Unique Biology of Pancreatic Ductal Adenocarcinoma Accompanied by Rapidly Impaired Diabetes: A Favorable Long-Term Survival Following Curative Resection.

BACKGROUND: Pancreatic ductal adenocarcinomas (PDACs) are sometimes diagnosed accompanied by rapidly impaired diabetes (PDAC-RID). Although this type of PDAC may have unusual biological features, these features have not been explained. METHODS: Patients with PDAC who underwent upfront pancreatectomy between 2010 and 2018 were retrospectively reviewed. PDAC-RID was defined as a glycated hemoglobin (HbA1c) value of ≥ 8.0% of newly diagnosed diabetes, and acute exacerbation of previously diagnosed diabetes. Other patients were classified as PDAC with stable glycometabolism (PDAC-SG). Clinicopathological factors, long-term survival rates, and recurrence patterns were evaluated. RESULTS: Of the 520 enrolled patients, 104 were classified as PDAC-RID and 416 as PDAC-SG. There was no significant difference regarding TNM staging, resectability, or adjuvant chemotherapy rate between the groups. However, 5-years cancer-specific survival (CSS) was significantly higher in the PDAC-RID group than in the PDAC-SG group (45.3% vs. 31.1%; p = 0.02). This survival difference was highlighted in relatively early-stage PDAC (≤ pT2N1) (CSS: 60.8% vs. 43.6%; p = 0.01), but the difference was not significant for advanced-stage PDAC. A multivariate analysis of early-stage PDAC showed that PDAC-SG was an independent risk factor of shorter CSS (hazard ratio 1.76; p = 0.02). The hematogenous metastatic rate in early-stage PDAC was lower in the PDAC-RID group than in the PDAC-SG group (18.3% vs. 35.8%; p = 0.01). CONCLUSIONS: PDAC-RID showed a favorable long-term survival rate after curative resection with low hematogenous metastases, which may be due to its unique biology.

Jejunum Patch Technique During Robot-Assisted Central Pancreatectomy: A Lesson from Open Procedure Experience.

BACKGROUND: Central pancreatectomy (CP) has been established as the most common type of parenchyma-sparing pancreatectomy;1 however, CP is associated with higher morbidity and a higher pancreatic fistula (PF) rate than distal pancreatectomy or pancreaticoduodenectomy.2,3 The jejunum patch technique (JPT) for distal pancreatectomy has recently been applied, which efficiently decreases the incidence of PF.4 We have adapted this technique to CP as well as distal pancreatectomy with celiac axis resection.5 Here, we retrospectively evaluated the usefulness of JPT for open CP cases, and report the experience of robot-assisted CP using the JPT. METHODS: Among 37 consecutive cases who underwent CP at our institution between 2011 and 2022, clinical characteristics and postoperative short-term outcomes were compared between patients who underwent CP with and without the JPT. In robot-assisted CP using the JPT, after resection of the middle of the pancreas the transected jejunum was elevated through the retrocolic route in a Roux-en-Y fashion. The pancreatic stump was covered by the JPT using a modified Blumgart technique, following pancreaticojejunostomy for the distal side.6 RESULTS: Among the entire cohort, 19 patients underwent CP using the JPT. The clinically relevant PF rate of the JPT group was significantly lower (47.4%) than the no-JPT group (83.3%, p = 0.022), and the length of drainage and hospital stay were shorter in the JPT group (p= 0.010 and p = 0.017, respectively). The blood loss of robot-assisted CP using the JPT was 20 mL, and the JPT took only 15 min. CONCLUSION: Robot-assisted CP using the JPT is an easy-to-use and promising procedure, based on experience and outcomes from open surgery.

New Diagnostic Modality Combining Mass Spectrometry and Machine Learning for the Discrimination of Malignant Intraductal Papillary Mucinous Neoplasms.

