Prognostic Value of Mesorectal Lymph Node Micrometastases in ypN0 Rectal Cancer After Chemoradiation.

INTRODUCTION: More than 25% of patients with node-negative colorectal cancer experience a recurrent disease even after curative surgery. This suggests the existence and oncologic influence of micrometastasis in regional lymph nodes or in distant organs. The objective of this study was to identify mesorectal lymph node micrometastases using an immunohistochemical analysis and to determine its prognostic value in node-negative rectal cancer after neoadjuvant chemoradiation. MATERIALS AND METHODS: A total of 91 patients who received preoperative chemoradiation and radical resection for rectal cancer were included. Based on conventional hematoxylin and eosin staining, all patients had a node-negative disease. Mesorectal lymph nodes from resected specimens were re-evaluated to detect micrometastases by immunohistochemistry using anticytokeratin antibody AE1/AE3. The clinicopathologic data were collected from a prospectively maintained database of colorectal cancer patients and analyzed retrospectively. RESULTS: Micrometastases of mesorectal lymph nodes were detected in nine patients (9.9%). The three-year overall survival was similar regardless of micrometastasis (88.9% in the positive group versus 90.7% in the negative group, P = 0.681); however, the three-year disease-free survival was significantly poorer in the patients with micrometastases (40.0% versus 84.2%, P = 0.001). In the multivariate analysis, the advanced pT category (ypT3/T4 versus ypT0: hazard ratio [HR] 10.477, 95% confidence interval [CI] 1.102-99.594, P = 0.041) and micrometastases in mesorectal lymph nodes (HR 5.655, 95% CI 1.837-17.409, P = 0.003) were independent prognostic factors for disease-free survival. CONCLUSIONS: In node-negative rectal cancer after preoperative chemoradiation, immunohistochemically detected micrometastases of mesorectal lymph nodes were significantly correlated with poor disease-free survival.

Laparoscopic repair of perforated peptic ulcer: a multicenter, propensity score matching analysis.

BACKGROUND: Perforated peptic ulcer (PPU) is a common emergency condition requiring surgery using laparoscopy or open repair of the perforated site. The aim of this study was to assess the role of laparoscopic surgery (LS) based on the safety and efficacy for PPU. METHODS: Medical records of the consecutive patients who underwent LS or open surgery (OS) for PPU at five hospitals between January 2009 and December 2019 were retrospectively reviewed. After propensity score matching, short-term perioperative outcomes were compared between LS and OS in selected patients. RESULTS: Among the 598 patients included in the analysis, OS was more frequently performed in patients with worse factors, including older age, a higher American Society of Anesthesiologists score, more alcohol use, longer symptom duration, a higher Boey score, a higher serum C-reactive protein level, a lower serum albumin level, and a larger-diameter perforated site. After propensity score matching, 183 patients were included in each group; variables were well-balanced between-groups. Postoperative complications were not different between groups (24.6% LS group vs. 31.7% OS group, p = 0.131). However, postoperative length of hospital stay (10.03 vs. 12.53 days, respectively, p = 0.003) and postoperative time to liquid intake (3.75 vs. 5.26 days, p < 0.001) were shorter in the LS group. CONCLUSIONS: LS resulted in better functional recovery than OS and can be safely performed for treatment of PPU. When performed by experienced surgeons, LS is an alternative option, even for hemodynamically unstable patients.

Short-term Outcomes of Single-port Versus Multiport Laparoscopic Surgery for Colon Cancer: The SIMPLE Multicenter Randomized Clinical Trial.

OBJECTIVE: To compare short-term perioperative outcomes of single-port laparoscopic surgery (SPLS) and multiport laparoscopic surgery (MPLS) for colon cancer. SUMMARY BACKGROUND DATA: Although many studies reported short- and long-term outcomes of SPLS for colon cancer compared with MPLS, few have reported results of randomized controlled trials. METHODS: This was a multicenter, prospective, randomized controlled trial with a noninferiority design. It was conducted between August 2011 and June 2017 at 7 sites in Korea. A total of 388 adults (aged 19-85 yrs) with clinical stage I, II, or III adenocarcinoma of the ascending or sigmoid colon were enrolled and randomized. The primary endpoint was 30-day postoperative complication rates. Secondary endpoints were the number of harvested lymph nodes, length of the resection margin, postoperative pain, and time to functional recovery (bowel movement and diet). Patients were followed for 30 days after surgery. RESULTS: Among 388 patients, 359 (92.5%) completed the study (SPLS, n = 179; MPLS, n = 180). The 30-day postoperative complication rate was 10.6% in the SPLS group and 13.9% in the MPLS group (95% confidence interval, -10.05 to 3.05 percentage points; P < 0.0001). Total incision length was shorter in the SPLS group than in the MPLS group (4.6 cm vs 7.2 cm, P < 0.001), whereas the length of the specimen extraction site did not differ (4.4 cm vs 4.6 cm, P = 0.249). There were no significant differences between groups for all secondary endpoints and all other outcomes. CONCLUSIONS: Even though there was no obvious benefit to SPLS over MPLS when performing colectomy for cancer, our data suggest that SPLS is noninferior to MPLS and can be considered an option in selected patients, when performed by experienced surgeons.Trial registration: ClinicalTrials.gov Identifier: NCT01480128.

