Robotic lateral pelvic lymph node dissection after chemoradiation for rectal cancer: a Western perspective

AIM

There are limited outcome data for lateral pelvic lymph node dissection (LPLND) following neoadjuvant chemoradiotherapy (nCRT), particularly in the West. Our aim was to evaluate the short-term perioperative and oncological outcomes of robotic LPLND at a single cancer centre.

METHOD

A retrospective analysis of a prospective database of consecutive patients undergoing robotic LPLND for rectal cancer between November 2012 and February 2020 was performed. The main outcomes were short-term perioperative and oncological outcomes. Major morbidity was defined as Clavien-Dindo grade 3 or above.

RESULTS

Forty patients underwent robotic LPLND during the study period. The mean age was 54 years (SD ± 15 years) and 13 (31.0%) were female. The median body mass index was 28.6 kg/m² (IQR 25.5-32.6 kg/m² ). Neoadjuvant CRT was performed in all patients. Resection of the primary rectal cancer and concurrent LPLND occurred in 36 (90.0%) patients, whilst the remaining 4 (10.0%) patients had subsequent LPLND after prior rectal resection. The median operating time was 420 min (IQR 313-540 min), estimated blood loss was 150 ml (IQR 55-200 ml) and length of hospital stay was 4 days (IQR 3-6 days). The major morbidity rate was 10.0% (n = 4). The median lymph node harvest from the LPLND was 6 (IQR 3-9) and 13 (32.5%) patients had one or more positive LPLNs. The median follow-up was 16 months (IQR 5-33 months), with 1 (2.5%) local central recurrence and 7 (17.5%) patients developing distant disease, resulting in 3 (7.5%) deaths.

CONCLUSION

Robotic LPLND for rectal cancer can be performed in Western patients to completely resect extra-mesorectal LPLNs and is associated with acceptable perioperative morbidity.

Digital health for optimal supportive care in oncology: benefits, limits, and future perspectives

BACKGROUND

Digital health provides solutions that capture patient-reported outcomes (PROs) and allows symptom monitoring and patient management. Digital therapeutics is the provision to patients of evidence-based therapeutic interventions through software applications aimed at prevention, monitoring, management, and treatment of symptoms and diseases or for treatment optimization. The digital health solutions collecting PROs address many unmet needs, including access to care and reassurance, increase in adherence and treatment efficacy, and decrease in hospitalizations. With current developments in oncology including increased availability of oral drugs and reduced availability of healthcare professionals, these solutions offer an innovative approach to optimize healthcare resource utilization.

DESIGN

This scoping review clarifies the role and impact of the digital health solutions in oncology supportive care, with a view of the current segmentation according to their technical features (connection to sensors, PRO collection, remote monitoring, self-management in real time…), and identifies evidence from clinical studies published about their benefits and limitations and drivers and barriers to adoption. A qualitative summary is presented.

RESULTS

Sixty-six studies were identified and included in the qualitative synthesis. Studies supported the use of 38 digital health solutions collecting ePROs and allowing remote monitoring, with benefits to patients regarding symptom reporting and management, reduction in symptom distress, decrease in unplanned hospitalizations and related costs and improved quality of life and survival. Among those 38 solutions 21 provided patient self-management with impactful symptom support, improvement of QoL, usefulness and reassurance. Principal challenges are in developing and implementing digital solutions to suit most patients, while ensuring patient compliance and adaptability for use in different healthcare systems and living environments.

CONCLUSIONS

There is growing evidence that digital health collecting ePROs provide benefits to patients related to clinical and health economic endpoints. These digital solutions can be integrated into routine supportive care in oncology practice to provide improved patient-centered care.

Robotic rectal cancer surgery: comparative study of the impact of obesity on early outcomes

The aim of this study was to compare the outcomes of robotic total mesorectal excision (TME) in obese versus non-obese patients. A total of 533 patients, of whom 161 were obese (30·2 per cent) underwent robotic proctectomy during the study interval. Patient obesity was not associated with adverse short-term clinical outcomes after robotic rectal cancer surgery. Indicated in the obese perhaps?

Phase II study of nab-paclitaxel in refractory small bowel adenocarcinoma and CpG island methylator phenotype (CIMP)-high colorectal cancer

Background

Hypermethylation of promoter CpG islands [CpG island methylator phenotype (CIMP)] represents a unique pathway for the development of colorectal cancer (CRC), characterized by lack of chromosomal instability and a low rate of adenomatous polyposis coli (APC) mutations, which have both been correlated with taxane resistance. Similarly, small bowel adenocarcinoma (SBA), a rare tumor, also has a low rate of APC mutations. This phase II study evaluated taxane sensitivity in SBA and CIMP-high CRC.

Patients and methods

The primary objective was Response Evaluation Criteria in Solid Tumors version 1.1 response rate. Eligibility included Eastern Cooperative Oncology Group performance status 0/1, refractory disease, and SBA or CIMP-high metastatic CRC. Nab-paclitaxel was initially administered at a dose of 260 mg/m2 every 3 weeks but was reduced to 220 mg/m2 owing to toxicity.

