Impact of a Liver Immune Status Index among Living Liver Transplant Recipients with Hepatocellular Carcinoma.

Introduction: Hepatocellular carcinoma (HCC) is a major global health challenge, being the fifth most prevalent neoplasm and the third leading cause of cancer-related deaths worldwide. Liver transplantation offers a potentially curative approach for HCC, yet the risk of recurrence posttransplantation remains a significant concern. This study investigates the influence of a liver immune status index (LISI) on the prognosis of patients undergoing living-donor liver transplantation for HCC. Methods: In a single-center study spanning from 2001 to 2020, 113 patients undergoing living-donor liver transplantation for HCC were analyzed. LISI was calculated for each donor liver using body mass index, serum albumin levels, and the fibrosis-4 index. This study assessed the impact of donor LISI on short-term recurrence rates and survival, with special attention to its correlation with the antitumor activity of natural killer (NK) cells in the liver. Results: The patients were divided into two grades (high donor LISI, >-1.23 [n = 43]; and low donor LISI, ≤-1.23 [n = 70]). After propensity matching to adjust the background of recipient factors, the survival rates at 1 and 3 years were 92.6% and 88.9% and 81.5% and 70.4% in the low and high donor LISI groups, respectively (p = 0.11). The 1- and 3-year recurrence-free survival were 88.9% and 85.2% and 74.1% and 55.1% in the low and high donor LISI groups, respectively (p = 0.02). Conclusions: This study underscores the potential of an LISI as a noninvasive biomarker for assessing liver NK cell antitumor capacity, with implications for living-donor liver transplantation for HCC. Donor LISI emerges as a significant predictor of early recurrence risk following living-donor liver transplantation for HCC, highlighting the role of the liver antitumor activity of liver NK cells in managing liver malignancies.

Pharmacogenomic study of gemcitabine efficacy in patients with metastatic pancreatic cancer: A multicenter, prospective, observational cohort study (GENESECT study).

BACKGROUND: Genetic polymorphisms of molecules are known to cause individual differences in the therapeutic efficacy of anticancer drugs. However, to date, germline mutations (but not somatic mutations) for anticancer drugs have not been adequately studied. The objective of this study was to investigate the association between germline polymorphisms of gemcitabine metabolic and transporter genes with carbohydrate antigen 19-9 (CA 19-9) response (decrease ≥50% from the pretreatment level at 8 weeks) and overall survival (OS) in patients with metastatic pancreatic cancer who receive gemcitabine-based chemotherapy. METHODS: This multicenter, prospective, observational study enrolled patients with metastatic pancreatic cancer patients who were receiving gemcitabine monotherapy or gemcitabine plus nanoparticle albumin-bound paclitaxel combination chemotherapy. Thirteen polymorphisms that may be involved in gemcitabine responsiveness were genotyped, and univariate and multivariate logistic regression analyses were used to determine the association of these genotypes with CA 19-9 response and OS. The significance level was set at 5%. RESULTS: In total, 180 patients from 11 hospitals in Japan were registered, and 159 patients whose CA 19-9 response could be assessed were included in the final analysis. Patients who had a CA 19-9 response had significantly longer OS (372 vs. 241 days; p = .007). RRM1 2464A>G and RRM2 175T>G polymorphisms suggested a weak association with CA 19-9 response and OS, but it was not statistically significant. COX-2 -765G>C polymorphism did not significantly correlate with CA 19-9 response but was significantly associated with OS (hazard ratio, 2.031; p = .019). CONCLUSIONS: Genetic polymorphisms from the pharmacokinetics of gemcitabine did not indicate a significant association with efficacy, but COX-2 polymorphisms involved in tumor cell proliferation might affect OS.

Immunotherapy Using Activated Natural Killer Cells Improves Postoperative Neutrophil-to-Lymphocyte Ratio and Long-Term Prognosis of Living Donor Liver Transplant Recipients With Hepatocellular Carcinoma.

