Local oncolytic adenovirotherapy produces an abscopal effect via tumor-derived extracellular vesicles.

Extracellular vesicles (EVs) play important roles in various intercellular communication processes. The abscopal effect is an interesting phenomenon in cancer treatment, in which immune activation is generally considered a main factor. We previously developed a telomerase-specific oncolytic adenovirus, Telomelysin (OBP-301), and occasionally observed therapeutic effects on distal tumors after local treatment in immunodeficient mice. In this study, we hypothesized that EVs may be involved in the abscopal effect of OBP-301. EVs isolated from the supernatant of HCT116 human colon carcinoma cells treated with OBP-301 were confirmed to contain OBP-301, and they showed cytotoxic activity (apoptosis and autophagy) similar to OBP-301. In bilateral subcutaneous HCT116 and CT26 tumor models, intratumoral administration of OBP-301 produced potent antitumor effects on tumors that were not directly treated with OBP-301, involving direct mediation by tumor-derived EVs containing OBP-301. This indicates that immune activation is not the main factor in this abscopal effect. Moreover, tumor-derived EVs exhibited high tumor tropism in orthotopic HCT116 rectal tumors, in which adenovirus E1A and adenovirus type 5 proteins were observed in metastatic liver tumors after localized rectal tumor treatment. In conclusion, local treatment with OBP-301 has the potential to produce abscopal effects via tumor-derived EVs.

Surgical technique of suprapancreatic D2 lymphadenectomy focusing on the posterior hepatic plexus for advanced gastric cancer.

PURPOSE: Although D2 lymphadenectomy is currently considered a standard procedure for advanced gastric cancer (GC) worldwide, there is room for discussion about the appropriate range of suprapancreatic D2 lymphadenectomy. Focusing on the posterior hepatic plexus (PHP), which is not well recognized, we developed a surgical technique of suprapancreatic D2 lymphadenectomy, which we have called PHP-D2, and its short-term and long-term efficacies were evaluated in comparison with non-PHP-D2. METHODS: GC patients who underwent distal gastrectomy with D2 lymphadenectomy between July 2006 and May 2013 were enrolled, from which patients who had peritoneal metastasis and/or were peritoneal cytology-positive during surgery were excluded. Their medical records were retrospectively reviewed. RESULTS: Ninety-two patients (non-PHP-D2: 48, PHP-D2: 44) were enrolled. Shorter operation time (330 min vs 275 min, p < 0.0001) and less blood loss (290 mL vs 125 mL, p < 0.0001) were observed in PHP-D2, and no pancreatic fistulas were observed in PHP-D2. More lymph nodes of #11p (1 vs 1.5, p = 0.0328) and #12a lymph nodes (0 vs 1, p = 0.0034) were retrieved in PHP-D2, with no significant differences in #8a and #9 lymph nodes. Lymphatic recurrence was significantly less in PHP-D2 (p = 0.0166), and univariate and multivariate analyses showed that non-PHP-D2 was a significant risk factor for lymphatic recurrence (p = 0.0158), although there were no significant differences between non-PHP-D2 and PHP-D2 in 5-year overall survival and 5-year relapse-free survival. CONCLUSION: PHP-D2 was a safe and feasible procedure that had the potential to reduce lymphatic recurrence, and it can be a standard procedure of D2 lymphadenectomy for advanced GC.

Immune Modulation by Telomerase-Specific Oncolytic Adenovirus Synergistically Enhances Antitumor Efficacy with Anti-PD1 Antibody.

The clinical benefit of monotherapy involving immune checkpoint inhibitors (ICIs) such as anti-programmed death-1 antibody (PD-1 Ab) is limited to small populations. We previously developed a telomerase-specific oncolytic adenovirus, Telomelysin (OBP-301), the safety of which was confirmed in a phase I clinical study. Here, we examined the potential of OBP-502, an OBP-301 variant, as an agent for inducing immunogenic cell death (ICD) and synergistically enhancing the efficacy of OBP-502 with PD-1 Ab using CT26 murine colon cancer and PAN02 murine pancreatic cancer cell lines. OBP-502 induced the release of ICD molecules such as adenosine triphosphate (ATP) and high-mobility group box protein 1 (HMGB1) from CT26 and PAN02 cells, leading to recruitment of CD8-positive lymphocytes and inhibition of Foxp3-positive lymphocyte infiltration into tumors. Combination therapy involving OBP-502 intratumoral administration and PD-1 Ab systemic administration significantly suppressed the growth of not only OBP-502-treated tumors but also tumors not treated with OBP-502 (so-called abscopal effect) in CT26 and PAN02 bilateral subcutaneous tumor models, in which active recruitment of CD8-positve lymphocytes was observed even in tumors not treated with OBP-502. This combined efficacy was similar to that observed in a CT26 rectal orthotopic tumor model involving liver metastases. In conclusion, telomerase-specific oncolytic adenoviruses are promising candidates for combined therapies with ICIs.

