. Initial and recurrent groups were compared.

RESULTS

Of 437 CRS/HIPECs performed for mucinous appendiceal adenocarcinoma, 50 (11.4%) were for recurrent disease. Patients who underwent CRS/HIPEC for recurrent disease were more often treated with an oxaliplatin or cisplatin perfusion (35%/44% recurrent vs. 4%/1% initial, p < 0.001), had a longer operative time (median 629 min recurrent vs. 511 min initial, p = 0.002), and had a lower median length of stay (10 days repeat vs. 13 days initial, p < 0.001). Thirty-day complication and 90-day mortality rates did not differ between groups. Both cohorts enjoyed comparable recurrence free survival (p = 0.82). Compared with patients with recurrence treated with systemic chemotherapy alone, this select cohort of patients undergoing repeat CRS/HIPEC enjoyed better overall survival (p < 0.001).

CONCLUSIONS

In appropriately selected patients with recurrent appendiceal mucinous adenocarcinoma, CRS/HIPEC can provide survival benefit equivalent to primary CRS/HIPEC and that may be superior to that conferred by systemic therapy alone in select patients. These patients should receive care at a high-volume center in the context of a multidisciplinary team.

Novel Clinical Tool to Estimate Risk of False-Negative KRAS Mutations in Circulating Tumor DNA Testing

PURPOSE

In metastatic colorectal cancer, the detection of RAS mutations by circulating tumor DNA (ctDNA) has emerged as a valid and noninvasive alternative approach to determining RAS status. However, some RAS mutations may be missed, that is, false negatives can occur, possibly compromising important treatment decisions. We propose a statistical model to assess the probability of false negatives when performing ctDNA testing for RAS.

METHODS

Cohorts of 172 subjects with tissue and multipanel ctDNA testing from MD Anderson Cancer Center and 146 subjects from Massachusetts General Hospital were collected. We developed a Bayesian model that uses observed frequencies of reference mutations (the maximum of APC and TP53) to provide information about the probability of KRAS false negatives. The model was alternatively trained on one cohort and tested on the other. All data were collected on Guardant assays.

RESULTS

The model suggests that negative KRAS findings are believable when the maximum of APC and TP53 frequencies is at least 8% (corresponding posterior probability of false negative <5%). Validation studies demonstrated the ability of our tool to discriminate between false-negative and true-negative subjects. Simulations further confirmed the utility of the proposed approach.

CONCLUSION

We suggest clinicians use the tool to more precisely quantify KRAS false-negative ctDNA results when at least one of the reference mutations (APC, TP53) is observed; usage may be especially important for subjects with a maximum reference frequency of <8%. Extension of the methodology to predict false negatives of other genes is possible. Additional reference genes can also be considered. Use of personal training data sets is supported. An open-source R Shiny application is available for public use.

Efficacy of Systemic Chemotherapy in Patients With Low-grade Mucinous Appendiceal Adenocarcinoma: A Randomized Crossover Trial

Importance

Appendiceal adenocarcinoma is a rare tumor, and given the inherent difficulties in performing prospective trials in such a rare disease, there are currently minimal high-quality data to guide treatment decisions, highlighting the need for more preclinical and clinical investigation for this disease.

Objective

To prospectively evaluate the effectiveness of fluoropyrimidine-based systemic chemotherapy in patients with inoperable low-grade mucinous appendiceal adenocarcinoma.

Design, Setting, and Participants

This open-label randomized crossover trial recruited patients at a single tertiary care comprehensive cancer center from September 2013 to January 2021. The data collection cutoff was May 2022. Enrollment of up to 30 patients was planned. Eligible patients had histological evidence of a metastatic low-grade mucinous appendiceal adenocarcinoma, with radiographic imaging demonstrating the presence of mucinous peritoneal carcinomatosis and were not considered candidates for complete cytoreductive surgery. Key exclusion criteria were concurrent or recent investigational therapy, evidence of bowel obstruction, and use of total parenteral nutrition. Data were analyzed from November 2021 to May 2022.

Interventions

Patients were randomized to either 6 months observation followed by 6 months of chemotherapy, or initial chemotherapy followed by observation.

Main Outcomes and Measures

The primary end point was the percentage difference in tumor growth in treatment and observation groups. Key secondary end points included patient-reported outcomes in the chemotherapy and observation periods, objective response rate, rate of bowel complications, and differences in overall survival (OS).

Results

A total of 24 patients were enrolled, with median (range) age of 63 (38 to 82) years, and equal proportion of men and women (eg, 12 men [50%]); all patients had ECOG performance status of 0 or 1. A total of 11 patients were randomized to receive chemotherapy first, and 13 patients were randomized to receive observation first. Most patients (15 patients [63%]) were treated with either fluorouracil or capecitabine as single agent; 3 patients (13%) received doublet chemotherapy (leucovorin calcium [folinic acid], fluorouracil, and oxaliplatin or folinic acid, fluorouracil, and irinotecan hydrochloride), and bevacizumab was added to cytotoxic chemotherapy for 5 patients (21%). Fifteen patients were available to evaluate the primary end point of difference in tumor growth during treatment and observation periods. Tumor growth while receiving chemotherapy increased 8.4% (95% CI, 1.5% to 15.3%) from baseline but was not significantly different than tumor growth during observation (4.0%; 95% CI, -0.1% to 8.0%; P = .26). Of 18 patients who received any chemotherapy, none had an objective response (14 patients [77.8%] had stable disease; 4 patients [22.2%] had progressive disease). Median (range) OS was 53.2 (8.1 to 95.5) months, and there was no significant difference in OS between the observation-first group (76.0 [8.6 to 95.5] months) and the treatment-first group (53.2 [8.1 to 64.1] months; hazard ratio, 0.64; 95% CI, 0.16-2.55; P = .48). Patient-reported quality-of-life metrics identified that during treatment, patients experienced significantly worse fatigue (mean [SD] score, 18.5 [18.6] vs 28.9 [21.3]; P = .02), peripheral neuropathy (mean [SD] score, 6.67 [12.28] vs 38.89 [34.88]; P = .01), and financial difficulty (mean [SD] score, 8.9 [15.2] vs 28.9 [33.0]; P = .001) compared with during observation.