OBJECTIVE: Preoperative neutrophil-to-lymphocyte ratio (NLR) is a well-known prognostic indicator in various malignancies; however, the impact of postoperative NLR on living donor liver transplant (LDLT) recipients is unknown. Immunotherapy with donor liver-derived activated natural killer (NK) cells may improve postoperative NLR by coactivating immune cells or suppressing activated neutrophils. This study aims to clarify the clinical significance of postoperative NLR in recipients after LDLT with HCC and assess whether immunotherapy improves postoperative NLR. METHODS: We conducted a retrospective study of LDLT recipients between 2001 and 2022 to evaluate the clinical significance of postoperative NLR. Furthermore, the correlation between postoperative NLR and the activation marker of infused NK cells was also evaluated. The postoperative NLR was examined 4 weeks after LDLT. RESULTS: The postoperative high NLR group (N = 78) had preoperative lower NLR and higher model for end-stage liver disease and a higher rate of postoperative infection within 30 days after LDLT than the postoperative low NLR group (N = 41). Postoperative high NLR (hazard ratio [HR], 2.62; 95% confidence interval [CI], 1.01-6.79; P = .047) and nontreatment of immunotherapy (HR, 3.10; 95% CI, 1.33-7.22; P < .01) were independent risk factors for poor overall survival in multivariate analysis. Furthermore, the activation marker of infused NK cells is inversely correlated with decreased postoperative NLR. CONCLUSIONS: The higher level of postoperative NLR was independently associated with poor prognosis in patients after LDLT with HCC. Immunotherapy using activated NK cells may improve postoperative NLR and long-term prognosis.

Effect of Abdominal Aortic Calcification on Recurrence Following Initial Hepatectomy for Colorectal Liver Metastases.

BACKGROUND/AIM: The aim of the study was to analyze the association between abdominal aortic calcification (AAC) and patient prognosis following resection of colorectal liver metastases (CRLM). AAC potentially reflects intrahepatic immunity and is involved in tumor development and progression. However, the clinical effects of AAC on colorectal cancer (CRC) prognosis after curative-intent liver resection for CRLM remain unclear. PATIENTS AND METHODS: We evaluated the effect of AAC on the clinical prognosis and metastatic patterns in 99 patients who underwent hepatectomy for CRLM between 2010 and 2019. RESULTS: The high-AAC group had significantly worse overall survival (OS) and remnant liver recurrence rate (RR) after propensity score matching to adjust for differences in baseline characteristics of patients and tumors. In multivariate Cox regression analyses, high AAC volume was an independent risk factor for poor OS and liver RR, but not poor lung RR. The expression of tumor necrosis factor-related apoptosis-inducing ligand, known as an anti-tumor marker, in liver natural killer (NK) cells was lower in the high-AAC group than in the low-AAC group. CONCLUSION: High AAC volume showed a strong relationship with remnant liver RR after curative resection of CRLM. High AAC volume may be responsible for the suppression of anti-tumor activity of liver NK cells, which results in an increased risk of liver recurrence and poor prognosis.

Long-Term Follow-up Data of a Multi-Institutional Phase-2 Study of S-1/oxaliplatin and Bevacizumab Therapy in Patients with Advanced Colorectal Cancer: The HiSCO-02 Study.

Oral fluoropyrimidines (FUs) have certain advantages over intravenous FUs, such as longer intervals between outpatient visits, no requirement for central venous port (CVP) implantation, and lower incidence of neutropenia. We previously reported the efficacy of S-1/oxaliplatin (SOX) with bevacizumab therapy as a first-line treatment for advanced colorectal cancer (CRC) in a prospective phase-II multi-institutional clinical trial (HiSCO-02 study). However, our prognostic data at the time lacked a sufficient observation period. Herein, we analyze the longer-term follow-up data, focusing on the status of eventual CVP implantation via an open-label, non-randomized, multicenter study. This study enrolled 55 patients (mean age, 64 years), of whom 43 died (41 of primary cancer). The median overall survival was 22.7 months (95% CI: 20.1-34.7 months). Post-treatment regimens after failure of first-line treatment were initiated in 43 patients; CPT11-based regimens were selected in most cases, and other oral FU combinations in nine. CVP was implanted in 35 patients prior to first-line treatment; eleven of the remaining 20 patients did not require CVP implantation. In conclusion, we report here the final prognostic update of the Phase II clinical trial examining the efficacy of SOX plus bevacizumab therapy, the results of which confirm the clinical efficacy of this regimen.

Donor Age Correlates With Liver-Resident Natural Killer Cell Activity in Adoptive Immunotherapy Using Donor Liver Natural Killer Cells in Liver Transplantation.