Long-term Survival with a Rare Advanced Primary Gastrointestinal Malignant Melanoma Treated with Laparoscopic Surgery/Immune Checkpoint Inhibitor.

Targeted therapies for malignant melanoma have improved patients' prognoses. A primary gastrointestinal malignant melanoma is very rare, with no standard treatment strategy. We treated a 78-year-old Japanese female with advanced primary gastrointestinal melanoma of the descending colon and gallbladder. We administered a multidisciplinary treatment: surgical resection of the descending colon and gallbladder tumors, resection of the metastatic lymph nodes behind the pancreas head, and immune checkpoint antibody-blockade therapy (nivolumab) for ~4 years. PET/CT demonstrated no recurrent lesion for > 3 years. Multidisciplinary therapies (e.g., surgery, chemotherapy, radiotherapy, target therapy, and immune checkpoint antibody-blockade therapy) can successfully treat primary gastrointestinal malignant melanoma.

Accreditation as a qualified surgeon improves surgical outcomes in laparoscopic distal gastrectomy.

PURPOSE: The Endoscopic Surgical Skill Quantification System for qualified surgeons (QSs) was introduced in Japan to improve surgical outcomes. This study reviewed the surgical outcomes after initial experience performing laparoscopic distal gastrectomy (LDG) and evaluated the improvement in surgical outcomes following accreditation as a QS. METHODS: Eighty-seven consecutive patients who underwent LDG for gastric cancer by a single surgeon were enrolled in this study. The cumulative sum method was used to analyze the learning curve for LDG. The surgical outcomes were evaluated according to the two phases of the learning curve (learning period vs. mastery period) and accreditation (non-QS period vs. QS period). RESULTS: The learning period for LDG was 48 cases. Accreditation was approved at the 67th case. The operation time and estimated blood loss were significantly reduced in the QS period compared to the non-QS period (230 vs. 270 min, p < 0.001; 20.5 vs. 59.8 ml, p = 0.024, respectively). Furthermore, the major complication rate was significantly lower in the QS period than in the non-QS period (0 vs. 10.6%, p = 0.044). CONCLUSIONS: Experience performing approximately 50 cases is required to reach proficiency in LDG. After receiving accreditation as a QS, the surgical outcomes, including the complication rate, were improved.

Induction chemoradiotherapy including docetaxel, cisplatin, and 5-fluorouracil for locally advanced esophageal cancer.

BACKGROUND: Locally advanced esophageal cancer (EC) invading surrounding organs (T4b) is difficult to treat. In general, definitive chemoradiotherapy (d-CRT) has been chosen as treatment for such cases. However, the outcome has not been good. Recently, the effectiveness of d-CRT with docetaxel, cisplatin, and 5-fluorouracil (DCF-RT) has been reported. Furthermore, surgery after d-CRT has a better prognosis than d-CRT alone in some reports, although it has a high risk of surgical complications. This study investigated the effectiveness and safety of induction DCF-RT. METHODS: The subjects were EC patients who underwent induction DCF-RT in Okayama University Hospital between January 2011 and December 2017. Their background characteristics, treatment details, histopathological factors, adverse events during CRT, postoperative complications, and overall survival (OS) were assessed. RESULTS: A total of 16 cases were performed induction DCF-RT. In 10 cases, death occurred, with 9 cancer-related deaths, and 1 death due to other disease. For all cases, OS was 37.5% at 3 years. 12 cases underwent esophagectomy after DCF-RT. Their OS was 50% at 3 years. 13 patients (81.3%) had Grade 3 febrile neutropenia. In 7 cases (62.5%), fasting for the treatment of diarrhea was needed. Three patients (25%) developed anastomotic leakage. Some recurrent laryngeal nerve paralysis was observed in 6 cases (50%). CONCLUSION: Although the rates of adverse events and surgical complications were slightly higher than in past reports, they were acceptable. It is useful to perform induction DCF-RT for T4b EC.

[A Case of Inverted LECS for GIST in the Remnant Stomach after Distal Gastrectomy].