Conclusions and Relevance

In this prospective randomized crossover trial of systemic chemotherapy in patients with low-grade mucinous appendiceal adenocarcinoma, patients did not derive clinical benefit from fluorouracil-based chemotherapy, given there were no objective responses, no difference in OS when treatment was delayed 6 months, and no difference in the rate of tumor growth while receiving chemotherapy.

Trial Registration

ClinicalTrials.gov Identifier: NCT01946854.

Prospective Study of Perioperative Circulating Tumor DNA Dynamics in Patients Undergoing Hepatectomy for Colorectal Liver Metastases

OBJECTIVE

To evaluate the association of perioperative ctDNA dynamics on outcomes after hepatectomy for CLM.

SUMMARY BACKGROUND DATA

Prognostication is imprecise for patients undergoing hepatectomy for CLM, and ctDNA is a promising biomarker. However, clinical implications of perioperative ctDNA dynamics are not well established.

METHODS

Patients underwent curative-intent hepatectomy after preoperative chemotherapy for CLM (2013-2017) with paired prehepatectomy/postoperative ctDNA analyses via plasma-only assay. Positivity was determined using a proprietary variant classifier. Primary endpoint was recurrence-free survival (RFS). Median follow-up was 55 months.

RESULTS

Forty-eight patients were included. ctDNA was detected before and after surgery (ctDNA+/+) in 14 (29%), before but not after surgery (ctDNA+/-) in 19 (40%), and not at all (ctDNA-/-) in 11 (23%). Adverse tissue somatic mutations were detected in TP53 (n = 26; 54%), RAS (n = 23; 48%), SMAD4 (n = 5; 10%), FBXW7 (n = 3; 6%), and BRAF (n = 2; 4%). ctDNA+/+ was associated with worse RFS (median: ctDNA+/+, 6.0 months; ctDNA+/-, not reached; ctDNA-/-, 33.0 months; P = 0.001). Compared to ctDNA+/+, ctDNA+/- was associated with improved RFS [hazard ratio (HR) 0.24 (95% confidence interval (CI) 0.1-0.58)] and overall survival [HR 0.24 (95% CI 0.08-0.74)]. Adverse somatic mutations were not associated with survival. After adjustment for prehepatectomy chemotherapy, synchronous disease, and ≥2 CLM, ctDNA+/- and ctDNA-/- were independently associated with improved RFS compared to ctDNA+/+ (ctDNA+/-: HR 0.21, 95% CI 0.08-0.53; ctDNA-/-: HR 0.21, 95% CI 0.08-0.56).

CONCLUSIONS

Perioperative ctDNA dynamics are associated with survival, identify patients with high recurrence risk, and may be used to guide treatment decisions and surveillance after hepatectomy for patients with CLM.

Incidence of Primary End Point Changes Among Active Cancer Phase 3 Randomized Clinical Trials

Importance

Primary end point (PEP) changes to an active clinical trial raise questions regarding trial quality and the risk of outcome reporting bias. It is unknown how the frequency and transparency of the reported changes depend on reporting method and whether the PEP changes are associated with trial positivity (ie, the trial met the prespecified statistical threshold for PEP positivity).

Objectives

To assess the frequency of reported PEP changes in oncology randomized clinical trials (RCTs) and whether these changes are associated with trial positivity.

Design, Setting, and Participants

This cross-sectional study used publicly available data for complete oncology phase 3 RCTs registered in ClinicalTrials.gov from inception through February 2020.

Main Outcomes and Measures

The main outcome was change between the initial PEP and the final reported PEP, assessed using 3 methods: (1) history of tracked changes on ClinicalTrials.gov, (2) self-reported changes noted in the article, and (3) changes reported within the protocol, including all available protocol documents. Logistic regression analyses were performed to evaluate whether PEP changes were associated with US Food and Drug Administration approval or trial positivity.

Results

Of 755 included trials, 145 (19.2%) had PEP changes found by at least 1 of the 3 detection methods. Of the 145 trials with PEP changes, 102 (70.3%) did not have PEP changes disclosed within the manuscript. There was significant variability in rates of PEP detection by each method (χ2 = 72.1; P < .001). Across all methods, PEP changes were detected at higher rates when multiple versions of the protocol (47 of 148 [31.8%]) were available compared with 1 version (22 of 134 [16.4%]) or no protocol (76 of 473 [16.1%]) (χ2 = 18.7; P < .001). Multivariable analysis demonstrated that PEP changes were associated with trial positivity (odds ratio, 1.86; 95% CI, 1.25-2.82; P = .003).

Conclusions and Relevance

This cross-sectional study revealed substantial rates of PEP changes among active RCTs; PEP changes were markedly underreported in published articles and mostly occurred after reported study completion dates. Significant discrepancies in the rate of detected PEP changes call into question the role of increased protocol transparency and completeness in identifying key changes occurring in active trials.

Resistance Mechanisms to Anti-Epidermal Growth Factor Receptor Therapy in RAS/RAF Wild-Type Colorectal Cancer Vary by Regimen and Line of Therapy

PURPOSE

Acquired resistance to anti-epidermal growth factor receptor (EGFR) inhibitor (EGFRi) therapy in colorectal cancer (CRC) has previously been explained by the model of acquiring new mutations in KRAS/NRAS/EGFR, among other MAPK-pathway members. However, this was primarily on the basis of single-agent EGFRi trials and little is known about the resistance mechanisms of EGFRi combined with effective cytotoxic chemotherapy in previously untreated patients.

METHODS

We analyzed paired plasma samples from patients with RAS/BRAF/EGFR wild-type metastatic CRC enrolled in three large randomized trials evaluating EGFRi in the first line in combination with chemotherapy and as a single agent in third line. The mutational signature of the alterations acquired with therapy was evaluated. CRC cell lines with resistance to cetuximab, infusional fluorouracil, leucovorin, and oxaliplatin, and SN38 were developed, and transcriptional changes profiled.

RESULTS

Patients whose tumors were treated with and responded to EGFRi alone were more likely to develop acquired mutations (46%) compared with those treated in combination with cytotoxic chemotherapy (9%). Furthermore, contrary to the generally accepted hypothesis of the clonal evolution of acquired resistance, we demonstrate that baseline resistant subclonal mutations rarely expanded to become clonal at progression, and most remained subclonal or disappeared. Consistent with this clinical finding, preclinical models with acquired resistance to either cetuximab or chemotherapy were cross-resistant to the alternate agents, with transcriptomic profiles consistent with epithelial-to-mesenchymal transition. By contrast, commonly acquired resistance alterations in the MAPK pathway do not affect sensitivity to cytotoxic chemotherapy.