Quality of life and patient satisfaction after single- and multiport laparoscopic surgery in colon cancer: a multicentre randomised controlled trial (SIMPLE Trial).

BACKGROUND: The clinical benefits of single-port laparoscopic surgery (SPLS) in patients with colon cancer patients are unclear because only a few studies have reported on the quality of life (QoL) of such patients. This study aimed to compare the QoL and patient satisfaction between SPLS and multiport laparoscopic surgery (MPLS) in colon cancer. METHODS: The multicentre randomised controlled SIngle-port versus MultiPort Laparoscopic surgEry (SIMPLE) trial included patients with colon cancer who underwent radical surgery at seven hospitals in South Korea. We performed a pre-planned secondary analysis of the QoL data of 359 patients from that trial. The QoL was surveyed using the European Organisation for Research and Treatment of Cancer (EORTC) QLQ-C30 preoperatively and at 1, 3, 6, and 12 months postoperatively. Patient satisfaction was measured with a 5-point questionnaire at these postoperative time points. RESULTS: Overall, 145 and 147 patients were included in the SPLS and MPLS groups, respectively. Most QoL domains were similar between the groups. In the subgroup analysis of patients without adjuvant chemotherapy, patients in the SPLS group presented with significantly better global health status (p = 0.017), fatigue (p = 0.047), and pain (p = 0.005) scores and tended to have improved physical (p = 0.055), emotional (p = 0.064), and social (p = 0.081) functioning, with marginal significance at 1 month postoperatively, compared to those in the MPLS group. Patient satisfaction regarding surgery (p = 0.002) and appearance of the abdominal scar (p = 0.002) was significantly higher with SPLS than with MPLS at 12 months postoperatively. CONCLUSION: Patients who underwent SPLS without adjuvant chemotherapy had better global health status, fatigue status, and pain at 1 month postoperatively; however, these improvements were minimal and temporary. In the near future, the effect of SPLS on postoperative QoL should be confirmed through a randomised controlled trial targeting the QoL in colon cancer patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01480128.

Clinical and oncologic outcomes of laparoscopic versus open surgery in elderly patients with colorectal cancer: a retrospective multicenter study.

BACKGROUND: Laparoscopic surgery is commonly used in elderly patients over 80 years old. The purpose of this study was to compare the perioperative and oncologic outcomes between laparoscopic surgery and open surgery in elderly patients with colorectal cancer. METHODS: We retrospectively analyzed the medical records of patients aged ≥ 80 years who underwent curative resection of colorectal cancer at six Hallym University-affiliated hospitals. The perioperative outcomes and oncologic outcomes were compared between laparoscopic and open surgery RESULTS: Of 294 elderly patients, 104 (35.3%) underwent open surgery and 190 (64.7%) underwent laparoscopic surgery. The postoperative hospital stay (P = 0.019) and time to soft diet (P = 0.009) were shorter in the laparoscopic group than in the open group. Postoperative complications were less frequent in the laparoscopic group than in the open group (P < 0.001), including wound infection (P = 0.005), ileus (P = 0.005), and pneumonia (P = 0.001). The 3-year overall survival (OS) (P = 0.982) and recurrence-free survival rates (RFS) (P = 0.532) were similar in both groups. In multivariable analyses, positive lymph node status was the only independent factor associated with OS (P = 0.019) and RFS (P = 0.012). Laparoscopic surgery was not associated with OS (P = 0.874) and RFS (P = 0.772). CONCLUSION: Laparoscopic surgery offers several perioperative advantages over open surgery and similar long-term oncological outcomes for elderly patients with colorectal cancer. Therefore, we suggest that laparoscopic surgery can be safely performed for the treatment of elderly patients (≥ 80 years old) with colorectal cancer.