Laparoscopy and endoscopy cooperative surgery(LECS)is the surgical procedure used to avoid excessive resection of the gastrointestinal wall and preserve its function. We report the case of a patient who was successfully treated with inverted LECS for gastrointestinal stromal tumor(GIST)in the remnant stomach and underwent distal gastrectomy. The patient was a 75- year-old man who received distal gastrectomy for gastric ulcer 28 years before. Three years before he was diagnosed as having gastric submucosal tumor(SMT)as a gastrointestinal tumor(GIST)by using EUS. As the tumor increased, he was admitted to our hospital. Upper gastrointestinal endoscopy revealed a 30mm SMT just below the cardiac part of the remnant stomach. Biopsy by EUS-FNA revealed CD34(-), c-kit(+), S-100(-), and a-SMA(-), which indicated gastric GIST. Inverted LECS was performed. His postoperative course was good, and he was discharged from the hospital 9 days after the surgery.

Sarcopenia and Comorbidity in Gastric Cancer Surgery as a Useful Combined Factor to Predict Eventual Death from Other Causes.

BACKGROUND: Sarcopenia is recognized as an important prognostic factor in various types of cancer, including gastric cancer. While long-term survival analyses typically focus on overall and disease-specific survival, death from other causes has received far less attention. METHODS: We reviewed medical records of 491 gastric cancer patients who underwent gastrectomy from January 2005 to March 2014 and whose preoperative computed tomography (CT) images were available for evaluation of sarcopenia. Sarcopenia was defined as the SMA/BSA index (skeletal muscle area divided by body surface area) below the sex-specific lowest quartile. RESULTS: Sarcopenia was significantly associated with age, high body mass index (BMI), presence of comorbidity, high American Society of Anesthesiologists physical status (ASA-PS), high T score, advanced stage, large blood loss, and long hospital stay, but was not significantly associated with postoperative complications. Univariate and multivariate analyses of prognostic factors for overall survival revealed that sarcopenia is an independent predictor of poor prognosis [hazard ratio (HR) 1.46, 95% confidence interval (CI) 1.01-2.09, p  =  0.0454]. Our analysis of death due to other causes found that non-gastric cancer-related deaths were more frequent among sarcopenia patients with comorbidities than in the rest of our study population (p  =  0.0001), while univariate and multivariate analyses revealed that sarcopenia with comorbidity was an independent risk factor for non-gastric cancer-related death (HR 1.84, 95% CI 1.31-3.61, p  =  0.0308), as was age. CONCLUSION: For gastric cancer patients, sarcopenia increases the risk of death from other causes following surgery, which reveals the importance of developing treatment strategies based not only on cancer status but also on other clinical factors, including sarcopenia and comorbidity.

HER2-targeted gold nanoparticles potentially overcome resistance to trastuzumab in gastric cancer.

An issue of concern is that no current HER2-targeted therapeutic agent is effective against Trastuzumab (Tmab)-resistant gastric cancer. Gold nanoparticles (AuNPs) are promising drug carriers with unique characteristics of a large surface area available for attachment of materials such as antibodies. Here, we created HER2-targeted AuNPs (T-AuNPs) and examined their therapeutic efficacy and cytotoxic mechanisms using HER2-postive Tmab-resistant (MKN7) or Tmab-sensitive (NCI-N87) gastric cancer cell lines. In vitro, T-AuNPs showed stronger cytotoxic effects than controls against MKN7 and NCI-N87 cells although Tmab had no effect on MKN7 cells. Autophagy played an important role in T-AuNP cytotoxic mechanisms, which was considered to be driven by internalization of T-AuNPs. Finally, T-AuNPs displayed potent antitumor effects against NCI-N87 and MKN7 subcutaneous tumors in in vivo mouse models. In conclusion, HER2-targeted AuNPs with conjugated Tmab is a promising strategy for the development of novel therapeutic agents to overcome Tmab resistance in gastric cancer.

Randomized Controlled Trial of Epidural versus Patient-controlled Intravenous Analgesia for Postoperative Pain Control after Laparoscopic Gastrectomy.

Although epidural analgesia (EDA) is considered standard postoperative analgesia for open gastrectomy, it has been unclear whether EDA has benefits in laparoscopic gastrectomy (LG) because postoperative pain after a laparoscopic procedure is significantly reduced. We are conducting a two-arm, single-center, prospective randomized non-inferiority trial to evaluate the postoperative pain relief of patient-controlled intravenous analgesia (PCIA) compared to EDA. A total of 132 patients undergoing LG will be randomized to EDA and PCIA groups (n=64 each) for postoperative pain control. The primary endpoint is postoperative pain at 24 h after surgery. This study will clarify the optimal pain management after LG.

