ARAF mutations confer resistance to the RAF inhibitor belvarafenib in melanoma.

Although RAF monomer inhibitors (type I.5, BRAF(V600)) are clinically approved for the treatment of BRAFV600-mutant melanoma, they are ineffective in non-BRAFV600 mutant cells1-3. Belvarafenib is a potent and selective RAF dimer (type II) inhibitor that exhibits clinical activity in patients with BRAFV600E- and NRAS-mutant melanomas. Here we report the first-in-human phase I study investigating the maximum tolerated dose, and assessing the safety and preliminary efficacy of belvarafenib in BRAFV600E- and RAS-mutated advanced solid tumours (NCT02405065, NCT03118817). By generating belvarafenib-resistant NRAS-mutant melanoma cells and analysing circulating tumour DNA from patients treated with belvarafenib, we identified new recurrent mutations in ARAF within the kinase domain. ARAF mutants conferred resistance to belvarafenib in both a dimer- and a kinase activity-dependent manner. Belvarafenib induced ARAF mutant dimers, and dimers containing mutant ARAF were active in the presence of inhibitor. ARAF mutations may serve as a general resistance mechanism for RAF dimer inhibitors as the mutants exhibit reduced sensitivity to a panel of type II RAF inhibitors. The combination of RAF plus MEK inhibition may be used to delay ARAF-driven resistance and suggests a rational combination for clinical use. Together, our findings reveal specific and compensatory functions for the ARAF isoform and implicate ARAF mutations as a driver of resistance to RAF dimer inhibitors.

Exploring Molecular Genetic Alterations and RAF Fusions in Melanoma: A Belvarafenib Expanded Access Program in Patients with RAS/RAF-Mutant Melanoma.

BACKGROUND: Melanoma incidence is on the rise in East Asia, yet studies of the molecular landscape are lacking in this population. We examined patients with melanoma who underwent next-generation sequencing (NGS) at a single tertiary center in South Korea, focusing on patients harboring NRAS or RAF alterations who received belvarafenib, a pan-RAF dimer inhibitor, through the Expanded Access Program (EAP). PATIENTS AND METHODS: Data were collected from 192 patients with melanoma who underwent NGS between November 2017 and May 2023. Variant call format data were obtained and annotated. Patients in the EAP received 450 mg twice daily doses of belvarafenib. RESULTS: Alterations in the RAS/RTK pathway were the most prevalent, with BRAF and NRAS alteration rates of 22.4% and 17.7%, respectively. NGS enabled additional detection of fusion mutations, including 6 BRAF and 1 RAF1 fusion. Sixteen patients with NRAS or RAF alterations received belvarafenib through the EAP, and disease control was observed in 50%, with 2 patients demonstrating remarkable responses. CONCLUSIONS: Our study highlights the value of NGS in detecting BRAF, NRAS mutations and RAF fusions, expanding possibilities for targeted therapies in malignant melanoma. Belvarafenib showed clinical benefit in patients harboring these alterations. Ongoing trials will provide further insights into the safety and efficacy of belvarafenib.

Real-world outcomes of third-line immune checkpoint inhibitors versus irinotecan-based chemotherapy in patients with advanced gastric cancer: a Korean, multicenter study (KCSG ST22-06).

BACKGROUND: Immune checkpoint inhibitor (ICI) or irinotecan-based chemotherapy is frequently used after failure of second-line paclitaxel plus ramucirumab treatment for patients with locally advanced unresectable or metastatic advanced gastric cancer (AGC). This study aimed to compare the efficacy between ICI and irinotecan-based chemotherapy as third-line treatment in patients with AGC. METHODS: We retrospectively reviewed patients with AGC, whose third-line treatment started between July 2019 and June 2021 at 17 institutions in Korea. The ICI group included patients who received nivolumab or pembrolizumab, and the irinotecan-based chemotherapy group included patients who received irinotecan or FOLFIRI (5-fluorouracil, leucovorin and irinotecan). RESULTS: A total of 363 patients [n = 129 (ICI) and n = 234 (irinotecan-based chemotherapy)] were analyzed. The median progression-free survival was 2.3 and 2.9 months in ICI and irinotecan-based chemotherapy groups, respectively (p = 0.802). The median overall survival (OS) was 5.5 and 6.0 months in ICI and irinotecan-based chemotherapy groups, respectively (p = 0.786). For all patients included in this study, multivariable analysis showed that weight loss, peritoneal metastasis, low serum sodium or albumin, and short duration of second-line treatment were associated with inferior OS (p < 0.05). ICI showed significantly longer OS than irinotecan-based chemotherapy in patients without peritoneal metastasis. Whereas ICI showed significantly shorter OS in patients without PD-L1 expression than irinotecan-based chemotherapy. CONCLUSIONS: No significant difference in survival outcome was observed between ICI and irinotecan-based chemotherapy as third-line treatment for AGC patients. ICI might be preferred for patients without peritoneal metastasis and irinotecan-based chemotherapy for patients with tumors without PD-L1 expression. TRIAL REGISTRATION: This study was registered in the Clinical Trial Registry of Korea ( https://cris.nih.go.kr : KCT 0007732).

