Neoadjuvant chemotherapy for borderline resectable colorectal cancer liver metastases: a single-institution retrospective study

INTRODUCTION

This study aimed to extract prognostic factors in patients undergoing neoadjuvant chemotherapy (NAC) for borderline resectable colorectal liver metastasis (BR-CRLM) (tumor size ≥5 cm, number of tumors ≥4, or resectable extrahepatic diseases) and assess validity of this strategy.

MATERIALS AND METHODS

Since 2010, patients with BR-CRLM were treated with hepatectomy after six cycles of NAC. Prognostic factors of these patients were evaluated using clinicopathological data.

RESULTS

Of 650 patients who underwent initial hepatectomy for CRLM from 2010 to 2018, 246 BR-CRLM cases underwent hepatectomy after NAC (BR-NAC). The 5-year recurrence-free survival rate was 16.7% and the 5-year overall survival rate (5y-OS) was 52.9%. Number of tumors ≥6, carcinoembryonic antigen (CEA) level ≥25 ng/mL, tumor diameter ≥5 cm, and progressive disease (PD) after NAC were identified as independent poor prognostic factors for OS. Patients were divided into four groups according to the number of risk factors, and prognoses of the four groups were well stratified.

CONCLUSION

In patients with BR-NAC, number of tumors ≥6, CEA ≥25 ng/mL, tumor diameter ≥5 cm, and PD after NAC were independent poor prognostic factors. Patients with three or four risk factors showed poor prognosis and may need to switch chemotherapy.

Clinical utility of the carcinoembryonic antigen level in patients with stage III colon cancer after surgery and adjuvant chemotherapy

PURPOSE

The association between perioperative and post-adjuvant carcinoembryonic antigen (CEA) levels and recurrence and prognosis remains unclear. We aimed to evaluate whether perioperative CEA levels are an integral component of the assessment of recurrence and prognosis of patients with stage III colon cancer (CC).

METHODS

This retrospective study was conducted at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research from 2005 to 2013. We enrolled patients with stage III CC who underwent complete resection of a primary tumor and received adjuvant chemotherapy. We analyzed the association between perioperative and post-adjuvant CEA levels and recurrence-free survival (RFS) and overall survival (OS).

RESULTS

A total of 564 consecutive patients were included in the analysis. The RFS and OS of patients with high postoperative CEA levels were significantly worse than those of patients with normal postoperative CEA levels. In the multivariate analysis, high postoperative CEA levels were associated with shorter RFS and OS. The number of risk factors, postoperative CEA levels, and T/N-stage all had a cumulative effect on RFS and OS.

CONCLUSIONS

High postoperative CEA levels and the number of risk factors are associated with recurrence and worse prognosis for patients with stage III CC.

Prognostic Impact of Tumor Markers (CEA and CA19-9) on Patients with Resectable Colorectal Liver Metastases Stratified by Tumor Number and Size: Potentially Valuable Biologic Markers for Preoperative Treatment

BACKGROUND

Although patients with resectable colorectal liver metastasis (CLM), a population with good prognosis, have been treated with upfront surgery, some patients have had a poor prognosis. This study aimed to investigate biologic prognostic factors in patients with resectable CLMs.

METHODS

This single-center retrospective study enrolled consecutive patients who underwent liver resection for initial CLMs at the Cancer Institute Hospital between 2010 and 2020. The study defined CLMs as resectable (tumor size < 5 cm; < 4 tumors; no extrahepatic metastasis) or borderline resectable (BR). Preoperative chemotherapy was administered to patients with BR CLMs.

RESULTS

During the study period, 309 CLMs were classified as resectable without preoperative chemotherapy and 345 as BR with preoperative chemotherapy. For the 309 patients with resectable CLMs, the independent poor prognostic factors associated with overall survival in the multivariable analysis were high tumor marker levels (CEA ≥ 25 ng/mL and/or CA19-9 ≥ 50 U/mL; (hazard ratio [HR], 2.45; p = 0.0007), no adjuvant chemotherapy (HR, 1.69; p = 0.043), and age of 75 years or older (HR, 2.09; p = 0.012). The 5-year survival rates for the patients with high tumor marker (TM) levels (CEA ≥25 ng/mL and/or CA19-9 ≥50 U/mL) were significantly worse than for those with low TM levels (CEA < 25 ng/mL and CA19-9 < 50 U/mL) (55.3% vs. 81.1%; p <0.0001) and similar to the rate for those with BR CLMs (52.1%; p = 0.864). Postoperative adjuvant chemotherapy had an impact on prognosis only in the high-TM group (HR, 2.65; p = 0.007).

CONCLUSIONS

High TM levels have a prognostic impact on patients with resectable CLMs stratified by tumor number and size. Perioperative chemotherapy improves long-term outcomes for patients with CLM and high TM levels.

Sidedness-Dependent Prognostic Impact of Gene Alterations in Metastatic Colorectal Cancer in the Nationwide Cancer Genome Screening Project in Japan (SCRUM-Japan GI-SCREEN)

The treatment strategies and prognoses of patients with metastatic colorectal cancer (CRC) differ according to the sidedness of the primary tumor. TP53 gain-of-function (GOF) and non-GOF variants have been reported to be differentially associated with prognosis by sidedness. We aimed to evaluate the sidedness-dependent prognostic impact of gene alterations in metastatic CRC. Patients enrolled between April 2017 and March 2019 were included in this study. Those excluded were individuals whose tumor tissues were obtained after chemotherapy and those who were enrolled in the study more than six months after starting first-line chemotherapy. Finally, we assessed 531 patients who underwent complete gene sequencing. The study revealed a significant difference in overall survival between individuals with left-sided CRC (n = 355) and right-sided colon cancer (CC) (n = 176) when considering the TP53 non-GOF variant, KRAS wild-type, NOTCH1 wild-type, NOTCH1 covariant, NOTCH3 sole variant, and MYC amplification. Multivariate analysis on each side revealed that the TP53 GOF and KRAS variants were independent poor prognostic factors for left-sided CRC (p = 0.03 and p < 0.01, respectively), and the TP53 non-GOF variant, BRAF V600E, and MYC amplification for right-sided CC (p < 0.05, p < 0.01, and p = 0.02, respectively). The NOTCH3 sole variant was an independent and favorable prognostic factor for left-sided CRC (p < 0.01). The prognostic significance of gene alterations differed between left-sided CRC and right-sided CC.

Efficacy and Safety of Trastuzumab Deruxtecan and Nivolumab as Third- or Later-Line Treatment for HER2-Positive Advanced Gastric Cancer: A Single-Institution Retrospective Study

PURPOSE

Determination of optimal treatment strategies for HER2-positive advanced gastric cancer (AGC) in randomized trials is necessary despite difficulties in direct comparison between trastuzumab deruxtecan (T-DXd) and nivolumab as third or later-line treatments.

MATERIALS AND METHODS

This single-institution, retrospective study aimed to describe the real-world efficacy and safety of T-DXd and nivolumab as ≥ third line treatments for HER2-positive AGC between March 2016 and May 2022. Overall, 58 patients (median age, 64 years; 69% male) were eligible for the study (T-DXd group, n=20; nivolumab group, n=38).

RESULTS

Most patients exhibited a HER2 3+ status (72%) and presented metastatic disease at diagnosis (66%). The response rates of 41 patients with measurable lesions in the T-DXd and nivolumab groups were 50% and 15%, respectively. The T-DXd and nivolumab groups had a median progression-free survival of 4.8 months (95% confidence interval [CI], 3.3, 7.0) and 2.3 months (95% CI, 1.5, 3.5), median overall survival (OS) of 10.8 months (95% CI, 6.9, 23.8) and 11.7 months (95% CI, 7.6, 17.1), and grade 3 or greater adverse event rates of 50% and 2%, respectively. Overall, 64% patients received subsequent treatment. Among 23 patients who received both regimens, the T-DXd-nivolumab and nivolumab-T-DXd groups had a median OS of 14.0 months (95% CI, 5.0, not reached) and 19.3 months (95% CI, 9.5, 25.1), respectively.

CONCLUSIONS

T-DXd and nivolumab showed distinct efficacy and toxicity profiles as ≥ third line treatments for HER2-positive AGC. Considering the distinct features of each regimen, they may help clinicians personalize optimal treatment approaches for these patients.

Morphological response and tumor shrinkage as predictive factors in metastatic colorectal cancer treated with first-line capecitabine, oxaliplatin, and bevacizumab

BACKGROUND

Morphologic response (MR) is a novel chemotherapeutic efficacy predictor of solid tumors, especially those treated with anti-vascular endothelial growth factor antibodies. Nevertheless, the importance of systemic chemotherapy MR for colorectal liver metastases (CLM) remains unclear. We aimed to evaluate the usefulness of MR as a factor associated with the therapeutic effects of chemotherapy plus bevacizumab for initially unresectable CLM cases.

METHODS

We retrospectively evaluated the associations between MR and/or Response Evaluation Criteria in Solid Tumors (RECIST), progression-free survival (PFS), and overall survival (OS) in patients who received first-line capecitabine, oxaliplatin, and bevacizumab treatment for initially unresectable CLM using multivariate analysis. Patients who showed a complete or partial response based on the RECIST, or an optimal response based on MR, were defined as "responders."

RESULTS

Ninety-two patients were examined, including 31 (33%) patients who responded optimally. PFS and OS estimates were comparable in MR responders and non-responders (13.6 vs. 11.6 months, p = 0.47; 26.6 vs. 24.6 months, p = 0.21, respectively). RECIST responders showed better PFS and OS than non-responders (14.8 vs. 8.6 months, p < 0.01; 30.7 vs. 17.8 months, p < 0.01, respectively). The median PFS and OS estimates of MR and RECIST responders were better than those of single responders or non-responders (p < 0.01). Histological type and RECIST response were independently associated with PFS and OS.

CONCLUSION

MR predicts neither PFS nor OS; nevertheless, it may be useful when combined with the RECIST. The Ethics Committee of The Cancer Institute Hospital of JFCR approved this study in 2017 (No. 2017-GA-1123): retrospectively registered.

NEXUS trial: a multicenter phase II clinical study evaluating the efficacy and safety of the perioperative use of encorafenib, binimetinib, and cetuximab in patients with previously untreated surgically resectable BRAF V600E mutant colorectal oligometastases

BACKGROUND

The optimal treatment strategy for resectable BRAF V600E mutant colorectal oligometastases (CRM) has not been established due to the rarity and rapid progression of the disease. Since the unresectable recurrence rate is high, development of novel perioperative therapies are warranted. On December 2020, the BEACON CRC triplet regimen of encorafenib, binimetinib, and cetuximab was approved for unresectable metastatic colorectal cancer in Japan.