Results

A total of 21 patients with CIMP-high CRC and 13 with SBA were enrolled from November 2012 to October 2014. The efficacy-assessable population (patients who received at least three doses of the treatment) comprised 15 CIMP-high CRC patients and 10 SBA patients. Common grade 3 or 4 toxicities were fatigue (12%), neutropenia (9%), febrile neutropenia (9%), dehydration (6%), and thrombocytopenia (6%). No responses were seen in the CIMP-high CRC cohort and two partial responses were seen in the SBA cohort. Median progression-free survival was significantly greater in the SBA cohort than in the CIMP-high CRC cohort (3.2 months compared with 2.1 months, P = 0.03). Neither APC mutation status nor CHFR methylation status correlated with efficacy in the CIMP-high CRC cohort. In vivo testing of paclitaxel in an SBA patient-derived xenograft validated the activity of taxanes in this disease type.

Conclusion

Although preclinical studies suggested taxane sensitivity was associated with chromosomal stability and wild-type APC, we found that nab-paclitaxel was inactive in CIMP-high metastatic CRC. Nab-paclitaxel may represent a novel therapeutic option for SBA.

Anti-EGFR-resistant clones decay exponentially after progression: implications for anti-EGFR re-challenge

BACKGROUND

Colorectal cancer (CRC) has been shown to acquire RAS and EGFR ectodomain mutations as mechanisms of resistance to epidermal growth factor receptor (EGFR) inhibition (anti-EGFR). After anti-EGFR withdrawal, RAS and EGFR mutant clones lack a growth advantage relative to other clones and decay; however, the kinetics of decay remain unclear. We sought to determine the kinetics of acquired RAS/EGFR mutations after discontinuation of anti-EGFR therapy.

PATIENTS AND METHODS

We present the post-progression circulating tumor DNA (ctDNA) profiles of 135 patients with RAS/BRAF wild-type metastatic CRC treated with anti-EGFR who acquired RAS and/or EGFR mutations during therapy. Our validation cohort consisted of an external dataset of 73 patients with a ctDNA profile suggestive of prior anti-EGFR exposure and serial sampling. A separate retrospective cohort of 80 patients was used to evaluate overall response rate and progression free survival during re-challenge therapies.

RESULTS

Our analysis showed that RAS and EGFR relative mutant allele frequency decays exponentially (r2=0.93 for RAS; r2=0.94 for EGFR) with a cumulative half-life of 4.4 months. We validated our findings using an external dataset of 73 patients with a ctDNA profile suggestive of prior anti-EGFR exposure and serial sampling, confirming exponential decay with an estimated half-life of 4.3 months. A separate retrospective cohort of 80 patients showed that patients had a higher overall response rate during re-challenge therapies after increasing time intervals, as predicted by our model.

CONCLUSION

These results provide scientific support for anti-EGFR re-challenge and guide the optimal timing of re-challenge initiation.

Real-world analysis of treatment patterns and persistence of octreotide LAR and other agents in patients with advanced gastrointestinal neuroendocrine tumors (GI NET): A multicenter study

424

Background: Limited data are available to document recent treatment paradigms that span NET disease course. This study aims to report long-term, real-world treatment patterns of advanced GI NET patients (pts) based on data from four tertiary cancer centers (Dana-Farber, MD Anderson, UCSF and Northwestern). Methods: Retrospective chart review was conducted in pts diagnosed with advanced, well differentiated GI NET at age ≥18 years and treated with somatostatin analogs (SSAs), targeted therapy (TT), cytotoxic chemotherapy (CC), peptide receptor radiotherapy, liver-directed therapy (LDT) or interferon from 7/2011-12/2014. Eligible pts were followed from advanced NET diagnosis date (earliest recorded diagnosis: 3/1987) to end of follow-up/death (latest recorded date: 5/2017). Analyses of treatment and dosing patterns were performed and persistence of therapy was estimated using Kaplan-Meir analysis. Results: 273 pts were included with mean age of 59 years at advanced NET diagnosis; 64% had functional NET; 57% had ileum as primary tumor site; and 63% had carcinoid syndrome (CS). Most common CS symptoms were diarrhea (87%) and flushing (73%). Majority of pts received octreotide alone (88%) or in combination (2%) with LDT, TT or CC as first-line. Of the 161 pts on second-line, 88% received octreotide alone or in combination; 5 pts (3%) received lanreotide. Most common dose at initiation for octreotide was 30mg/4 weeks (51%) and 20mg/4 weeks (32%); 68% of pts never received > 30mg/4 weeks over the entire treatment course. Median time to treatment discontinuation was 145 months (mos) for octreotide (functional NET: 145; non-functional NET: 117), 13 mos for TT and 6 mos for CC. Conclusions: This study showed that octreotide is the mainstay of treatment for advanced GI NET, as 90% of pts received octreotide alone or in combination with other treatment modalities agents as first-line therapy. 74% continued octreotide alone or in combination with other treatment modalities in the second-line. Most commonly prescribed dose was 30 mg/4 weeks. Pts remained on octreotide long term, with median treatment duration of 12 years.