Second-line chemoimmunotherapy with nivolumab and paclitaxel in immune-related biomarker-enriched advanced gastric cancer: a multicenter phase Ib/II study.

BACKGROUND: We conducted a trial to evaluate the efficacy and safety of nivolumab and paclitaxel as second-line therapy for immune-related biomarker-enriched advanced gastric cancer (AGC). METHODS: This open-label, single-arm, phase Ib/II study was a part of multi-institutional, biomarker-integrated umbrella study conducted in Korea. In phase Ib, patients received nivolumab (3 mg/kg) on Days 1 and 15 and paclitaxel (dose level 1, 70 mg/m2 or dose level 2, 80 mg/m2) on Days 1, 8, 15 every four weeks. In phase II, patients with Epstein-Barr virus-related, deficient mismatch repair or programmed cell death-ligand-1-positive AGC were enrolled. The primary endpoints were recommended phase II dose (RP2D, phase Ib) and progression-free survival (PFS, phase II). Secondary endpoints included objective response rate (ORR), overall survival (OS), safety, and exploratory biomarker analysis. RESULTS: Dose level 2 was selected as RP2D. In phase II, 48 patients were enrolled. The median PFS and OS were 3.9 and 11.2 months, respectively. The ORR was 23.3%, and the median response duration was 16.7 months. Grade 3 or higher treatment-related adverse events, mainly neutropenia, occurred in 20 patients (41.7%). Targeted sequencing revealed that patients with RTK/RAS pathway alterations or the HLA-A02 supertype had better survival. Patients with elevated baseline interleukin-1 receptor antagonist levels had worse survival. CONCLUSIONS: Although the study did not meet its primary end point, nivolumab and paclitaxel for AGC demonstrated a durable response with manageable toxicity profiles. Genomic analysis or plasma cytokine analysis may provide information for the selection of patients who would benefit more from immunotherapy combined with chemotherapy.

First-line pembrolizumab versus dabrafenib/trametinib treatment for BRAF V600-mutant advanced melanoma.

BACKGROUND: Limited data are available to assist the selection between immune checkpoint inhibitors and BRAF/mitogen-activated protein kinase kinase inhibitors as first-line treatment for patients with BRAF-mutant advanced malignant melanoma. OBJECTIVE: To investigate the outcomes associated with first-line pembrolizumab or dabrafenib/trametinib treatment for advanced melanoma with activating BRAF V600 mutation. METHODS: Data of patients with BRAF V600-mutant melanoma who were treated with first-line pembrolizumab (n = 40) or dabrafenib/trametinib (n = 32) were analyzed. Tumor response, progression-free survival, and overall survival were evaluated. Immune evasion accompanied with emerging resistance to BRAF/mitogen-activated protein kinase kinase inhibitors was assessed. RESULTS: A longer overall survival was observed after first-line pembrolizumab treatment than after first-line dabrafenib/trametinib treatment (hazard ratio = 2.910, 95% CI: 1.552-5.459), although there were no significant differences in progression-free survival (P = .375) and response rate (P = .123). Emergence of resistance to dabrafenib/trametinib co-occurred with immune evasion, enabling melanoma cells to escape recognition and killing by Melan-A-specific CD8+ T cells. LIMITATIONS: Analysis was conducted in a retrospective manner. CONCLUSION: Pembrolizumab may be recommended over BRAF/mitogen-activated protein kinase kinase inhibitors as the first-line treatment in patients with advanced BRAF V600-mutant melanoma.

