Effect of continuing osimertinib with chemotherapy in the post-progression setting on progression-free survival among patients with metastatic epidermal growth factor receptor (EGFR) positive non-small cell lung cancer

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Background: Continuing a 1st generation EGFR TKI with chemotherapy upon TKI progression was not shown to be beneficial in the IMPRESS trial. However, the validity of this approach with osimertinib remains under explored. We attempted to characterize the efficacy of continuing osimertinib with chemotherapy in the post-progression setting. Methods: A single-center retrospective review of patients with metastatic EGFR mutant NSCLC who had progressed on osimertinib was performed. Clinical characteristics and treatment outcomes were noted. Progression free survival (PFS), duration of treatment (DOT), overall survival (OS) and rates of intracranial progression were captured. ANOVA or a Fisher exact test were used to identify associations between cohort characteristics and treatment outcomes. Differences in PFS, DOT and OS were assessed using a log-rank test. A Cox proportional hazard model was used to adjust for potential confounders. Results: 73 patients with EGFR mutant NSCLC with post-osimertinib treatment outcomes were identified. Cohort characteristics are summarized in Table. Median duration of follow up was 41 months. Upon progression, osimertinib was discontinued in 34 patients (Cohort A) and continued with next line of therapy in 39 patients (Cohort B). Survival analyses were adjusted for prior lines of therapy, use of platinum doublet chemotherapy, and use of immune checkpoint inhibitors in the post-progression setting. After adjusting for covariates, continuing osimertinib post-progression was associated with an improved PFS (7 vs 4 months; HR 0.58; 95% CI 0.34 – 1.00; p = 0.003) and DOT (7 vs 4 months; HR 0.52; 95% CI 0.31 – 0.87; p = 0.006). There was no difference in OS between Group A and B (52 vs 41 months; HR 0.73; 95% CI 0.43 – 1.24; p = 0.234). Rates of intracranial progression were similar between Group A and B (28% vs 23%; p = 0.649). Conclusions: After adjusting for covariates, continuing osimertinib with chemotherapy in the post-progression setting was associated with a significant difference in PFS and DOT, but with no differences in OS. Continuing osimertinib does not appear to influence the rate of subsequent intracranial progression. Prospective studies are needed to identify the optimal practice pattern.[Table: see text]

Duration of pemetrexed maintenance therapy with or without pembrolizumab is associated with risk of renal toxicity in patients with metastatic nonsquamous NSCLC

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Background: Use of maintenance pemetrexed with pembrolizumab is the standard of care among patients with metastatic nonsquamous NSCLC without EGFR or ALK alterations treated with the KEYNOTE-189 regimen. Whether the addition of pembrolizumab to pemetrexed maintenance alters the risk of renal toxicity is not well characterized. Methods: A single center retrospective study was performed. The frequency of acute kidney injury as well as the rates of discontinuation due to renal injury was assessed. Acute renal injury was defined as ≥ 0.3 increase in serum creatinine (sCr) above the upper limit of normal or a rise in sCr ≥ 1.5 times baseline per KDIGO criteria. A Fisher exact test was conducted to compare the rate of renal injury between the two groups. Logistic regression adjusting for performance status, prior lines of treatment, and number of maintenance cycles was performed. Results: We identified 114 patients who received either maintenance pemetrexed or pemetrexed + pembrolizumab. The median number of cycles for the maintenance pemetrexed and pemetrexed + pembrolizumab groups was 5 and 7 cycles respectively. Of these, 41% (47/114) patients developed acute renal injury during their treatment course. Renal injury was seen in 14.3% (5/35) patients who received single agent pemetrexed maintenance and 25% (3/12) who received maintenance pemetrexed + pembrolizumab with no significant difference in the rates of renal injury between both arms (p = 0.403). Among patients who developed acute renal injury, 9% (4/47) permanently discontinued maintenance due to nephrotoxicity. All patients who permanently discontinued therapy received maintenance pemetrexed alone. When adjusting for covariates, ECOG performance status and number of prior lines of therapy did not increase the risk of renal toxicity. Logistic regression analysis identified that the rate of renal injury was significantly associated with the number of maintenance cycles received (p-value = 0.017, OR = 1.14, 95% CI 1.03 - 1.29). The odds of developing renal injury were 1.14 times higher with each additional cycle of maintenance therapy received. Conclusions: Renal injury is common among patients treated with patients receiving maintenance therapy. The addition of pembrolizumab to maintenance pemetrexed did not significantly increase the rate of renal injury. The risk of renal injury appears to correlate with the total number of maintenance cycles received suggesting a cumulative risk of nephrotoxicity over time.

Impact of Radiation Dose on Postoperative Complications in Esophageal and Gastroesophageal Junction Cancers

Introduction: The impact of radiation prescription dose on postoperative complications during standard of care trimodality therapy for operable stage II-III esophageal and gastroesophageal junction cancers has not been established. Methods: We retrospectively reviewed 82 patients with esophageal or gastroesophageal junction cancers treated between 2004 and 2016 with neoadjuvant chemoradiation followed by resection at a single institution. Post-operative complications within 30 days were reviewed and scored using the Comprehensive Complication Index (CCI). Results were compared between patients treated with <50 Gy and ≥ 50 Gy, as well as to published CROSS study neoadjuvant chemoradiation group data (41.4 Gy). Results: Twenty-nine patients were treated with <50 Gy (range 39.6-46.8 Gy) and 53 patients were treated with ≥ 50 Gy (range 50.0-52.5 Gy) delivered using IMRT/VMAT (41%), 3D-CRT (46%), or tomotherapy IMRT (12%). Complication rates and CCI scores between our <50 Gy and ≥ 50 Gy groups were not significantly different. Assuming a normal distribution of the CROSS data, there was no significant difference in CCI scores between the CROSS study neoadjuvant chemoradiation, <50 Gy, or ≥ 50 Gy groups. Rates of pulmonary complications were greater in the CROSS group (50%) than our <50 Gy (38%) or ≥ 50 Gy (30%) groups. Conclusions: In selected esophageal and gastroesophageal junction cancer patients, radiation doses ≥ 50 Gy do not appear to increase 30 day post-operative complication rates. These findings suggest that the use of definitive doses of radiotherapy (50-50.4 Gy) in the neoadjuvant setting may not increase post-operative complications.