Clinical outcomes of laparoscopic versus open surgery for repairing colonoscopic perforation: a multicenter study.

PURPOSE: We conducted this study to compare the perioperative outcomes of laparoscopic surgery (LS) vs. open surgery (OS) for repairing colonoscopic perforation, and to evaluate the possible predictors of complications. METHOD: We reviewed the medical records of patients who underwent surgical repair of colonoscopic perforation by LS or OS between January 2005 and June 2019 at six Hallym University-affiliated hospitals. Multivariable analysis was performed to identify the predictors of postoperative complications. RESULTS: Of the total 99 patients, 40 underwent OS and 59 underwent LS. The postoperative hospital stay and the time to resuming a soft diet were shorter in the LS group than in the OS group (P = 0.017 and 0.026, respectively). The complication rate and Clavien-Dindo classification were not significantly different between the two groups. Multivariable analysis revealed that an American Society of Anesthesiologists score (ASA) ≥ 3 and switching from non-operative management to surgical treatment were independently associated with complications (P = 0.025 and 0.010, respectively). CONCLUSION: LS may be a safe alternative to OS for repairing colonoscopic perforation with a shorter postoperative hospital stay and time to resuming a soft diet. Patients with an ASA score ≥ 3 and those with changes to their planned treatment should be monitored carefully to minimize their risk of complications.

Clinical outcomes of sigmoid volvulus and risk factors for its recurrence: a multicenter study in Korea.

PURPOSE: Sigmoid volvulus is one of the leading causes of colonic obstruction. The aims of this study were to review the treatment characteristics and clinical outcomes of patients diagnosed with sigmoid volvulus over 10 years at five university-affiliated hospitals in Korea, and to identify possible risk factors for its recurrence. METHODS: Retrospective review was performed for medical records of patients who were diagnosed with sigmoid volvulus and managed surgically or conservatively at the five Hallym University-affiliated hospitals between January 2005 and July 2018. RESULTS: A total of 69 patients were diagnosed, of whom 11 patients underwent emergency surgery and 58 patients were conservatively managed. Non-operative management was successful in 53 of 58 patients (91.4%) at initial admission. Of the non-operative managed patients, six patients required emergency surgery due to unsuccessful decompression or recurrence whereas 23 patients underwent regular surgery for definitive treatment. And overall recurrence rate and mortality rate were 25.8% (15/58) and 1.7% (1/58), respectively. A total of 40 patients underwent surgery; 23 underwent regular surgery and 17 underwent emergency surgery. Restoration of bowel continuity was more frequently performed in the regular surgery group than in the emergency surgery group (87.0% vs 52.9%, P = 0.03). In multivariable analysis, only non-operative management at the initial admission (P = 0.029) was independently associated with recurrence. CONCLUSION: Although non-operative treatment can be initially attempted, surgery is required for preventing recurrence. Regular surgery should be considered to restore continuity of the bowel.

Korean Society of Coloproctology (KSCP) trial of cONsolidation Chemotherapy for Locally advanced mid or low rectal cancer after neoadjUvant concurrent chemoraDiothErapy: a multicenter, randomized controlled trial (KONCLUDE).