Phase 2 study of TAS-117, an allosteric akt inhibitor in advanced solid tumors harboring phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene homolog gene mutations.

TAS-117 is a potent and selective allosteric pan-v-akt murine thymoma viral oncogene homolog (Akt) inhibitor. We conducted a single-arm single-center phase 2 study of TAS-117 in heavily treated patients with tumors refractory to systemic chemotherapy and harboring phosphatidylinositol 3-kinase (PI3K)/Akt mutations. Patients with gastrointestinal (GI) cancers were orally administered 16 mg TAS-117 daily, and those with non-GI tumors were administered 24 mg on a 4 days on/3 days off schedule. The primary endpoint was overall response rate (ORR). Secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS), PFS ratio, safety, and tolerability. Thirteen patients were enrolled: eight with non-GI (breast, ovarian, endometrial, and non-small cell lung) and five with GI (colon, rectal, gastric, and gallbladder) cancers. Ten patients were treated with TAS-117 after ≥ 4 lines of therapy. Twelve patients showed PIK3 catalytic subunit alpha (PIK3CA) mutations; one harbored an Akt1E17K mutation. The median treatment duration was 1.4 months; the median number of treatment cycles was 2. The ORR was 8 %, and DCR was 23 %. The median PFS and OS were 1.4 and 4.8 months, respectively. Grade 3-4 treatment-related adverse events were anorexia (grade 3, 8 %) and hyperglycemia (grade 3, 8 %; grade 4, 8 %).Grade 3-4 treatment-related adverse events occurred in 27 % of grade 3 anorexia (9 %) and hyperglycemia (grade 3, 8 %; grade 4, 9\%). TAS-117 showed limited antitumor activity and manageable toxicity. Clinical efficacy was observed in patients with ovarian cancer harboring PIK3CA E545K mutations and in patients with breast cancer harboring PIK3CA H1047R and Akt1E17K mutations.Trial registration: This study was retrospectively registered with ClinicalTrial.gov (NCT03017521 on January 11, 2017).

Objectively measured physical activity during chemotherapy in colon cancer patients.

PURPOSE: Although adjuvant chemotherapy can have an impact on physical activity (PA), PA level has not been studied in patients with stage II-III colon cancer. This study investigated PA levels during and between chemotherapy cycles. METHODS: We objectively measured PA levels for 2 weeks during the 2nd and 11th chemotherapy cycles. In addition, self-reported PA levels were assessed before chemotherapy initiation, during 2nd, 6th, and 12th chemotherapy cycles. This study included 22 men and 33 women with stage II-III colon cancer patients (57 ± 9 years). RESULTS: Before the initiation of chemotherapy, most cancer patients were minimally active. Compared with the 1st week of chemotherapy, moderate- and light-intensity PA levels significantly increased during the 2nd week of chemotherapy. Patients increased moderate- and light-intensity PA from 217.4 to 290.3 min per week and from 585.7 to 657.8 min per week, respectively (p < 0.01). PA levels did not show any difference between the 2nd and 12th cycles when objectively measured, or between baseline and 2nd, 6th, and 12th cycles when self-reported. CONCLUSION: PA levels during chemotherapy cycles are initially low, and then increase towards the end of the cycle; however, PA levels do not change between chemotherapy cycles. Future work with broader and larger samples size is recommended.

Inhibiting casein kinase 2 overcomes paclitaxel resistance in gastric cancer.