BACKGROUND: An intraductal papillary mucinous neoplasm (IPMN) is a pancreatic tumor with malignant potential. Although we anticipate a sensitive method to diagnose the malignant conversion of IPMN, an effective strategy has not yet been established. The combination of probe electrospray ionization-mass spectrometry (PESI-MS) and machine learning provides a promising solution for this purpose. METHODS: We prospectively analyzed 42 serum samples obtained from IPMN patients who underwent pancreatic resection between 2020 and 2021. Based on the postoperative pathological diagnosis, patients were classified into two groups: IPMN-low grade dysplasia (n = 17) and advanced-IPMN (n = 25). Serum samples were analyzed by PESI-MS, and the obtained mass spectral data were converted into continuous variables. These variables were used to discriminate advanced-IPMN from IPMN-low grade dysplasia by partial least square regression or support vector machine analysis. The areas under receiver operating characteristics curves were obtained to visualize the difference between the two groups. RESULTS: Partial least square regression successfully discriminated the two disease classes. From another standpoint, we selected 130 parameters from the entire dataset by PESI-MS, which were fed into the support vector machine. The diagnostic accuracy was 88.1%, and the area under the receiver operating characteristics curve was 0.924 by this method. Approximately 10 min were required to perform each method. CONCLUSION: PESI-MS combined with machine learning is an easy-to-use tool with the advantage of rapid on-site analysis. Here, we show the great potential of our system to diagnose the malignant conversion of IPMN, which would be a promising diagnostic tool in clinical settings.

Probe electrospray ionization mass spectrometry-based rapid diagnosis of liver tumors.

BACKGROUND AND AIM: Prompt differential diagnosis of liver tumors is clinically important and sometimes difficult. A new diagnostic device that combines probe electrospray ionization-mass spectrometry (PESI-MS) and machine learning may help provide the differential diagnosis of liver tumors. METHODS: We evaluated the diagnostic accuracy of this new PESI-MS device using tissues obtained and stored from previous surgically resected specimens. The following cancer tissues (with collection dates): hepatocellular carcinoma (HCC, 2016-2019), intrahepatic cholangiocellular carcinoma (ICC, 2014-2019), and colorectal liver metastasis (CRLM, 2014-2019) from patients who underwent hepatic resection were considered for use in this study. Non-cancerous liver tissues (NL) taken from CRLM cases were also incorporated into the analysis. Each mass spectrum provided by PESI-MS was tested using support vector machine, a type of machine learning, to evaluate the discriminatory ability of the device. RESULTS: In this study, we used samples from 91 of 139 patients with HCC, all 24 ICC samples, and 103 of 202 CRLM samples; 80 NL from CRLM cases were also used. Each mass spectrum was obtained by PESI-MS in a few minutes and was evaluated by machine learning. The sensitivity, specificity, and diagnostic accuracy of the PESI-MS device for discriminating HCC, ICC, and CRLM from among a mix of all three tumors and from NL were 98.9%, 98.1%, and 98.3%; 87.5%, 93.1%, and 92.6%; and 99.0%, 97.9%, and 98.3%, respectively. CONCLUSION: This study demonstrated that PESI-MS and machine learning could discriminate liver tumors accurately and rapidly.

Radical Antegrade Modular Pancreatosplenectomy for Left-Sided Pancreatic Ductal Adenocarcinoma May Reduce the Local Recurrence Rate.

INTRODUCTION: Although several clinical applications have reported the usefulness of the radical antegrade modular pancreatosplenectomy (RAMPS) procedure for left-sided pancreatic ductal adenocarcinoma, few studies have reported the advantages of RAMPS with respect to the local recurrence (LR) rate. METHODS: As of 2018, 68 and 62 patients underwent RAMPS and standard retrograde pancreatosplenectomy (SRPS). The first recurrence and all subsequent recurrence sites observed on images during a follow-up period and/or chemotherapy. The clinical variables are collected retrospectively. RESULTS: LR only was found in 5 patients in the RAMPS group (5/68, 7.3%) and in 15 patients in the SRPS group (15/62, 24.2%; p = 0.008) as the first recurrence site. Any chemotherapies were not a risk factor for the incidence of LR. The 5-year cumulative LR rate was significantly lower in patients in the RAMPS group compared with those in the SRPS group (23.6% vs. 49.6%; p = 0.019). The 5-year overall survival was 42.2% in the RAMPS group and 33.0% in the SRPS group (p = 0.251). CONCLUSION: The RAMPS procedure for left-sided pancreatic ductal adenocarcinoma may reduce the LR, cumulative LR rates.

A new rapid diagnostic system with ambient mass spectrometry and machine learning for colorectal liver metastasis.