BACKGROUND: Natural killer (NK) cells are involved in innate immunity and have been reported to play an important role in hepatocellular carcinoma recurrence and post-liver transplantation (LT) infection. However, the relationship between donor age and liver-resident NK cell activity remains to be elucidated. METHODS: We successfully performed NK cell immunotherapy in 19 living donor LT recipients to prevent post-LT bloodstream infections. Liver mononuclear cells (LMNCs) were collected from the liver graft perfusate and stimulated with interleukin 2 for 3 days. Liver-resident NK cells were analyzed using flow cytometry and a chromium release assay before and after cell culture. RESULTS: The median donor age was 44 years (range, 24-64 years). The graft weight was 492 g (range, 338-642 g), and the median number of LMNCs was 584 million cells (range, 240-1472 million cells). The proportion of NK cells before and after culture was 22% and 33%, respectively. A significant correlation was found between graft weight and the number of LMNCs. However, no correlation was found between donor age and the number or percentage of NK cells in the liver. Moreover, donor age showed a significant inverse correlation with NKp46 and NKp44 expression before culture and with NKp44, tumor necrosis factor-related apoptosis-inducing ligand, and CD69 expression after culture. CONCLUSION: A significant inverse correlation was observed between donor age and NK cell activity in the liver. This information may be useful for cell therapy during LT.

C-Reactive Protein/Albumin Ratio Is an Independent Risk Factor for Recurrence and Survival Following Curative Resection of Stage I-III Colorectal Cancer in Older Patients.

BACKGROUND: The number of older patients with cancer has increased, and colorectal cancer is expected to be affected by this trend. This study aimed to compare prognostic factors, including nutritional and inflammation-based indices, between patients aged ≥ 70 and < 70 years following curative resection of stage I-III colorectal cancer. PATIENTS AND METHODS: This study included 560 patients with stage I-III colorectal cancer who underwent curative resection between May 2010 and June 2018. A retrospective analysis was performed to identify prognosis-associated variables in patients aged ≥ 70 and < 70 years. RESULTS: Preoperative low body mass index, high C-reactive protein/albumin ratio, and comorbidities were mainly associated with poor prognosis in patients aged ≥ 70 years. Tumor factors were associated with a poor prognosis in patients aged < 70 years. The C-reactive protein/albumin ratio was independently associated with poor overall survival and recurrence-free survival in those aged ≥ 70 years. The time-dependent area under the curve for the C-reactive protein/albumin ratio was superior to those of other nutritional and inflammation-based indices in most postoperative observation periods in patients aged ≥ 70 years. CONCLUSIONS: Tumor factors were associated with a poor prognosis in patients aged < 70 years. In addition to lymph node metastasis, preoperative statuses were associated with poor prognosis in patients aged ≥ 70 years. Specifically, the preoperative C-reactive protein/albumin ratio was independently associated with long-term prognosis in patients aged ≥ 70 years with stage I-III colorectal cancer after curative resection.

Survival outcomes of patients with stage III colorectal cancer aged ≥ 80 years who underwent curative resection: the HiSCO-04 prospective cohort study.

BACKGROUND: The efficacy of adjuvant chemotherapy in elderly patients aged ≥ 80 years with stage III colorectal cancer remains unclear. In parallel with a multicenter prospective phase II trial evaluating the efficacy of uracil-tegafur and leucovorin as adjuvant chemotherapy (HiSCO-03), we conducted a prospective observational study of these patients to assess survival outcomes, including those ineligible for chemotherapy. METHODS: This multi-institutional prospective cohort study included 17 institutions in Hiroshima, Japan. Patients aged ≥ 80 years with stage III colorectal cancer who underwent curative resection were enrolled. The primary endpoint was 3-year disease-free survival, and the secondary endpoints were 3-year overall and relapse-free survival. Propensity score matching was used to assess the effects of adjuvant chemotherapy on survival outcomes. RESULTS: A total of 214 patients were analyzed between 2013 and 2018, including 99 males and 115 females with a median age of 84 years (range 80-101 years). Recurrence occurred in 58 patients and secondary cancers were observed in 17. The 3-year disease-free, overall, and relapse-free survival rates were 63.3%, 76.9%, and 62.9%, respectively. Adjuvant chemotherapy was administered to 65 patients with a completion rate of 52%. In a study of 80 patients that adjusted for background factors using propensity score matching, patients who completed the planned treatment showed improved disease-free survival (3-year disease-free survival: completed, 80.0%; not received, 65.5%; and discontinued, 56.3%; p = 0.029). CONCLUSIONS: Completion of adjuvant chemotherapy may improve the prognosis of patients with colorectal cancer aged ≥ 80 years, although the number of patients who would benefit from it is limited.

Association between social background and implementation of postoperative adjuvant chemotherapy for older patients undergoing curative resection of colorectal cancers, sub-analysis of the HiSCO-04 study.