BACKGROUND: Neoadjuvant chemoradiotherapy (CRT) followed by total mesorectal excision (TME) has been a standard treatment option for locally advanced rectal cancer with improved local control. However, systemic recurrence despite neoadjuvant CRT remained unchanged. The only significant prognostic factor proven to be important was pathologic complete response (pCR) after neoadjuvant CRT. Several efforts have been tried to improve survival of patients who treated with neoadjuvant CRT and to achieve more pCR including adding cytotoxic chemotherapeutic agents, chronologic modification of chemotherapy schedule or adding chemotherapy during the perioperative period. Consolidation chemotherapy is adding several cycles of chemotherapy between neoadjuvant CRT and TME. It could increase pCR rate, subsequently could show better oncologic outcomes. METHODS: Patients with advanced mid or low rectal cancer who received neoadjuvant CRT will be included after screening. They will be randomized and assigned to undergo TME followed by 8 cycles of adjuvant chemotherapy (control arm) or receive 3 cycles of consolidation chemotherapy before TME, and receive 5 cycles of adjuvant chemotherapy (experimental arm). The primary endpoints are pCR and 3-year disease-free survival (DFS), and the secondary endpoints are radiotherapy-related complications, R0 resection rate, tumor response rate, surgery-related morbidity, and peripheral neuropathy at 3 year after the surgery. The authors hypothesize that the experimental arm would show a 15% improvement in pCR (15 to 30%) and in 3-year DFS (65 to 80%), compared with the control arm. The accrual period is 2 years and the follow-up period is 3 years. Based on the superiority design, one-sided log-rank test with α-error of 0.025 and a power of 80% was conducted. Allowing for a drop-out rate of 10%, 358 patients (179 per arm) will need to be recruited. Patients will be followed up at every 3 months for 2 years and then every 6 months for 3 years after the last patient has been randomized. DISCUSSION: KONCLUDE trial aims to investigate whether consolidation chemotherapy shows better pCR and 3-year DFS than adjuvant chemotherapy alone for the patients who received neoadjuvant CRT for locally advanced rectal cancer. This trial is expected to provide evidence to support clear treatment guidelines for patients with locally advanced rectal cancer. TRIAL REGISTRATION: Clinicaltrials.gov NCT02843191 (First posted on July 25, 2016).

Single-port laparoscopic surgery in uncomplicated acute appendicitis: a randomized controlled trial.

BACKGROUND: Single-port laparoscopic surgery (SPLS) is an alternative, minimally invasive surgical approach for managing appendicitis. The aim of this randomized trial was to evaluate the safety and efficacy of SPLS in uncomplicated appendicitis. METHODS: Between December 2009 and November 2010, 194 patients with radiologically diagnosed acute appendicitis were randomly allocated to undergo either SPLS or multiport laparoscopic surgery (MPLS). Patients with intraoperative findings of perforated appendicitis were excluded from the analysis. The primary endpoint was perioperative morbidity. All data were analyzed according to the intention-to-treat principle. RESULTS: Fourteen cases were excluded from the analysis. Of the remaining 180 patients, 90 were assigned to the SPLS group, and 90 to the MPLS group. Baseline characteristics were well balanced between the groups. In the SPLS group, the rate of conversion to MPLS was 11.1%. The operation time was 14.5 min longer for SPLS than for MPLS (p < 0.01), but there was no between-group difference in the rate of intraoperative complications (SPLS, 4.4%; MPLS, 0%; p = 0.12) or postoperative complications (SPLS, 4.4%; MPLS, 2.2%; p = 0.68). Compared to the MPLS group, the SPLS group had higher cumulative dose of analgesics (tramadol; 73.9 vs. 51.7 mg, p = 0.04), longer postoperative time to first passage of flatus (27.7 vs. 20.1 h, p < 0.01), longer postoperative hospitalization (2.5 vs. 2.1 days, p < 0.05), and higher total cost (1826.9 vs. 1662.4 USD, p < 0.01). CONCLUSIONS: This randomized trial indicates that, compared to MPLS, SPLS does not increase the rate of perioperative or postoperative complications in uncomplicated appendicitis, but may have disadvantages such as increased operation time, later postoperative functional recovery, longer hospital stay, and higher costs, although the difference is minimal (ClinicalTrials.gov Identifier: NCT01007318).

Safety and feasibility of laparoscopic surgery for appendiceal mucocele: a multicenter study.

BACKGROUND: Although laparoscopic appendectomy has been widely performed since 1987, concerns over potential spillage of mucus into the peritoneal cavity during laparoscopic manipulation have prevented the use of laparoscopic surgery (LS) for appendiceal mucocele. The purpose of the present study was to evaluate the safety, feasibility, and short-term perioperative outcomes of LS for appendiceal mucocele. METHODS: A retrospective review was performed to identify patients diagnosed with appendiceal mucocele based on their imaging studies and who underwent surgery at one of six Hallym-University-affiliated hospitals between January 2007 and June 2016. Patient demographics, surgical outcomes, and postoperative outcomes were retrospectively analyzed. RESULTS: A total of 96 patients were evaluated, of whom 58 underwent LS (LS group) and 38 underwent open surgery (OS; OS group). There were no significant differences in patient characteristics between groups. The operation time was similar in both groups (P = 0.399). Intraoperative rupture occurred in two patients in each group (no significant difference, P = 0.647). Time to flatus, time to soft food intake, and length of hospital stay were shorter in the LS group than in the OS group (2.4 vs. 3.2 days, P = 0.003; 3.6 vs. 4.5 days, P = 0.024; 6.5 vs. 8.8 days, P = 0.011, respectively). The rate of postoperative complications was similar between the groups (P = 0.786). Univariate analysis revealed that rupture of appendiceal mucocele was associated with white blood cell count > 10,000/µL (P = 0.032) but not with LS (P = 0.647). CONCLUSIONS: The results showed that LS is safe and feasible for the surgical treatment of appendiceal mucocele. An elevated WBC count was associated with a risk of appendiceal mucocele rupture.