METHODS

The NEXUS trial is a multicenter phase II clinical study evaluating the efficacy and safety of the perioperative use of encorafenib, binimetinib, and cetuximab in patients with previously untreated surgically resectable BRAF V600E mutant CRM. The key inclusion criteria are as follows: histologically diagnosed with colorectal adeno/adenosquamous carcinoma; RAS wild-type and BRAF V600E mutation by tissue or blood; and previously untreated resectable distant metastases. The triplet regimen (encorafenib: 300 mg daily; binimetinib: 45 mg twice daily; cetuximab: 400 mg/m2, then 250 mg/m2 weekly, 28 days/cycle) is administered for 3 cycles each before and after curative resection. The primary endpoint of the study is the 1-year progression-free survival (PFS) rate and the secondary end points are the PFS, disease-free survival, overall survival, and objective response rate. The sample size is 32 patients. Endpoints in the NEXUS trial as well as integrated analysis with the nationwide registry data will be considered for seeking regulatory approval for the perioperative use of the triplet regimen.

DISCUSSION

The use of the triplet regimen in the perioperative period is expected to be safe and effective in patients with resectable BRAF V600E mutant CRM.

TRIAL REGISTRATION

jRCT2031220025, April. 16, 2022.

Real-world evidence of trifluridine/tipiracil plus bevacizumab in metastatic colorectal cancer using an administrative claims database in Japan

BACKGROUND

Trifluridine/tipiracil (FTD/TPI) and regorafenib (REG) are standard therapies for refractory metastatic colorectal cancer (mCRC). No results of large real-world data directly comparing FTD/TPI + bevacizumab (BEV) with FTD/TPI or REG monotherapy have been reported. We evaluated the efficacy and safety of FTD/TPI + BEV in a real-world setting.

MATERIALS AND METHODS

This retrospective study used a Japanese claims database provided by Medical Data Vision Co., Ltd. (Tokyo, Japan). Eligible patients were aged 20 years and over with a diagnosis of mCRC, and received their first dose of FTD/TPI or REG from 2014 to 2021. The primary endpoint was overall survival (OS) in a propensity score matching (PSM) population in which PSM was carried out by matching using a 1 : 1 ratio for the FTD/TPI + BEV group and the control group (FTD/TPI or REG) by propensity score. To enhance robustness, sensitivity analyses of OS were carried out using the inverse probability treatment weighted (IPTW) approach and the analysis in the all eligible population. Secondary endpoints included time to treatment discontinuation (TTD), incidence of adverse events, and post-treatment.

RESULTS

Eligible population was 2369 for the FTD/TPI + BEV group and 9318 for the control group. The PSM population was 1787 for each group. Median OS (mOS) was longer in the FTD/TPI + BEV group compared to the control group [17.0 versus 11.6 months, hazard ratio (HR) = 0.70, P < 0.001] in the PSM population. Similarly, mOS was longer for the FTD/TPI + BEV group compared to that for the control group in IPTW analyses and in the all eligible population (both HRs = 0.68). Median TTD was 3.3 months for the FTD/TPI + BEV group and 1.8 months for the control group in the PSM population (P < 0.001).

CONCLUSIONS

Real-world data showed that FTD/TPI + BEV was significantly associated with OS and TTD compared to FTD/TPI or REG. In clinical practice, FTD/TPI + BEV can be a favorable regimen for refractory mCRC.

Adding Induction Chemotherapy Before Chemoradiotherapy with Total Mesorectal Excision and Selective Lateral Lymph Node Dissection for Patients with Poor-Risk, Locally Advanced, Mid-to-Low Rectal Cancer May Improve Oncologic Outcomes: A Propensity Score-Matched Analysis

BACKGROUND

This study aimed to investigate whether the addition of induction chemotherapy before chemoradiotherapy (CRT) and total mesorectal excision (TME) with selective lateral lymph node dissection improves disease-free survival for patients with poor-risk, mid-to-low rectal cancer.

METHODS

The authors' institutional prospective database was queried for consecutive patients with clinical stage II or III, primary, poor-risk, mid-to-low rectal cancer who received neoadjuvant treatment followed by TME from 2004 to 2019. The outcomes for the patients who received induction chemotherapy before neoadjuvant CRT (induction-CRT group) were compared (via log-rank tests) with those for a propensity score-matched cohort of patients who received neoadjuvant CRT without induction chemotherapy (CRT group).

RESULTS

From 715 eligible patients, the study selected two matched cohorts with 130 patients each. The median follow-up duration was 5.4 years for the CRT group and 4.1 years for the induction-CRT group. The induction-CRT group had significantly higher rates of 3-year disease-free survival (83.5 % vs 71.4 %; p = 0.015), distant metastasis-free survival (84.3 % vs 75.2 %; p = 0.049), and local recurrence-free survival (98.4 % vs 94.4 %; p = 0.048) than the CRT group. The pathologically complete response rate also was higher in the induction-CRT group than in the CRT group (26.2 % vs 10.0 %; p < 0.001). Postoperative major complications (Clavien-Dindo classification ≥III) did not differ significantly between the two groups (12.3 % vs 10.8 %; p = 0.698).

CONCLUSIONS

The addition of induction chemotherapy to neoadjuvant CRT appeared to improve oncologic outcomes significantly, including disease-free survival, for the patients with poor-risk, mid-to-low rectal cancer who underwent TME using selective lateral lymph node dissection.

Incidence, clinicopathological features, and clinical outcomes of low HER2 expressed, inoperable, advanced, or recurrent gastric/gastroesophageal junction adenocarcinoma

BACKGROUND

According to the DESTINY-Breast04 trial, treating patients with breast cancer and low human epidermal growth factor receptor 2 expressions (HER2-low) varies from that of those with no HER2 expression. However, it is interesting to know if HER2-low indicates for anti-HER2 therapy in the gastric or gastroesophageal junction (G/GEJ) adenocarcinoma. Hence we conducted this study to assess the incidence, clinicopathological features, and treatment outcomes of patients with HER2-low G/GEJ adenocarcinoma.

PATIENTS AND METHODS

This was a single-center, retrospective observational study. Patients with previously untreated G/GEJ adenocarcinoma were classified based on their HER2 status using immunohistochemistry (IHC) with or without in situ hybridization (ISH) as follows: HER2 negative (IHC 0), HER2-low (IHC 1+ or 2+/ISH-), and HER2-positive (IHC2+/ISH+ or 3+).

RESULTS

In total, 734 patients with G/GEJ adenocarcinoma were divided into three groups (HER2-negative, n = 410; HER2-low, n = 154, and HER2-positive, n = 170). The intestinal-type histology, peritoneal metastasis, and higher serum carcinoembryonic antigen (CEA) levels differed significantly among patients with negative, low, and positive HER2 statuses: intestinal-type histology (21.0%, 44.2%, and 59.8%, respectively), peritoneal metastasis (56.3%, 44.8%, and 21.8%, respectively), and higher serum CEA level (32.2%, 41.6%, and 56.5%, respectively). Improved survival was observed in the HER2-positive group than in the HER2-negative G/GEJ adenocarcinoma group [hazard ratio (HR) = 0.73, 95% confidence interval (CI) 0.59-0.89; P = 0.002]. However, the prognoses of the HER2-low and HER2-negative groups were similar (HR = 1.01, 95% CI 0.82-1.23; P = 0.843).

CONCLUSIONS

Patients with HER2-low G/GEJ adenocarcinoma exhibited intermediate and distinct characteristics than those in the HER2-negative group. Similarly, the HER2-low group's prognosis was worse than that of the HER2-positive group. Therefore developing novel therapeutic strategies targeting HER2-low G/GEJ adenocarcinoma is required.

Single-organ pulmonary metastasis is a favorable prognostic factor in metastatic colorectal cancer patients treated with FOLFIRI and vascular endothelial growth factor inhibitors

BACKGROUND

Few studies have focused on the impact of single-organ pulmonary metastases on progression-free survival and overall survival in patients with metastatic colorectal cancer. Recognizing differences in prognosis and chemotherapeutic efficacy based on metastasized organs may help in optimizing treatment strategies. The exploratory study was conducted to evaluate the comparative clinical outcomes and prognoses of patients with metastatic colorectal cancer presenting with single-organ pulmonary metastases and treated with folinic acid, 5-fluorouracil, irinotecan, and vascular endothelial growth factor inhibitors as second-line chemotherapy.

METHODS

This retrospective study included 289 patients with metastatic colorectal cancer treated with second-line folinic acid, 5-fluorouracil, irinotecan, and vascular endothelial growth factor inhibitors. The response rate, disease control rate, progression-free survival, and overall survival were assessed in the participants.

RESULTS

Among the 289 patients enrolled, 26 (9.0%) had single-organ pulmonary metastasis with left-sided primary locations, lower levels of tumor markers at the initiation point of chemotherapy, a significantly higher disease control rate (96.2% vs. 76.7%, P = .02), and a longer progression-free survival (median 29.6 months vs. 6.1 months, P < .001) and overall survival (median 41.1 months vs. 18.7 months, P < .001) than patients with other forms of metastatic colorectal cancer. Multivariate analysis showed that single-organ pulmonary metastasis was an independent predictor of longer progression-free survival (hazard ratio 0.35, P = .00075) and overall survival (hazard ratio 0.2, P = .006).

CONCLUSION

Single-organ pulmonary metastasis was a strong predictor of progression-free survival and overall survival in patients with metastatic colorectal cancer treated with folinic acid, 5-fluorouracil, irinotecan, and vascular endothelial growth factor inhibitors as second-line chemotherapy; this provides preliminary evidence for medical guidelines and clinical decision-making on novel therapeutic strategies for these patients.

A multi-institutional observational study evaluating the incidence and the clinicopathological characteristics of NeoRAS wild-type metastatic colorectal cancer

PURPOSE

As circulating tumor DNA (ctDNA) measurement becomes more widespread, the "NeoRAS" phenomenon, where tissue rat sarcoma viral oncogene homolog (RAS) status converts from mutant (MT) to wild-type (WT) after treatment in metastatic colorectal cancer (mCRC), is gaining attention because ineffective epidermal growth factor receptor (EGFR) inhibitors may made effective. This study investigated its incidence and clinicopathological characteristics.