BACKGROUND: Probe electrospray ionization-mass spectrometry (PESI-MS) can rapidly visualize mass spectra of small, surgically obtained tissue samples, and is a promising novel diagnostic tool when combined with machine learning which discriminates malignant spectrum patterns from others. The present study was performed to evaluate the utility of this device for rapid diagnosis of colorectal liver metastasis (CRLM). METHODS: A prospectively planned study using retrospectively obtained tissues was performed. In total, 103 CRLM samples and 80 non-cancer liver tissues cut from surgically extracted specimens were analyzed using PESI-MS. Mass spectra obtained by PESI-MS were classified into cancer or non-cancer groups by using logistic regression, a kind of machine learning. Next, to identify the exact molecules responsible for the difference between CRLM and non-cancerous tissues, we performed liquid chromatography-electrospray ionization-MS (LC-ESI-MS), which visualizes sample molecular composition in more detail. RESULTS: This diagnostic system distinguished CRLM from non-cancer liver parenchyma with an accuracy rate of 99.5%. The area under the receiver operating characteristic curve reached 0.9999. LC-ESI-MS analysis showed higher ion intensities of phosphatidylcholine and phosphatidylethanolamine in CRLM than in non-cancer liver parenchyma (P < 0.01, respectively). The proportion of phospholipids categorized as monounsaturated fatty acids was higher in CRLM (37.2%) than in non-cancer liver parenchyma (10.7%; P < 0.01). CONCLUSION: The combination of PESI-MS and machine learning distinguished CRLM from non-cancer tissue with high accuracy. Phospholipids categorized as monounsaturated fatty acids contributed to the difference between CRLM and normal parenchyma and might also be a useful diagnostic biomarker and therapeutic target for CRLM.

Thick silk fibroin vascular graft: A promising tissue-engineered scaffold material for abdominal vein grafts in middle-sized mammals.

Abdominal vein replacement with synthetic tissue-engineered vascular grafts constructed from silk-based scaffold material has not been reported in middle-sized mammals. Fourteen canines that underwent caudal vena cava replacement with a silk fibroin (SF) vascular graft (15 mm long and 8 mm diameter) prepared with natural silk biocompatible thread were allocated to two groups, thin and thick SF groups, based on the graft wall thickness. The short-term patency rate and histologic reactions were compared. The patency rate at 2 weeks after replacement in the thin and thick SF groups was 50% and 88%, respectively (p = 0.04). CD31-positive endothelial cells covered the luminal surface of both groups at 4 weeks. The elastic modulus of the thick SF graft was significantly better than that of the thin SF graft (0.0210 and 0.0007 N/m2, p < 0.01). Roundness of thick SF groups (o = 0.8 mm) was better than thin SF (o = 2.0 mm). There was significant difference between the groups (p = 0.01). SF vascular grafts are a promising tissue-engineered scaffold material for abdominal venous system replacement in middle-sized mammals, with thick-walled grafts being superior to thin-walled grafts.

Transient loss of consciousness immediately after total pancreatectomy for pancreatic metastases from renal cell carcinoma: a case report.

BACKGROUND: Total pancreatectomy (TP) is often selected for treatment of various pancreatic diseases. However, the resultant lack of autoregulation of glycometabolism necessitates careful postoperative management. CASE PRESENTATION: A 77-year-old man who had undergone right nephrectomy for renal cell carcinoma 11 years previously presented with multiple histologically diagnosed pancreatic metastases. The patient had no notable comorbidities, including diabetes. Because no extrapancreatic organ metastasis was identified, he underwent TP as a curative treatment. He awoke from anesthesia and was extubated without any problems in the operating room. However, 15 min after entering the intensive care unit, he suddenly lost consciousness and became apneic, resulting in reintubation. Blood gas analysis revealed an increased glucose concentration (302 mg/dL) and mixed acid-base disorder (pH of 7.21) due to insulin insufficiency and fentanyl administration. After induction of continuous intravenous insulin infusion and termination of fentanyl, the glucose concentration and pH gradually improved. He regained clear consciousness and spontaneous ventilation and was extubated the next day with no difficulties or complications. CONCLUSION: This case highlights the importance of active monitoring of the glycemic state and pH after TP because of the possibility of deterioration due to TP itself as well as the lingering effects of anesthesia.

Venous invasion and lymphatic invasion are correlated with the postoperative prognosis of pancreatic neuroendocrine neoplasm.