Multicenter, randomized single-port versus multiport laparoscopic surgery (SIMPLE) trial in colon cancer: an interim analysis.

BACKGROUND: Single-port laparoscopic surgery (SPLS) was recently introduced as an innovative minimally invasive surgery method. Retrospective studies have revealed the safety and feasibility of SPLS for colon cancer treatment. However, no prospective randomized trials have been performed. The multicenter, randomized SIMPLE (single-port versus multiport laparoscopic surgery) trial aimed to investigate short-term perioperative outcomes of SPLS for colon cancer treatment, compared with multiport laparoscopic surgery (MPLS). METHODS: Between August 2011 and April 2014, a total of 194 patients with colon cancer were recruited from seven hospitals in Korea. Patients were randomly allocated into the SPLS group (n = 99) or MPLS group (n = 95). The primary endpoint was postoperative complications. Operative, postoperative, and pathologic outcomes were analyzed after 50% of the patient study population had been recruited. RESULTS: The patients' demographic characteristics, operative times, estimated blood volume losses, numbers of harvested lymph nodes, and lengths of both resection margins were not significantly different between groups. In the SPLS group, the rates of conversion to MPLS and open surgery were 12.9 and 2.2%, respectively. Postoperative complications occurred in 10.8% of the SPLS, and 12.5% of the MPLS patients (p = 0.714). Times to functional recovery, pain scores, and amounts of analgesia were similar between groups. CONCLUSION: The results of this interim analysis suggested that SPLS is technically safe and appropriate when used for radical resection of colon cancer. (ClinicalTrials.gov Identifier: NCT01480128).

Single-port laparoscopic surgery in acute appendicitis: retrospective comparative analysis for 618 patients.

BACKGROUND: Transumbilical single-port laparoscopic appendectomy (SPLA) is a promising procedure that features less pain, faster recovery of postoperative bowel function and superior cosmetic results. We performed a retrospective comparative analysis of SPLA versus conventional laparoscopic surgery (CLA) to evaluate the safety and efficacy in acute appendicitis. METHODS: From December 2008 to November 2013, laparoscopic surgery was performed on 636 patients with acute appendicitis at the Department of Surgery, Chuncheon Sacred Heart Hospital. Under approval of Institutional Review Board, data concerning baseline characteristics, operative outcomes, postoperative complications and postoperative functional recovery were compared between both procedures. RESULTS: After exclusion of 18 patients, 618 patients treated for acute appendicitis were included. SPLA was performed in 375 patients and CLA in 243 patients. Complicated appendicitis was more prevalent in the CLA group (26.3 %) than in the SPLA group (17.1 %) (p = 0.005). There was no difference between groups in operation time (p = 0.235), postoperative duration of hospital stay (p = 0.672) and readmission rate (p = 0.688). The rate of postoperative complications was similar in both groups (10.7 % in SPLA vs. 11.1 % in CLA, p = 0.862). In subgroup analysis of complicated appendicitis, more patients needed conversion to open surgery in the SPLA group (15.6 vs. 1.6 %, p = 0.005). CONCLUSION: In uncomplicated appendicitis, SPLA can be performed safely and efficiently. However, more selective indication for SPLA should be applied in cases of complicated appendicitis because of the greater risk of open conversion.

Head-to-head Comparison of Green Fluorescent Protein (GFP) Imaging With Luciferase-luciferin Imaging In Vivo Using Single-nanometer Laser-excitation Tuning and an Ultra-low-light-detection Camera and Optics Demonstrates the Superiority of GFP.