PATIENTS AND METHODS

In total, 107 mCRC patients (refractory or intolerant to previous chemotherapies) with tissue RAS MT were enrolled in four institutions from June 2021 to August 2022. The RAS status in ctDNA was assessed using OncoBEAM™ RAS CRC assay. Clinicopathologic features were compared between patients according to their RAS status in ctDNA, whether WT conversion was noted or not.

RESULTS

The incidence rate of NeoRAS WT mCRC was 21.5% (23/107). According to tissue RAS mutation sites, NeoRAS WT frequency in patients with KRAS mutation in exon 2 was significantly lower than those in exon 3 and 4 or NRAS (18.2% [18/99] vs 62.5% [5/8], P = 0.011). Regarding clinical background, there were significant differences in NeoRAS WT frequency between male vs female patients (30.6% [19/62] vs 8.9% [4/45], P = 0.008), and absence vs presence of liver metastasis (38.6% [17/44] vs 9.5% [6/63], P < 0.001). Comparing the two groups divided by the median value, NeoRAS WT was associated with smaller tumor diameter (>60.9 mm vs ≤, 3.8% [2/53] vs 38.9% [21/54], P < 0.001), lower carcinoembryonic antigen level (>38.2 ng/ml vs ≤, 11.3% [6/53] vs 31.5% [17/54], P = 0.018), and lower carbohydrate antigen 19-9 level (>158.0 U/ml vs ≤, 9.4% [5/53] vs 33.3% [18/54], P = 0.004). In the logistic regression multivariate analysis, liver metastasis absence (Odds ratio [OR], 4.62; P = 0.019), smaller tumor diameter (OR, 7.92; P = 0.012), and tissue RAS MT in other than KRAS exon 2 (OR, 9.04; P = 0.026) were significantly related to the conversion to NeoRAS WT in ctDNA.

CONCLUSIONS

Original RAS variants in tissue, tumor diameter, and liver metastasis are related to conversion to NeoRAS WT mCRC in ctDNA.

Prognostic Factors in Patients with Advanced HER2-Positive Gastric Cancer Treated with Trastuzumab-Based Chemotherapy: a Cohort Study

PURPOSE

Prognostic factors for the survival of patients with advanced HER2-positive gastric cancer treated with trastuzumab-based chemotherapy remain controversial. The aim of this study was to identify the clinical factors that predict prognosis in patients with advanced HER2-positive gastric cancer.

METHODS

We retrospectively reviewed the medical records of HER2-positive gastric cancer patients treated with trastuzumab-based chemotherapy at our institution. Clinical features and laboratory test results that considered prognostic factors were re-examined. Overall survival (OS) was estimated using the Kaplan-Meier method. Univariate analysis was performed with the log-rank test and multivariate analysis was performed using Cox's proportional hazard regression model.

RESULTS

A total of 133 patients with advanced HER2-positive gastric cancer were enrolled. The median OS in this cohort was 18.7 months. Four prognostic factors: visceral metastasis (lung or liver), levels of hemoglobin (Hb) (< 11.6 g/dl), lactate dehydrogenase (LDH) (> 222 mg/dl), and C-reactive protein (CRP) (> 0.14 mg/dl), were identified as independent prognostic factors. The patients were placed into three groups according to their number of prognostic factors. These included low (0, 1), moderate (2, 3), and high (4) risk factors. The OS was separated into three categories with a median OS of 32.0, 18.7, and 10.1 months, respectively. Compared to the low-risk group, hazard ratios for the moderate- and high-risk groups were 1.75 and 3.49, respectively.

CONCLUSION

Visceral metastasis and abnormal Hb, LDH, and CRP levels were associated with unfavorable OS. These findings may be beneficial for the management of advanced HER2-positive gastric cancer treated with trastuzumab-based chemotherapy.

Efficacy of aluminum chloride in severe regorafenib-associated hand-foot skin reactions: a single-arm trial

BACKGROUND

Regorafenib, a multikinase inhibitor, causes a high frequency of hand-foot skin reactions (HFSRs). The present study evaluated the efficacy of topical aluminum chloride, a perspiration suppressant, in reducing the severity of hand-foot skin reactions (HFSRs) caused by regorafenib.

METHODS

The present single-arm study included patients with metastatic colorectal cancer receiving regorafenib. Aluminum chloride ointment was applied topically one week prior to the start of regorafenib treatment, and the observation period was 12 weeks. The primary endpoint was the incidence of regorafenib-related grade 3 HFSR. Secondary endpoints were the incidence of all grades of HFSR, time to any grade of HFSR, time to improvement from grade 2 or higher to grade 1 or lower, treatment discontinuation rate, treatment interruption rate or dosage reduction due to HFSR, and incidence of adverse effects of aluminum chloride.

RESULTS

In total 28 patients were enrolled, and 27 patients were analyzed. The incidence of grade 3 HFSR was 7.4%, meeting the primary endpoint. The incidence of all grades of HFSR was 66.7%, and the median time to the occurrence of any grade of HFSR was 15 days. No patients discontinued or reduced the regorafenib dosage because of HFSR. The most common reason for the interruption of regorafenib therapy was liver dysfunction in nine patients (33%) and HFSR in three patients (11%). No serious adverse events related to aluminum chloride were observed.

CONCLUSIONS

Aluminum chloride ointment, a drug commonly used in routine practice to treat hyperhidrosis, is safe to use, has no serious side effects, and may be effective in reducing the occurrence of severe, regorafenib-related HFSR.

TRAIL REGISTRATION

ClinicalTrials.gov. identifier: jRCTs031180096, Registered on 25/01/2019.

Regulation of MEK inhibitor selumetinib sensitivity by AKT phosphorylation in the novel BRAF L525R mutant

BACKGROUND

Oncogenic mutations in BRAF genes are found in approximately 5-10% of colorectal cancers. The majority of BRAF mutations are located within exons 11-15 of the catalytic kinase domains, with BRAF V600E accounting for more than 80% of the observed BRAF mutations. Sensitivity to BRAF- and mitogen-activated protein kinase (MEK) inhibitors varies depending on BRAF mutations and tumor cell types. Previously, we newly identified, BRAF L525R-mutation, in the activation segment of the kinase in colorectal cancer patient. Here, we characterized the function of the BRAF L525R mutation.

METHODS

HEK293 cells harboring a BRAF mutation (V600E or L525R) were first characterized and then treated with cetuximab, dabrafenib, and selumetinib. Cell viability was measured using WST-1 assay and the expression of proteins involved in the extracellular signal-regulated kinase (ERK) and protein kinase B (AKT) signaling pathways was evaluated using western blot analysis.

RESULTS

The MEK inhibitor selumetinib effectively inhibited cell proliferation and ERK phosphorylation in BRAF L525R cells but not in BRAF V600E cells. Further studies revealed that AKT phosphorylation was reduced by selumetinib in BRAF L525R cells but not in BRAF V600E cells or selumetinib-resistant BRAF L525R cells. Moreover, the AKT inhibitor overcame the selumetinib resistance.

CONCLUSIONS

We established a model system harboring BRAF L525R using HEK293 cells. BRAF L525R constitutively activated ERK. AKT phosphorylation caused sensitivity and resistance to selumetinib. Our results suggest that a comprehensive network analysis may provide insights to identify effective therapies.

Abstract 4565: Drug screening by layered 3D co-cultured tumor model including vascularized stromal tissue

Introduction: In vivo, tumor microenvironments consist of not only cancer cells but also extracellular matrix and stromal tissues, such as fibroblasts, blood vessels, and so on. The interactions between cancer cells and stromal tissue have been reported to affect the behavior of cancer cells. So that ex vivo model recapturing the tumor microenvironment is needed to evaluate the efficacy of drugs under the condition mimicking the patient tumor tissue. Here, we developed the unique tissue engineering technique, which easily enables the construction of cell - stacked three dimensional (3D) tissue, and co-culture of 3D stromal tissues and patient-derived cancer cells (PDCs). We investigated drug sensitivity in conventional 2D culture, our 3D co-cultured model and in vivo tumor.

Methods: Fibroblasts and vascular endothelial cells were suspended in a buffer solution containing heparin and collagen to support cell aggregation. The heparin/collagen-treated cells were seeded in culture-inserts in over-confluent manner, and 3D layered stromal tissue called were constructed. PDCs established from colorectal cancer (CRC) and non-small cell lung cancer (NSCLC) patients in the Cancer Institute Hospital of JFCR were co-cultured with the 3D stromal tissue. The 3D co-cultured model applied to drug screening, and the results were compared with those of 2D culture model. In vivo drug evaluations were performed with the compounds in which marked differences were observed between 2D and 3D models.

Results: In our 3D model, drug sensitivities to most of the tested compounds tended to be decreased in comparison with those in 2D culture condition. Interestingly, a part of drugs did not effective in 2D showed marked tumor growth inhibition in our 3D model. The compounds that showed favorable efficacy in 3D rather than 2D in multiple PDCs were accounted for about 5% of tested compounds. At least half of these drugs showed significant tumor growth suppression or tumor regression in vivo. On the contrary, in the case of drug sensitivities were considerably fallen in our 3D model, most of the evaluated compounds represented almost no anti-tumor effect in vivo. Results from gene and protein expression analyses supported that cancer cells co-cultured in our 3D stromal tissue have some similar profiles to in vivo tumor rather than 2D culture condition.

Conclusion: Our study proposed the unique 3D co-cultured tumor model. The model may enable more accurate drug screening reflecting the in vivo circumstances. Further studies are needed to confirm the model’s predictability of clinical outcomes.

Citation Format: Yuki Takahashi, Yumi Nomura, Yuma Yokokawa, Shiro Kitano, Satoshi Nagayama, Eiji Shinozaki, Ryohei Katayama, Naoya Fujita. Drug screening by layered 3D co-cultured tumor model including vascularized stromal tissue. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4565.

KRAS mutation as a predictor of insufficient trastuzumab efficacy and poor prognosis in HER2-positive advanced gastric cancer

PURPOSE

Although RAS and PIK3CA mutations have been associated with resistance to anti-EGFR antibody in colorectal cancer or trastuzumab in breast cancer, their implications for trastuzumab resistance in HER2-positive advanced gastric cancer (AGC) remains unclear. We aimed to assess the relationship between trastuzumab efficacy and mutation status in the HER family signaling pathway.