PURPOSE: Casein kinase (CK) 2 activation has been implicated in the proliferation of various tumor types and resistance to chemotherapy. We investigated the mechanistic basis for the association between CK2 activation and paclitaxel resistance in a gastric cancer (GC). EXPERIMENTAL DESIGN: CK2 expression was evaluated in 59 advanced GC patients treated with paclitaxel as the second-line therapy. The efficacy of a CK2 inhibitor, CX-4945, and paclitaxel was evaluated in GC cell lines and a xenograft model. RESULTS: Patients with high CK2 expression (29/59, 39%) showed lower disease control rates (47.7% vs. 72.3%, p = 0.017) and shorter progression-free survival (2.8 vs. 4.8 months, p = 0.009) than patients with low CK2 expression. CK2 protein expression was associated with sensitivity to paclitaxel in 49 GC cell lines. Combination therapy with CX-4945 and paclitaxel exerted synergistic antiproliferative effects and inhibited the downregulation of phosphatidylinositol 3-kinase/AKT signaling in SNU-1 cells. In the SNU-1 xenograft model, the combination treatment was significantly superior to either single agent, suppressing tumor growth without notable toxicities. CONCLUSIONS: These results demonstrated that CK2 activation was related to paclitaxel resistance and that CX-4945 in combination with paclitaxel could be used as a potential treatment for paclitaxel resistance in GC.

Marked Loss of Muscle, Visceral Fat, or Subcutaneous Fat After Gastrectomy Predicts Poor Survival in Advanced Gastric Cancer: Single-Center Study from the CLASSIC Trial.

BACKGROUND: There is increasing interest in the influence of body composition on oncological outcomes. We evaluated the role of skeletal muscle and fat among patients with gastric cancer (GC) who underwent gastrectomy with or without adjuvant chemotherapy, as well as those changes' associations with survival outcomes. METHODS: The present study evaluated 136 patients with GC who were enrolled in the CLASSIC Trial at Yonsei Cancer Center. Baseline body compositions including skeletal muscle area, Hounsfield units (HU), visceral fat area, and subcutaneous fat area were measured by preoperative computed tomography (CT). CT before and after the gastrectomy were used to determine the 6-month relative changes in body composition parameters. Continuous variables were dichotomized according to the best cutoff values by Contal and O'Quigley method. RESULTS: Seventy-three patients (53.7%) underwent surgery alone, and 63 patients (46.3%) underwent surgery followed by adjuvant chemotherapy. The baseline body composition parameters were not associated with disease-free survival (DFS) or overall survival (OS). Except for the HU, the marked loss of muscle, visceral fat, or subcutaneous fat significantly predicted shorter DFS and OS. Patients with a marked loss in at least one significant body composition parameter had significantly shorter DFS (hazard ratio 2.9, 95% confidence interval 1.7-4.8, P < 0.001) and OS (hazard ratio 2.9, 95% confidence interval 1.7-5.0, P < 0.001). CONCLUSIONS: Marked loss in body composition parameters significantly predicted shorter DFS and OS among patients with GC who underwent gastrectomy. Postoperative nutrition and active healthcare interventions could improve the prognosis of these GC patients.

Multidisciplinary treatment for patients with stage IV gastric cancer: the role of conversion surgery following chemotherapy.

BACKGROUND: With advances in gastric cancer chemotherapy, conversion surgery has drawn attention as a new strategy to improve the outcome of stage IV disease. We investigated the efficacy of conversion surgery following chemotherapy for patients with stage IV gastric cancer. METHODS: We retrospectively reviewed clinico-pathologic variables and oncologic outcomes for 101 patients with stage IV gastric cancer who were treated with systemic chemotherapy followed by gastrectomy with intension of curative resection from January 2005 to December 2012. RESULTS: In terms of the best response from palliative chemotherapy, complete or partial response were observed in 65 patients (64.4%) in overall. Complete response of metastatic site were observed in 72 (71.3%) and 66 (65.3%) patients as best and pre-operative response, respectively. The overall complete macroscopic resection, rate was 56.4%. Eleven patients (10.9%) received combined metastasectomy. There was no postoperative surgery-related mortality for 1 month. The median overall survival time was 26.0 months. Multivariable analysis identified complete macroscopic resection, chemotherapy response (complete response/partial response) of metastatic sites, and change in CEA level as independent prognostic factors contributing to overall survival. CONCLUSIONS: Patients with stage IV gastric cancer who exhibit a good clinical response to chemotherapy might obtain greater survival benefit from gastrectomy following chemotherapy compared with patients who exhibit a poor response to chemotherapy. Prospective, randomized trials are required to determine the best strategy for combining initial chemotherapy with subsequent gastrectomy.

The prognostic value of volume-based parameters using 18F-FDG PET/CT in gastric cancer according to HER2 status.