BACKGROUND/AIM: Genetic reporters encoding fluorescent proteins or luciferase have been used in vivo for the last three decades with claims about their superiority or inferiority over each other. In the present report, a head-to-head in vivo comparison of green fluorescent protein (GFP) fluorescence imaging and luciferase-luciferin imaging, using single-nanometer laser-excitation tuning of fluorescence excitation and an ultra-low-light-detection camera and optics was performed. MATERIALS AND METHODS: Mouse Lewis-lung carcinoma cells labeled with GFP (LLC-GFP) or luciferase (LL/2-Luc2) were injected subcutaneously into the flank of nude mice. One week after injection, GFP-fluorescence imaging and luciferase-luciferin imaging was performed using the UVP Biospectrum Advanced system with excitation at 487 nm and peak emission at 513 nm for GFP, and with emission at 560 nm for luciferase-luciferin. GFP fluorescence images were obtained at 0, 10, and 20 min. Luciferase-luciferin images were obtained 10 and 20 min after the injection of D-luciferin. RESULTS: The intensity of GFP images was 55,909 at 0 min, 56,186 at 10 min, and 57,085 at 20 min, and maintained after 20 min. The intensity of luciferase-luciferin images was 28,065 at 10 min after the injection of D-luciferin and 5,199 at 20 min after the injection. The intensity of luciferase-luciferin images decreased by approximately 80% at 20 min compared to 10 min. An exposure time of 30 s for luciferase-luciferin imaging was needed compared to 100 ms for GFP fluorescence imaging in order to detect signals. CONCLUSION: An imaging system with single-nanometer tuning fluorescence excitation and an ultra-low-light detection camera and optics was able to directly visualize both GFP and luciferase-luciferin images in vivo. The intensity and stability of the signals were both greater for GFP than for luciferase-luciferin, and the exposure time for GFP was 300 times faster, demonstrating the superiority of GFP.

Extensive Shrinkage and Long-term Stable Disease in a Teenage Female Patient With High-grade Glioma Treated With Temozolomide and Radiation in Combination With Oral Recombinant Methioninase and a Low-methionine Diet.

BACKGROUND/AIM: Gliomas are the most common and recalcitrant malignant primary brain tumors. All cancer types are addicted to methionine, which is a fundamental and general hallmark of cancer known as the Hoffman effect. Particularly glioma cells exhibit methionine addiction. Because of methionine addiction, [11C]-methionine positron emission tomography (MET-PET) is widely used for glioma imaging in clinical practice, which can monitor the extent of methionine addiction. Methionine restriction including recombinant methioninase (rMETase) and a low-methionine diet, has shown high efficacy in preclinical models of gliomas, especially in combination with chemotherapy. The aim of the present study was to determine the efficacy of methionine restriction with oral rMETase (o-rMETase) and a low-methionine diet, combined with radiation and temozolomide (TMZ), on a teenage female patient with high-grade glioma. CASE REPORT: A 16-year-old girl was diagnosed with high-grade glioma. Magnetic resonance imaging (MRI) showed a left temporal-lobe tumor with compression to the left lateral ventricle and narrowing of sulci in the left temporal lobe. After the start of methionine restriction with o-rMETase and a low-methionine diet, along with TMZ combined with radiotherapy, the tumor size shrunk at least 60%, with improvement in the left lateral ventricle and sulci. The patient's condition remains stable for 19 months without severe adverse effects. CONCLUSION: Methionine restriction consisting of o-rMETase and a low-methionine diet, in combination with radiation and TMZ as first-line chemotherapy, were highly effective in a patient with high-grade glioma.

Expression of PD-L1 Is Increased by Methionine Restriction Using Recombinant Methioninase in Human Colorectal Cancer Cells.

BACKGROUND/AIM: It has been recently demonstrated that a methionine-restricted diet increases the response to immune checkpoint inhibitors (ICIs) via an increase in PD-L1 in a syngeneic mouse colorectal-cancer model. Our laboratory has developed recombinant methioninase (rMETase) to restrict methionine. The aim of the present study was to determine if rMETase can increase PD-L1 expression in a human colorectal cancer cell line in vitro. MATERIALS AND METHODS: We evaluated the half-maximal inhibitory concentration (IC50) value of rMETase on HCT-116 human colorectal cancer cells. HCT-116 cells were treated with rMETase at the IC50 Western immunoblotting was used to compare PD-L1 expression in HCT-116 cells treated with and without rMETase. RESULTS: The IC50 value of rMETase on HCT-116 was 0.79 U/ml. Methionine restriction using rMETase increased PD-L1 expression compared to the untreated control (p<0.05). CONCLUSION: Methionine restriction with rMETase up-regulates PD-L1 expression in human colorectal cancer cells and the combination of rMETase and ICIs may have the potential to improve immunotherapy in human colorectal cancer.