METHODS

This study retrospectively evaluated patients with HER2-positive AGC who received first-line trastuzumab-containing chemotherapy between March 2011 and November 2015. Multiplex genotyping, including KRAS, NRAS, PIK3CA, and BRAF, was then performed using the Luminex Assay, after which KRAS amplification was measured using quantitative real-time reverse transcription-polymerase chain reaction. Thereafter, the association between genetic alterations and clinical outcomes were evaluated.

RESULTS

KRAS mutation (MT) was detected in 6 of 77 patients (7.8%), whereas KRAS amplification was found in 15 of 67 patients (22%). No mutations in NRAS, PIK3CA, or BRAF were identified. The KRAS MT group showed significantly worse response rates (16.7% vs. 66.2%, P = 0.016), progression-free survival [median, 4.8 vs. 11.6 months; hazard ratio (HR), 3.95; 95% CI, 1.60-9.76; P = 0.0029], and overall survival (11.5 vs. 23.6 months; HR, 3.80; 95% CI, 1.56-9.28; P = 0.033) compared to the KRAS wild-type group. KRAS amplification had no effect on clinical outcomes.

CONCLUSION

KRAS mutation was an independent prognostic factor for poor survival and might predict insufficient trastuzumab efficacy, whereas KRAS amplification showed no prognostic significance during trastuzumab treatment. Further investigations are warranted to confirm the predictive value of KRAS status in HER2-positive AGC.

Circulating Tumor DNA: The Dawn of a New Era in the Optimization of Chemotherapeutic Strategies for Metastatic Colo-Rectal Cancer Focusing on RAS Mutation

Genotyping of tumor tissues to assess RAS and BRAF V600E mutations enables us to select optimal molecularly targeted therapies when considering treatment strategies for patients with metastatic colorectal cancer. Tissue-based genetic testing is limited by the difficulty of performing repeated tests, due to the invasive nature of tissue biopsy, and by tumor heterogeneity, which can limit the usefulness of the information it yields. Liquid biopsy, represented by circulating tumor DNA (ctDNA), has attracted attention as a novel method for detecting genetic alterations. Liquid biopsies are more convenient and much less invasive than tissue biopsies and are useful for obtaining comprehensive genomic information on primary and metastatic tumors. Assessing ctDNA can help track genomic evolution and the status of alterations in genes such as RAS, which are sometimes altered following chemotherapy. In this review, we discuss the potential clinical applications of ctDNA, summarize clinical trials focusing on RAS, and present the future prospects of ctDNA analysis that could change daily clinical practice.

Clinicopathological features of HER2-low expressed advanced gastric cancers

459

Background: The DESTINY-Breast04 data demonstrated the antibody-drug conjugate trastuzumab deruxtecan (T-DXd) was also effective for metastatic breast patients (pts) with HER2-low expression. Now that the HER2-low expressed cancer is categorized as an independent subset in breast cancer patients. It is unknown whether patients with the HER2-low expression are distinguishable from the HER2 negative or positive and are potential candidates for the anti-HER2 therapy in advanced gastric cancer (AGC) patients. Methods: We retrospectively reviewed the medical records of AGC pts who received standard chemotherapy with platinum containing regimens as the first-line treatment between Jan, 2011 and Dec, 2018 at the Cancer Institute Hospital of the JFCR. AGC pts were classified according to the HER2 status using immunohistochemistry (IHC) and in situ hybridization (ISH) as follows; HER2 negative (IHC 0), HER2-low (IHC 1+ or 2+/ISH-) and HER2 positive (IHC2+/ISH+ or 3+). This study was conducted to investigate the clinicopathological features and prognosis of HER2-low AGC pts compared with HER2 negative and positive. Results: A total of 734 AGC pts were received HER2 testing and classified into three groups according to HER2 status (HER2 negative; n=410, HER2-low; n=154, HER2 positive; n=170). The proportion of male (negative; 61.5%, low; 63.6% and positive; 69.4%), intestinal histology (negative; 21.0%, low; 44.2% and positive; 59.8%), liver metastases (negative; 18.3%, low; 24.8% and positive; 46.5%), higher serum CEA level (>ULN) (negative; 32.2%, low; 41.6% and positive; 56.5%) and higher serum CA19-9 level (>ULN) (negative; 34.1%, low; 36.7% and positive; 56.5%) were gradually increased along with HER2 expression level. The proportion of peritoneum metastasis (negative; 56.3%, low; 44.8% and positive; 21.8%) was decreased along with the HER2 expression level. One hundred and fifty-two pts (89.4%) received combination chemotherapy with trastuzumab in the first-line treatment. Sixteen pts received trastuzumab in the HER2-low (n=3) and HER2 negative (n=13) in the clinical trial. The median survival time (MST) of pts with HER-low was the same with that of HER2 negative (15.7ms). The statistically significant difference was observed in OS between the HER2-low and HER2 positive (HR 1.43 95% CI: 1.12-1.83, P=0.003). Conclusions: AGC Pts with HER2-low have intermediate clinicopathological features between HER2 negative and positive. A Novel effective anti-HER2 therapy for the HER2-low expressed tumor would be warranted in AGC treatment.

Impact of high-dose dexamethasone and prolonged infusion time to prevent hypersensitivity reaction related to oxaliplatin in patients with colorectal cancer

49

Background: Oxaliplatin (OXA) is one of the major cytotoxic agents for the treatment of gastrointestinal tumors. Hypersensitivity reaction (HSR) is one of major reasons of not continuing OXA-based chemotherapy, similar to chemotherapy-induced peripheral neuropathy (CIPN). We developed prevention of the HSR protocol and evaluated its clinical application. Methods: We have retrospectively evaluated and characterized HSR reaction in metastatic colorectal cancer patients exposed to an OXA-containing regimen between 2005 and 2019. We also evaluated the clinical utility of a prevention of the HSR protocol for mCRC patients occurred in grade 1, grade 2 or grade 3 HSR after administration of OXA-based chemotherapy. The prevention of HSR protocol is based on increasing the dose of dexamethasone to 16.5 mg/body, chlorpheniramine to 5 mg, famotidine to 20mg, and the administration time of OXA is extended to 4 hours. Results: A total of 209 patients (median age 61 years, range: 27 to 80) were experienced grade 1 (106 patients, 50.7%), grade 2 (98 patients, 46.0%), or grade 3 HSR (5 patients, 3.3%). Most of the patients had been treated with the FOLFOX4 or modified FOLFOX6 regimen (86.6%). The median number of cycles of OXA administration until the initial onset of HSR was 11 (range: 2 to 48). 111 patients (53.1%) succeeded in OXA re-administration under the prevention of HSR protocol. The median OXA free interval was 23 days (range: 13 to 890). The median progression-free survival after OXA re-administration was 7.0 months (95%CI: 5.3 to 10.4). The reason for the prevention of HSR protocoldiscontinuation was HSR in 98 patients (46.9%), disease progression in 77 patients (36.9%) and CIPN in 17 patients (8.1%), respectively. Forty-eight patients (49.0%) had HSR during the first cycle of OXA re-administration and the median time to HSR after OXA re-administration was 14 days (95%CI 0-19). Grade 3 HSR after OXA re-administrationwere observed in only 6 patients (6.1%) and no one experienced Grade 4 or 5 HSR. Conclusions: Hi-dose dexamethasone and an increased infusion time may allow for OXA re-administration. The prevention of the HSR protocol may provide an alternative to permanent discontinuation of OXA.

A multi-institutional observational study evaluating the incidence and the clinicopathological characteristics of NeoRAS wild-type metastatic colorectal cancer

206

Background: The ’’Neo RAS’’ phenomenon, in which tissue rat sarcoma viral oncogene homolog ( RAS) status converts from mutant (MT) to wild-type (WT) after treatment in metastatic colorectal cancer (mCRC), is gaining attention because epidermal growth factor receptor (EGFR) inhibitors, which were originally considered to be ineffective, may converted to be effective. This multi-center study investigated its incidence and clinicopathological characteristics that are still unclear. Methods: 107 mCRC patients with tissue RAS MT, confirmed using MEBGEN RASKET-B, who were refractory or intolerant to previous chemotherapies, including fluoropyrimidines, oxaliplatin, or irinotecan were enrolled in 4 institutions from June 2021 to August 2022. The RAS status in ctDNA was investigated after prior chemotherapy using ONCOBEAMTM RAC CRC. Clinicopathological characteristics were compared between patients with RAS MT and RAS WT (Neo RAS) in ctDNA. Results: The incidence of Neo RAS WT mCRC was 21.5% (23/107). The frequency of Neo RAS in KRAS exon 2 was significantly lower than that in other alleles such as exon 3 and 4 or NRAS (18.2% [18/99] vs 62.5% [5/8], P = 0.011). There were significant differences in frequency of Neo RAS between male vs female (30.6% [19/62] vs 8.9% [4/45], P = 0.008), absence vs presence of liver metastasis (38.6% [17/44] vs 9.5% [6/63], P < 0.001), and between two groups divided at the median: tumor diameter (> 60.9 mm vs ≤, 3.8% [2/53] vs 38.9% [21/54], P < 0.001), carcinoembryonic antigen level (> 38.2 ng/ml vs ≤, 11.3% [6/53] vs 31.5% [17/54], P = 0.018), carbohydrate antigen 19-9 level (> 158.0 U/ml vs ≤, 9.4% [5/53] vs 33.3% [18/54], P = 0.004). Logistic regression multivariate analysis, absence of liver metastasis (Odds ratio [OR], 4.62; P = 0.019), smaller tumor diameter (OR, 7.92; P = 0.012) and tissue RAS MT in other than KRAS exon 2 (OR, 9.04; P = 0.026) were significantly related to the appearance of Neo RAS WT mCRC. Conclusions: Original RAS status in tissue, tumor diameter and liver metastasis are related to conversion to Neo RAS WT mCRC.