BACKGROUND: We aimed to find the clinical value of metastatic tumor burden evaluated with F18-FDG PET/CT in gastric cancer patients, considering the human epidermal growth factor receptor 2 (HER2) status. METHODS: We retrospectively reviewed 124 patients with locally advanced or metastatic gastric cancer at Yonsei Cancer Center between January 2006 and December 2014 who had undergone baseline FDG PET/CT before first-line chemotherapy. We measured the maximum standardized uptake value from the primary tumor (SUVmax) and whole-body (WB) PET/CT parameters, including WB SUVmax, WB SUVmean, WB metabolic tumor volume (WB MTV), and WB total lesion glycolysis (WB TLG), in all metabolically active metastatic lesions (SUV threshold ≥2.5 or 40% isocontour for ≤2.5), and we determined their association with patient survival outcomes. RESULTS: SUVmax was higher in HER2-positive gastric cancers (median 12.1, range 3.4-34.6) compared to HER-2 negative (7.4, 1.6-39.1, P < 0.001). Among all patients, WB TLG > 600, which is indicative of a high metastatic tumor burden, showed worse progression-free survival (PFS) [hazard ratio (HR), 2.003; 95% CI, 1.300-3.086; P = 0.002] and overall survival (OS) (HR, 3.001; 95% CI, 1.950-4.618; P < 0.001) than did WB TLG ≤ 600. Among HER2-positive gastric cancer patients treated with trastuzumab, higher metabolic tumor burden predicted worse OS, but not PFS. CONCLUSIONS: HER2-positive gastric cancers had higher SUVmax compared to HER2-negative gastric cancers. In both HER2-negative patients and -positive patients receiving trastuzumab, FDG PET/CT volume-based parameters may have a role in further stratifying the prognosis of stage IV gastric cancer.

Phase II study of oxaliplatin, irinotecan and S-1 therapy in patients with advanced gastric cancer: the Korean Cancer Study Group ST14-11.

BACKGROUND: Doublet chemotherapy of platinum and 5-fluorouracil is a standard first-line treatment for patients with unresectable gastric cancer. Although the addition of taxane or irinotecan to this regimen has yielded promising efficacy, its use has been limited due to severe toxicities. To overcome this limitation, we evaluated the efficacy and safety of the combination of irinotecan, oxaliplatin, and S-1 (OIS) for the treatment of advanced gastric cancer. METHODS: Chemotherapy-naïve patients with pathologically proven advanced gastric adenocarcinoma were assessed for eligibility. Irinotecan (135 mg/m2) and oxaliplatin (65 mg/m2) were administered intravenously on day 1, and S-1 (80 mg/m2/day) was administered orally on days 1-7 of every 2-week cycle. RESULTS: Forty-four patients (median age 57 years) were enrolled and all but one patient had a good performance status (ECOG 0 or 1). A total of 529 cycles were administered, with a median of 9.5 (range 1-31) cycles per patient. The overall response rate was 61.4% (95% confidence interval [CI] 46.6-74.3). The median progression-free survival and overall survival were 10.8 months (95% CI 7.6-14.0) and 15.4 months (95% CI 12.6-18.2), respectively. Major toxicities included grade 3/4 neutropenia (38.6%), febrile neutropenia (13.6%), abdominal pain (9.1%), and diarrhea (9.1%). CONCLUSION: These data suggest that the OIS regimen is effective and relatively well tolerated in patients with advanced gastric cancer. Given that all the patients treated, but one, had a good performance status, these results must be confirmed in a patient population more representative of regular clinical practice. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02527785.

Efficacy and tolerability of ramucirumab monotherapy or in combination with paclitaxel in gastric cancer patients from the Expanded Access Program Cohort by the Korean Cancer Study Group (KCSG).