A single-institution experience using total neoadjuvant therapy to treat locally advanced rectal cancer

64

Background: The management of locally advanced rectal cancer has historically included preoperative chemoradiation followed by surgery and then adjuvant chemotherapy. Recently there has been an increasing utilization of preoperative chemotherapy in addition to standard chemoradiation, a strategy known as total neoadjuvant therapy (TNT). TNT has been offered to patients at the University of Colorado Cancer Center since 2015. Methods: Records of all patients presenting to the University of Colorado colorectal multidisciplinary clinic since 2015 were screened for treatment with TNT. Data collected on these patients included demographic information, diagnosis and initial staging, preoperative treatment received, and surgical outcomes including treatment response and pathological stage. TNT included preoperative chemotherapy with oxaliplatin combined with either 5-FU (FOLFOX) or capecitabine (CAPOX) as well as chemoradiation, generally given with concurrent capecitabine. Patients then underwent surgical resection; if a complete clinical response was achieved with TNT, non-operative management (NOM) was offered. Results: A total of 81 patients thus far have undergone TNT followed by resection or, if complete clinical response and preferred by the patient, NOM. The mean age of patients was 56 years, ranging from 23 to 87, and 60% of patients were male. The majority of patients (67) had stage III disease at presentation while 1 had stage 1 (T2N0) disease, 11 had stage II disease and 2 patients had oligometastatic disease. Ultimately 13 patients (16%) opted for non-operative management after being found to have a complete clinical response following TNT. Of the 68 patients who underwent surgical resection, 21 (31%) had a pathological complete response, with another 14 (21%) with near-complete response. 28 patients (41%) had a partial treatment response and 5 (7%) had no treatment response. In total, the rate of complete clinical or pathologic response was 42%. Treatment was overall well-tolerated with 90% of patients receiving the full planned dose of radiation and 98% of patients completing all planned cycles of chemotherapy, though most of them with typical dose reductions needed. Of the patients who underwent surgery, 49 (72%) had low anterior resection and 19 (28%) had an abdominoperineal resection. Of patients with temporary ileostomies, 85% of them had their ileostomy reversed within 10 weeks of surgery. Conclusions: Treatment of locally advanced rectal cancer by a total neoadjuvant approach is well-tolerated and results in a high rate of clinical and pathological complete response.

Namodenoson in Advanced Hepatocellular Carcinoma and Child-Pugh B Cirrhosis: Randomized Placebo-Controlled Clinical Trial

Namodenoson, an A3 adenosine-receptor agonist, showed promising results in advanced hepatocellular carcinoma (HCC) and moderate hepatic dysfunction (Child-Pugh B; CPB) in a phase I/II clinical study. This phase II study investigated namodenoson as second-line therapy in such patients. Patients were randomized 2:1 to twice a day (BID) namodenoson (25 mg; n = 50) or placebo (n = 28). The primary endpoint (overall survival [OS]) was not met. Median OS was 4.1/4.3 months for namodenoson/placebo (hazard ratio [HR], 0.82; 95% confidence interval [CI] 0.49-1.38; p = 0.46). Pre-planned subgroup analysis of CPB7 patients (34 namodenoson-treated, 22 placebo-treated) showed a nonsignificant improvement in OS/progression-free survival (PFS). OS: 6.9 versus 4.3 months; HR, 0.81; 95% CI: 0.45-1.43, p = 0.46. PFS: 3.5 versus 1.9 months; HR, 0.89; 95% CI: 0.51-1.55, p = 0.67 (log-rank test). The difference in 12-month OS was significant (44% versus 18%, p = 0.028). Response rates were determined in patients for whom ≥ 1 assessment post-baseline was available (34 namodenoson-treated, 21 placebo-treated). Partial response was achieved by 3/34 (8.8%) and 0/21 (0%) patients, respectively. Namodenoson was well-tolerated, with a safety profile comparable to that of the placebo group. No treatment-related deaths were reported; no patients withdrew due to toxicity. In conclusion, namodenoson demonstrated a favorable safety profile and a preliminary efficacy signal in HCC CPB.

High incidence of prolonged rectal bleeding and advanced stage cancer in early-onset colorectal cancer patients

Background: We examined characteristics of early-onset colorectal cancer (CRC) patients to identified factors, which may lead to earlier diagnosis. Materials & methods: This is a retrospective study with inclusion criteria: CRC diagnosed between 2012 and 2018 and age at diagnosis <50 years. Results: A total of 209 patients were included (mean age 41.8 years). Of those patients 42.5% had rectal cancer and 37.8% were stage IV at initial diagnosis. Of patients with data available for rectal bleeding history (n = 173), 50.8% presented with rectal bleeding and median time from onset of bleeding to diagnosis was 180 days (interquartile range 60–365), with longer duration noted in advanced cancer. Conclusion: Prolonged rectal bleeding history was noted in a significant proportion of early-onset CRC patients, with longer duration of rectal bleeding noted in stage IV patients. Patients and primary care physicians should be made aware of this finding in order to facilitate timely referral for diagnostic workup.