CONCLUSION

These findings support a model of resistance whereby transcriptomic mechanisms of resistance predominate in the presence of active cytotoxic chemotherapy combined with EGFRi, with a greater predominance of acquired MAPK mutations after single-agent EGFRi. The proposed model has implications for prospective studies evaluating EGFRi rechallenge strategies guided by acquired MAPK mutations, and highlights the need to address transcriptional mechanisms of resistance.

Abstract B028: Changes in exosomal RNA expression associate with treatment response to BRAF + EGFR + PD-1 blockade in MSS, BRAFV600E colorectal cancer: A liquid biopsy approach

Introduction: BRAF + EGFR inhibition induces decreased expression of mismatch repair (MMR) genes in preclinical models of microsatellite stable (MSS), BRAFV600E metastatic colorectal cancer (mCRC) but has not been reported in patients. We evaluated exosomal RNA (exoRNA) isolated from serial blood specimens collected from patients (pts) with MSS, BRAFV600E mCRC treated with encorafenib (E) + cetuximab (C) + nivolumab (N) as a novel blood-based approach to compare differences in gene expression according to treatment response. Methods: Pts with refractory MSS, BRAFV600E mCRC were treated with E (300 mg daily), C (500 mg/m2 q2 weeks), and N (480 mg q4 weeks) on an IRB-approved clinical trial at MD Anderson. Responses to treatment were assessed every 8 weeks (RECIST v1.1). ExoRNA isolated from pretreatment and on-treatment (week 8) blood samples were sequenced (SMART-seq) and deconvoluted (DeMix) in order to estimate cancer-specific gene expression. Previously validated MAPK and interferon (IFN)-γ gene expression signatures were used for measuring transcriptomic changes following treatment with E+C+N. Scores between responders and non-responders were compared by unpaired t-tests. For Gene Set Enrichment Analysis (GSEA), an adjusted false discovery rate (FDR) &lt; 0.25 was applied to find significantly enriched pathways between on-treatment and pretreatment samples separately for responders and non-responders. Results: 26 pts were treated with E+C+N, and 24 were evaluable for response. Overall response rate was 50% (95% confidence interval (CI), 29-71), and median progression-free survival was 7.4 months (95% CI, 6.0-NA). Four pts remained on study &gt; 12 months. Between responders vs non-responders (N=12 each), mean changes in MAPK signature score was decreased (-0.63 vs 0.15, respectively; p=.13). Both patients with response &gt; 18 months demonstrated dramatic increases in IFN-γ score following treatment with E+C+N (+13.1 and +14.6), a trend not observed in all other patients (range, -18.0 to 3.6). Among responders to E+C+N, GSEA analysis demonstrated dynamic pathway changes in normalized enrichment score (NES) for DNA repair (NES -2.3; p-adj=.008), IL6/JAK/STAT3 (NES -2.1, p-adj=.02), and IFN-α response (NES -2.0, p-adj=.03). For non-responders, relative increases in NES were observed for angiogenesis (NES 2.1, p-adj=.02) and IL-2/STAT5 (NES 2.0, p-adj= .02). Conclusions: Transcriptome analysis using exoRNA isolated from serial blood samples is feasible for assessing treatment response in pts with mCRC. Decreased MAPK score in exoRNA may be associated with treatment response to E+C+N in pts with MSS, BRAFV600E mCRC. Changes in immune NES scores following treatment may distinguish responders from non-responders to MAPK + PD-1 blockade and highlight targets for novel immune-mediated combinations for MSS, BRAFV600E mCRC.

Citation Format: Van Karlyle Morris, Kimal I. Rajapakshe, Vahid Bahrambeigi, Christine M. Parsehgian, Benny Johnson, Kanwal P. Raghav, Arvind Dasari, Ryan W. Huey, Michael J. Overman, Jason Willis, Michael S. Lee, Robert A. Wolff, Bryan K. Kee, Phat Le, Paola A. Guerrero, Scott Kopetz, Anirban Maitra. Changes in exosomal RNA expression associate with treatment response to BRAF + EGFR + PD-1 blockade in MSS, BRAFV600E colorectal cancer: A liquid biopsy approach [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr B028.

Abstract A023: Influence of pre-diagnosis obesity and post-diagnosis aspirin use on survival from stage IV colorectal cancer

Background: The relationship between obesity and colorectal cancer (CRC) outcome is poorly understood in late-stage patients. Increased body mass may negate aspirin use for cancer prevention, but the influence of body mass index (BMI) on post-diagnosis aspirin use is unclear. This study aims to evaluate impacts of pre-diagnosis BMI and post-diagnosis aspirin use on overall survival in late-stage CRC patients on the Assessment of Targeted Therapies Against Colorectal Cancer (ATTACC) clinical protocol. Methods: Patients with metastatic or treatment refractory disease were consented on the ATTACC protocol at MD Anderson Cancer Center and invited to complete a survey on risk factors relevant to CRC etiology. Using survey data, BMI was calculated from the decade prior to initial CRC diagnosis for 656 patients. Survival was measured from stage IV diagnosis until death or last follow-up. Cox Proportional Hazards models were constructed to estimate associations of pre-diagnosis obesity and post-diagnosis aspirin use with overall survival. Results: Controlling for age, sex, race, stage at initial diagnosis, and weight change between pre-diagnosis and survey date, patients with pre-diagnosis obesity had significantly higher likelihood of death (HR 1.45, 95% CI: 1.11, 1.91) compared to those with normal pre-diagnosis BMI. Further, only patients with normal weight pre-diagnosis experienced a survival benefit with post-diagnosis aspirin use (HR 0.59, 95% CI: 0.39, 0.90). Conclusions: Our findings suggest potentially differential tumor development resulting from the long-term physiologic host environment, here obesity. Confirmation and further evaluation are needed to determine whether pre-diagnosis BMI may predict benefit from post-diagnosis aspirin use.