PURPOSE: Adjuvant chemotherapy is recommended following colorectal cancer resection based on risk of recurrence. In older patients, treatment decisions should consider recurrence rates and tolerability, as well as functional prognosis, residual disease, and social factors. This study aims to investigate factors, including social background, influencing implementation of postoperative adjuvant chemotherapy in older patients undergoing curative resection for colorectal cancer. METHODS: This multi-institutional prospective cohort study included 15 institutions belonging to the Hiroshima Surgical study group for Clinical Oncology. We analyzed 159 older patients aged ≥ 80 years, who underwent curative resection for stage III colorectal cancer between December 2013 and June 2018, as sub-analysis of the HiSCO-04 study. RESULTS: In total, 62 (39.0%) patients underwent postoperative adjuvant chemotherapy. Four factors were significantly associated with its implementation: performance status < 2, Charlson Comorbidity Index < 2, prognostic nutritional index ≥ 40, and presence of a spouse or siblings as lifestyle supporters. No significant difference was found in the backgrounds between complete and incomplete postoperative adjuvant chemotherapy patients. CONCLUSION: Performance status, Charlson Comorbidity Index, nutritional status, and presence of a spouse or siblings as lifestyle supporters are possible factors influencing the implementation of postoperative adjuvant chemotherapy in older patients. To select appropriate treatment options, including postoperative adjuvant chemotherapy, it is essential to consider physical condition and comorbidities of older patients, thoroughly explain the situation to their families, and establish a support system to enhance understanding of the available treatment options.

Impact of a new liver immune status index among patients with hepatocellular carcinoma after initial hepatectomy.

Aim: The anti-tumor effects of natural killer (NK) cells vary among individuals. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) expressed on liver NK cells is a marker of anti-tumor cytotoxicity against hepatocellular carcinoma (HCC) in immune cell therapy. This study aimed to develop a liver immune status index (LISI) that predicts low TRAIL expression and validates its ability to predict recurrence after initial hepatectomy for primary HCC. Methods: A functional analysis of liver NK cells co-cultured with interleukin-2 for 3 days was performed of 40 liver transplant donors. The LISI, which predicted low TRAIL expression (25% quartile: <33%) in liver NK cells, was calculated using multiple logistic regression analysis. Next, 586 initial hepatectomy cases were analyzed based on the LISI. Results: Our model was based on the Fibrosis-4 index+0.1 (odds ratio [OR], 1.33), body mass index (OR, 0.61), and albumin levels+0.1 (OR, 0.54). The area under the receiver operating characteristic curve (AUC) of the LISI for low TRAIL expression was 0.89. Stratification of the recurrence rates (RR) revealed that LISI was an independent predictive factor of RR (moderate risk: hazard ratio, 1.44; high risk: hazard ratio, 3.02). The AUC was similar for the LISI, albumin-indocyanine green evaluation grade, albumin-bilirubin score, and geriatric nutritional risk index for predicting RR. Among the vascular invasion cases, the LISI was more useful than the other indexes. Conclusion: Our model facilitates the prediction of RR in high-risk patients by providing LISI to predict the anti-tumor effects of NK cells.

Stomal Prolapse Due to Sidedness of Transverse Loop Colostomy: A Retrospective Cohort Study.

Objectives: Stomal prolapse (SP) is one of the most common complications of loop colostomy and can impair a patient's quality of life. Herein, we evaluated the risk factors for SP to prevent its occurrence after a transverse loop colostomy. Methods: This retrospective study included 84 patients who underwent loop transverse colostomy between January 2016 and December 2020. We evaluated the incidence of SP and examined the relationship between perioperative factors and SP using univariate and multivariate logistic regressions. Results: SP occurred in 11 (13.0%) patients. Median time to SP was 99 postoperative days. In the univariate analysis, a right side abdominal wall stoma site, perioperative chemotherapy, and anti-VEGF antibody therapy were associated with a significantly higher incidence of SP. Multivariate analysis identified that construction of a temporary loop colostomy in the right transverse colon during rectal cancer surgery (odds ratio, 5.07; 95% confidence interval, 1.12-22.86) is an independent risk factor. Conclusions: In this study, multivariate analysis showed that the right side of the transverse colon was a risk factor for SP. Therefore, when constructing a transverse colon loop stoma, the stoma should be constructed in the left transverse colon to prevent SP.

The aryl hydrocarbon receptor maintains antitumor activity of liver resident natural killer cells after partial hepatectomy in C57BL/6J mice.