BACKGROUND: To determine treatment strategies corresponding to a wide range of pancreatic neuroendocrine neoplasms staging, easier-to-use and detailed prognostic classification is required. METHODS: Patients with pancreatic neuroendocrine neoplasms who underwent curative-intent surgery at the University of Tokyo Hospital between 2000 and 2018 were retrospectively reviewed. The presence or absence of venous and lymphatic invasion was assessed. Multivariable analysis was performed to identify the risk factors of shorter overall survival and recurrence-free survival. Patients were classified into the following 3 groups: a lymphovascular invasion 0 group, whereby both venous and lymphatic invasion were negative; an lymphovascular invasion 1 group, where either of the 2 was positive; and an lymphovascular invasion 2 group, where both were positive. The survival curves and recurrence patterns of the 3 groups were compared. RESULTS: Eighty-nine patients were analyzed. Multivariable analysis revealed that lymphatic invasion and Ki-67 index (≥ 3.0%) were independent prognostic factors of recurrence-free survival (hazard ratio: 5.2 and 3.6). Fifty-three patients were classified as lymphovascular invasion 0, 26 as lymphovascular invasion 1, and 10 as lymphovascular invasion 2. The recurrence-free survival curves of the 3 groups were significantly stratified (10-year recurrence-free survival: 89.1% in lymphovascular invasion 0, 57.1% in lymphovascular invasion 1, and 18.3% in lymphovascular invasion 2). Five-year cumulative liver and lymph node metastasis of lymphovascular invasion 0, lymphovascular invasion 1, and lymphovascular invasion 2 were well stratified at 0% and 3.8%, 15.8% and 23.1%, and 33.3% and 70.0%, respectively. CONCLUSION: Postoperative prognosis of resected pancreatic neuroendocrine neoplasms could be finely classified by venous invasion and lymphatic invasion. Management after curative-intent surgery for pancreatic neuroendocrine neoplasms may be changed by this new classification.

Diabetogenic liver metastasis from pancreatic cancer: a case report.

BACKGROUND: Although new-onset diabetes has been described in up to 20% of patients with newly diagnosed pancreatic cancer, reports regarding new-onset diabetes associated with newly developed liver metastasis from pancreatic cancer are limited. CASE PRESENTATION: A 60-year-old man was diagnosed with pancreatic tail cancer without impaired glycemic control. A curative-intent distal pancreatectomy with adjuvant S-1 chemotherapy was performed. Two years after surgery, a high HbA1c concentration and solitary liver metastasis were identified on follow-up examination. Two major chemotherapy regimens, gemcitabine/nab-paclitaxel and modified FOLFIRINOX, were sequentially administered to the patient; however, his carbohydrate 19-9 concentration continued to increase. Because the patient's glycemic control rapidly worsened in synchrony with the tumor growth, insulin therapy was initiated. Although the liver metastasis was refractory to chemotherapy, curative-intent left hepatectomy was performed because only one tumor remained. His impaired glycemic control improved immediately after surgery, and insulin therapy was terminated. When writing this report (2 years after hepatectomy), the patient was alive and recurrence-free. CONCLUSIONS: New-onset diabetes appeared with the progression of metachronous liver metastasis from pancreatic cancer, without recurrence at any other site. The patient's diabetic state was improved by resection of the liver tumor, and liver metastasis itself was proven to have caused the glucometabolic disorder by increasing insulin resistance.

Survey of surgical resections for neuroendocrine liver metastases: A project study of the Japan Neuroendocrine Tumor Society (JNETS).

BACKGROUND/PURPOSE: Hepatic resection is considered the treatment of choice for neuroendocrine liver metastases (NELM). However, the safety and efficacy of resection have not been fully evaluated using a large cohort. The aim of the present study was to collect real-world data regarding hepatic resections for NELM. METHODS: A retrospective, multicenter survey was conducted. The background characteristics of patients undergoing an initial hepatic resection for NELM, the operative details, pathological findings, and patient outcomes were investigated. RESULTS: A total of 222 patients were enrolled from 30 institutions. The primary tumor site was the pancreas in 58.6%, and the presentation of NELM was synchronous in 63.1% of the cases. Concomitant resection of the primary tumor and liver metastases was performed for 66.4% of the synchronous metastases, and the 90-day morbidity and mortality rates were 12.6% and 0.9%, respectively. The operations resulted in R2 resections in 26.1% of the cases, and 83.4% of the patients experienced recurrence after R0/1 resections. However, the patients were treated using multiple modalities after R2 resection or recurrence, and the overall survival rate was relatively favorable, with 5-year and 10-year survival rates of 70.2%, and 43.4%, respectively. Univariable and multivariable analyses identified the tumor grading (G3) of the primary tumor as a significant prognostic factor for both the recurrence-free and overall survivals. CONCLUSIONS: The present data confirmed the safety of the surgical resection of NELM. Although recurrences were frequent, the survival outcomes after resection were favorable when a multi-disciplinary treatment approach was used.

High-performance Collective Biomarker from Liquid Biopsy for Diagnosis of Pancreatic Cancer Based on Mass Spectrometry and Machine Learning.