Citation Format: Jennifer S. Davis, Janelle C. Chavez, Melissa Kok, Yazmin San Miguel, Hwa Young Lee, Henry Henderson, Michael J. Overman, Van Karlyle Morris, Bryan Kee, David Fogelman, Shailesh M. Advani, Benny Johnson, Christine Parseghian, John Paul Shen, Arvind Dasari, Kenna R. Shaw, Eduardo Vilar, Kanwal P. Raghav, Imad Shureiqi, Robert A. Wolff, Funda Meric-Bernstam, Dipen Maru, David G. Menter, Scott Kopetz, Shine Chang. Influence of pre-diagnosis obesity and post-diagnosis aspirin use on survival from stage IV colorectal cancer [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr A023.

Association of Prediagnosis Obesity and Postdiagnosis Aspirin With Survival From Stage IV Colorectal Cancer

IMPORTANCE

The potential relationship between obesity and colorectal cancer (CRC) outcome is poorly understood in patients with late-stage disease. Increased body mass index may negate aspirin use for cancer prevention, but its role as a factor on the effectiveness of postdiagnosis aspirin use is unclear.

OBJECTIVE

To evaluate how prediagnosis obesity and postdiagnosis aspirin use may be associated with overall survival in patients with late-stage colorectal cancer.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study used self-reported data from patients with metastatic or treatment-refractory disease who consented to a clinical protocol at MD Anderson Cancer Center, a large US cancer treatment center. Patients were enrolled between 2010 and 2018 and followed up for mortality through July 2020. Analyses were conducted through March 2022.

EXPOSURES

Body mass index in the decade prior to initial diagnosis and regular aspirin use at survey completion.

MAIN OUTCOMES AND MEASURES

Overall survival was measured from stage IV diagnosis until death or last follow-up. Cox proportional hazards models were constructed to estimate associations of prediagnosis obesity and postdiagnosis aspirin use with overall survival.

RESULTS

Of 656 patients included in this analysis, 280 (42.7%) were women, 135 (20.6%) were diagnosed with CRC before age 45 years, 414 (63.1%) were diagnosed between ages 45 and 65 years, and 107 (16.3%) were diagnosed at 65 years or older; 105 patients (16.0%) were Black or Hispanic, and 501 (76.4%) were non-Hispanic White. Controlling for age, sex, race, stage at initial diagnosis, and weight change between prediagnosis and survey date, patients with obesity in the decade prior to CRC diagnosis had significantly higher likelihood of death (hazard ratio, 1.45; 95% CI, 1.11-1.91) compared with those with normal prediagnosis body mass index. Furthermore, only patients with normal prediagnosis body mass index experienced significant survival benefit with postdiagnosis aspirin use (hazard ratio, 0.59; 95% CI, 0.39-0.90).

CONCLUSIONS AND RELEVANCE

In this cross-sectional study, our findings suggest potentially differential tumor development in the long-term physiologic host environment of obesity. Confirmation and further evaluation are needed to determine whether prediagnosis body mass index may be used to estimate the benefit from postdiagnosis aspirin use.

Efficacy of pembrolizumab in patients with advanced cancer of unknown primary (CUP): a phase 2 non-randomized clinical trial

BACKGROUND

Cancer of unknown primary (CUP) is an aggressive rare malignancy with limited treatment options. Data regarding clinical activity of immune checkpoint inhibitors in CUP is lacking. Therefore, we evaluated the efficacy of pembrolizumab, a programmed cell death-1 inhibitor, in patients with CUP.

METHODS

The study was designed as a phase 2 basket trial for independent rare tumor cohorts including CUP. Adult patients with CUP who had progressed on previous systemic therapy, performance status 0/1 and measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST V.1.1) were eligible. Patients received pembrolizumab (200 mg) intravenously every 21 days. Twenty-nine patients were enrolled and treated between August 2016 and June 2020. The primary endpoint was non-progression rate (NPR) at 27 weeks (NPR-27) per immune-related RECIST. Key prespecified secondary endpoints were confirmed objective response rate (ORR), safety, duration of response (DoR), progression-free survival (PFS) and overall survival (OS). Pretreatment biopsies were examined for biomarkers of response (programmed cell death ligand-1 (PD-L1) expression and tumor infiltrating lymphocytes (TILs)).

RESULTS

Among 25 (of 29 enrolled) eligible and evaluable patients, 14 (56%) had poorly differentiated carcinoma. Patients received a median of two lines of therapy prior to enrollment. Median follow-up was 27.3 months. NPR-27 was observed in seven patients (28.0% (95% CI: 12.1 to 49.4)). ORR was 20.0% (95% CI: 6.8 to 40.7) with five patients achieving immune-related partial response with median DoR of 14.7 months (95% CI: 9.8 to 19.6). Median PFS and OS were 4.1 (95% CI: 3.1 to 5.1) and 11.3 (95% CI: 5.5 to 17.1) months, respectively. Treatment-related adverse events of any and grade ≥3 were seen in 19 (76%) and 4 (16%) patients, respectively. One (4%) patient had grade 3 immune-related acute kidney injury requiring treatment discontinuation. Neither PD-L1 nor TILs were associated with NPR-27. Both positive PD-L1 staining (44.4% vs 6.3%; p=0.040) and intense TIL infiltration (44.4% vs 6.3%; p=0.040) were associated with response.

CONCLUSION

Pembrolizumab showed encouraging efficacy in patients with CUP with acceptable safety profile.

TRIAL REGISTRATION NUMBER

NCT02721732.

Malignant Peritoneal Mesothelioma Associated With Endometriosis: A Clinicopathologic Study of 15 Cases

Only a few cases of malignant peritoneal mesothelioma (MPeM) associated with endometriosis have been published; with chronic inflammation of the peritoneum associated with the latter being postulated as an inducing factor in the pathogenesis of this tumor. We assessed the clinicopathologic characteristics of MPeM associated with endometriosis to determine if there were other factors besides inflammation that may contribute to the pathogenesis in this patient population. Fifteen MPeM associated with endometriosis were retrieved from our files. Most presented with abdominal/pelvic pain, mass or distention; median age was 45 yr. Only 16% of patients had a history of asbestos exposure. In contrast, a third of the patients had a personal history of other neoplasms, and >80% had a family history of malignancies. Although most tumors had gross and microscopic features typical of MPeM, some had confounding features including "adhesion-like" appearance or gelatinous cysts/nodules, and signet ring cells. Tumors were epithelioid (9) and biphasic (6). MPeM was misdiagnosed as Müllerian carcinoma in 40% of cases. All patients (n=15) had cytoreductive surgery in addition to other therapies. Only 2/12 patients died of disease (17%). The 3- and 5-yr overall survival was 90%. MPeM associated with endometriosis tends to occur in patients with personal/familial history of malignancies, which may be a predisposing factor. In light of this finding, the role of endometriosis in the pathogenesis of MPeM is likely less relevant. The favorable outcome seen in these patients may be related to germline mutations or the hormonal milieu and needs further investigation.