PrE0505: Phase II multicenter study of anti-PD-L1, durvalumab, in combination with cisplatin and pemetrexed for the first-line treatment of unresectable malignant pleural mesothelioma (MPM)—A PrECOG LLC study

9003

Background: First-line CP was FDA-approved in 2004 for unresectable MPM. Given the role of inflammation in MPM and promising responses to PD-1 pathway blockade in pretreated MPM, we conducted a phase 2 single arm study of the anti-PD-L1 antibody, durvalumab (durva), combined with CP for patients (pts) with untreated MPM of any subtype. Methods: Eligible pts were treatment-naïve with surgically unresectable MPM. Primary endpoint was overall survival (OS); pts received up to 6 cycles of durva-CP, followed by maintenance durva up to 1 year. Carboplatin was permitted for pts with baseline hearing or renal impairment. The first 15 pts were monitored for dose-limiting toxicities (DLTs). Secondary endpoints included toxicity, objective response by modified RECIST, progression-free survival (PFS), and correlative analyses. With a sample size of 55 patients and 32 events, the study had 90% power to detect a 58% improvement in median OS from 12 months (m) (historical control) to 19 m with durva-CP. Results: PrE0505 enrolled 55 patients at 15 US-based sites between 06/2017 and 06/2018. Histologic subtypes were epithelioid (75%), biphasic (11%), sarcomatoid (13%), and desmoplastic (2%). There were no DLTs during the run-in period. As of January 2020 the median follow up is 20.6 m and 29 deaths have occurred. The median OS at the time of report is 21.1 m. The 12 m OS rate was 70% with a 2 sided 95% confidence interval (56%, 81%) and two-sided 80% CI (62%, 78%). Analyses for the secondary endpoints were ongoing at abstract submission. Exome sequencing, TCR sequencing and dual PD-L1/CD8 staining have been completed on baseline tumors from at least 45 of the 55 patients enrolled as well as RNA sequencing for those with adequate tissue. Initial results show that tumors harbored an average tumor mutation burden of 22 somatic sequence alterations and varying levels of aneuploidy were detected. Conclusions: The combination of chemotherapy with durvalumab delivered a promising median OS for previously untreated pts with unresectable MPM. Full results from the study along with the extensive correlative analyses performed will be reported. The phase 3 PrE0506/DREAM3R trial evaluating CP-durvalumab versus CP alone will commence enrollment in the United States and Australia in 2020. Clinical trial information: NCT02899195.

Results from the safety lead-in for a phase II study of pembrolizumab in combination with binimetinib and bevacizumab in patients with refractory metastatic colorectal cancer (mCRC)

4031

Background: The majority of pts with mCRC have microsatellite stable (MSS) tumors with minimal response to PD-L1/PD-1 blockade. MEK inhibition and VEGF inhibition have immunomodulatory effects (upregulation of tumor major histocompatibility complex-I expression, enhanced T-cell infiltration, reduced MDSCs and Tregs in tumors) supporting clinical evaluation of combined MEKi (B), anti–PD-1 (P), and anti-VEGF (BV) in pts with mCRC. We hypothesize that the combination of binimetinib, pembrolizumab, and bevacizumab (BPBV) will result in greater clinical benefit than pembrolizumab alone. Methods: Patients with chemotherapy-refractory mCRC were evaluated (20 planned in the safety lead-in and 50 planned for total accrual). B was dosed at 45mg PO BID, P was administered at 200mg IV Q21 days, and BV was administered at 7.5mg/kg IV Q21 days. Primary objectives were safety, tolerability, and investigator-assessed ORR by RECIST 1.1. Clinical benefit rate (CR+PR+SD) and progression-free survival were secondary endpoints. Descriptive statistics were used to summarize safety and clinical activity. Results: As of January 9, 2020, 21 pts (10 KRAS/NRASmt, 11 RASwt, 21 MSS) were enrolled into the safety lead-in and were evaluable. The median number of prior therapies was 6. The BPBV combination was tolerable. Treatment-related Gr 1-2 and Gr 3-4 AEs occurred at 60% and 38%, respectively. The most frequent related Gr 3-4 AEs were aceniform rash, diarrhea, and hypertension (19%, 14%, 14% respectively). No treatment-related Gr 5 AEs occurred. A total of 17 patients were evaluable for response. Confirmed PR was observed in 2 pts (12%). SD was noted in 14 patients (82%) leading to a clinical benefit rate of 94%. 1 patient had PD as the best response to treatment. Median PFS was 6.4 months (95% CI 4.2-8.9). Molecular determinants, immune biomarkers, and updated tumor assessments of response will be presented. Conclusions: B + P + BV demonstrated a tolerable safety profile and improvements in ORR and clinical benefit rate compared to those reported with SOC in heavily pretreated pts with mCRC. Objective responses observed in pts were durable, suggesting benefit of this novel combination in a patient population refractory to immune therapies. Clinical trial information: NCT03475004 .

Cecal Volvulus as a Rare Complication of Osimertinib Dosed at 160 mg in Patients With EGFR-Mutant Non-small Cell Lung Cancer

Background: Osimertinib is a 3rd-generation tyrosine kinase inhibitor (TKI) that blocks the epidermal growth factor receptor (EGFR) in non-small lung cancer (NSCLC) and has dramatically improved outcomes for patients with EGFR mutations. While gastrointestinal complications such as diarrhea have been reported with EGFR inhibitors (due to off-target interactions with EGFR receptors within the gut lining), cecal volvulus is an extremely rare complication in advanced malignancy. To date, there are no reported cases associating cecal volvulus with any EGFR TKIs.

Case Presentation: In this case series, we present three cases of cecal volvulus among patients with EGFR-positive NSCLC patients treated with osimertinib dosed at double the standard 80 mg dose (160 mg daily). No patient was receiving concurrent chemotherapy or bevacizumab at the time of this described complication. In two cases where pathology was available for review, peritoneal carcinomatosis or intra-abdominal spread was not observed. In a retrospective evaluation of 101 patients treated with osimertinib in our institution, there was a statistically significant difference in the incidence of cecal volvulus among patients receiving osimertinib at 160 mg vs. patients receiving the 80 mg dose (27 vs. 0%; p < 0.001).