A phase II trial of LEE011 in combination with everolimus in the treatment of advanced well differentiated neuroendocrine tumors of foregut origin

TPS546

Background: Changes in the retinoblastoma (Rb) tumor suppressor pathway are believed to contribute to the development of well differentiated neuroendocrine tumors (WDNETs). In the pre-clinical setting, loss or downregulation of proteins that normally inhibit the cyclin dependent kinases Cdk4 and Cdk6 have contributed to NET development. Separately, rigorous investigation of everolimus in WDNETs has demonstrated a survival benefit in this patient (pt) population. Pre-clinical data suggests that the Cdk4/Cdk6 inhibitor LEE011 is synergistically active with everolimus. The aim of this study is to evaluate the efficacy and safety of LEE011 in combination with everolimus in pts with advanced WDNETs of foregut origin (thymic, bronchopulmonary, gastric, duodenal, pancreatic). Methods: This study is a multicenter, non-randomized, open-label phase II clinical trial using a Simon two stage optimal design. Main inclusion criteria include: adult patients with WDNET of foregut origin, low to intermediate grade, unresectable and/or metastatic, disease progression ≤ 12 months prior to enrollment, ECOG 0-1. Between 15 and 43 patients will be enrolled from three sites across the US. LEE011 300mg daily, 3 weeks on and 1 week off, in combination with everolimus 2.5mg daily (final dosing based on phase 1b clinical trial performed in metastatic breast cancer; LEE011X2106) will be administered orally until disease progression, unacceptable toxicity, investigator decision, or pt withdrawal. All enrolled pts will be followed by telephone contact for overall survival until death or consent withdrawal. The primary endpoint, progression free survival, will be assessed based on radiographic review by RECISTv1.1. Main secondary endpoints include establishing the safety of this drug combination in this patient population, objective response rate, clinical benefit rate, and overall survival. Correlative objectives include exploring the effect of this drug combination on biomarkers related to the Rb pathway and/or WDNET pathogenesis. This trial began enrollment in 2/27/2017, with 10 patients enrolled to date. Clinical trial information: NCT03070301.

Living with neuroendocrine tumors: Assessing quality of life (QoL) through a mobile application

359

Background: The study aim was to understand neuroendocrine tumor (NET) patients’ (pts) QoL through PROMIS-29, symptom tracking and patient journaling via the Carcinoid Health Storylines mobile application (app). Methods: This 12-week prospective, observational study was conducted among US NET pts recruited through the Carcinoid Cancer Foundation on either Lanreotide depot (L) or octreotide LAR (O) via surveys at baseline, week (w) 6, and w 12 with PROMIS-29 and symptom questionnaires at baseline, w 4 & w 8. Pts were asked to monitor symptoms, mood, bowel movement frequency, food, activity and sleep in their app 5x / week. Demographics and medical history were collected at baseline. Results: Of the 120 NET pts, 78% were female (mean age=57); 76% were gastroenteropancreatic NETs and 88% with metastases. L and O use was at 41% and 59% respectively. 82% completed ≥ 1 follow-up survey; the most common symptoms at baseline were fatigue (76.7%), diarrhea (62.5%), abdominal discomfort (64.1%) and trouble sleeping (57.5%). The baseline PROMIS-29 assessment revealed high proportions endorsing clinically significant depression (17.7%), anxiety (24.2%), fatigue (58.8%), dissatisfaction with social role (i.e. daily routine, 42.2%), difficulty with physical functioning (i.e. run errands, 16%) and insomnia (34.9%). Thus, 26.9% reported their QoL being poor and yet, a high percentage of patients were hopeful and reported their life as being meaningful (72.3%). Reported symptoms decreased significantly from initial to subsequent surveys (e.g. 59.3% to 33% for diarrhea; p=0.002). App tracking effectively captured day to day variations in reported symptoms and weekly averages correlated well with symptom surveys and PROMIS-29 scores. Seventy-seven pts journaled with 26 providing unsolicited injection experience (L =10; O =16). Conclusions: This study suggests that the use of apps for recording daily symptoms in NET pts, with decreased symptom reporting over time perhaps due to reduced recall bias from frequent tracking, or a potential therapeutic effect of journaling. Apps should be developed further to record the experiences and needs of NET pts.

The rate of novel actionable mutations in standard of care NGS panel testing in gastrointestinal malignancies

640

Background: In advanced gastrointestinal (GI) malignancies, genetic profiling is often performed with the goal of facilitating enrollment of patients into clinical trials. While multigene genetic profiling has become the standard of care in many practices, the data on success rate of identifying actionable genomic alterations remain limited. In this study, we aimed to characterize the rate of actionable mutations using larger ( > 150 genes) and smaller ( < 150 genes) panels across different GI malignancies. Methods: We reviewed all reports of formalin-fixed paraffin-embedded clinical specimens sent for next-generation sequencing (NGS-using assays of at least 45 genes) for patients with advanced GI malignancies between 2012-2017 at MD Anderson Cancer Center. Actionable mutations were defined as those matching or informing the use of targeted therapies available in clinical trials, or FDA-approved. These were determined by a precision oncology support team (pct.mdanderson.org), using available literature and functional genomic screens. Novel actionable mutations were defined as those not used in current testing guidelines for GI malignancies. Results: Out of 11968 detected mutations, 3832(32.0%) were deemed to be actionable mutations and the remainder were either in non-actionable genes, deemed benign, or variants of unknown significance. Therefore, 1987 (65.1%) of assays had actionable mutations. When limited to novel actionable mutations, the rate fell to 21.5% (659/3052). Compared to CRC, other GI malignancies were 1.65 times more likely to have a novel actionable mutation (95% CI 1.35-2.00, p< .001). The use of larger and smaller panels did not differ in detecting novel actionable mutations, but larger panels resulted in a 3.5-fold higher number of mutations not deemed clinically actionable. Conclusions: Despite incorporation of NGS in oncology practice for GI malignancies, the success rate of detecting novel actionable mutations beyond those in the current guidelines remains low. Using assays with larger gene numbers does not seem to improve this detection rate. Future studies are required to evaluate the success rate of clinical interventions when actionable alterations are present.