BACKGROUND: Liver-resident natural killer (lr-NK) cells are distinct from conventional NK cells and exhibit higher cytotoxicity against hepatoma via tumor necrosis factor-related apoptosis-inducing ligand (TRAIL). However, the mechanism by which partial hepatectomy (PH) significantly suppresses TRAIL expression in lr-NK cells remains unclear. METHODS: This study aimed to investigate the PH influence on the function and characteristics of liver-resident NK (lr-NK) cells using a PH mouse model. RESULTS: Here, we report that PH alters the differentiation pattern of NK cells in the liver, and an aryl hydrocarbon receptor (AhR) molecule is involved in these changes. Treatment with the AhR agonist 6-formylindolo[3,2-b]carbazole (FICZ) inhibited the maturation of NK cells. FICZ increased the immature subtype proportion of NK cells with high TRAIL activity and decreased the mature subtype of NK cells with low TRAIL activity. Consequently, FICZ increased the expression of TRAIL and cytotoxic activity of NK cells in the liver, and this effect was confirmed even after hepatectomy. The participation of AhR promoted FoxO1 expression in the mTOR signaling pathway involved in the maturation of NK cells, resulting in TRAIL expression. CONCLUSION: Our findings provide direct in-vivo evidence that partial hepatectomy affects lrNK cell activity through NK cell differentiation in the liver. Perioperative therapies using an AhR agonist to improve NK cell function may reduce the recurrence of hepatocellular carcinoma after hepatectomy.

Laparoscopic excision of a retroperitoneal pseudocyst using a modified medial approach: A case report.

INTRODUCTION: Retroperitoneal pseudocysts of non-pancreatic origin are rare. Although the laparoscopic approach has been used for their treatment, laparotomy remains the mainstream strategy for these lesions. PRESENTATION OF CASE: We report the case of an asymptomatic 51-year-old male patient who was incidentally diagnosed with a retroperitoneal pseudocyst. Computed tomography showed a 3 × 3 cm cystic lesion in the retroperitoneum, localized between the third part of the duodenum and the inferior vena cava. The patient underwent complete laparoscopic excision using a modified right-sided colonic resection procedure (modified medial approach), and histopathological examination revealed a non-pancreatic retroperitoneal pseudocyst. The patient was discharged without any complications, and no postoperative recurrence was detected. DISCUSSION: Complete excision is of great significance in the treatment of retroperitoneal cysts. There have been few studies on the laparoscopic approach for retroperitoneal pseudocysts. A laparoscopic procedure is less invasive and helps identify the correct tissue planes to ensure complete resection and prevent inadvertent injury to adjacent vital structures. We detached the retroperitoneal lesion from the duodenum and safely removed it without damaging the surrounding organs by a modified medial approach. CONCLUSIONS: Retroperitoneal pseudocysts can be resected laparoscopically by identifying the correct tissue planes and adjacent vital structures.

Successful resection of rectal cancer and perirectal abscess following systemic chemotherapy and chemoradiotherapy: A case report.

INTRODUCTION AND IMPORTANCE: Perirectal abscesses are uncommon in colorectal cancer. Although abscess infection should be controlled before colorectal cancer treatment, abscess formation makes surgical resection and preoperative treatment difficult. There is currently no established treatment for colorectal cancer with perirectal abscesses. Here, we present a case of rectal cancer with a perirectal abscess that was resected after systemic chemotherapy followed by chemoradiotherapy. CASE PRESENTATION: A 73-year-old man presented to the outpatient clinic with complaints of weight loss and general malaise. Colonoscopy revealed a circumferential tumor 3 cm from the anal verge, and examination of the endoscopic biopsy specimen indicated a well-differentiated tubular adenocarcinoma. Pelvic magnetic resonance imaging revealed a perirectal abscess on the ventral aspect of the rectum. After sigmoid colostomy was performed to control the infection, 4 cycles of panitumumab and modified fluorouracil, leucovorin, and oxaliplatin were administered. After the perirectal abscess disappeared, chemoradiotherapy to the whole pelvis (radiotherapy 45Gy/25 fractions plus tegafur-gimeracil-oteracil) was administered. Total pelvic exenteration with an ileal conduit was performed via open surgery. The pathological diagnosis was well-differentiated tubular adenocarcinoma with complete resection and negative resection margins. No recurrence of cancer has been observed 26 months after surgery. CLINICAL DISCUSSION: Treatment of colorectal cancer with perirectal abscess is difficult to define the extent of resection due to the spread of inflammation. We believe that treatment should address high risk of local recurrence. CONCLUSION: After sigmoid colostomy, complete resection of colorectal cancer with perirectal abscess could be achieved by systemic chemotherapy followed by chemoradiotherapy.