Real-world effectiveness and safety of trifluridine/tipiracil plus bevacizumab in metastatic colorectal cancer: A retrospective observational study using an administrative database

44

Background: Trifluridine/tipiracil (FTD/TPI) and regorafenib (REG) are standard of care for refractory metastatic colorectal cancer (mCRC). Several phase II trials of FTD/TPI plus bevacizumab (BEV) have been conducted, showing promising efficacy with manageable safety, and it is widely used for patients with refractory mCRC in Japan. No result has been reported for large-scale real-world data directly comparing FTD/TPI plus BEV with FTD/TPI or REG monotherapy. Here, we evaluated the efficacy and safety of FTD/TPI plus BEV in real-world clinical practice. Methods: We used a nationwide claims database provided by Medical Data Vision Co., Ltd. (Tokyo, Japan) in Japan. Eligible patients were aged 20 years or older in mCRC who received their first dose of FTD/TPI or REG between May 2014 and January 2021. The primary outcome was overall survival (OS) in a propensity score matching (PSM) population that was performed matching using a 1:1 ratio for FTD/TPI plus BEV and control group (FTD/TPI or REG) by propensity score. To enhance robustness, sensitivity analyses of OS were performed using the inverse probability treatment weighted (IPTW) approach and the analysis in all eligible population. Main secondary outcomes were OS for subgroups, time to treatment discontinuation (TTD), adverse events (assessed in all eligible population), and post-treatment. Results: The eligible population was 2,369 for FTD/TPI plus BEV and 9,318 for control group (FTD/TPI: 6,500 and REG: 2,818). The PSM population was 1,787 for FTD/TPI plus BEV and 1,787 for control group (FTD/TPI: 1,252 and REG: 535). Median OS (mOS) was 17.0 months for FTD/TPI plus BEV and 11.6 months for control group (HR: 0.70; 95% CI: 0.63–0.78; P < 0.001) in PSM population. Similarly, mOS was longer for FTD/TPI plus BEV compared to that for control group in IPTW analyses (HR: 0.68; 95% CI: 0.65–0.71; P < 0.001) and in all eligible population (HR: 0.68; 95% CI: 0.63–0.73; P < 0.001). In all eligible population, mOS were 17.6 months for FTD/TPI plus BEV and 12.6 months for control group (FTD/TPI: 12.9 months and REG: 12.1 months). Median TTD was 101 days for FTD/TPI plus BEV and 56 days for control group in PSM population (Wilcoxon rank-sum test P < 0.001). The incidence of hand-foot syndrome was significantly higher in REG compared with that in FTD/TPI plus BEV (Fisher's Exact test P < 0.001. Leukopenia incidence was significantly higher in FTD/TPI plus BEV than that in REG (Fisher's Exact test P < 0.001. Granulocyte colony-stimulating factor was administered to 20.6%, 16.5%, and 1.1% of patients in FTD/TPI plus BEV, FTD/TPI, and REG, respectively. Conclusions: The real-world data showed that FTD/TPI plus BEV had significantly longer OS and TTD than FTD/TPI or REG in mCRC. Thus, FTD/TPI plus BEV may be a favorable regimen for refractory mCRC in clinical practice.

Treatment efficacy of ramucirumab-containing chemotherapy in patients with alpha-fetoprotein producing gastric cancer

BACKGROUND

Alpha-Fetoprotein Producing Gastric Cancer (AFPGC) is an aggressive subgroup of gastric cancer. Recently ramucirumab has shown survival benefits in hepatocellular carcinoma, but only in those with higher Alpha-Fetoprotein (AFP) levels. However, the efficacy of ramucirumab-containing chemotherapy in AFPGC remains unclear.

METHODS

We retrospectively assessed 352 patients who received ramucirumab-containing chemotherapy between June 2015 and December 2019. AFPGC was defined when serum AFP levels were elevated at diagnosis and correlated with the disease state during treatment. Non-AFPGC was defined when serum AFP levels were normal at diagnosis.

RESULTS

Among the 352 patients, 28 patients were defined as AFPGC and 246 patients were defined as non-AFPGC. AFPGC was characterized by high frequency of liver metastasis and low frequency of peritoneal metastasis compared to non-AFPGC. Ramucirumab containing chemotherapy showed higher response rates in AFPGC (39.1% vs 24.8%, p = 0.198) and disease control rates (86.9% vs 61.5%, p = 0.028) than those of non-AFPGC, respectively. Median progression-free survival (PFS) was 5.5 months (95%CI 3.9-7.1) in AFPGC and 4.0 months (95%CI 3.6-4.6) in non-AFPGC (HR: 0.91, 95% CI 0.61-1.36, p = 0.66), and median overall survival (OS) was 10.7 months (95% CI 7.4-20.8) in AFPGC and 9.2 months (95% CI 8.1-10.4) in non-AFPGC (HR: 0.72, 95% CI 0.48-1.08, p = 0.11), respectively. In multivariate analysis, AFPGC was not a negative prognostic factor both for PFS and OS.

CONCLUSION

Ramucirumab containing chemotherapy showed higher response and comparable survival in AFPGC compared to those of non-AFPGC. Considering the generally poor prognosis of AFPGC, ramucirumab-containing chemotherapy might be a promising treatment option in AFPGC.

Implementation of microsatellite instability testing for the assessment of solid tumors in clinical practice

BACKGROUND

In Japan, microsatellite instability (MSI) testing for solid tumors was introduced in clinical practice in December 2018. Although immune checkpoint inhibitors (ICIs) are established standards of care for patients with MSI-high tumors, the status of implementing MSI testing in clinical practice remains unclear.

METHODS

We retrospectively reviewed the medical records of patients with solid tumors who underwent MSI testing between January 2019 and December 2020 at our institution.

RESULTS

In total, 1,052 MSI tests were performed in 1,047 patients. Regardless of specimen volume and condition, the MSI status was successfully determined in 1,041 (99.0%) tests, encompassing 27 tumor types (microsatellite stable [MSS] or MSI-low: n = 991 [95.2%] and MSI-high: n = 50 [4.8%]). Patients whose specimens were fixed with 20% neutral buffered formalin (NBF) and who had specimens with prolonged storage (98.4% and 95.4%) showed lower success rates than those whose specimens were fixed with 10% NBF and who had specimens with nonprolonged storage (100.0% and 99.6%), respectively. The prolonged turnaround time (TAT) in MSI-high cases (median TAT: 24 days) was a critical issue that directly resulted in treatment delay. Of the 50 patients with MSI-high tumors, 24 (48.0%) received ICIs and 34 (68.0%) were referred to the Department of Clinical Genetic Oncology where 6 (12.0%) patients were diagnosed with Lynch syndrome.

CONCLUSIONS

MSI testing was successfully performed for various types of tumors and specimens in clinical practice. Our study results identified certain issues associated with the clinical implementation of MSI testing, including optimal specimen selection, extended TAT in MSI-high cases, and awareness of hereditary tumors.

Druggable gene alterations in Japanese patients with rare malignancy

Without a current standard of care, patients with rare malignancy are subjected to precision oncology with next-generation sequencing to identify a course of treatment. We sought to establish the clinical relevance of comprehensive genomic profiling (CGP) among patients with rare malignancy. Rare malignancy was defined using the Rare Cancers in Europe definition (<6 cases per 100,000 individuals). We analyzed gene mutations, fusions, tumor mutational burden (TMB), and microsatellite instability (MSI) status. Level A gene alterations, categorized using Clinical Interpretations of Variants in Cancer and MD Anderson Knowledge Base for Precision Oncology, were considered druggable. Rare malignancy accounted for 149 (45%) cases, with female genital cancers (32%) most common. Among the rare malignancy cases, we identified a lower frequency of mutation in TP53 (41% vs. 60%, P<0.001), KRAS (13% vs. 43%, P<0.001) and APC (3% vs. 25%, P<0.001), and a higher frequency of ARID1A mutation (14% vs. 6%, P=0.03), as compared with common malignancies. TMB-high and MSI-high cases were found in 8% and 2% of cases, respectively. Druggable alterations were detected in 37 patients with rare malignancy; this percentage tended to be higher than that for patients with common malignancies (25% vs. 17%, P=0.08). Common druggable alterations were BRAF V600E, ERBB2 amplification, PIK3CA E542K, and BRCA1/2 variant. Five of the 37 patients with druggable alterations received genome-driven treatment. There was no significant difference in overall survival between the rare and common malignancy groups. Our results provide clues for future clinical development and treatment success among Japanese patients with rare cancers.

Multicentre single-arm phase II trial evaluating the safety and effiCacy of Panitumumab and iRinOtecan in NeoRAS Wild-type mEtaStatic colorectal cancer patientS (C-PROWESS trial): study protocol

INTRODUCTION

A new concept of 'NeoRAS wild-type (WT)', which means conversion of RAS status from RAS mutant to RAS WT after treatment, has been reported. Previous observational and proof-of-concept studies have demonstrated the efficacy of epidermal growth factor receptor inhibitors in patients with NeoRAS WT metastatic colorectal cancer (mCRC). Moreover, posthoc biomarker analyses of these studies have suggested that not only the RAS status in the circulating tumour DNA (ctDNA) but also other gene mutational status may be useful as biomarkers of epidermal growth factor receptor inhibitors for NeoRAS WT mCRC.

METHODS AND ANALYSIS

This trial is a multicentre, single-arm, phase II trial to assess the efficacy and safety of panitumumab plus irinotecan therapy for patients with NeoRAS mCRC. The key eligibility criteria include RAS mutant mCRC initially proven in tumour tissue refractory or intolerant to fluoropyrimidine, oxaliplatin and irinotecan; RAS WT in ctDNA (defined as plasma mutant allele frequencies of all RAS ≤0.1%) within 28 days before enrolment and Eastern Cooperative Oncology Group performance status ≤2. The primary endpoint is the response rate. The target sample size is 30 patients. Biomarker analyses are planned to be performed using next-generation sequencing-based ctDNA analysis.

ETHICS AND DISSEMINATION

This study was approved by the certified review board of National Cancer Center Hospital. The main results of the trial will be presented in international meetings and in medical journals.

TRIAL REGISTRATION NUMBER

s031210565.

Clinical Usefulness of Postoperative Serum Carcinoembryonic Antigen in Patients with Colorectal Cancer with Liver Metastases

BACKGROUND

Colorectal cancer with liver metastasis (CLM) has high postoperative recurrence rates; therefore, optimizing perioperative treatment is imperative. Postoperative carcinoembryonic antigen (CEA) can aid in detecting minimal residual disease in colon cancer following curative resection. This study aimed to identify the potential role of serum CEA following liver resection in patients with CLM.

METHODS

This retrospective study was conducted at the Cancer Institute Hospital of the Japanese Foundation for Cancer Research from 2004 to 2018 and enrolled patients with CLM who underwent complete resection of primary tumors and CLM. Associations between perioperative CEA levels and characteristics of recurrence were investigated.