Clinical, pathological, and demographic factors associated with development of recurrences after surgical resection in elderly patients with neuroendocrine tumors

Background

Incidence of locoregional neuroendocrine tumors (NETs) is rising. However, after curative resection, the patterns and risk factors associated with recurrence remain unknown. Consensus guidelines recommend surveillance every 6-12 months for up to 10 years after surgery for resected, well-differentiated NETs irrespective of patient demographics, site, grade or stage of tumor with few exceptions.

Patients and methods

From the Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we identified localized and regional stage NET patients who underwent surgical resection between January 2002 and December 2011. Development of recurrence was identified by capturing at least two claims indicative of metastatic disease until 31 December 2013.

Results

Of the 2366 identified patients (median age 73 years), 369 (16%) developed metastatic disease within 5 years and only an additional 1% developed metastases between years 5 and 10 with the majority dying due to unrelated causes. The 5-year risk of developing metastases (hazard ratio, HR) varied significantly (log-rank P < 0.001) by grade: 9.9% versus 25.9% (2.2) versus 48.1% (4.4) for grades 1, 2, and  ≥ 3, respectively; stage: 10.3% versus 31.1% (2.8) for localized versus regional; primary tumor size: 7.6% versus 15% (1.3) versus 26.6% (1.5) for <1, 1-2, and > 2 cm, respectively; and site: ranging from 11.3% for colon to 23.9% for pancreas.

Conclusions

Contrary to current guidelines, our study suggests that surveillance recommendations should be tailored according to patient and tumor characteristics. Surveillance past 5 years may be avoided in elderly patients with competing morbidities or low risk of recurrence. Pancreatic, lung, higher grade, and regional NETs have a higher risk of recurrence and may be considered for future adjuvant trials.

LUNA: A randomized phase II trial of liver resection plus chemotherapy or chemotherapy alone in patients with unresectable lung and resectable liver metastases from colorectal adenocarcinoma

TPS3625

Background: Liver resection for metastatic colorectal cancer is associated with 5-year overall survival (OS) of 58% and accepted as standard of care. However, the role of liver resection with unresectable low-volume lung metastases is unknown. A recent retrospective study showed that resection of liver metastases was associated with statistically improved OS compared to a matched group of patients treated with systemic therapy alone for lung and liver metastases (3-year OS 43% vs. 14%; Mise Y, Ann Surg Oncol 2015). LUNA is a single-institution phase 2 randomized trial designed to determine the overall survival benefit of liver resection in patients with unresectable lung metastases and to integrate biological surrogates to risk stratify patients and optimize patient selection for hepatectomy. Methods: Eligibility criteria include resectable liver metastases, defined as sufficient liver remnant volume, adequate vascular inflow and outflow, and preservation of 2 contiguous liver segments. Low-volume lung metastases are defined as solid pulmonary nodules < 2 cm in size and < 15 in number. Chest computed tomography is reviewed by an attending thoracic surgeon, and lung metastases are deemed unresectable due to anatomic location, distribution, or patients’ comorbidities. Previous treatment with systemic chemotherapy and/or biologic agents is permitted. After stratification by KRAS status and primary tumor location in the colon vs. rectum, patients are randomized 1:1 to liver resection plus chemotherapy or no liver resection with chemotherapy at the discretion of the treating oncologist as routine standard of care. Patients are restaged every 3‒6 months until 3 years after randomization or death. The primary endpoint is OS. Secondary endpoints include quality of life and identification of biological surrogates in blood and resected liver tissue associated with response to chemotherapy, time to tumor progression, and survival. Targeting an effect size of extending median OS from 17 to 34 months will provide 80% power with 0.05 one-sided alpha with a sample size of 80 patients. Clinical trial information: NCT02738606.

Prevalence of co-morbidities in elderly patients with distant stage neuroendocrine tumors

e15699

Background: The median age of diagnosis of neuroendocrine tumors (NETs), an indolent tumor characterized by hormone production (carcinoid syndrome, CS) when metastatic is 63 years. Patients (pts) in this age group have multiple co-morbidities. However, their prevalence among elderly pts with metastatic NET is unknown. Methods: The Surveillance, Epidemiology and End Results (SEER)-Medicare database was used to identify 2,388 elderly patients with distant stage NET (Age: < 70: 631; 70-79: 1200; > 80: 557; Race: white: 83.4%, black: 8.6%) diagnosed between 1/03 and 12/11 identified by ICD-O-3 codes with continuous Medicare Parts A and B enrollment during the one year after NET diagnosis. We examined the prevalence of common co-morbidities in the elderly population: dementia, heart conditions including ischemic heart disease (IHD), hypertension (HTN) & congestive heart failure, chronic obstructive pulmonary disease, chronic kidney disease, hyperlipidemia, diabetes, arthritis, and two additional relevant comorbidities: osteoporosis (OP) and non-rheumatic tricuspid valve (TV) disorders. Pts were considered to have a condition if they had ≥ 1 inpt or ≥ 2 outpt visits indicative of the condition. We compared the prevalence in the NET group with that in a propensity score matched non-cancer group using chi-square test. Within the NET group, we also examined the association between pt characteristics and the presence of the conditions using a logistic regression model. Results: Compared to the matched non-cancer control group, NET pts were significantly (P < 0.01) more likely to have HTN (74% vs. 66%), OP (14% vs. 11%) & TV disorders (1.72% vs. 0.98%) and less likely to have dementia (7.3% vs 17.4%), IHD (23.2% vs 29%) and diabetes (30.3% vs 33.5%). CS was noted in 25.7% of the NET group and logistic regression showed that these pts with were significantly more likely to have TV disorders (AOR = 2.52, 95% CI: 1.24-5.14) and osteoporosis (AOR: 1.34, 95% CI: 1.01-1.81). Conclusions: This population-based study showed that elderly NET pts have significantly different prevalence of co-morbidities compared to non-cancer controls. The impact of these conditions on survival and therapeutic decisions is being evaluated.