[A Case of Advanced Esophageal Cancer with Esophago-Bronchial Fistula Closed by Pembrolizumab plus Chemotherapy Therapy].

We report a case of unresectable advanced esophageal cancer with an esophageal fistula that was treated with pembrolizumab plus CDDP plus 5-FU therapy and the fistula was closed. A 73-year-old male was diagnosed with cervical-upper thoracic esophageal cancer and esophago-bronchial fistula on CT and esophagogastroduodenoscopy. He underwent chemotherapy containing pembrolizumab. The fistula was closed after 4 cycles and oral intake became possible. Six months have passed since the first visit and chemotherapy is ongoing. The prognosis of esophago-bronchial fistula is extremely poor, and there is no established treatment, including fistula closure. Chemotherapy containing immune checkpoint inhibitors could considered to be expected not only for local control but also for long-term survival.

Arteriosclerosis Decreases Tumor Necrosis Factor-Related Apoptosis-Inducing Ligand Expression on Liver Natural Killer Cells in Living Donor Liver Transplantation.

BACKGROUND: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is critical for natural killer (NK) cell-mediated anti-tumor and anti-microbe killing. The TRAIL expression on the donor's liver NK cells from the liver perfusate after interleukin-2 stimulation varies between individuals and is unpredictable. This study aimed to clarify the risk factors for low TRAIL expression by analyzing perioperative donor characteristics. METHODS: This retrospective study of living donor liver transplant (LDLT) donors between 2006 and 2022 was performed to analyze low TRAIL expression risk factors. Seventy-five donors who had undergone hepatectomy for LDLT were divided into 2 groups, low and high TRAIL, according to their TRAIL expression on liver NK cells, using median values. RESULTS: The low TRAIL group (N = 38) was older and had lower nutrition and a higher low-density lipoprotein/high-density lipoprotein (LDL/HDL) cholesterol ratio, related to arteriosclerosis, than the high TRAIL group (N = 37). In multivariate analysis, the geriatric nutritional risk index (GNRI) (odds ratio, 0.86; 95% CI, 0.76-0.94; P < .001) and LDL/HDL cholesterol ratio (odds ratio, 2.32; 95% CI, 1.10-4.86; P = .005) were independent predictive factors for low TRAIL expression on liver NK cells. Furthermore, the TRAIL expression of liver NK cells decreased in donors who already had atherosclerosis and in donors at risk of potentially developing atherosclerosis. CONCLUSIONS: The TRAIL expression on liver NK cells in donors had a strong relationship with atherosclerosis and GNRI. Atherosclerosis can reflect the TRAIL expression on liver NK cells.

Chemotherapy-induced neutropenia as a prognostic factor in patients with extensive-stage small cell lung cancer.

PURPOSE: Chemotherapy-induced neutropenia (CIN) is a dose-limiting factor for cytotoxic chemotherapy, but recently, it was suggested that CIN contributes to prolonged survival. In this study, we examined the association between severe CIN and survival and determined whether CIN affected survival in patients with extensive-stage small cell lung cancer (ES-SCLC). METHODS: The medical records from 214 patients with ES-SCLC treated with etoposide or irinotecan in combination with cisplatin (EP/IP) between 2012 and 2016 were collected and retrospectively analyzed. Landmark analysis was performed at the end of cycle 4, and the relationship between severe CIN and survival was determined by a log-rank test. In addition, a multivariate analysis using the COX proportional hazard model was performed to identify independent predictive factors. The Landmark analysis included 102 patients in the IP group and 47 patients in the EP group. RESULTS: No significant difference was found between grades 0-3 and grade 4 neutropenia and overall survival (OS) in the EP group (P = 0.57). Contrariwise, for the IP patients, the median OS was 444 days for grades 0-3 and 633 days for grade 4 neutropenia, which was significantly longer for patients who developed grade 4 neutropenia (P = 0.03). Multivariate analysis adjusted for potential factors revealed that the development of grade 4 CIN was identified as a significant predictor of longer OS (hazard ratio [HR], 0.50; 95% confidence interval (CI), 0.28-0.87, P = 0.015). CONCLUSION: The results indicated that the development of severe CIN with IP therapy is associated with prolonged OS.