RESULTS

Recurrence was detected during a median follow-up period of 90.1 months in 343 (54.2%) out of 633 analyzed patients. Patients in the postoperative CEA level > 5 ng/ml group had a significantly higher recurrence rate (75.7% versus 50.0%, p < 0.01) and shorter time until recurrence (4.4 versus 36.9 months, p < 0.01) than those in the postoperative CEA level ≤ 5 ng/ml group. Multivariate analysis revealed that postoperative CEA level > 5 ng/ml was an independent predictor, with hazard ratios of 2.77 (p < 0.01) for recurrence-free survival (RFS) and 3.18 (p < 0.01) for overall survival (OS). Additionally, RFS was significantly shorter among patients in the postoperative CEA level > 5 ng/ml group who did not have normalized CEA levels following adjuvant chemotherapy than among those in the normalized CEA group.

CONCLUSIONS

The postoperative and post-adjuvant chemotherapy CEA levels in the CEA level > 5 ng/ml group may be predictors of RFS and OS.

Clinical Activity of Mitogen-Activated Protein Kinase-Targeted Therapies in Patients With Non-V600 BRAF-Mutant Tumors

PURPOSE

Non-V600 mutations comprise approximately 35% of all BRAF mutations in cancer. Many of these mutations have been identified as oncogenic drivers and can be classified into three classes according to molecular characteristics. Consensus treatment strategies for class 2 and 3 BRAF mutations have not yet been established.

METHODS

We performed a systematic review and meta-analysis with published reports of individual patients with cancer harboring class 2 or 3 BRAF mutations from 2010 to 2021, to assess treatment outcomes with US Food and Drug Administration-approved mitogen-activated protein kinase (MAPK) pathway targeted therapy (MAPK TT) according to BRAF class, cancer type, and MAPK TT type. Coprimary outcomes were response rate and progression-free survival.

RESULTS

A total of 18,167 studies were screened, identifying 80 studies with 238 patients who met inclusion criteria. This included 167 patients with class 2 and 71 patients with class 3 BRAF mutations. Overall, 77 patients achieved a treatment response. In both univariate and multivariable analyses, response rate and progression-free survival were higher among patients with class 2 compared with class 3 mutations, findings that remain when analyses are restricted to patients with melanoma or lung primary cancers. MEK ± BRAF inhibitors demonstrated greater clinical activity in class 2 compared with class 3 BRAF-mutant tumors than BRAF or EGFR inhibitors.

CONCLUSION

This meta-analysis suggests that MAPK TTs have clinical activity in some class 2 and 3 BRAF-mutant cancers. BRAF class may dictate responsiveness to current and emerging treatment strategies, particularly in melanoma and lung cancers. Together, this analysis provides clinical validation of predictions made on the basis of a mutation classification system established in the preclinical literature. Further evaluation with prospective clinical trials is needed for this population.

Abstract 6027: Layered 3D co-cultured tumor model including vascularized stromal tissue may reflect drug sensitivities in vivo tumor

Background: Multiple 3D culture models have been reported as a superior tumor model than 2D culture. The importance of interaction between cancer and stromal cells has been widely recognized in tumor progression and resistance to treatment. Therefore, ex vivo model recapturing the tumor microenvironment is needed to evaluate the drug efficacy under the condition imitating the patient tumor tissue. Purpose: We developed a unique 3D co-cultured tumor model with stromal tissues containing a microvascular network. Here, we investigated drug sensitivity in conventional 2D culture, our 3D co-cultured model and in vivo tumor.

Methods: Drug sensitivity and gene expression on our model were evaluated using patient-derived cancer cells (PDC) established from colorectal cancer (CRC) patients in JFCR. The characteristics were compared with those of conventional 2D cultured cells or patient-derived xenograft (PDX).

Results: In our 3D model, the drug sensitivities tended to be decreased in comparison with those of 2D. However, some drugs presented potent efficacy in our 3D model rather than 2D, and such drugs showed significant tumor growth suppression or tumor regression in vivo. Transcriptome profiles of our 3D model showed relatively higher similarity to those of in vivo tumors than those of 2D.

Conclusion: Our study proposed the unique 3D co-cultured tumor model which may enable more accurate evaluation of drug sensitivities reflecting the in vivo circumstances.

Citation Format: Yuki Takahashi, Shiro Kitano, Eiji Shinozaki, Satoshi Nagayama, Ryohei Katayama, Naoya Fujita. Layered 3D co-cultured tumor model including vascularized stromal tissue may reflect drug sensitivities in vivo tumor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6027.

Abstract 5735: Druggable gene alterations in Japanese patients with rare malignancy

Background: In the absence of a current standard of care, precision oncology with next-generation sequencing provides an important therapeutic option for patients with rare malignancy. Here, we sought to establish the clinical relevancy of comprehensive genomic profiling (CGP) for patients with rare malignancy.

Methods: We reviewed 341 patients who underwent CGP (FoundationOne CDx; OncoGuide NCC OncoPanel System)in our institution between 2019 and 2021. Cases were classified as common or rare malignancy based on the Rare Cancers in Europe (RARECARE) definition (incidence of &lt;6 cases per 100,000 individuals). We analyzed the genomic features in the rare malignancy cohort, including gene mutations, gene fusions, tumor mutational burden (TMB), and microsatellite instability (MSI) status. Gene variants, amplifications, and fusions categorized as evidence level A using Clinical Interpretations of Variants in Cancer (CIViC) and MD Anderson Knowledge Base for Precision Oncology were considered as druggable alterations. CGP testing was used to calculate overall survival (OS) to death or at the last follow-up.

Results: With the exception of 7 unclassifiable cases, rare malignancy accounted for 149 of the 334 cases (45%), with the most common being female genital cancers (32%), followed by digestive cancers (24%), sarcoma (16%), and others (28%). Many (83%) of the patients with rare malignancy harbored at least one pathogenic/likely-pathogenic variant. The commonly mutated genes were TP53 (41%), PIK3CA (20%), ARID1A (14%), and KRAS (13%). ERBB2amplification was detected in 6% of patients (median copy number, 8). Gene fusion in EWSR1 was found in 4% of patients (sarcoma) and in FGFR2 in 1% (cholangiocarcinoma and salivary duct carcinoma). TMB-high (≥10 mut/Mb) and MSI-high cases were found in 8% and 2% of cases, respectively. Druggable alterations were detected in 36 patients; this percentage was not significantly different to that of common malignancy (24% vs. 17%, P=0.10). The common druggable alterations were BRAF V600E (n=10), ERBB2 amplification (n=9), PIK3CA E542K (n=6), and BRCA1/2 variant (n=6). There was no significant difference in OS between the rare and common malignancy groups (1-year OS rate: 62% vs. 46%, P=0.24).

Conclusion: In this study, the ratio of rare malignancy was higher than that typically found in previous epidemiological studies (about 20%-25%). We observed no adverse impact for OS, which might be due to the high number of patients (n=48) with intractable pancreatic cancer. Remarkably, &gt;20% of patients harbored a potential druggable alteration. Our results suggest the clinical relevance of CGP for patients with rare malignancy, and its potential utility to provide clues for future clinical development.

Citation Format: Akihiro Ohmoto, Naomi Hayashi, Ippei Fukada, Masumi Yamazaki, Mayu Yunokawa, Akiyoshi Kasuga, Eiji Shinozaki, Arisa Ueki, Akiko Tonooka, Kengo Takeuchi, Seiichi Mori, Kazuma Kiyotani, Shunji Takahashi. Druggable gene alterations in Japanese patients with rare malignancy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5735.

Clinical impact of DNA methylation status on first-line antiepidermal growth factor receptor treatment in patients with metastatic colorectal cancer

3528

Background: The CpG island methylator phenotype (CIMP), important for carcinogenesis, is a predictor of prognosis and chemotherapy sensitivity in colorectal cancer. However, there is a lack of consensus of CIMP markers, and thus, more comprehensive methylation markers are required to reliably predict the clinical outcomes. Previously, we reported that genome-wide DNAmethylation statuscould predict the effect of epidermal growth factor receptor (EGFR) inhibitors more accurately than previously reported methylation classifications (Ouchi et al. Cancer Sci 2015). Moreover, we had developed a DNA methylation assay based on MethyLight to reflect genome-wide DNA methylation status and reported its usefulness in predicting prognosis in patients with metastatic colorectal cancer (mCRC) treated with EGFR inhibitors as a third-line chemotherapy (Ouchi et al. Cancer Sci 2022). This study aimed to clarify the effects of genome-wide DNA methylation status on clinical outcomes in patients with mCRC treated with first-line EGFR inhibitors. Methods: We enrolled 241 patients with mCRC, who received chemotherapy plus EGFR inhibitors as a first-line treatment, and analyzed the associations between genome-wide DNA methylation status using a novel comprehensive methylation marker panel and clinical outcomes and evaluated the predictive power and value of the methylation status. Results: Total 169 patients were included in the final analyses. The frequency of highly methylated CRC (HMCC) was 8.9% (15/169). The characteristics of patients with HMCC included right-sided primary tumor location (P = 0.042), undifferentiated histology (P = 0.047), and BRAFV600E mutation (P < 0.001). Patients with HMCC showed worse clinical outcomes than those with low methylated CRC in terms of response rate (P = 0.017), progression-free survival (PFS; P = 0.004), and overall survival (P = 0.019). In the multivariate analysis, peritoneal metastasis (Hazard ratio (HR): 2.24, P = 0.017), methylation status (HR: 3.04, P = 0.037), and BRAFV600E mutations (HR: 5.83, P = 0.0001) were independent factors for shorter PFS. Conclusions: Genome-wide DNA methylation status may be an independent predictor of first-line EGFR inhibitors in patients with mCRC.

Real-World Data Analysis of Second-Line Antiangiogenic Targeted Treatments Following Anti-Epidermal Growth Factor Receptor Monoclonal Antibodies and First-Line FOLFOX for Patients with Metastatic Colorectal Cancer

Introduction

Evidence is lacking on second-line and later treatments for patients with RAS wild-type colorectal cancer (CRC) who receive first-line anti-epidermal growth factor receptor (EGFR) antibody therapy. In this study, we explored the real-world treatment sequences, treatment duration, and factors associated with treatment sequences and durations in Japanese patients with CRC.