Conclusions: To our knowledge, these are the first cases to highlight a potentially important and serious gastrointestinal complication associated with the 160 mg dose of osimertinib.

An assessment of dose intensity of the TNT approach on outcomes in locally advanced rectal cancer

258

Background: Patients with clinical stage II or III locally advanced rectal cancer may be treated with the total neoadjuvant therapy (TNT) approach; chemotherapy with 4 mths of FOLFOX followed by chemoradiation (chemo/XRT) with capecitabine for 5 wks administered before surgery. We hypothesized that full dose intensity is not necessary for treatment benefit. Methods: A retrospective chart review was conducted on patients with newly diagnosed rectal cancer recommended to receive TNT by the multidisciplinary (multiD) colorectal cancer tumor board at the University of Colorado Cancer Center (UCCC). The primary objective was to evaluate dose intensity of TNT and its impact on response assessed by biopsy and/or imaging (MRI). Results: Between January 31, 2016 and January 31, 2019, 80 patients were recommended the TNT approach for cancer management by the multiD team. Of those, 48 completed their neoadjuvant treatment at UCCC and were included in the analysis. The average age was 55 years (range 23-80) and 61% were male. Thirty-one patients had an ECOG of 0 and 17 had an ECOG of 1. Overall responses were 44% complete response (CR, n = 21), 15% near complete response (nCR, n = 7), 35% partial response (PR, n = 17), and 6% no response (NR, n = 3). See Table for responses seen by dose intensity for chemotherapy. Two patients did not receive their full planned XRT course, and 9 patients had their capecitabine doses held/decreased during chemoradiation. Conclusions: This single center retrospective analysis of patients receiving the TNT approach for rectal cancer provides data supporting that achieving full dose intensity is not necessary to achieve treatment benefit.

[Table: see text]

Clinicopathologic Characteristics, Treatment Outcomes, and Acquired Resistance Patterns of Atypical EGFR Mutations and HER2 Alterations in Stage IV Non-Small-Cell Lung Cancer

BACKGROUND

The clinicopathologic characteristics, acquired resistance patterns, and outcomes among patients with atypical EGFR mutations and HER2 alterations remain underexplored.

PATIENTS AND METHODS

A single-center retrospective review was conducted. Oncogenes assessed include typical EGFR (t-EGFR; exon 19 del and L858R), atypical EGFR (a-EGFR; G719X, exon 20, L861Q), HER2 (exon 19, exon 20, amplifications), gene fusions (ALK, ROS1, RET), RAS (KRAS, NRAS), and RAF (BRAF V600E). Progression-free survival (PFS), overall survival (OS), disease control rate, and objective response rate (Response Evaluation Criteria in Solid Tumors 1.1) were collected.

RESULTS

Among 570 patients, we found 55 a-EGFR mutations (13 G719X, 38 exon 20, 4 L861Q) and 31 HER2 alterations (2 exon 19 mutations, 27 exon 20 insertions, 2 amplifications). Patients with EGFR and HER2 alterations had increased lung and bone metastases relative to patients with gene fusions, RAS/RAF mutations, and no identified driver oncogenes (P < .001). Patients with EGFR exon 20 insertions had a median PFS to EGFR tyrosine kinase inhibitors (TKIs) of 5 months and an OS of 16 months-significantly worse than exon 19 del and L858R (Bonferroni correction; P < .001), but not G719X or L861Q. Relative to t-EGFR mutations, T790M and MET amplification occurred less frequently as acquired resistance mechanisms among a-EGFR samples (P < .001). Ten patients with a-EGFR mutations and HER2 alterations received single-agent immune checkpoint inhibitors (ICIs) with no radiographic responses and a median PFS of 2 months.

CONCLUSION

EGFR and HER2-mutated NSCLC have a high rate of synchronous lung and bone metastases. Patients with a-EGFR mutations have inferior responses to EGFR-directed therapies with lower rates of acquired T790M and MET amplification. Responses to ICIs are uniformly poor. Novel therapeutic approaches are needed.

A phase II, randomized, double-blind, placebo-controlled trial evaluating efficacy and safety of namodenoson (CF102), an A3 adenosine receptor agonist (A3AR), as a second-line treatment in patients with Child-Pugh B (CPB) advanced hepatocellular carcinoma (HCC)

2503

Background: There is no established primary treatment for patients with advanced HCC and severe liver dysfunction (Child-Pugh B class; CPB), thus this representing a clear unmet need. Namodenoson, an A3AR agonist, showed promising preliminary results in this population in an open label phase 1/2 clinical study (NCT00790218), with median overall survival (OS) of 8.1 months. We present the results of a double blind, randomized phase 2, placebo-controlled study (NCT02128958), assessing the efficacy and safety of namodenoson as a second-line therapy of patients with advanced HCC and CPB class. Methods: Patients were randomized 2:1 to BID namodenoson (25 mg; n = 50) or placebo (n = 28) in 15 centers globally. Primary endpoint was OS and secondary endpoints were safety, progression-free survival (PFS), objective response (OR) and disease control rate (DCR). Assessment of OS and PFS was done by log rank test at a one final analysis when 75 deaths had occurred. Response was assessed by RECIST (local investigator) and mRECIST (central review). Results: The study did not meet the primary end point, with median OS 4.1 months (mo) for namodenoson vs. 4.3 mo for placebo (HR: 0.82). Pre-planned subgroup analysis of Child-Pugh 7 patients (n=56; namodenoson=34, placebo=21) showed median survival 6.8mo vs 4.3 mo [HR: 0.77 (95% CI 0.49-1.40)]. Similarly, for this subgroup of patients PFS was 3.5 mo vs 1.9 (HR=0.87). In terms of objective response, 3/34 patients assessed achieved OR (9%) with namodenoson vs 0% for placebo. Namodenoson was generally well-tolerated, with no treated patients being withdrawn for toxicity and no cases of treatment-related deaths. The most common adverse event (>10%) were anemia, abdominal pain, ascites, nausea, asthenia, fatigue, peripheral edema, and increased AST. Treatment-related grade 3 toxicities accounted for anemia, fatigue and hyponatremia. Conclusions: Namodenoson has demonstrated favorable clinical safety profile in patients with advanced HCC and severe liver dysfunction. Although the primary end-point was not met, the subgroup analysis showed a positive signal of efficacy for OS in patients with Child-Pugh 7. Both safety and efficacy results warrant testing this drug in a phase III trial. Clinical trial information: NCT02128958.