A phase IB study of the combination of selumetinib (AZD6244, ARRY-142886) and cyclosporin A (CsA) in patients with advanced solid tumors with an expansion cohort in metastatic colorectal cancer (mCRC)

2587

Background: MEK inhibition is of interest in cancer drug development. However, better strategies are needed to overcome acquired resistance to MEK inhibitors. Preclinical studies have shown Wnt pathway overexpression in KRAS mutant cell lines resistant to the MEK inhibitor, selumetinib. The combination of selumetinib and cyclosporin A (CsA), a non-canonical Wnt pathway modulator, demonstrated antitumor activity in patient-derived xenograft (PDX) models. We conducted an NCI CTEP-approved Phase I/IB trial (NCI # 9571/COMIRB # 13-2628/NCT02188264) of selumetinib and CsA combination. Biomarkers of response are being co-developed. Methods: Patients with advanced solid tumors were treated with the combination of selumetinib and CsA in dose escalation followed by an expansion cohort in patients with irinotecan and oxaliplatin-refractory mCRC (n = 20). The expansion cohort utilized a selumetinib “run-in” to evaluate efficacy in RAS-WT and RAS-MT mCRC to identify those patients most likely to respond to the combination. Results: As of January 2017, 18 patients were enrolled in the dose escalation phase and 20 patients were enrolled in the dose expansion phase. The most common adverse events and grade 3/4 toxicities were rash, hypertension, and edema. Three DLTs - Grade 3 hypertension, rash and increased creatinine were reported. The maximum tolerated dose was identified as selumetinib 75 mg BID and CsA 2 mg/kg BID on a 28-day cycle. The selumetinib “run-in” did not favor a specific RAS type. Two partial responses were noted. Sixteen patients had stable disease, and 6 patients had progression of disease as their best response to therapy. Conclusions: Selumetinib in combination with cyclosporin A appears to be well tolerated with evidence of activity in mCRC. Tumor response data are currently being updated. FZD will be evaluated as a potential biomarker of response. Clinical trial information: NCT02188264.

Pre-existing symptoms, resource utilization, and healthcare costs prior to diagnosis of neuroendocrine tumors: A SEER-Medicare database study

4092

Background: The incidence and prevalence of neuroendocrine tumors (NETs) are continually increasing. While it is known that NET symptoms often predate diagnosis, the prevalence of these symptoms and the impacts on resource utilization and costs are largely unknown. Methods: We identified 12,052 elderly patients diagnosed with NET between 1/2003 and 12/2011 by ICD-O-3 codes from the Surveillance, Epidemiology and End Results (SEER)-Medicare database with continuous Medicare Parts A and B enrollment during the one year before NET diagnosis. We used propensity score matching to identify a group of comparable elderly patients from a non-cancer Medicare cohort. We captured patients’ potentially relevant conditions (defined as > 1 indicative claim), resource utilization and costs from patients’ medical claims during the year before diagnosis. We examined a) resource utilization in terms of number of outpatient visits, percentage of patients having any emergency room (ER) visits and hospitalizations, and b) health care costs including inpatient, outpatient and total costs. We used chi-square test for categorical variables and Mann-Whitney U test for continuous variables. Results: NET patients were more likely to have diagnoses of diarrhea (8% vs. 2%), abdominal pain (37% vs. 8%), irritable bowel syndrome (1.5% vs. 0.6%), hypertension (72% vs. 55%), heart failure (16% vs. 8%), and peripheral edema (7% vs. 4%) compared to the non-cancer control group. They also had much higher resource utilization including number of outpatient visits (mean: 27.25 vs. 18.45); and percentage with ER visits (64% vs. 36%), and hospitalizations (66% vs. 34%). Similarly, NET patients incurred significantly higher total (mean: $32924 vs. $10048), outpatient (mean: $8869 vs. 4580), and inpatient costs (mean: $24055 vs. $10048). All p < 0.001. Conclusions: To the best of our knowledge, this is the first population-based study to examine potentially relevant pre-existing symptoms, resource utilization and healthcare costs before NET diagnosis. NET patients were more likely to have certain conditions and incurred higher resource utilizations and costs in the year preceding diagnosis of NET.