Phase 2 study of pembrolizumab in patients with advanced rare cancers

Background

Patients with advanced rare cancers have poor prognosis and few treatment options. As immunotherapy is effective across multiple cancer types, we aimed to assess pembrolizumab (programmed cell death 1 (PD-1) inhibitor) in patients with advanced rare cancers.

Methods

In this open-label, phase 2 trial, patients with advanced rare cancers whose tumors had progressed on standard therapies, if available, within the previous 6 months were enrolled in nine tumor-specific cohorts and a 10th cohort for other rare histologies. Pembrolizumab 200 mg was administered intravenously every 21 days. The primary endpoint was non-progression rate (NPR) at 27 weeks; secondary endpoints were safety and tolerability, objective response rate (ORR), and clinical benefit rate (CBR).

Results

A total of 127 patients treated between August 15, 2016 and July 27, 2018 were included in this analysis. At the time of data cut-off, the NPR at 27 weeks was 28% (95% CI, 19% to 37%). A confirmed objective response (OR) was seen in 15 of 110 (14%) evaluable patients (complete response in one and partial response in 14). CBR, defined as the percentage of patients with an OR or stable disease ≥4 months, was 38% (n=42). Treatment was ongoing in 11 of 15 patients with OR at last follow-up. In the cohort with squamous cell carcinoma (SCC) of the skin, the NPR at 27 weeks was 36%, ORR 31%, and CBR 38%. In patients with adrenocortical carcinoma (ACC), NPR at 27 weeks was 31%, ORR 15%, and CBR 54%. In the patients with carcinoma of unknown primary (CUP), NPR at 27 weeks was 33%, ORR 23%, and CBR 54%. In the paraganglioma–pheochromocytoma cohort, NPR at 27 weeks was 43%, ORR 0%, and CBR 75%. Treatment-related adverse events (TRAEs) occurred in 66 of 127 (52%) patients, and 12 (9%) had grade ≥3 TRAEs. The most common TRAEs were fatigue (n=25) and rash (n=17). There were six deaths, all of which were unrelated to the study drug.

Conclusions

The favorable toxicity profile and antitumor activity seen in patients with SCC of skin, ACC, CUP, and paraganglioma–pheochromocytoma supports further evaluation of pembrolizumab in this patient population.

Trial registration number

NCT02721732

Randomized Trial of Irinotecan and Cetuximab With or Without Vemurafenib in BRAF-Mutant Metastatic Colorectal Cancer (SWOG S1406)

PURPOSE

BRAFV600E mutations are rarely associated with objective responses to the BRAF inhibitor vemurafenib in patients with metastatic colorectal cancer (CRC). Blockade of BRAFV600E by vemurafenib causes feedback upregulation of EGFR, whose signaling activities can be impeded by cetuximab.

METHODS

One hundred six patients with BRAFV600E-mutated metastatic CRC previously treated with one or two regimens were randomly assigned to irinotecan and cetuximab with or without vemurafenib (960 mg PO twice daily).

RESULTS

Progression-free survival, the primary end point, was improved with the addition of vemurafenib (hazard ratio, 0.50, P = .001). The response rate was 17% versus 4% (P = .05), with a disease control rate of 65% versus 21% (P < .001). A decline in circulating tumor DNA BRAFV600E variant allele frequency was seen in 87% versus 0% of patients (P < .001), with a low incidence of acquired RAS alterations at the time of progression. RNA profiling suggested that treatment benefit did not depend on previously established BRAF subgroups or the consensus molecular subtype.

CONCLUSION

Simultaneous inhibition of EGFR and BRAF combined with irinotecan is effective in BRAFV600E-mutated CRC.

Abstract B35: Outcomes of patients with metastatic pancreatic cancer who progress on first restaging imaging

Background: Objective responses to first-line systemic chemotherapy in patients (pts) with metastatic pancreatic cancer (mPC) are seen in less than one third of cases. While disease stabilization is achievable for a significant percentage, many of these pts will have radiographic evidence of disease progression (PD) on their first restaging imaging. With patients’ short life expectancy in the metastatic setting, limited systemic treatment options, and significant toxicities associated with multidrug chemotherapy, it is crucial for clinicians to be prudent when deciding whom and when to treat. The purpose of our study was to evaluate outcomes of pts who progressed on their first restaging imaging while on first-line therapy.

Methods: We retrospectively analyzed mPC pts treated at MD Anderson since 2011 whose first restaging imaging on first-line therapy demonstrated PD. Data collected included patient demographics, choice of first-line therapy, and whether they received second-line therapy. Primary outcome was overall survival (OS) from date of metastatic diagnosis to death or last follow-up.

Results: A total of 121 pts were included in the analysis. Seventy-two received second-line therapy, and 49 did not pursue second-line therapy. The median ages for pts who did and did not receive second-line therapy were 61 and 67, respectively (p=0.001). More pts had a poor Eastern Cooperative Oncology Group (ECOG) performance status (ECOG 2-3) at the time of initial diagnosis in the non-second-line therapy group (31% vs. 6.9%, p=0.003). Forty-two pts (34.7%) received combination 5-fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) first-line, while 72 pts (59.5%) received gemcitabine + nab-paclitaxel (GnP). Thirty-four pts (80%) who received FOLFIRINOX first-line did proceed with second-line therapy, and 29 pts (40%) who received GnP proceeded with second-line therapy. Median OS for those receiving second-line therapy was 8.28 months compared to 2.73 months for those not receiving second-line therapy (p&lt;0.001).

Conclusions: Although likely biased due to better performance status and younger age, our mPC pts who progressed rapidly on first-line therapy showed an OS benefit if they received second-line therapy. These results suggest that pts maintaining a good performance status after immediate progression on first-line therapy should be offered second-line therapy.