High incidence of advanced stage cancer and prolonged rectal bleeding history before diagnosis in young-onset patients with colorectal cancer

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Background: In contrast to the older population, the incidence of colorectal cancer (CRC) in younger patients (aged < 50 years) has been increasing in the last three decades. Younger patients tend to present with more advanced disease, thought to be in part related to lack of routine screening colonoscopies. The goal of this study was to examine characteristics of young-onset CRC and potentially identify factors that may aid in earlier diagnosis and treatment. Methods: We collected data for patients available through the University of Colorado Cancer Center Cancer Registry. Inclusion criteria included: 1) Diagnosis of colon or rectal cancer between the years 2012-2018 and 2) age at diagnosis of less than 50 years. Pertinent data including baseline characteristics, clinical presentation, family history, pathology, molecular testing, staging, and treatment were collected. Results: 211 patients with young-onset CRC were available for review. Mean age at diagnosis was 42.4 years and 55.5% were males. A total of 42.1% had rectal cancer and a majority of the colon cancer diagnoses had left-sided tumors (66%). Regarding clinical presentation, 52.2% presented with rectal bleeding prior to diagnosis. Of those who presented with rectal bleeding, the average time from the onset of bleeding to diagnosis was 271.17 days. 42.9% of young-onset CRC were stage IV at the time of initial diagnosis. Evaluation of the pathology specimens showed that 89.6% were adenocarcinomas and 63.5% were grade 2 or higher. At diagnosis, the mean BMI was 26.6 and the mean CEA was 135.5. A total of 72.5% of young-onset patients had a positive family history of any cancer. KRAS or NRAS mutations were present in 49.6% of patients, BRAF V600E mutations were present in 3.8%, and 10.8% were MSI-H. Conclusions: Prolonged rectal bleeding history prior to diagnosis was noted in a significant proportion of young-onset patients with colorectal cancer. Patients and primary care physicians should be made aware of this finding in order to facilitate timely referral for colonoscopy which may lead to earlier diagnosis, less advanced disease at diagnosis, and improved outcomes.

Clinicopathologic profile and treatment outcomes of non-sensitizing EGFR and HER2 (ERBB2) activating mutations in NSCLC: Results from a single-center retrospective study

9090

Background: The clinicopathologic characteristics and optimal treatment strategies for non-sensitizing EGFR ( ns- EGFR) and HER2 activating mutations in NSCLC remain unclear. Methods: Single-center retrospective study of patients seen at University of Colorado from 2008 – 2018 with stage IV NSCLC was performed. Clinicopathologic features and treatment outcomes of patients with ns-EGFR (Exon 18, Exon 20, L861Q) and HER2 mutations were collected. Best response to TKI was determined (RECIST v1.1). PFS was calculated using Kaplan-Meier method. Results: Among 359 patients, we identified 49 ns-EGFR (36 Exon 20, 10 Exon 18, 3 L861Q) and 28 HER2 mutations (27 Exon 20, 1 gene amplification) detected via NGS (65/77), real-time PCR (9/77), FISH (1/77) and undocumented (2/77). PDL1 > 50% was seen in 44% ns- EGFR and 57% HER2. Adenocarcinoma was the most common histology (97%). Most patients were female (62%), never smokers (63%), and presented with metastatic disease (stage: I 5%, II 4%, III 6%, IV 85%). HER2+ NSCLC demonstrated a tropism for lung metastases (64%) that was significant when compared to EGFR Exon 19, EGFR L858R, ALK, ROS1, and KRAS cohorts (p < 0.001). No differences were found when other metastatic sites were compared. Among evaluable patients, response rates to TKI therapy is shown. Aggregate median PFS on TKI for ns-EGFR and HER2+ NSCLC was 6 months compared to EGFR Exon 19 (15 months; p < 0.01; HR 0.4; CI 0.24 – 0.67) and EGFR L858R (22 months; p < 0.01; HR 0.27 and 0.8; CI 0.14 – 0.54). Aggregate median OS for ns-EGFR and HER2+ NSCLC was 28 months with no differences when compared to EGFR Exon 19 and L858R subgroups. Conclusions: HER2+ NSCLC appears to have a predisposition for lung metastases. Higher DCR was observed with newer generation TKIs, but novel targeted therapeutic approaches are needed as overall outcomes remain poor. [Table: see text]

QIM19-130: Quality Improvement Project to Standardize a Prehabilitation Pathway for Patients With Esophageal Cancer Receiving Neoadjuvant Chemoradiation