BACKGROUND: Ramucirumab improves survival in gastric cancer patients. The efficacy and safety of ramucirumab outside of a clinical trial were evaluated using an expanded access program (EAP). METHODS: Advanced gastric cancer patients treated with ramucirumab in combination with paclitaxel or with ramucirumab monotherapy in a Korean EAP were evaluated. Baseline characteristics were assessed for progression-free survival (PFS) and overall survival (OS), and adverse events were evaluated according to the treatment regimen. RESULTS: Of 265 patients, 228 received ramucirumab plus paclitaxel, and 37 received ramucirumab monotherapy. Grade 3 or 4 neutropenia was more common with ramucirumab plus paclitaxel than with ramucirumab monotherapy (46.7 vs. 8.1%). Gastrointestinal (GI) perforation developed in seven patients (3.1%) in the ramucirumab plus paclitaxel group. The overall response and disease control rates were 16.6 and 66.3% in the ramucirumab plus paclitaxel group, and 5.4 and 37.8% in the ramucirumab monotherapy group, respectively. PFS and OS were 3.8 and 8.6 months in the ramucirumab plus paclitaxel group, and 1.8 and 6.4 months in the ramucirumab monotherapy group, respectively. In multivariate analysis, alkaline phosphatase, albumin, and neutrophil-to-lymphocyte ratio (NLR) were the independent prognostic factors for PFS, while albumin, NLR, number of metastatic sites, and large amount of ascites were independent prognostic factors for OS. CONCLUSION: In the Korean EAP cohort, ramucirumab showed similar efficacy to the results of the previous trials for gastric cancer. However, the level of GI perforation was slightly increased in the ramucirumab plus paclitaxel group.

Preoperative Serum Carcinoembryonic Antigen Level as a Prognostic Factor for Recurrence and Survival After Curative Resection Followed by Adjuvant Chemotherapy in Stage III Colon Cancer.

BACKGROUND: Carcinoembryonic antigen (CEA) is the most widely used tumor marker in colon cancer; however, there has been controversy regarding the significance of preoperative serum CEA level as a prognostic factor for recurrence. In this study, we evaluated the optimal cutoff value and prognostic significance of preoperative serum CEA level in stage III colon cancer. METHODS: Based on a retrospective cohort of 965 patients with stage III colon cancer who underwent elective curative surgery and adjuvant chemotherapy with fluoropyrimidine and oxaliplatin (training set), we determined the optimal cutoff value of CEA for recurrence using the Contal and O'Quigley method. We assessed the prognostic value of this cutoff value in terms of disease-free survival (DFS) and overall survival (OS) in a prospective cohort of 268 patients with stage III colon cancer (validation set). A Cox proportional hazards model was used to explore the association of prognostic variables with DFS and OS. RESULTS: The statistically determined best cutoff value for CEA was 3 ng/mL in the training set. A high CEA level (≥3 ng/mL) was associated with inferior DFS (hazard ratio [HR] 4.609, 95 % confidence interval [CI] 2.028-10.474) and OS (HR 3.956, 95 % CI 1.127-13.882) in the validation set, while multivariate analysis showed that a high CEA level was an independent risk factor for DFS and OS in both study subsets. CONCLUSION: Preoperative serum CEA level is an independent prognostic factor for DFS and OS in patients with stage III colon cancer after curative resection and adjuvant chemotherapy.

Role of adjuvant chemotherapy in locally advanced rectal cancer with ypT0-3N0 after preoperative chemoradiation therapy and surgery.

BACKGROUND: We aimed to explore the clinical benefit of adjuvant chemotherapy (AC) with fluoropyrimidine in patients with ypT0-3N0 rectal cancer after preoperative chemoradiation therapy (CRT) followed by total mesorectal excision (TME). METHODS: Patients with ypT0-3N0 rectal cancer after preoperative CRT and TME were included using prospectively collected tumor registry cohort between January 2001 and December 2013. Patients were categorized into two groups according to the receipt of AC. Disease-free survival (DFS) and overall survival (OS) were compared between the adjuvant and observation groups. To control for potential confounding factors, we also calculated propensity scores and performed propensity score-matched analysis for DFS and OS. RESULTS: Of the 339 evaluated patients, 87 patients (25.7%) did not receive AC. There were no differences in DFS (hazard ratio [HR], 0.921; 95% confidence interval [CI], 0.562-1.507; P = 0.742) and OS (HR, 0.835; 95% CI, 0.423-1.648; P = 0.603) between the adjuvant and observation groups. After propensity score matching, DFS (HR, 1.129; 95% CI, 0.626-2.035; P = 0.688) and OS (HR, 1.200; 95% CI, 0.539-2.669; P = 0.655) did not differ between the adjuvant and observation groups. Advanced T stage and positive resection margin were independently associated with inferior DFS and OS on multivariate analysis. CONCLUSIONS: AC did not improve DFS and OS for patients with ypT0-3N0 rectal cancer after preoperative CRT followed by TME in this cohort study. The confirmative role of AC in locally advanced rectal cancer should be evaluated in prospective randomized trials with a larger sample size.