Background: Most pancreatic cancers are found at progressive stages when they cannot be surgically removed. Therefore, a highly accurate early detection method is urgently needed. Methods: This study analyzed serum from Japanese patients who suffered from pancreatic ductal adenocarcinoma (PDAC) and aimed to establish a PDAC-diagnostic system with metabolites in serum. Two groups of metabolites, primary metabolites (PM) and phospholipids (PL), were analyzed using liquid chromatography/electrospray ionization mass spectrometry. A support vector machine was employed to establish a machine learning-based diagnostic algorithm. Results: Integrating PM and PL databases improved cancer diagnostic accuracy and the area under the receiver operating characteristic curve. It was more effective than the algorithm based on either PM or PL database, or single metabolites as a biomarker. Subsequently, 36 statistically significant metabolites were fed into the algorithm as a collective biomarker, which improved results by accomplishing 97.4% and was further validated by additional serum. Interestingly, specific clusters of metabolites from patients with preoperative neoadjuvant chemotherapy (NAC) showed different patterns from those without NAC and were somewhat comparable to those of the control. Conclusion: We propose an efficient screening system for PDAC with high accuracy by liquid biopsy and potential biomarkers useful for assessing NAC performance.

Repeat hepatectomy for patients with recurrent neuroendocrine liver metastasis: Comparison with first hepatectomy.

BACKGROUND: The value of repeat hepatectomy for intrahepatic recurrence after curative resection of neuroendocrine liver metastasis (NELM) remains unclear. The aim of this retrospective cohort study was to determine the significance of repeat hepatectomy for recurrent NELM. METHODS: Patients who underwent hepatectomy for NELM between 1994 and 2016 were identified. The indications for a first hepatectomy were adequate liver remnant volume and no extrahepatic metastasis. The diagnosis of recurrent NELM was based on radiographic examinations. The indications for a repeat hepatectomy were the same as those for the first hepatectomy. Clinicopathologic factors, short-term survival, and long-term survival were investigated using clinical records. RESULTS: Forty-four patients enrolled in this study. Thirty-three patients among them underwent a curative hepatectomy, and 28 of them developed recurrence. Of them, 16 patients underwent a repeat hepatectomy. The overall survival of the repeat hepatectomy cohort (n = 16) was significantly better than that of the no repeat hepatectomy cohort (n = 12) (P < .001). The progression free survival after the first hepatectomy (n = 44) and that after repeat hepatectomy (n = 16) were similar (P = .546). No significant difference was seen between the frequency of major complications (Clavien-Dindo score ≥ 3a) after the first and repeat hepatectomy (P = .279). No repeat hepatectomy (hazard ratio [HR] 5.0, P = .036) was identified as an independent predictive factor of a poor outcome among the recurrent cohort, along with the presence of multiple nodules (HR 26.2, P = .008) and a CA19-9 level ≥40 U/mL (HR 11.2, P = .012). CONCLUSIONS: A repeat hepatectomy is feasible in selected patients with recurrent NELM.

Silk fibroin vascular graft: a promising tissue-engineered scaffold material for abdominal venous system replacement.

No alternative tissue-engineered vascular grafts for the abdominal venous system are reported. The present study focused on the development of new tissue-engineered vascular graft using a silk-based scaffold material for abdominal venous system replacement. A rat vein, the inferior vena cava, was replaced by a silk fibroin (SF, a biocompatible natural insoluble protein present in silk thread), tissue-engineered vascular graft (10 mm long, 3 mm diameter, n = 19, SF group). The 1 and 4 -week patency rates and histologic reactions were compared with those of expanded polytetrafluoroethylene vascular grafts (n = 10, ePTFE group). The patency rate at 1 and 4 weeks after replacement in the SF group was 100.0% and 94.7%, and that in the ePTFE group was 100.0% and 80.0%, respectively. There was no significant difference between groups (p = 0.36). Unlike the ePTFE graft, CD31-positive endothelial cells covered the whole luminal surface of the SF vascular graft at 4 weeks, indicating better endothelialization. SF vascular grafts may be a promising tissue-engineered scaffold material for abdominal venous system replacement.

A selective oral vasopressin V2-receptor antagonist for patients with end-stage liver disease awaiting liver transplantation: a preliminary study.