The Combination of Methionine Restriction and Docetaxel Synergistically Arrests Androgen-independent Prostate Cancer But Not Normal Cells.

Background/Aim: Androgen-independent prostate cancer (AIPC) is resistant to androgen-depletion therapy and is a recalcitrant disease. Docetaxel is the first-line treatment for AIPC, but has limited efficacy and severe side-effects. All cancers are methionine-addicted, which is termed the Hoffman effect. Recombinant methioninase (rMETase) targets methionine addiction. The purpose of the present study was to determine if the combination of docetaxel and rMETase is effective for AIPC. Materials and Methods: The half-maximal inhibitory concentrations (IC50) of docetaxel and rMETase alone were determined for the human AIPC cell line PC-3 and Hs27 normal human fibroblasts in vitro. The synergistic efficacy for PC-3 and Hs27 using the combination of docetaxel and rMETase at their IC50s for PC-3 was determined. Results: The IC50 of docetaxel for PC-3 and for Hs27 was 0.72 nM and 0.94 nM, respectively. The IC50 of rMETase for PC-3 and for Hs27 was 0.67 U/ml and 0.76 U/ml, respectively. The combination of docetaxel and rMETase was synergistic for PC-3 but not Hs27 cells. Conclusion: The combination of a relatively low concentration of docetaxel and rMETase was synergistic and effective for AIPC. The present results also suggest that the effective concentration of docetaxel can be reduced by using rMETase, which may reduce toxicity. The present results also suggest the future clinical potential of the combination of docetaxel and rMETase for AIPC.

Reduction of Tumor Biomarkers from very High to Normal and Extensive Metastatic Lesions to Undetectability in a Patient With Stage IV HER2-positive Breast Cancer Treated With Low-dose Trastuzumab Deruxtecan in Combination With Oral Recombinant Methioninase and a Low-methionine Diet.

BACKGROUND/AIM: Breast cancer is the most common and the deadliest cancer among women in the world. Treatment options for HER2-positive metastatic breast cancer patients are limited. Trastuzumab deruxtecan (T-DXd), an antibody-drug conjugate (ADC), has recently been introduced as second-line chemotherapy for HER2-positive metastatic breast cancer. The aim of the present study was to evaluate the efficacy of methionine restriction with oral recombinant methioninase (o-rMETase) and a low-methionine diet combined with T-DXd, on a patient with HER2-positive recurrent stage IV breast cancer. CASE REPORT: A 66-year-old female was diagnosed with HER2-positive metastatic breast cancer. Computed tomography (CT) indicated peritoneal dissemination, thickening of the sigmoid colon and splenic flexure and widespread bone metastases. The patient was previously treated with fulvestrant, trastuzumab, pertuzumab, paclitaxel and capecitabine which were ineffective. T-DXd was administered as a second-line chemotherapy. Since the patient experienced strong side effects, the dose of T-Dxd was decreased. The patient began methionine restriction using o-rMETase and a low-methionine diet along with T-DXd. After the start of the combined treatment, CA15-3 and CA27.29, tumor markers for breast cancer, decreased rapidly from a very high level. The levels of both tumor markers are currently normal. Additionally, peritoneal-dissemination nodules, ascites and the thickness of the sigmoid colon and splenic flexure are no longer detected on CT. The patient maintains a high performance status, without severe side effects of the combination treatment. CONCLUSION: Methionine restriction consisting of o-rMETase and a low-methionine diet, in combination with T-DXd as second-line chemotherapy, was highly effective in a patient with HER2-positive stage IV breast cancer.

Extensive Synergy Between Recombinant Methioninase and Eribulin Against Fibrosarcoma Cells But Not Normal Fibroblasts.

BACKGROUND/AIM: The aim of the present study was to determine the synergy of recombinant methioninase (rMETase) and the anti-tubulin agent eribulin on fibrosarcoma cells, in comparison to normal fibroblasts, in vitro. MATERIALS AND METHODS: HT1080 human fibrosarcoma cells and HS27 human fibroblasts were used for in vitro experiments. Four groups were analyzed in vitro: No-treatment control; eribulin; rMETase; eribulin plus rMETase. Dual-color HT1080 cells which express red fluorescent protein (RFP) in the cytoplasm and green fluorescent protein (GFP) in the nuclei were used to visualize cytoplasmic and nuclear dynamics during treatment. RESULTS: Eribulin combined with rMETase greatly decreased the viability of HT 1080 cells. In contrast, eribulin combined with rMETase did not show synergy on Hs27 normal fibroblasts. Eribulin combined with rMETase also caused more fragmentation of the nucleus than all other treatments. CONCLUSION: The combination treatment of eribulin plus rMETase demonstrated efficacy on fibrosarcoma cells in vitro. In contrast, normal fibroblasts were resistant to this combination, indicating the potential clinical applicability of the treatment.