Methods

This retrospective observational cohort study used a Japanese administrative claims database (April 2008 to July 2021). Patients with confirmed CRC (presumed RAS wild-type) who received first-line FOLFOX (leucovorin + 5-fluorouracil + oxaliplatin) plus anti-EGFR therapy in or after May 2016, followed by second-line irinotecan-based chemotherapy plus an antiangiogenic drug, were included. Treatment durations were estimated by the Kaplan–Meier method. Cox regression analysis was used to identify factors associated with treatment duration.

Results

Analysis populations consisted of 1163 (first-line and second-line) and 645 (third-line) patients. At the start of first-line therapy, 67.8% of patients were male, the mean age was 64 years, 83.4% had left-sided CRC, and 84.3% were prescribed FOLFOX plus panitumumab. For second-line therapy, patients were prescribed bevacizumab (63%), ramucirumab (27%), or aflibercept beta (10%). Median (95% CI) treatment durations from the start of second-line therapy to the end of antitumor drug therapies were similar for bevacizumab (12.5 months [11.2, 14.0]), ramucirumab (12.5 months [11.2, 14.8]), and aflibercept beta (14.0 months [10.4, 17.0]). Treatment duration from second-line was positively associated with first-line treatment duration of 6 months or more, CRC surgery before starting first-line therapy, and liver surgery during first-line therapy, and was negatively associated with use of nonsteroidal anti-inflammatory drugs before second-line therapy.

Conclusion

Real-world data revealed that all three antiangiogenic drugs were used as second-line therapy after first-line anti-EGFR antibodies and showed similar treatment durations.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-022-02122-4.

Plasma RAS dynamics and anti-EGFR rechallenge efficacy in patients with RAS/BRAF wild-type metastatic colorectal cancer: REMARRY and PURSUIT trials

3518

Background: Rechallenge with anti-EGFR monoclonal antibody (EGFR mAb) showed certain activities in patients (pts) with RAS/ BRAF V600E wild-type (wt) metastatic colorectal cancer (mCRC), particularly in pts with negative plasma RAS (p RAS) mutation by circulating-tumor DNA (ctDNA) assay at ‘just before’ the rechallenge therapy. However, the efficacy is unknown in pts with RAS/ BRAF wt mCRC whose p RAS was converted to positive once during or after EGFR mAb. Therefore, we conducted REMARRY, a prospective longitudinal study to investigate the p RAS dynamics, and PURSUIT trials, a phase II trial to investigate the efficacy of EGFR mAb rechallenge in pts with p RAS wt just before rechallenge therapy. Methods: The eligibility criteria of REMARRY trial included RAS/ BRAF V600E wt mCRC; ECOG PS 0-1; CR or PR during EGFR mAb; and a refractory ≤ 2 months from the last administration of EGFR mAb. p RAS status by the BEAMing method was prospectively monitored at timepoints of progression on EGFR mAb and each subsequent therapy. The eligibility criteria of PURSUIT trial included enrollment in the REMARRY trial with confirmed p RAS wt prior to enrollment in PURSUIT trial; being refractory or intolerant to fluoropyrimidine, oxaliplatin, and irinotecan; and ≥ 4 months of EGFR mAb-free interval. Study treatment was rechallenge with panitumumab + irinotecan (6 mg/kg + 150 mg/m2 q2wks). Primary endpoint was a confirmed objective response rate (ORR) according to RECIST v1.1. The required number of pts was 45, with a null ORR of 10%, an expected ORR of 25%, power of 85%, and one-sided α of 0.05. Results: Between May 2019 and May 2021, 183 pts with 343 timepoints (median, 2) were enrolled in REMARRY trial from 27 institutions, and 50 pts were enrolled in PURSUIT trial; median age, 68 years; left-sided primary, 44 pts; prior EGFR mAb, 1st/2nd/≥3rd lines was 28/6/16 pts; and p RAS status at progression on prior EGFR mAb, wt/mutant (mt)/unknown in 31/7/12 pts. Confirmed ORR and disease control rate were 14% (90% CI, 7.8%–23.9%) and 80% (95% CI, 67.0%–88.8%), respectively. In addition, 4 pts showed an unconfirmed PR. With a median follow-up time of 8.7 months, median progression-free survival was 3.6 months (95% CI, 3.0 – 4.7 months). The subgroup analysis showed a significantly higher confirmed ORR in pts with a longer EGFR mAb-free interval than a shorter one (> vs. < 365 days, 44.4% vs. 7.3%, p = 0.0037). Without any unexpected safety signals, 58.5% of pts had ≥ grade 3 adverse events. Of 31 patients with wt p RAS at progression on prior EGFR mAb, 5 had a confirmed response (ORR, 16%), whereas no response was observed in patients with 7 p RAS mt (ORR, 0%) (p = 0.25). Conclusions: The primary endpoint of confirmed ORR was not met; however, pts with p RAS wt at progression on prior EGFR mAb may benefit from rechallenge with, implying a lack of or worse response if p RAS becomes positive even once during or after EGFR mAb. Clinical trial information: REMARRY: UMIN000036424 PURSUIT: jRCTs031190096.

Effects of Metastatic Sites on Circulating Tumor DNA in Patients With Metastatic Colorectal Cancer

PURPOSE

Low concordance between plasma-based and tissue-based tests for determining the RAS mutational status have been reported in some but not all patients with limited-extent metastatic colorectal cancer (mCRC). In this study, we investigated the relationship between metastatic site and circulating tumor DNA (ctDNA) detection using ctDNA genotyping, an alternative to tissue genotyping for precision oncology.

MATERIALS AND METHODS

We investigated the relationship between metastatic site and ctDNA detection using Guardant360, a next-generation sequencing ctDNA assay, in mCRC patients with single-organ metastasis in the SCRUM-Japan GOZILA study (UMIN000029315).

RESULTS

Of 1,187 patients with mCRC enrolled in GOZILA, 138 were eligible (49 with liver-only, 15 with lymph node-only, 27 with peritoneum-only, and 47 with lung-only metastases). The concordance of RAS/BRAF status between Guaradant360 and tissue in vitro diagnostic tests was 95.9% in patients with liver-only, 80.0% in lymph node-only, 56.0% in peritoneum-only, and 65.9% in lung-only metastases. ctDNA fraction, as measured by the median maximum variant allelic fraction (max VAF), and median number of detected variants were 23.1% and five in liver-only, 6.0% and five in lymph node-only, 0.4% and three in peritoneum-only, and 0.4% and three in lung-only metastases, respectively (all P < .001, Kruskal-Wallis test). Few patients with liver-only (2.0%) and lymph node-only metastasis (13.3%) had a max VAF < 0.2%, which is required to ensure a detection limit of 95%, but max VAF was more frequently < 0.2% in patients with lung-only (27.7%) or peritoneum-only metastasis (29.6%).

CONCLUSION

Patients with lung-only and peritoneum-only metastatic disease have significantly lower levels of ctDNA, suggesting decreased clinical sensitivity for subclonal variants. This observation suggests that such patients may benefit from concurrent tissue and plasma testing to provide optimal genotyping for subsequent therapy selection.

Non-operative management after chemoradiotherapy plus consolidation or sandwich (induction with bevacizumab and consolidation) chemotherapy in patients with locally advanced rectal cancer: a multicentre, randomised phase II trial (NOMINATE trial)

INTRODUCTION

Total mesorectal excision (TME) and postoperative adjuvant chemotherapy following neoadjuvant chemoradiotherapy (CRT) is the standard treatment for locally advanced rectal cancer (LARC). However, neoadjuvant CRT has no recognised impact on reducing distant recurrence, and patients suffer from a long-lasting impairment in quality of life (QOL) associated with TME. Total neoadjuvant therapy (TNT) is an alternative approach that could reduce distant metastases and increase the proportion of patients who could safely undergo non-operative management (NOM). This study is designed to compare two TNT regimens in the context of NOM for selecting a more optimal regimen for patients with LARC.

METHODS AND ANALYSIS

NOMINATE trial is a prospective, multicentre, randomised phase II selection design study. Patients must have clinical stage II or III (T3-T4Nany) LARC with distal location (≤5 cm from the anal verge or for those who are candidates for abdominoperineal resection or intersphincteric resection). Patients will be randomised to either arm A consisting of CRT (50.4 Gy with capecitabine) followed by consolidation chemotherapy (six cycles of CapeOx), or arm B consisting of induction chemotherapy (three cycles of CapeOx plus bevacizumab) followed by CRT and consolidation chemotherapy (three cycles of CapeOx). In the case of clinical complete response (cCR) or near cCR, patients will progress to NOM. Response assessment involves a combination of digital rectal examination, endoscopy and MRI. The primary endpoint is the proportion of patients achieving pathological CR or cCR≥2 years, defined as the absence of local regrowth within 2 years after the start of NOM among eligible patients. Secondary endpoints include the cCR rate, near cCR rate, rate of NOM, overall survival, distant metastasis-free survival, locoregional failure-free survival, time to disease-related treatment failure, TME-free survival, permanent stoma-free survival, safety of the treatment, completion rate of the treatment and QOL. Allowing for a drop-out rate of 10%, 66 patients (33 per arm) from five institutions will be accrued.

ETHICS AND DISSEMINATION

The study protocol was approved by Wakayama Medical University Certified Review Board in December 2020. Trial results will be published in peer-reviewed international journals and on the jRCT website.

TRIAL REGISTRATION NUMBER

jRCTs051200121.

Clinical Validity of Plasma-Based Genotyping for Microsatellite Instability Assessment in Advanced GI Cancers: SCRUM-Japan GOZILA Substudy

PURPOSE

Circulating tumor DNA (ctDNA) genotyping may guide targeted therapy for patients with advanced GI cancers. However, no studies have validated ctDNA genotyping for microsatellite instability (MSI) assessment in comparison with a tissue-based standard.

PATIENTS AND METHODS

The performance of plasma-based MSI assessment using Guardant360, a next-generation sequencing–based ctDNA assay, was compared with that of tissue-based MSI assessment using a validated polymerase chain reaction–based method in patients with advanced GI cancers enrolled in GOZILA study, a nationwide ctDNA profiling study. The primary end points were overall percent agreement, positive percent agreement (PPA), and negative percent agreement. The efficacy of immune checkpoint inhibitor therapy was also evaluated.