Administration of the selective arginine vasopressin V2 receptor antagonist tolvaptan to cirrhotic patients is controversial. There are no reports of tolvaptan use for patients with far-advanced end-stage liver disease (ESLD) and refractory ascites awaiting liver transplantation. Between 2013 and 2016, 64 patients awaiting adult-to-adult living donor liver transplantation (LDLT) were screened for enrollment. Patients with refractory ascites and on dual conventional diuretics (≥ 50 mg/day of spironolactone and ≥ 20 mg/day of a loop diuretic) were enrolled and assigned to the tolvaptan (TOL) group (n = 10), and low-dose tolvaptan, 3.75 mg/day, was started. The remaining patients who had no or little ascites on conventional diuretic therapy (CDT) were assigned to the CDT group (n = 23). The median model for end-stage liver disease and Child-Pugh scores were 16 (range 7-41) and 10 (7-15), respectively. The median dose of spironolactone in the TOL group was 88 mg (range 50-200) vs. 50 (0-100) in the CDT group (p < 0.01). The median dose of loop diuretics in the TOL group was 70 mg (20-120) vs. 20 (0-80) in the CDT group (p = 0.03). No significant liver damage was detected during tolvaptan therapy. Tolvaptan demonstrated favorable effects in 60% (6/10) of the patients, decreasing the body weight by at least 1.5 kg during the 7 day treatment. These findings suggest that low-dose of tolvaptan may be safe for patients having far-advanced ESLD patients with apparent and refractory ascites taking dual conventional diuretics for a short period before LDLT.

Multi-center clinical evaluation of streptozocin-based chemotherapy for advanced pancreatic neuroendocrine tumors in Japan: focus on weekly regimens and monotherapy.

PURPOSE: Streptozocin (STZ) is a key agent for treating advanced pancreatic neuroendocrine tumors (pNET). Most STZ regimens for pNET are daily and also include 5-fluorouracil (5FU), whereas STZ monotherapy and weekly regimens have also been applied in daily practice in Japan. The present study aimed to evaluate responses to weekly regimens and to STZ monotherapy, and to identify a predictive marker of a response to STZ. METHODS: Clinical data regarding STZ-based chemotherapy for pNET were collected between 2015 and 2017 at 25 facilities. We analyzed the effects, safety, progression-free survival (PFS), and factors that correlate with responses to STZ. RESULTS: The overall objective response rate (ORR) of 110 patients who underwent STZ-based chemotherapy (monotherapy, 81.8%; weekly regimen 46.4%) was 21.8%, and PFS was 9.8 months. The ORR of weekly vs. daily regimens was 21.6 vs. 22.0% (P = 1.000), and that of monotherapy vs. combination therapy was 21.1 vs. 25.0% (P = 0.766). A Ki67 proliferation index (Ki67) of > 5% was a predictive marker of a response to STZ (P = 0.017), whereas regimen type, mono- or combination therapy, treatment line and liver tumor burden were not associated with responses. The frequencies of Grade ≥ 3 nausea and hematological adverse events were significantly lower for monotherapy than combination therapy (P = 0.032). CONCLUSIONS: The effects of weekly STZ monotherapy on pNET are comparable to those previously reported and the toxicity profile was acceptable. Ki67 > 5% was the sole predictive marker of an objective response.

Near-infrared photothermal/photodynamic therapy with indocyanine green induces apoptosis of hepatocellular carcinoma cells through oxidative stress.

Indocyanine green (ICG) is a photothermal agent, photosensitizer, and fluorescence imaging probe which shows specific accumulation in hepatocellular carcinoma (HCC) cells. We recently developed a photodynamic therapy (PDT) using ICG and near-infrared (NIR) laser as a new anti-cancer treatment for HCC. However, the molecular mechanism underlying this effect needs to be elucidated. HuH-7 cells, a well-differentiated human HCC cell line, were transplanted subcutaneously into BALB/c-nu/nu mice for in vivo experiment. ICG was administered 24 h before NIR irradiation. The irradiation was performed at three tumor locations by 823-nm NIR laser on days 1 and 7. The temperature of HuH-7 xenografts increased to 48.5 °C 3 minutes after ICG-NIR irradiation start. Reactive oxygen species (ROS) production was detected after ICG-NIR irradiation both in vitro and in vivo. There was certain anti-tumor effect and ROS production even under cooling conditions. Repeated NIR irradiation increased the cell toxicity of ICG-NIR therapy; the mean tumor volume on day 9 was significantly smaller after ICG-NIR irradiation compared to tumor without irradiation (87 mm3 vs. 1332 mm3; p = 0.01) in HCC mice xenografts model. ICG-NIR therapy induced apoptosis in HCC cells via a photothermal effect and oxidative stress. Repeated ICG-NIR irradiation enhanced the anti-tumor effect.