Citation Format: Jonathan D. Mizrahi, Jane E. Rogers, Graciela M. Nogueras-Gonzalez, Robert A. Wolff, Gauri R. Varadhachary, Milind M. Javle, Rachna T. Shroff, Linus Ho, David R. Fogelman, Kanwal P. Raghav, Michael J. Overman, Shubham Pant. Outcomes of patients with metastatic pancreatic cancer who progress on first restaging imaging [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr B35.

Abstract B36: Maintenance chemotherapy after chemoradiation in patients with locally advanced pancreatic cancer

Background: More than half of patients (pts) with pancreatic cancer (PC) initially present with unresectable, locally advanced disease (LAPC). Data on management of these pts after systemic chemotherapy are scarce. Many clinicians utilize a strategy of induction chemotherapy followed by consolidative concurrent chemoradiation (CRT) for pts not progressing on initial chemotherapy. How to manage pts after CRT is controversial. We sought to evaluate the role of maintenance chemotherapy (MCT) after CRT in pts with LAPC.

Methods: We retrospectively analyzed LAPC pts treated with CRT at MD Anderson from 2005-2018. Pts who were taken for curative-intent surgery were excluded. Primary and secondary outcomes were median progression-free survival (mPFS) and median overall survival (mOS), respectively, as measured from the start date of CRT. Data were also obtained on pt demographics, response, and duration of induction chemotherapy as well as MCT regimens.

Results: We included 165 pts with LAPC treated with CRT in our analysis. Median age was 66 (range 39 – 84), and 97 (59%) pts were male. Median follow-up was 12.9 months. The median duration from initiation of induction chemotherapy to start of CRT was 4.4 months. Most pts (84%) received 1 line of induction chemotherapy prior to CRT. Ten pts (6%) did not receive induction chemotherapy and 17 pts (10%) received at least 2 lines prior to CRT. All but 9 pts (94%) developed disease progression (PD) after CRT, and 49 pts (33%) had PD within 3 months of CRT. On univariate analysis, PD on the induction chemotherapy regimen immediately prior to CRT was associated with shortened PFS (HR 2.46, p &lt; 0.001) and OS (HR 2.96, p &lt; 0.001) after CRT. Most pts (78%) did not receive MCT after CRT. 69% of pts who received MCT were male, compared to 56% of those who did not receive MCT. The percentages of pts who had PD on the chemotherapy regimen immediately prior to CRT in the MCT and no-MCT groups were 9% and 12%, respectively. Sixteen pts who received MCT were treated with either gemcitabine alone or a gemcitabine-containing regimen, while 14 pts received capecitabine monotherapy. On univariate analysis, the use of MCT after CRT was associated with prolonged mPFS (9.0 vs. 4.2 months, p = 0.01), but was not associated with an increase in mOS (15.5 vs. 12.5 months, p = 0.14). On multivariable analysis controlling for race, radiation dose, age, and whether there was progression on the chemotherapy regimen prior to CRT, the use of MCT was significantly associated with both prolonged PFS (HR 0.45, p &lt; 0.001) and OS (HR 0.66, p = 0.047).

Conclusions: In this single-institution retrospective analysis of 165 pts with LAPC treated with CRT, treatment with post-CRT MCT was associated with a significant improvement in both PFS and OS as measured from the start date of CRT. Based on these results, MCT may be an appropriate option for pts with LAPC who have not progressed following consolidative CRT, and a prospective trial should be performed to better address this knowledge gap.

Citation Format: Jonathan D. Mizrahi, Shalini Moningi, Graciela M. Nogueras-Gonzalez, Robert A. Wolff, Milind M. Javle, Gauri R. Varadhachary, Linus Ho, David R. Fogelman, Kanwal P. Raghav, Michael J. Overman, Christopher H. Crane, Joseph M. Herman, Albert C. Koong, Eugene J. Koay, Jane E. Rogers, Shubham Pant. Maintenance chemotherapy after chemoradiation in patients with locally advanced pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr B36.

Discrepancies in endpoints between clinical trial protocols and clinical trial registration in randomized trials in oncology

Background

Clinical trials are an essential part of evidence-based medicine. Hence, to ensure transparency and accountability in these clinical trials, policies for registration have been framed with emphasis on mandatory submission of trial elements, specifically outcome measures. As these efforts evolve further, we sought to evaluate the current status of endpoint reporting in clinical trial registries.

Methods

We reviewed 71 oncology related randomized controlled trials published in three high impact journals. We compared primary (PEP) and non-primary endpoints (NPEP) between the clinical trial protocols of these trials and their corresponding registration in one of the 14 primary global clinical trial registries. A discrepancy was defined as the non-reporting or absence of an endpoint in either the protocol or registry. The primary endpoint was the rate of discrepancy between secondary endpoints in clinical trial protocols and clinical trial registries.

Results

Of the 71 clinical trials, a discrepancy in PEP was found in only 4 trials (6%). Secondary endpoint (SEP) differences were found in 45 (63%) trials. Among these 45 trials, 36 (80%) had SEPs that were planned in the protocol but not reported in the registry and 19 (42%) had SEPs with endpoints in the registry that were not found in the protocol. The total number of SEPs that were absent from the corresponding registry and protocol were 84 and 29, respectively. Of these endpoints, 48 (57%) and 9 (31%) were included in the published report of these trials.

Conclusion

Although recent regulations and enhanced procedures have improved the number and quality of clinical trial registrations, inconsistencies regarding endpoint reporting still exist. Though further guidelines for the registration of clinical trials will help, greater efforts to provide a correct, easily accessible, and complete representation of planned endpoints are needed.

Electronic supplementary material

The online version of this article (10.1186/s12874-018-0627-2) contains supplementary material, which is available to authorized users.

Utility of Appendiceal Calcifications Detected on Computed Tomography as a Predictor for an Underlying Appendiceal Epithelial Neoplasm

BACKGROUND

Mucinous appendiceal neoplasms can contain radiopaque calcifications. Whether appendiceal radiographic calcifications indicate the presence of an appendiceal epithelial neoplasm is unknown. This study aimed to determine whether appendiceal calcifications detected by computed tomography (CT) correlate with the presence of appendiceal epithelial neoplasms.