Recombinant Methioninase Decreased the Effective Dose of Irinotecan by 15-fold Against Colon Cancer Cells: A Strategy for Effective Low-toxicity Treatment of Colon Cancer.

BACKGROUND/AIM: Irinotecan (IRN), a topoisomerase I inhibitor and pro-drug of SN-38, is first-line treatment of colon cancer as part of FOLFIRI and FOLFOXIRI combination chemotherapy. However, IRN causes dose-limiting adverse events such as neutropenia and diarrhea. Dose reductions are sometimes required, which reduce efficacy. Recombinant methioninase (rMETase) targets the fundamental basis of cancer, methionine addiction, known as the Hoffman effect, and enhances the efficacy of numerous chemotherapy drugs. The present study determined the efficacy of rMETase when administered in combination with IRN. MATERIALS AND METHODS: Cell viability was assessed by cultivating the HCT-116 human colorectal cancer cell line in 96-well plates at 1×103 cells per well in Dulbecco's modified Eagle's medium (DMEM). Subsequently, HCT-116 cells were treated with increasing concentrations of SN-38, the active form of IRN, ranging from 0.5 nM to 32 nM, and/or rMETase ranging from 0.125 to 8 U/ml. After treatment for 72 h, the half-maximal inhibitory concentration (IC50) of SN-38 alone and rMETase alone for HCT-116 cells were determined. Using the IC50 concentration of rMETase, we determined the IC50 of SN-38 in combination with rMETase. Cell viability was determined with the cell-counting Kit-8 with the WST-8 reagent.. RESULTS: The IC50 of rMETase alone for the HCT-116 cells was 0.55 U/ml, and the IC50 of IRN (SN-38) alone was 3.50 nM. rMETase at 0.55 U/ml lowered the IC50 of SN-38 to 0.232 nM (p<0.0001), a 15-fold reduction. CONCLUSION: rMETase and IRN are strongly synergistic, giving rise to the possibility of lowering the effective dose of IRN for the treatment of patients with colon cancer, thereby reducing its severe toxicity. This new strategy will allow more patients with cancer to be effectively treated with IRN.

DNA-Binding Agent Trabectedin Combined With Recombinant Methioninase Is Synergistic to Decrease Fibrosarcoma Cell Viability and Induce Nuclear Fragmentation But Not Synergistic on Normal Fibroblasts.

BACKGROUND/AIM: The alkylating agent trabectedin, which binds the minor groove of DNA, is second-line therapy for soft-tissue sarcoma but has only moderate efficacy. The aim of the present study was to determine the synergistic efficacy of recombinant methioninase (rMETase) and trabectedin on fibrosarcoma cells in vitro, compared with normal fibroblasts. MATERIALS AND METHODS: HT1080 human fibrosarcoma cells expressing green fluorescent protein (GFP) in the nucleus and red fluorescent protein (RFP) in the cytoplasm and Hs27 normal human fibroblasts, were used. Each cell line was cultured in vitro and divided into four groups: no-treatment control; trabectedin treated; rMETase treated; and trabectedin plus rMETase treated. The dual-color HT1080 cells were used to quantitate nuclear fragmentation in each treatment group. RESULTS: The combination of rMETase and trabectedin was highly synergistic to decrease HT1080 cell viability. In contrast, there was no synergy on Hs27 cells. Moreover, nuclear fragmentation occurred synergistically with the combination of trabectedin and rMETase on dual-color HT1080 cells. CONCLUSION: The combination treatment of trabectedin plus rMETase was highly synergistic on fibrosarcoma cells in vitro suggesting that the combination can improve the outcome of trabectedin alone in future clinical studies. The lack of synergy of rMETase and trabectedin on normal fibroblasts suggests the combination is not toxic to normal cells. Synergy of the two drugs may be due to the high rate of nuclear fragmentation on treated HT1080 cells, and the late-S/G2 cell-cycle block of cancer cells by rMETase, which is a target for trabectedin. The results of the present study suggest the future clinical potential of the combination of rMETase and trabectedin for soft-tissue sarcoma.