Background: At our institution, the standard treatment recommendation for esophageal cancer patients with stage IB–IIIB disease is for neoadjuvant chemoradiation per the CROSS regimen prior to surgery. This regimen can be difficult for patients to tolerate, and they may be unable to receive full dose therapy without treatment dose reductions and delays. Methods: We conducted a quality improvement (QI) project, STRENGTH (Seeking to Reactivate Esophageal and Gastric Treatment Health), to implement supportive care interventions in the prehabilitation phase of neoadjuvant treatment. Our QI program included a standardized chemotherapy order template with supportive care interventions implemented at specific time points. Following implementation of the STRENGTH pathway, a retrospective QI analysis assessed an equal number of patients in the pre-STRENGTH and STRENGTH group for chemotherapy and radiation therapy dose intensities, as well as treatment outcomes. Results: During the pre-STRENGTH period, patients received an average of 5 chemotherapy treatments (range, 2–6), with an average relative dose intensity of 91.8% for carboplatin and 86.7% for paclitaxel. During the STRENGTH period, patients received an average of 6 (range, 5–8) chemotherapy treatments, with an average relative dose intensity of 111.4% for carboplatin and 112.9% for paclitaxel. In the pre-STRENGTH group, one patient did not complete their planned radiation dose due to nausea, vomiting, and dehydration. All patients in the STRENGTH group received their planned radiation dose. In the STRENGTH group, there is a trend of improved pathologic response, longer progression-free survival, and shortened time to surgery. Conclusion: Implementation of the STRENGTH pathway improved chemotherapy dose intensity, with potentially improved oncologic outcomes in the STRENGTH group. We plan to further optimize the STRENGTH program with implementation of standardized dose reduction and delay protocols for both chemotherapy and radiation, and assess the effects of STRENGTH interventions on patient quality of life.

Impact of neoadjuvant chemotherapy and stereotactic body radiation therapy (SBRT) on R0 resection rate for borderline resectable and locally advanced pancreas cancer

370

Background: Management for borderline resectable pancreas cancer (BRPC) and locally advanced pancreas cancer (LAPC) is controversial. Multiagent chemotherapy (CT) followed by SBRT may allow for tumor downstaging and the ability to perform an R0 resection. Methods: We retrospectively evaluated BRPC and LAPC patients (pts) treated on our multidisciplinary treatment pathway. Pts underwent 2-3 months of CT. Pts without systemic progression received five fractions of SBRT, delivered every other day, to a dose of 30-33 Gy. After restaging, pts underwent surgery if resectable. Overall survival (OS), distant metastasis free survival (DMFS) and local progression free survival (LPFS) were estimated and compared by Kaplan-Meier and log-rank methods. Results: We identified 80 pts with BRPC (65) or LAPC (15) treated with neoadjuvant CT + SBRT between 2011-2017. Median follow up was 20 months. CT primarily included FOLFIRINOX (65%) and gemcitabine/nab-paclitaxel (30%). Of pts completing CT + SBRT, 67 (84%) went to surgery and 53 (79%) of those pts underwent definitive surgery including seven LAPC patients. The remaining 14 pts underwent palliative or exploratory surgery due to intraoperative metastases (43%) or vascular involvement (57%). Of pts undergoing definitive surgery, 51 had R0 resection (96%) and 5 (9%) had a complete pathologic response (PR) to CT + SBRT. The R0 resection rate of the cohort was 64%. OS was 24.5 months. Pts with a complete or marked (14%) PR had significantly better OS than those with a moderate (40%) PR (41.3 vs 30 months, p = 0.04) and pts unable to undergo definitive surgery (18.2 months, p < 0.001). Zero of 11 pts who had a marked or complete PR had local progression, significant compared to those with moderate PR (p = 0.012). DMFS between these two groups was not statistically significantly different. Conclusions: Neoadjuvant CT + SBRT are associated with favorable PR rates and R0 resection rates. Marked or complete PR was associated with improved LPFS and OS compared to moderate PR and pts who did not undergo definitive surgery. DMFS was not significantly different between complete and marked PR compared to those with moderate PR.

Impact of multidisciplinary management in the diagnosis and treatment of neuroendocrine tumors (NET)

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Background: The incidence and prevalence of NETs is increasing and diagnosis and pathologic evaluation of NETs is complex. Given the new advances in local and systemic therapies, multidisciplinary management models have been suggested to assist in treatment decisions. However, scientific data showing definite change in management with multidisciplinary clinic (MDC) review is lacking. We aim to address this need in this study. Methods: 113 GI-NET patients from 2012-18 were reviewed from a dedicated MDC where patients are seen simultaneously by multiple subspecialties, and data on patient characteristics, radiology, tumor pathology and treatment strategies were collected. Change in diagnosis was defined as any change in radiographic or pathologic findings that resulted in a change in the tumor type, grade, site or stage of cancer. Change in management was defined as any recommended change in treatment approach for NETs compared to the prior treatment plan. For patients who did not have a prior treatment plan or were seen directly at MDC, a change of management was considered as yes only if there was a change in diagnosis post MDC. Results: The mean age of patients evaluated was 61, with locally advanced or metastatic disease seen in 81% of patients. Small bowel and pancreatic NETs were the most common primaries (36% each). Significant proportion of NETs were well-differentiated (72%) with < 2 mitosis/10 HPF (47.3%) and Ki-67 of < 3% (36%). Patients were referred to MDC at an average of 2.5 years from diagnosis, with 23% having the MDC as their first visit. 40% had prior resection of primary, 25% were on somatostatin analogues (SSAs) previously and 9% of patients had received prior liver directed therapy (LDT). A significant proportion of patients had change in diagnosis post MDC evaluation: change in site (7%), stage of disease (7%), tumor type (3.5%) and grade (0.1%). A change in management was recommended in 50% of patients, with SSAs recommended in 43.8%, surgery in 25.4% and LDT in 17.5% of the patients. Conclusions: The use of a dedicated MDC to manage NETs had a substantial impact in change in management in a significant percentage of patients evaluated. MDC care for patients diagnosed with NET is recommended for optimal management.