RAS heterogeneity as a prognostic marker in metastatic colorectal cancer

586

Background: The impact of intratumor heterogeneity on prognosis in metastatic colorectal cancer (mCRC) is unclear, however relative variant allele frequency (rVAF) of key mutations within a tumor may impact outcomes. Therefore, we sought to determine whether rVAF of RAS ( KRAS & NRAS) mutant (mt) clones impacts overall survival (OS) in mCRC patients (pts). Methods: Using a next generation sequencing panel of 201 cancer related genes, we tested 200 mCRC tumors / matched normals. Mutations, indels, and copy number variant (CNV) information were obtained. An rVAF of RAS clones was determined by dividing RAS mt VAF by the VAF of the mutated gene with the highest allele frequency. This truncal gene served as a marker of the total malignant population in a specimen. Pts were stratified at an rVAF of 50%. OS was compared with Kaplan-Meier curves, the log-rank test, and Cox regression. We assessed the impact of CNV on our findings by correcting the rVAF for CNVs in RASand truncal mutations. Results: Of 200 pts, 15% had RAS mt rVAF < 50%, 40.5% had rVAF ≥ 50%, and 44.5% were RAS wild type (WT). Age, gender, MSI status, histology, and stage at diagnosis were similar between groups. More RAS WT pts had BRAF mutations (19.1% vs 1.2% and 3.3%, P< 0.0001), left sided (78.7% vs 56.8% and 60%, P= 0.02), or poorly differentiated tumors (27.3% vs 8.6% and 13.3%, P= 0.003) compared to pts with rVAF ≥ 50% or rVAF < 50%, respectively. Mean coverage was 807x for RAS and 602x for truncal mutations. OS was better in pts with an rVAF < 50% compared to pts with rVAF ≥ 50% regardless of whether rVAF was corrected for CNV (HR 0.6; 95% CI 0.39-0.93, P =0.029) or not (HR 0.48; 95% CI 0.31-0.82, P= 0.010). mOS for pts with WT, rVAF < 50% and rVAF ≥ 50% tumors were 65.8, 55.7, and 38.6 months ( P= 0.0025). In multivariate models controlling for stage at diagnosis and BRAF mutation, pts with rVAF < 50% (HR 1.75; 95% CI 1.03-2.97, P = 0.04) and rVAF ≥ 50% (HR 2.46; 95% CI 1.66-3.65, P< 0.0001) had worse OS compared to WT pts. When rVAF was used as a continuous variable, every 1% increase in rVAF RAS mt resulted in a 1% increased hazard of death ( P <0.0001). Conclusions: Our findings suggest that clonal proportion of a tumor with a RAS mutation may impact OS and suggest the prognostic impact of RAS mutations is not an “all or none” phenomenon.

A phase IB study of the combination of selumetinib (AZD6244; ARRY-142886) and cyclosporin A (CsA) in patients with advanced solid tumors with an expansion cohort in metastatic colorectal cancer (mCRC)

609

Background: Targeting MEK is of interest in the development of novel agents for treatment of many malignancies. However, better strategies are needed to overcome acquired resistance to MEK inhibitors. Preclinical studies have shown Wnt pathway overexpression in KRAS mutant cell lines resistant to the MEK inhibitor, Selumetinib. The combination of selumetinib and cyclosporin A (CsA), a non-canonical WnT pathway modulator, demonstrated antitumor activity in patient-derived xenograft (PDX) models. We are conducting an NCI CTEP-approved Phase I/IB trial (NCI # 9571/COMIRB # 13-2628) of selumetinib and CsA combination. Biomarkers of response to therapy are being co-developed. We hypothesize that this combination will be safe and potentially effective in patients with mCRC and that upregulation of FZD2 may predict for sensitivity. Methods: Phase I trial with initial dose escalation investigating the combination of selumetinib and CsA in patients with advanced solid tumors (n = 18) followed by an expansion cohort in patients with irinotecan and oxaliplatin-refractory mCRC (n = 20). The expansion cohort utilizes a selumetinib “run-in” to evaluate efficacy in RAS-WT and RAS-MT mCRC to identify those patients most likely to respond to the combination. Results: 18 patients were enrolled in the dose escalation phase and 10 patients have been enrolled in the dose expansion phase as of September 2016. Grade 1 or 2 nausea and rash were reported as the most common AEs. Most commonly reported Grade 3 or 4 toxicities were hypertension, elevated liver enzymes and rash. Three DLTs were reported with Grade 3 hypertension noted at dose level 1 and 2 and grade 3 rash reported at dose level 2. The maximum tolerated dose was defined as Selumetinib 75 mg BID and CsA 2 mg/kg BID on a 28-day cycle. Two partial responses and sixteen stable disease responses have been observed. Six patients have exhibited progressive disease. Conclusions: Selumetinib in combination with cyclosporin A appears to be well-tolerated with evidence of activity in solid tumors. Expansion cohort will complete enrollment this month. Clinical trial information: NCT02188264.