METHODS

From prospective appendiceal and pathology databases, 332 cases of appendiceal neoplasm and 136 cases of control appendectomy were identified, respectively. Only cases with preoperative CT scans available for review were included in the study. Images were reviewed by two abdominal radiologists. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated, and the kappa statistic was used to determine agreement between the radiologists' interpretations.

RESULTS

Interobserver agreement between the radiologists was substantial, with a kappa of 0.74. Appendiceal mural calcifications were identified on CT scans in 106 appendiceal neoplasm cases (32%) and in 1 control case (1%) (P = 0.0001). In the appendiceal neoplasm subgroup, the presence of radiographic calcifications was associated with mucinous histology (35% vs 17%; P = 0.006; odds ratio [OR], 0.38; 95% confidence interval [CI], 0.18-0.78) and with well-differentiated histologic grade (40% vs 24%; P = 0.002; OR, 0.47; 95% CI, 0.29-0.76). The findings showed a sensitivity of 31.9% (95% CI, 26.9-37.2%), a specificity of 99.3% (95% CI, 96-100%), a PPV of 99.1% (95% CI, 94.9-100%), and an NPV of 37.4% (95% CI, 32.4-42.6%).

CONCLUSION

This case-control study showed that appendiceal mural calcifications detected on CT are associated with underlying appendiceal epithelial neoplasms and that the identification of incidental mural appendiceal calcifications may have an impact on decisions regarding surgical intervention.

Abstract 4742: APC WT /RAS WT /BRAF WT tumors represent an under recognized poor prognostic group of right sided colorectal cancer

Background: Side of primary tumor has prognostic and predictive significance in metastatic colorectal cancer (mCRC). RAS/BRAF wild type (WT) left (L) sided tumors have improved outcomes with anti-EGFR therapy while right (R) sided tumors do worse. We aimed to identify mutations (MTS) in RAS/BRAF WT patients (pts) which may explain the differing response.

Methods: Using a 46 gene panel, we compared MT frequencies by side in 1880 mCRC pts. Overall survival (OS) was summarized with Kaplan-Meier curves, the log rank test, and Cox models. Microsatellite unstable pts were excluded from univariate OS analysis.

Results: RAS mutant (MT) pts were more likely to be APC MT (OR 1.64, P&lt;0.0001) than RAS WT pts. Presence of APC MTS was associated with improved OS in WT RAS/BRAF (HR 0.58, P=0.0003) and MT RAS/BRAF pts (HR 0.69, P=0.0004). Multivariate analysis confirmed APC MTS were associated with improved OS (HR 0.67, P=0.001) after controlling for RAS/BRAF, side, and MSI.

Given the association of tumor location and OS, we stratified pts by side and compared APC MT/WT pts. Improved OS with APC MTS was independent of side (L-HR 0.70, P=0.0011; R-HR 0.62, P=0.0012), but pts with R APC WT tumors stood out as an extreme risk group with the worst OS of all L/R and APC MT/WT combinations even in RAS/BRAF WT pts (P&lt;0.0001). This group of R sided RAS/BRAF/APC WT pts represents a novel poor prognostic group and its baseline characteristics are summarized below.

When stratifying APC MT by genomic location, only MTS in the mutation cluster region (n=686) that contains axin and β-catenin binding sites remained prognostic in multivariate models (HR 0.63, P&lt;0.0001), while other APC MTS (n=163) were no longer significant (HR 0.82, P=0.27).

Conclusion: APC WT R sided pts represents a group with poor prognosis regardless of RAS/BRAF MT status. Given the difference in CTNNB1 MT rate and importance of MTS in axin/ β-catenin binding sites, WNT signaling differences between L and R sided tumors may be important to explore further.

Baseline Characteristics of Patients with APC/RAS/BRAF Wild Type Right Sided TumorsBaseline CharacteristicRight Sided APC/RAS/BRAF WT (N=88, 15.2%)Other Right Sided Tumors (N=492, 84.8%)P-ValueMedian Age (IQR)56 (47-61)56 (48-64)0.23GenderFemale46 (52.3%)241 (49.0%)0.56Male42 (47.7%)251 (51.0%)MSI-H8 (10.5%)25 (6.5%)0.22HistologyAdenocarcinoma50 (56.8%)366 (74.4%)0.0018Mucinous / Signet38 (43.2%)123 (25.0%)Other03 (0.6%)Average # of Mutations Per Patient (+/- SD)1.38+/- 2.013.10 +/- 1.79&lt;0.0001Synchronous Metastasis76 (86.4%)401 (81.5%)0.36TP53 MT47 (53.4%)275 (55.9%)0.67PIK3CA MT6 (6.8%)111 (22.6%)0.001CTNNB1 MT7 (8.0%)11 (2.2%)0.004

Citation Format: Jonathan M. Loree, Krittiya K. Korphaisarn, Michael Lam, Van K. Morris, Kanwal P. Raghav, Michael J. Overman, Cathy Eng, Arvind Dasari, Bryan K. Kee, David Fogelman, Robert A. Wolff, Kenna Shaw, Russell Broaddus, Mark J. Routbort, Rajyalakshmi Luthra, Dipen M. Maru, David G. Menter, Funda Meric-Bernstam, Scott Kopetz. APCWT/RASWT/BRAFWT tumors represent an under recognized poor prognostic group of right sided colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4742. doi:10.1158/1538-7445.AM2017-4742

Local therapy reduces the risk of liver failure and improves survival in patients with intrahepatic cholangiocarcinoma: A comprehensive analysis of 362 consecutive patients

BACKGROUND

Treatment methods for intrahepatic cholangiocarcinoma (ICC) have improved, but their impact on outcome remains unclear. We evaluated the outcomes of patients definitively treated with resection, radiation, and chemotherapy for ICC, stratified by era.

METHODS

Clinico-pathologic characteristics, cause of death, disease-specific survival (DSS), and intrahepatic progression-free survival (IPFS) were compared among patients who underwent resection, radiation, or chemotherapy as definitive treatment strategies for ICC (without distant organ metastasis) between 1997 and 2015. Variables were also analyzed by era (1997-2006 [early] or 2007-2015 [late]) within each group.