Effects of microsatellite instability on recurrence patterns and outcomes in colorectal cancers.

BACKGROUND: Among colorectal cancers (CRCs), high-frequency microsatellite instability (MSI-H) is associated with a better prognosis, compared with low-frequency MSI or microsatellite stability (MSI-L/MSS). However, it is unclear whether MSI affects the prognosis of recurrent CRCs. METHODS: This study included 2940 patients with stage I-III CRC who underwent complete resection. The associations of MSI status with recurrence patterns, disease-free survival (DFS), overall survival from diagnosis to death (OS1), and overall survival from recurrence to death (OS2) were analysed. RESULTS: A total of 261 patients (8.9%) had MSI-H CRC. Patients with MSI-H CRC had better DFS, compared to patients with MSI-L/MSS CRC (hazard ratio (HR): 0.619, P<0.001). High-frequency microsatellite instability CRC was associated with more frequent local recurrence (30.0% vs 12.0%, P=0.032) or peritoneal metastasis (40.0% vs 12.3%, P=0.003), and less frequent lung (10.0% vs 42.5%, P=0.004) or liver metastases (15.0% vs 44.7%, P=0.01). Recurrent MSI-H CRC was associated with worse OS1 (HR: 1.363, P=0.035) and OS2 (HR: 2.667, P<0.001). An analysis of patients with colon cancer yielded similar results. CONCLUSIONS: Recurrence patterns differed between MSI-H CRC and MSI-L/MSS CRC, and recurrent MSI-H CRCs had a worse prognosis.

Cumulative Metformin Use and Its Impact on Survival in Gastric Cancer Patients After Gastrectomy.

OBJECTIVE: The aim of this study was to evaluate the association between metformin and survival of gastric cancer (GC) patients. BACKGROUND: Metformin has recently received attention as a potential anticancer treatment. However, no study has shown the survival benefit of metformin for GC patients. METHODS: A total of 1974 GC patients who underwent curative gastrectomy were compared for survival according to groups; 132 diabetic patients treated with metformin, 194 diabetic patients without metformin, and 1648 non-diabetic patients. RESULTS: During the median follow-up period of 6.2 years (interquartile range, 4.7-7.8 years), 381 patients (19.3%) died, including 302 (15.3%) who died from GC. The non-diabetic patients had significantly better recurrence-free survival (RFS; P < 0.0001), cancer-specific survival (CSS; P = 0.006), and overall survival (OS; P < 0.0001). However, the diabetic patients treated with metformin had a significantly better prognosis than those who were not (OS: hazard ratio [HR] = 0.584, 95% confidence interval [CI], 0.369-0.926; CSS: HR = 0.57, 95% CI, 0.334-0.975; RFS: HR = 0.633, 95% CI, 0.410-0.977), and metformin treatment prolonged survival in diabetic patients to a rate comparable to that in non-diabetic patients. In multivariable analysis using the Cox proportional hazard model with time-dependent covariates, each cumulative 6 months of metformin use was significantly associated with a decreased risk of recurrence, cancer-specific mortality, and all-cause mortality (RFS: HR = 0.864, 95% CI, 0.797-0.937; CSS: HR = 0.865, 95% CI, 0.782-0.958; OS: HR 0.870, 95% CI, 0.801-0.945). CONCLUSIONS: The increased cumulative duration of metformin use decreased the recurrence, all-cause mortality, and cancer-specific mortality rates among GC patients with diabetes who underwent gastrectomy.

Benefit of Adjuvant Chemotherapy After Curative Resection of Lung Metastasis in Colorectal Cancer.