Signet ring cell colorectal cancer: Genomic insights into a rare subpopulation of colorectal adenocarcinoma

606

Background: Colorectal signet ring cell carcinoma (SRCC) has been shown to be associated with advanced tumor stage at presentation and worse outcomes. Due to the rarity of this subtype, 1% of all colorectal adenocarcinoma (CRC), little is known about its molecular characteristics. We aimed to characterize the molecular alterations of this subgroup. Methods: Metastatic CRC (mCRC) patients (pts) with signet ring cell (SC) histology who had tumors evaluated with next generation sequencing between February 2009 and November 2015 were reviewed. SC mCRC were classified into 2 groups; SRCC (>50% of signet cells) and adenocarcinoma (AC) with SC component. Genomic alterations, microsatellite instability (MSI) and CpG island methylator phenotype (CIMP) status noted in SC mCRC were compared to non-SC mCRC pts from the Assessment of Targeted Therapies Against Colorectal Cancer program at MD Anderson Cancer Center using Pearson’s χ 2 test. Results: A total of 665 mCRC pts were included in this study. 93 pts (14%) had SC histology of which 30 (32.3%) pts were SRCC. The Table below shows key cancer genes mutation frequencies. Conclusions: Colorectal SRCC has distinct molecular features compared with non-SC and AC with SC component CRC. The frequencies of KRAS, PIK3CA and APC mutations were lower than the frequencies reported in non-SC CRC. SRCC was not associated with MSI-H or CIMP-H tumor in this study. Further studies on identification of activated pathways underlying this worse prognosis and potential therapeutic targets are required. [Table: see text]

Utility of a molecular prescreening program in advanced colorectal cancer for enrollment on biomarker-selected clinical trials

BACKGROUND

Incorporation of multiple enrichment biomarkers into prospective clinical trials is an active area of investigation, but the factors that determine clinical trial enrollment following a molecular prescreening program have not been assessed.

PATIENTS AND METHODS

Patients with 5-fluorouracil-refractory metastatic colorectal cancer at the MD Anderson Cancer Center were offered screening in the Assessment of Targeted Therapies Against Colorectal Cancer (ATTACC) program to identify eligibility for companion phase I or II clinical trials with a therapy targeted to an aberration detected in the patient, based on testing by immunohistochemistry, targeted gene sequencing panels, and CpG island methylation phenotype assays.

RESULTS

Between August 2010 and December 2013, 484 patients were enrolled, 458 (95%) had a biomarker result, and 157 (32%) were enrolled on a clinical trial (92 on biomarker-selected and 65 on nonbiomarker selected). Of the 458 patients with a biomarker result, enrollment on biomarker-selected clinical trials was ninefold higher for predefined ATTACC-companion clinical trials as opposed to nonpredefined biomarker-selected clinical trials, 17.9% versus 2%, P < 0.001. Factors that correlated positively with trial enrollment in multivariate analysis were higher performance status, older age, lack of standard of care therapy, established patient at MD Anderson, and the presence of an eligible biomarker for an ATTACC-companion study. Early molecular screening did result in a higher rate of patients with remaining standard of care therapy enrolling on ATTACC-companion clinical trials, 45.1%, in contrast to nonpredefined clinical trials, 22.7%; odds ratio 3.1, P = 0.002.

CONCLUSIONS

Though early molecular prescreening for predefined clinical trials resulted in an increase rate of trial enrollment of nonrefractory patients, the majority of patients enrolled on clinical trials were refractory to standard of care therapy. Within molecular prescreening programs, tailoring screening for preidentified and open clinical trials, temporally linking screening to treatment and optimizing both patient and physician engagement are efforts likely to improve enrollment on biomarker-selected clinical trials.

CLINICAL TRIALS NUMBER

The study NCT number is NCT01196130.

Characterizing the patterns of clonal selection in circulating tumor DNA from patients with colorectal cancer refractory to anti-EGFR treatment

INTRODUCTION

KRAS and EGFR ectodomain-acquired mutations in patients with metastatic colorectal cancer (mCRC) have been correlated with acquired resistance to anti-EGFR monoclonal antibodies (mAbs). We investigated the frequency, co-occurrence, and distribution of acquired KRAS and EGFR mutations in patients with mCRC refractory to anti-EGFR mAbs using circulating tumor DNA (ctDNA).

PATIENTS AND METHODS

Sixty-two post-treatment plasma and 20 matching pretreatment archival tissue samples from KRAS (wt) mCRC patients refractory to anti-EGFR mAbs were evaluated by high-sensitivity emulsion polymerase chain reaction for KRAS codon 12, 13, 61, and 146 and EGFR 492 mutations.

RESULTS

Plasma analyses showed newly detectable EGFR and KRAS mutations in 5/62 [8%; 95% confidence interval (CI) 0.02-0.18] and 27/62 (44%; 95% CI 0.3-0.56) samples, respectively. KRAS codon 61 and 146 mutations were predominant (33% and 11%, respectively), and multiple EGFR and/or KRAS mutations were detected in 11/27 (41%) cases. The percentage of mutant allele reads was inversely correlated with time since last treatment with EGFR mAbs (P = 0.038). In the matching archival tissue, these mutations were detectable as low-allele-frequency clones in 35% of patients with plasma mutations after treatment with anti-EGFR mAbs and correlated with shorter progression-free survival (PFS) compared with the cases with no new mutations (3.0 versus 8.0 months, P = 0.0004).

CONCLUSION

Newly detected KRAS and/or EGFR mutations in plasma ctDNA from patients refractory to anti-EGFR treatment appear to derive from rare, pre-existing clones in the primary tumors. These rare clones were associated with shorter PFS in patients receiving anti-EGFR treatment. Multiple simultaneous mutations in KRAS and EGFR in the ctDNA and the decline in allele frequency after discontinuation of anti-EGFR therapy in a subset of patients suggest that several resistance mechanisms can co-exist and that relative clonal burdens may change over time. Monitoring treatment-induced genetic alterations by sequencing ctDNA could identify biomarkers for treatment screening in anti-EGFR-refractory patients.