Impact of radiation dose during neoadjuvant chemoradiation on postoperative complications in esophageal (EC) and gastroesophageal junction cancers (GEJC)

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Background: Neoadjuvant chemoradiation (nCRT) followed by resection is standard of care for operable stage II-III EC and GEJC; however, it can be associated with significant risk of postoperative complications (POC). The CROSS study group reported no increase in POC severity with nCRT using 41.4 Gy compared to surgery alone as defined by the Comprehensive Complication Index (CCI). We applied the CCI metric to evaluate the impact of nCRT radiation dose of < 50 Gy vs. ≥ 50 Gy on POC rates and compared to the CROSS rates. Methods: We retrospectively reviewed 82 pts (2004-2016) with EC or GEJC treated with nCRT followed by resection at our institution. 29 (35%) pts were treated with < 50 Gy (range 39.6-46.8 Gy) and 53 (65%) were treated with ≥ 50 Gy (range 50.0-52.5 Gy) delivered using IMRT/VMAT (41%), 3D-CRT (46%), or tomotherapy IMRT (12%). Concurrent chemotherapy were carboplatin/paclitaxel (59%), cisplatin/5-FU (17%), or other (24%). Resection was performed by Ivor Lewis esophagectomy (67%), esophagogastrectomy (14%), or trans-hiatal approach (11%). POC within 30 days were graded using the Clavien-Dindo scale and CCI scores were computed and compared between the two dose groups and with the CROSS nCRT group. Results: CCI scores and complication rates between our < 50 Gy and ≥ 50 Gy groups were not significantly different. Assuming a normal distribution of the CROSS CCI scores, there was no significant difference in CCI scores between the CROSS study nCRT, < 50 Gy, or ≥ 50 Gy groups. Rates of pulmonary complications were greater in the CROSS study. Conclusions: In highly selected EC and GEJC pts, definitive nCRT radiation doses do not appear to increase POC rates. Thus, 50 Gy can likely be delivered without increasing toxicity while also achieving a definitive dose for pts not able or willing to undergo subsequent surgery. [Table: see text]

The Incidence of Brain Metastases in Stage IV ROS1-Rearranged Non-Small Cell Lung Cancer and Rate of Central Nervous System Progression on Crizotinib

INTRODUCTION

Central nervous system (CNS) metastases in lung cancer are a frequent cause of morbidity and mortality. There are conflicting data on the incidence of CNS metastases in stage IV ROS1-positive NSCLC and the rate of CNS progression during crizotinib therapy.

METHODS

A retrospective review of 579 patients with stage IV NSCLC between June 2008 and December 2017 was performed. Brain metastases and oncogene status (ROS1, ALK receptor tyrosine kinase gene [ALK], EGFR, KRAS, BRAF, and others) were recorded. We measured progression-free survival and time to CNS progression in ROS1-positive and ALK-positive patients who were taking crizotinib.

RESULTS

We identified 33 ROS1-positive and 115 ALK-positive patients with stage IV NSCLC. The incidences of brain metastases for treatment-naive, stage IV ROS1-positive and ALK-positive NSCLC were 36% (12 of 33) and 34% (39 of 115), respectively. There were no statistically significant differences in incidence of brain metastases across ROS1, ALK, EGFR, KRAS, BRAF, or other mutations. Complete survival data were available for 19 ROS1-positive and 83 ALK-positive patients. The median progression-free survival times for ROS1-positive and ALK-positive patients were 11 and 8 months, respectively (p = 0.304). The CNS was the first and sole site of progression in 47% of ROS1-positive (nine of 19) and 33% of ALK-positive (28 of 83) patients, with no statistically significant differences between these groups (p = 0.610).

CONCLUSIONS

Brain metastases are common in treatment-naive stage IV ROS1-positive NSCLC, though the incidence does not differ from that in other oncogene cohorts. The CNS is a common first site of progression in ROS1-positive patients who are taking crizotinib. This study reinforces the importance of developing CNS-penetrant tyrosine kinase inhibitors for patients with ROS1-positive NSCLC.

Pilot Prehabilitation Program for Patients With Esophageal Cancer During Neoadjuvant Therapy and Surgery

BACKGROUND

Locally advanced esophageal cancer is often treated with neoadjuvant therapy followed by surgery. Many patients present with or experience clinical deconditioning during neoadjuvant therapy. Prehabilitation programs in other areas of surgery have demonstrated improved postoperative outcomes. The aims of this study were to evaluate the feasibility of a pilot prehabilitation program and determine preliminary effects on surgical and cancer-related outcomes.

METHODS

A retrospective review of patients treated at a single institution with resectable esophageal cancer was performed (n = 22). Patients in the prehabilitation group received protocol-structured intervention in several clinical domains including nutrition, psychosocial support, and physical exercise.

RESULTS

Clinical stage and comorbidities were well matched between groups. The structured prehabilitation program was feasible and well received by participants. Fewer patients required admission during neoadjuvant therapy in the prehabilitation group (27.3% versus 54.5%). Percentage weight loss during treatment was 3.0% in the prehabilitation group versus 4.3% in the control group. Compared with the control group, the prehabilitation group demonstrated 0.0% versus 18.2% 30-d postoperative readmission rate and 18.2% versus 27.3% 90-d postoperative readmission rate. There were no statistically significant differences between groups in regard to complications or mortality.

CONCLUSIONS

The pilot prehabilitation program demonstrated feasibility of implementing a structured program for patients receiving neoadjuvant therapy for esophageal cancer. Although the small population limits evaluation of statistical significance, trends in the data suggest a potential benefit of the prehabilitation program on neoadjuvant hospital admission rates, postsurgical readmission rates, and nutritional status.