BACKGROUND: The survival benefit of adjuvant chemotherapy after colorectal cancer (CRC) lung metastasectomy is uncertain. METHODS: We enrolled 221 CRC patients who underwent pulmonary metastasectomy between October 2002 and July 2013, including those with previous liver metastasis that had been curatively resected. Disease-free survival (DFS) and overall survival (OS) were calculated from the day of lung metastasectomy. RESULTS: Among all patients, 176 (79.6%) received adjuvant chemotherapy after lung metastasectomy. Median follow-up was 34.7 months from the time of lung metastasectomy [95% confidence interval (95% CI), 7.4-90.9 months]. Patients treated with adjuvant chemotherapy had longer DFS compared with surgery alone (median 32.7 vs 11.2 months respectively, P = 0.076). Multivariate analysis revealed previous liver metastasis, preoperative carcinoembryonic antigen ≥5 ng/mL, disease-free interval <24 months, and surgery without adjuvant chemotherapy as independent risk factors for recurrence. Low-risk patients who had 0-1 risk factors received a significant survival benefit from adjuvant chemotherapy [hazard ratio (HR) 0.54; 95% CI 0.32-0.91, P = 0.020]; however, high-risk patients with ≥2 risk factors did not (HR 1.02; 95% CI 0.48-2.14, P = 0.964). Patients treated with adjuvant chemotherapy showed no OS benefit compared with patients who received surgery alone (median 89.6 vs 86.8 months respectively, P = 0.833). CONCLUSIONS: CRC patients received lung metastasectomy could have a DFS benefit from adjuvant chemotherapy, especially in low-risk patients. Larger, prospective studies are needed to evaluate the role of adjuvant chemotherapy after CRC lung metastasectomy.

Proper timing of adjuvant chemotherapy affects survival in patients with stage 2 and 3 gastric cancer.

BACKGROUND: Adjuvant chemotherapy improves survival in patients with gastric cancer. However, the relationship between the timing of adjuvant chemotherapy and survival has not been investigated. METHODS: Patients with D2-resected stage 2 and 3 gastric cancer that received adjuvant chemotherapy from 2005 to 2011 at Yonsei University Health System were included. The patients were grouped according to intervals between surgery and adjuvant chemotherapy. RESULTS: Among 840 patients, the interval from surgery to the start of adjuvant therapy was less than 4 weeks in 337 (40.1 %) patients (early group), 4-8 weeks in 467 (55.6 %) patients (intermediate group), and more than 8 weeks in 36 (4.3 %) patients (late group). The 5-year RFS was 55.7 % in the early group, 54.4 % in the intermediate group, and 43.6 % in the late group (p = 0.076). The corresponding 5-year OS rates were 63.4, 62.8, and 51.7 % (p = 0.037). CONCLUSIONS: There is insufficient evidence to suggest starting adjuvant chemotherapy within 4 weeks after surgery for patients with D2 resected stage 2 and 3 gastric cancer. However, delayed treatment of adjuvant chemotherapy after 8 weeks showed worse survival outcomes than early and intermediate treatment initiation, suggesting that adjuvant chemotherapy should be considered start within 8 weeks after radical resection.

PTEN deficiency as a predictive biomarker of resistance to HER2-targeted therapy in advanced gastric cancer.

BACKGROUND: To investigate the role of the phosphoinositide 3-kinase (PI3K) pathway activation in human epidermal growth factor receptor 2 (HER2)-targeted therapy. METHODS: We evaluated the predictive roles of PI3K, catalytic alpha (PIK3CA), and phosphatase and tensin homolog (PTEN) in HER2-based therapy (either trastuzumab or lapatinib). PTEN expression and PIK3CA mutation were analyzed using immunohistochemistry and pyrosequencing. RESULTS: Forty-eight patients received trastuzumab (n = 39) or lapatinib (n = 9) combination chemotherapy. PTEN loss was found in 47.9% (n = 23), but no PIK3CA mutations were identified. Twenty-six (54.1%) patients responded to HER2-based therapy, without a significant difference between patients with PTEN loss and those without (52.2 vs. 56.0%). Among the patients with responsive disease, time to best response did not differ by PTEN status, but the duration of response was significantly shorter for patients with PTEN loss (median 4.2 vs. 6.1 months, p = 0.04). In addition, patients with PTEN loss had a significantly shorter progression-free survival time (median 4.9 vs. 7.3 months, p = 0.047). CONCLUSIONS: PTEN deficiency is an important predictive marker for early resistance to HER2 inhibitor treatment in gastric cancer patients. This finding may be useful for the development of drug combinations and identification of patients who need a modified treatment strategy.