Colorectal high-grade neuroendocrine carcinoma: A single institution experience

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Background: Colorectal high-grade neuroendocrine carcinoma (HGNEC) is a rare and aggressive disease that lacks standard management recommendations. Methods: The records of all patients with colorectal HGNEC diagnosed at MD Anderson Cancer Center between 1991 and 2013 were retrospectively reviewed for clinicopathological features and clinical outcomes. Results: One hundred patients with histologically confirmed colorectal HGNEC were identified. Median age at diagnosis was 55 years with 51 males. Family history of cancer was present in 59% (first degree) of patients and a tobacco smoking history in 54%. Most frequent symptoms at diagnosis were: abdominal or rectal pain (52%), rectal bleeding (49%) and change in bowel habit (52%). Small cell carcinoma was the most common histology (89%), with large cell neuroendocrine carcinoma in 8% and mixed histology 2%. The expression of chromogranin, synaptophysin and neuron specific enolase was positive in 58%, 93% and 87%, respectively. In our institution, 40% of HGNECs arise in the rectum, compared to 25% of adenocarcinomas (P<0.001 for comparison). Sixty four patients (64%) presented with metastatic disease at diagnosis. Median overall survival (OS) was 11.8 months, with 19.3 versus 8 months for localized and metastatic disease, respectively (p<0.01). Two and five year OS was 23% and 8%, respectively. Cecal primaries had a higher rates of metastatic disease at presentation (OR=5, P=0.026), but stage-specific outcomes did not differ by tumor location. Treatment with a platinum-based chemotherapy (CT) was used in 63 (81%) patients in first line palliative CT and the objective response rate was 43%. For localized disease, neoadjuvant treatment was used in 36% of patients and adjuvant therapy in 47% and was associated with a trend toward improved survival (median OS 20.4 versus 15.4 months, P=0.08). Conclusions: Colorectal HGNEC has an aggressive biology with rectum being the most common site and cecum the site most associated with distant metastases at diagnosis. For localized disease early diagnosis and multimodality approach are important for better outcomes while systemic CT appears to be the mainstay of treatment for advanced disease.

Medullary thyroid cancer and pseudocirrhosis: case report and literature review

Pseudocirrhosis is a rare form of liver disease that can cause clinical symptoms and radiographic signs of cirrhosis; however, its histologic features suggest a distinct pathologic process. In the setting of cancer, hepatic metastases and systemic chemotherapy are suspected causes of pseudocirrhosis. Here, we present a patient with medullary thyroid carcinoma metastatic to the liver who developed pseudocirrhosis while on maintenance sunitinib after receiving 5-fluorouracil, leucovorin, and oxaliplatin (folfox) in combination with sunitinib. Cirrhotic change in liver morphology was accompanied by diffusely infiltrative carcinomatous disease resembling the primary tumor. We discuss the diagnosis of pseudocirrhosis in this case and review the literature regarding pseudocirrhosis in cancer.

Tolerance of full-dose sorafenib (S) combined with irinotecan (I; weekly, two on, one off) and cetuximab (C) in previously treated patients with advanced colorectal cancer (CRC)

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Background: The epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) pathways are qualified targets in CRC, and are both inhibited by S. Preclinical evidence suggests S may also overcome cetuximab resistance. We previously reported (2008 GI Symposium, abstr#435) excessive toxicity of this combination with I 120 mg/m2 days (d) 1,8,15,22 every 42 d; the study was amended with an alternative I dose/schedule and the phase I results are presented.

Methods: Patients (pts) with advanced, pretreated CRC irrespective of KRAS mutation status with ECOG PS 0-2 and good organ function were eligible. The original dose/schedule of I was combined with C 400 mg/m2 IV d1 and 250 mg/m2 weekly; and S PO daily with dose level (DL) 1 = 200mg QD, DL2=200 mg BID and DL 3=400 mg BID. 2/4 pts had DLTs: grade (g) 3 fatigue and febrile neutropenia. The dose/schedule were amended to I 100 mg/m2 d1, 8 of 21d cycles (c) without changing S or C. As with the original design, there was a C/S lead-in for 2 weeks in c1, thus c1 (DLT window) was 5 weeks (w).

Results: In the original design, 5 subjects were recruited; after the study amendment, 13 additional pts were recruited (3, 3 and 7 pts respectively at amended DL1, DL2 and DL3). Overall, median age was 56.5 yrs, M: F 12:6 and colon: rectal cancer 16:2. All patients are evaluable and 3 are still on treatment (10+ - 20+ w). At the amended I dose/schedule, there were no further DLTs. Any c g3 toxicities included constitutional (fatigue:2, dehydration:1), gastrointestinal (nausea:1, vomiting:2, diarrhea:1), metabolic (hypomagnesemia:2 including one with tetany; hypokalemia:3), elevated ALT:1 and neutropenia:1. G 4 toxicities included neutropenia:1, thrombocytopenia:1. Two pts (one KRAS MT) had partial response with one pt (KRAS WT) on treatment for >44 w. 10 pts had stable disease (5–20+ w). PK/PD analysis is ongoing.

Conclusions: The recommended phase II dose is I 100 mg/m2d1,8; C 400 mg/m2 IV d1 and 250 mg/m2 weekly; and S 400 mg PO BID. The regimen is tolerable in advanced, pretreated CRC. Due to the limited responses and current phase III studies with S in CRC, there are no plans to open the phase II portion at this time.

No significant financial relationships to disclose.