RESULTS

Among 362 patients in our cohort, 122 underwent resection (early, 38; late, 84), 85 underwent radiation (early, 17; late, 68), and 148 underwent systemic chemotherapy alone (early, 51; late, 97) as definitive treatment strategies, and 7 patients received best supportive care. In the resection group, the 3-year DSS rate was 58% for the early era and 67% for the late era (P = .036), and the 1-year IPFS was 50% for the early era and 75% for the late era (P = .048). In the radiation group, the 3-year DSS was 12% for the early era and 37% for the late era (P = .048), and the 1-year IPFS was 48% for the early era and 64% for the late era (P = .030). In the chemotherapy group, DSS and IPFS did not differ by era. Patients treated with chemotherapy developed liver failure at the time of death significantly more frequently than patients treated with resection (P < .001) or radiation (P < .001). Multivariable analysis identified local therapy (resection or radiation) as a sole predictor of death without liver failure.

CONCLUSION

Survival outcomes have improved for local therapy-based definitive treatment strategies for ICC, which may be attributable to maintaining control of intrahepatic disease, thereby reducing the occurrence of death due to liver failure. Cancer 2017;123:1354-1362. © 2016 American Cancer Society.

cMET and phospho-cMET protein levels in breast cancers and survival outcomes

PURPOSE

To evaluate cMET (mesenchymal-epithelial transition factor gene) and phospho-cMET (p-cMET) levels in breast cancer subtypes and its impact on survival outcomes.

EXPERIMENTAL DESIGN

We measured protein levels of cMET and p-cMET in 257 breast cancers using reverse phase protein array. Regression tree method and Martingale residual plots were applied to find best cutoff point for high and low levels. Kaplan-Meier survival curves were used to estimate relapse-free (RFS) and overall (OS) survival. Cox proportional hazards models were fit to determine associations of cMET/p-cMET with outcomes after adjustment for other characteristics.

RESULTS

Median age was 51 years. There were 140 (54.5%) hormone receptor (HR) positive, 53 (20.6%) HER2 positive, and 64 (24.9%) triple-negative tumors. Using selected cutoffs, 181 (70.4%) and 123 (47.9%) cancers had high levels of cMET and p-cMET, respectively. There were no significant differences in mean expression of cMET (P < 0.128) and p-cMET (P < 0.088) by breast cancer subtype. Dichotomized cMET and p-cMET level was a significant prognostic factor for RFS [HR: 2.44, 95% confidence interval (CI): 1.34-4.44, P = 0.003 and HR: 1.64, 95% CI: 1.04-2.60, P = 0.033] and OS (HR: 3.18, 95% CI: 1.43-7.11, P = 0.003 and HR: 1.92, 95% CI: 1.08-3.44, P = 0.025). Within breast cancer subtypes, high cMET levels were associated with worse RFS (P = 0.014) and OS (P = 0.006) in HR-positive tumors, and high p-cMET levels were associated with worse RFS (P = 0.019) and OS (P = 0.014) in HER2-positive breast cancers. In multivariable analysis, patients with high cMET had a significantly higher risk of recurrence (HR: 2.06, 95% CI: 1.08-3.94, P = 0.028) and death (HR: 2.81, 95% CI: 1.19-6.64, P = 0.019). High p-cMET level was associated with higher risk of recurrence (HR: 1.79, 95% CI: 1.08-2.95.77, P = 0.020).

CONCLUSIONS

High levels of cMET and p-cMET were seen in all breast cancer subtypes and correlated with poor prognosis.

P4-09-09: Expression of c-MET and Phospho c-MET in Breast Cancers by Subtype and Its Impact on Survival Outcomes

Background

cMET is a tyrosine-kinase membrane receptor and its dysregulation is involved in tumor proliferation, survival, angiogenesis, and migration. High levels of cMET have been observed in various tumor types and correlate with adverse outcome. The purpose of this study was to evaluate levels of total cMET and phospho-cMET (p-cMET) in breast cancer and their impact on survival outcomes.

Materials and Methods: We measured quantitative expression of cMET and p-cMET in a cohort of 257 breast cancer primary tumor samples using reverse phase protein array. The level of cMET/p-cMET in each sample was expressed as a log-mean centered value after correction for protein loading with the use of the average expression levels of &gt; 50 proteins. The regression tree method and Martingale residual plots were applied to find the best cutoff point for high and low levels of each protein. Linear regression models were used to determine if mean expression was different among breast cancer subtypes. The Kaplan-Meier method was used to estimate relapse-free survival (RFS) and overall survival (OS) by cMET and p-cMET levels. Cox proportional hazards models were fit to determine the association of cMET and p-cMET levels with the risk of recurrence and death after adjustment for other patient and disease characteristics.

Results: Median age was 51, (range 23–85) years. There were 140 (54.5%) hormone receptor (ER/PR)-positive, 53 (20.6%) HER2−positive, and 64 (24.9%) triple-negative tumors. Using the selected cutoffs, a total of 181 (70.4%) and 123 (47.9%) patients had high expression of cMET and p-cMET, respectively.

There were no significant differences in the mean expression of cMET (P&lt;0.128) and p-cMET (P&lt;0.088) by breast cancer subtype. Dichotomized cMET and p-cMET expression was a significant prognostic factor of RFS (HR: 0.41, 95% CI: 0.23−0.75, P=0.004, and HR: 0.61, 95% CI:0.38−0.96, P=0.033, respectively) and OS (HR: 0.31, 95% CI:0.14−0.70, P=0.005, and HR: 0.52, 95% CI:0.29−0.93, P=0.025, respectively). Within breast cancer subtypes, high cMET expression was associated with worse RFS (P=0.02) and OS (P=0.01) in ER/PR-positive tumors, and high p-cMET expression was associated with worse RFS (P=0.03) and OS (P=0.03) for patients with HER2−positive breast cancer. Multivariable model after adjustment for patient and tumor characteristics showed that patients with tumors with high cMET levels had a significant higher risk of recurrence (HR 0.28; 95% CI, 0.36−0.80) and death (HR 0.24; 95% CI, 0.09−0.65). Similarly, patients with tumors with high p-cMET levels had a significant higher risk of recurrence (HR 0.53; 95% CI, 0.29−0.97).

Conclusion: In this cohort of patients, high expression of cMET and p-cMET was seen in all subtypes of breast cancer. High levels of cMET and p-cMET had a significant impact on breast cancers survival outcomes. cMET inhibition may a be promising novel target for therapy in breast cancer and deserves investigation.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-09-09.