Clinical Utility of Cell-Free DNA for the Detection of ALK Fusions and Genomic Mechanisms of ALK Inhibitor Resistance in Non-Small Cell Lung Cancer

Purpose: Patients with advanced non-small cell lung cancer (NSCLC) whose tumors harbor anaplastic lymphoma kinase (ALK) gene fusions benefit from treatment with ALK inhibitors (ALKi). Analysis of cell-free circulating tumor DNA (cfDNA) may provide a noninvasive way to identify ALK fusions and actionable resistance mechanisms without an invasive biopsy.Patients and Methods: The Guardant360 (G360; Guardant Health) deidentified database of NSCLC cases was queried to identify 88 consecutive patients with 96 plasma-detected ALK fusions. G360 is a clinical cfDNA next-generation sequencing (NGS) test that detects point mutations, select copy number gains, fusions, insertions, and deletions in plasma.Results: Identified fusion partners included EML4 (85.4%), STRN (6%), and KCNQ, KLC1, KIF5B, PPM1B, and TGF (totaling 8.3%). Forty-two ALK-positive patients had no history of targeted therapy (cohort 1), with tissue ALK molecular testing attempted in 21 (5 negative, 5 positive, and 11 tissue insufficient). Follow-up of 3 of the 5 tissue-negative patients showed responses to ALKi. Thirty-one patients were tested at known or presumed ALKi progression (cohort 2); 16 samples (53%) contained 1 to 3 ALK resistance mutations. In 13 patients, clinical status was unknown (cohort 3), and no resistance mutations or bypass pathways were identified. In 6 patients with known EGFR-activating mutations, an ALK fusion was identified on progression (cohort 4; 4 STRN, 1 EML4; one both STRN and EML4); five harbored EGFR T790M.Conclusions: In this cohort of cfDNA-detected ALK fusions, we demonstrate that comprehensive cfDNA NGS provides a noninvasive means of detecting targetable alterations and characterizing resistance mechanisms on progression. Clin Cancer Res; 24(12); 2758-70. ©2018 AACR.

Early outcomes in patients with locally advanced rectal cancer following total neoadjuvant therapy

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Background: The current standard treatment for locally advanced rectal cancer (LARC) is neoadjuvant chemoradiation followed by surgery, and then adjuvant chemotherapy. An alternative approach currently being offered to patients at University of Colorado is total neoadjuvant therapy (TNT), in which patients receive all of their planned treatment, including systemic chemotherapy, preoperatively. Methods: Records of patients from the University of Colorado multidisciplinary colorectal clinic between 2/2015 and 5/2017 were retrospectively reviewed. Treatment plans for included patients involved 8 cycles of preoperative chemotherapy with FOLFOX (5-fluoruracil, oxaliplatin, leucovorin), followed by chemoradiation with concurrent capecitabine, and then resection. Patient data collected includes demographic information, initial staging, chemotherapy and radiation received, adverse effects, surgical outcomes, and clinical and pathological response to treatment. Results: At the time of our analysis, 14 patients have completed TNT and undergone surgical resection, with either abdominoperineal resection or low anterior resection (LAR), at the University of Colorado. Patients ranged in age from 39 to 74 years (mean age 56) with 8 patients (57%) female sex. All 14 patients received 5-fluorouracil with all 8 cycles, though 4 (29%) required omission of oxaliplatin by cycle 8. Toxicities from preoperative treatment were as expected, without significant delays in surgery. Of the 14 patients, 4 (29%) showed a pathologic complete response (grade 0, no residual tumor) on their surgical pathology, with 8 (57%) having either grade 0 or 1 (minimal residual tumor) response. Of the 5 patients who underwent LAR with diverting loop ileostomies, mean time to ostomy reversal was 53.6 days (range 49-61). No patients developed clinically-apparent metastatic disease during preoperative therapy. Conclusions: The use of preoperative chemotherapy in addition to standard chemoradiation for locally advanced rectal cancer is well-tolerated, results in a high rate of pathologic complete response, and allows for early reversal of diverting ileostomies.

The impact of young adult colorectal cancer: incidence and trends in Colorado

Aim: Far less is known about colorectal cancer (CRC) incidence in individuals under the age of 50. This study examined CRC incidence in order to better understand the changing CRC population. Methods: This study analyzed 39,525 CRC cases from the Colorado Central Cancer Registry from 1992 through 2013. Age-adjusted incidence, observed and relative 5-year survival, and estimated annual percentage change was analyzed. Results: Age-adjusted rates averaging 1.7% per year were observed in the under-50 population, while falling on average 4.3% per year (p < 0.05) in the over-50 population. Average-adjusted incidence rose in males under 50 by 2.7% per year (p < 0.05). Conclusion: The absolute incidence of CRC continues to fall in Colorado, however incidence is rising in individuals under 50, particularly males.

Malignant pleural disease is highly associated with subsequent peritoneal metastasis in patients with stage IV non-small cell lung cancer independent of oncogene status

INTRODUCTION

Peritoneal metastasis from lung cancer is an uncommon clinical event and there are limited data on what factors predict peritoneal progression. This study retrospectively investigated whether patterns of metastatic spread and oncogene status in patients with advanced non-small cell lung cancer (NSCLC) are associated with peritoneal metastasis.

METHODS

Patients with metastatic non-squamous NSCLC (n=410) were identified at the University of Colorado Cancer Center. Sites of metastatic disease and baseline oncogene status (EGFR, ALK, KRAS, or triple negative) were documented via a retrospective chart review. In patients with EGFR mutations who developed peritoneal disease, we documented the presence of known resistance mechanisms. Median time to peritoneal metastasis, time from peritoneal disease to death, and overall survival were collected.

RESULTS

Eight percent (33/410) patients in this study developed peritoneal metastasis. Malignant pleural disease at baseline was significantly associated with subsequent peritoneal spread. There was no association between oncogene status and peritoneal metastasis. Three patients with EGFR mutations who developed peritoneal metastasis had documented resistance to tyrosine kinase inhibitors (TKIs) in the ascitic fluid. Median time from stage IV disease to peritoneal metastasis was 16.5 months (range 0.6-108 months). There were no differences in overall survival between patients who developed peritoneal metastasis and those who did not.

CONCLUSIONS

Malignant pleural disease is highly associated with peritoneal metastasis in patients with advanced NSCLC. The underlying mechanism is not clear. The presence of resistance mutations in ascitic fluid implies that poor drug penetration is unlikely to be the dominant mechanism. Despite being a late clinical finding, there were no differences in overall survival between patients who developed peritoneal metastasis and those who did not. Additional studies exploring treatment related factors in patients with malignant pleural disease that can reduce risk of peritoneal metastasis are warranted.