RESULTS

In 658 patients with advanced GI cancers who underwent both plasma and tissue testing for MSI, the overall percent agreement, PPA, and negative percent agreement were 98.2% (95% CI, 96.8 to 99.1), 71.4% (95% CI, 47.8 to 88.7), and 99.1% (95% CI, 98.0 to 99.7), respectively. In patients whose plasma samples had a ctDNA fraction ≥ 1.0%, the PPA was 100.0% (15/15; 95% CI, 78.2 to 100.0). Three patients with MSI-high (MSI-H) tumors detected only by ctDNA genotyping achieved clinical benefits after receiving anti–programmed cell death 1 therapy with the progression-free survival ranging from 4.3 to 16.7 months. One patient with an aggressive cancer of an unknown primary site benefited from pembrolizumab after rapid detection of MSI-H by ctDNA genotyping.

CONCLUSION

ctDNA genotyping was able to detect MSI with high concordance to validated tissue-based MSI testing, especially in patients with tumors that have sufficient ctDNA shedding. Furthermore, ctDNA genotyping enabled identification of patients with MSI-H tumors who benefited from immune checkpoint inhibitor treatment.

Clinical usefulness of postoperative serum carcinoembryonic antigen in colorectal cancer patients with liver metastases

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Background: Colorectal cancer with liver metastases (CLM) has high post operative recurrence rates, and optimizing the perioperative treatment is imperative. Post operative carcinoembryonic antigen (CEA) can help detecting minimal residual disease in colon cancer after curative resection. Methods: The aim of this study was to identify the potential role of serum CEA after liver resection in patients with CLM. This study was conducted at the Cancer Institute Hospital, Japanese Foundation for Cancer Research from 2004 to 2018. Patients with CLM who underwent complete resection of primary tumors and liver metastases were enrolled in this study. We studied the associations between the perioperative CEA levels and characteristics of recurrence. Results: Recurrence was detected during the median follow-up time of 50.9 months in 343 (54.1%) of the total 633 patients analyzed. Patients with postoperative CEA (>5) group had a significantly higher recurrence rate (75.7% vs 50.0%, p < 0.01), with a shorter time until recurrence (4.4 months vs 36.9 months, p < 0.01) than those with a postoperative CEA level (≤5) group. In multivariate analysis, a postoperative CEA level >5 ng/ ml was an independent predictor, with the highest hazard ratio for both recurrence free survival (RFS) and overall survival (OS) (RFS: 2.77, 95% confidence interval [CI] 2.14–3.60, p <0.01, OS: 3.18, 95% CI 2.41–4.19, p <0.01). In addition, there was a significantly shorter RFS in the postoperative CEA level (>5) group who did not have normalized CEA levels after adjuvant chemotherapy compared to normalized CEA group (3.3 months vs 18.5 months, p = 0.008). Conclusions: The postoperative CEA and postadjuvant chemotherapy CEA level in the CEA level (>5) group after surgery may be a predictor of RFS and OS.

Real-world data analysis of antiangiogenic targeted treatments in second-line following anti-EGFR antibodies and FOLFOX in first-line for patients with metastatic colorectal cancer

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Background: Three antiangiogenic (AA) drugs, bevacizumab (BEV), ramucirumab (RAM) and aflibercept (AFL) are recommended as the second-line (2L) treatment for metastatic colorectal cancer (mCRC) in the CRC treatment guidelines of multiple countries and regions including the US, EU and Japan. However, little evidence of 2L RAM and AFL after anti-EGFR antibodies (EGFRab) in first- line (1L) has been reported. This study assessed treatment sequence for mCRC patients who received 2L irinotecan-based chemotherapy with AA drug after FOLFOX + EGFRab in 1L, treatment duration from the start of 2L to the end of last treatment line (treatment duration from 2L) and factors associated with the treatment duration from 2L. Methods: This is a real-world observational study using a hospital-based claims database of 393 hospitals in Japan. The mCRC patients who started 1L treatment with FOLFOX + EGFRab between May 2016 and Sep 2019 (identification period) and further treated with irinotecan-based chemotherapy + AA drug were enrolled. The key outcomes were the treatment sequence, treatment duration from 2L by AA drug, and factors associated with the treatment duration from 2L. Survival curves were estimated using the Kaplan–Meier method. Associated factors were investigated using Cox regression analysis. Results: Among 2,453 patients with 1L FOLFOX + EGFRab during the identification period, 506 patients who received the intended 2L therapies were enrolled in this study (mean age 63.5 years, male 66.6%). Number (%) of patients who used BEV, RAM and AFL in 2L was 345 (68.2), 120 (23.7) and 41 (8.1), respectively. Patient characteristics involving tumor location, metastatic site and prior anti-tumor therapy before starting 2L were similar among BEV, RAM and AFL. The treatment duration from 2L (median month and its 95%CI) was 11.1 (10.2-12.5) in the overall population and was similar among the patients who received BEV (10.8 [9.9-13.1]), RAM (11.2 [10.0-14.2]) and AFL (12.8 [6.9-NA]) in 2L. The treatment duration from 2L (median month and its 95%CI) for the patients who took or didn’t take proteinuria tests during 2L was 12.5 (11.1-15.2) and 8.5 (6.5-11.2), respectively. Factors positively associated with treatment duration from 2L were left-sided CRC (HR [95%CI] = 0.71 [0.53-0.96]) and ≥6 months of 1L duration (0.72 [0.56-0.93]); having renal disease (1.92 [1.28-2.88]) or received NSAIDs (1.63 [1.25-2.13]) within 60 days before starting 2L were associated negatively. Conclusions: The real-world data revealed that treatment duration were similar among BEV, RAM and AFL in 2L after EGFRab. Tumor location and 1L duration were associated with the treatment duration from 2L positively, while negative association was observed with renal disease and received NSAIDs. Treatment management was important for treatment continuation.

OUP accepted manuscript

Background

In the past decade, several successful clinical trials provided new therapeutic agents approved for advanced gastric cancer (AGC). This study evaluated whether these practice-changing results actually altered the clinical practice.

Patients and Methods

We retrospectively reviewed medical records of treatment-naive AGC patients who received combination chemotherapy of fluoropyrimidine and platinum between 2007 and 2018 and divided them into three groups: Groups A (2007-10), B (2011-14), and C (2015-2018), respectively. We compared the clinicopathological features, treatment details, and clinical outcomes among the three groups.

Results

In total, 1004 consecutive patients were enrolled (A; n = 254, B; n = 300, and C; n = 450). The number of patients with poor performance status, older age, esophagogastric junction adenocarcinoma, and primary tumor increased during the study period. All groups had similar median overall survival (OS); ~16 months) without any statistical difference but steady prolongation of survival was observed in the adjusted with imbalance prognostic factors among groups (B/A; hazard ratio, HR 0.82, 95% C.I 0.68-0.98, C/A; HR 0.72, 95% CI 0.60-0.86); OS of HER2-positive AGC patients was clearly improved (HER2-positive vs HER2-negative in Group B, HR 0.80, 95% CI 0.60-1.06; Group C, HR 0.68, 95% CI 0.51-0.90) but that of diffuse-type AGC patients remained dismal.

Conclusions

The increasing availability of chemotherapy options potentially contributed to improved survival of AGC patients, but expanded chemotherapeutic indications made the survival benefit inconspicuous in the whole population. Future therapeutic development for the AGC subset not adequately receiving benefit from previous clinical trials is warranted.

A modified MethyLight assay predicts the clinical outcomes of anti-EGFR treatment in metastatic colorectal cancer

DNA methylation status correlates with clinical outcomes of anti‐epidermal growth factor receptor (EGFR) treatment. There is a strong need to develop a simple assay for measuring DNA methylation status for the clinical application of drug selection based on it. In this study, we collected data from 186 patients with metastatic colorectal cancer (mCRC) who had previously received anti‐EGFR treatment. We modified MethyLite to develop a novel assay to classify patients as having highly methylated colorectal cancer (HMCC) or low‐methylated colorectal cancer (LMCC) based on the methylation status of 16 CpG sites of tumor‐derived genomic DNA in the development cohort (n = 30). Clinical outcomes were then compared between the HMCC and LMCC groups in the validation cohort (n = 156). The results showed that HMCC had a significantly worse response rate (4.2% vs 33.3%; P = .004), progression‐free survival (median: 2.5 vs 6.6 mo, P < .001, hazard ratio [HR] = 0.22), and overall survival (median: 5.6 vs 15.5 mo, P < .001, HR = 0.23) than did LMCC in patients with RAS wild‐type mCRC who were refractory or intolerable to oxaliplatin‐ and irinotecan‐based chemotherapy (n = 101). The DNA methylation status was an independent predictive factor and a more accurate biomarker than was the primary site of anti‐EGFR treatment. In conclusion, our novel DNA methylation measurement assay based on MethyLight was simple and useful, suggesting its implementation as a complementary diagnostic tool in a clinical setting.

Correlation between circulating tumor DNA and carcinoembryonic antigen levels in patients with metastatic colorectal cancer

Background

Circulating tumor DNA (ctDNA) is a biomarker with potential to reflect comprehensive genomic information and overcome intratumor heterogeneity. In contrast, carcinoembryonic antigen (CEA) is a conventional tumor marker for predicting recurrence, survival, and chemotherapeutic efficacy in patients with metastatic colorectal cancer (mCRC). However, the relationship between them remains unclear. Here, the relationship between plasma ctDNA and CEA levels was evaluated to clarify the advantages and disadvantages of their clinical use.

Methods

A total of 110 patients with mCRC underwent chemotherapy were enrolled. Amplicon‐based plasma genomic profiling of 14 genes that are commonly mutated in CRC by next‐generation sequencing was compared to the CEA level and tumor diameter using Spearman’s correlation coefficient.

Results

The overall concordance rate between the ctDNA and CEA levels was 75.5% (83/110). The correlation coefficient between the ctDNA and CEA levels was lower in the group of patients without liver and lymph node metastases (r = 0.18, p = 0.44) than in the group of patients with liver metastasis (r = 0.48, p < 0.0001). Although the correlation coefficients between tumor diameter and both ctDNA and CEA levels were high in the group of patients with liver metastasis, only the CEA correlation coefficient was maintained in the group of patients without liver and lymph node metastases (r = 0.53, p = 0.01). The characteristics that influenced discordance were liver metastasis and the sum of tumor diameter.

Conclusions

The status of ctDNA and CEA may not be consistent in patients with mCRC without liver metastasis or with a low tumor volume; both results should be considered when deciding a treatment strategy.