Clinical characteristics and management of gastric tube cancer after esophagectomy.

BACKGROUND: Gastric cancer is the second most common malignancy, overlapping with thoracic esophageal cancer (TEC). Among them, metachronous gastric tube cancers after TEC surgery have been increasing. The aims of this study were to examine the clinicopathological factors and treatment outcomes of gastric tube cancer (GTC) after TEC surgery. METHODS: Thirty-three GTCs in 30 cases after TEC treated between 1997 and 2016 were investigated retrospectively. RESULTS: Most cases were males. The median interval from TEC surgery to GTC occurrence was 57 (6.5-107.5) months. Almost 2/3 lesions occurred in the lower third of the gastric tube (21/33); 29 lesions (in 26 cases) were superficial cancers, and 4 lesions were advanced cancers. Twenty-two lesions of superficial cancer were differentiated type, and the remaining seven lesions were undifferentiated type. Treatment for superficial cancer had previously been performed with partial gastric tube resection (10 lesions), and the number of cases undergoing endoscopic submucosal dissection (ESD) had increased recently (19 lesions). Most cases with superficial cancer survived without relapse. Four lesions of advanced cancer were found after a relatively long interval following TEC surgery. Most lesions of advanced cancer were scirrhous, undifferentiated type, and they died due to GTC. CONCLUSION: GTCs may occur late in the postoperative course following TEC surgery. If they are discovered at an early stage, these lesions can be cured with ESD. Long-term periodic endoscopic examinations after TEC surgery are important.

Laparoscopic and luminal endoscopic cooperative surgery can be a standard treatment for submucosal tumors of the stomach: a retrospective multicenter study.

Background and study aims We have developed a combined laparoscopic and luminal endoscopic surgery technique for resection of gastric submucosal tumors (SMTs) that can be performed without excessive resection of the stomach. In a multicenter retrospective study we aimed to evaluate the feasibility and safety of laparoscopic and endoscopic cooperative surgery (LECS) for gastric SMT resection. Patients and methods Between October 2007 and December 2011, 126 patients with gastric SMTs underwent LECS at 8 institutions. Patient demographics, tumor histopathologic characteristics, and operative and follow-up data were reviewed. Results 16 tumors (12.7 %) were located in the upper third of the stomach, 88 (69.8 %) in the middle third, 5 (4.0 %) in the lower third, and 17 (13.5 %) at the esophagogastric junction. The mean (standard deviation [SD]) operation time for LECS was 190.2 (66.8) min, with a mean estimated blood loss of 15.1 (38.6) mL. In 2 cases (1.6 %), the procedure was converted to open surgery because of intra-abdominal adhesions or stenosis. Morbidity was found in 6 cases (4.8 %), including 2 leakage, 2 gastric stasis, 1 fever, and 1 cystitis. Histologically, a gastrointestinal stromal tumor (GIST) was found in 86 (68.3 %) cases. The median follow-up period was 54.7 months; no local or distant tumor recurrence was observed and all patients were alive. Conclusions LECS proved to be a safe and feasible procedure for the resection of gastric SMTs, with a reasonable operation time, low bleeding, and an acceptable complication rate in this multicenter study in Japan.

Nonexposure laparoscopic and endoscopic cooperative surgery (closed laparoscopic and endoscopic cooperative surgery) for gastric submucosal tumor.

Laparoscopic and endoscopic cooperative surgery (LECS) is increasingly applied for gastric submucosal tumors (SMTs) such as gastrointestinal stromal tumors. However, the conventional LECS procedure has the potential risk that gastric contents and even tumor cells could spread into the abdominal cavity because the gastric wall has to be opened during the resection. To avoid this problem, we have developed a modified LECS procedure named "closed LECS." Ten patients underwent closed LECS for the resection of gastric SMTs. Closed LECS consists of the following steps: endoscopic submucosal layer dissection around the tumor, laparoscopic marking of a resection line on the serosal surface along submucosal dissection line, seromuscular suturing with the marked lesion inverted into the inside of the stomach, endoscopic circumferential seromuscular dissection, and peroral retrieval. In three of the initial five cases, the closed LECS procedure was not completed as planned because of the tumor size and endoscopic inappropriate seromuscular dissection. After modification of the procedure, the entire procedure was successful in all five cases. The mean resected tumor diameter was 24.1 ± 7.6 mm. The mean operation time was 253 ± 45 min. One patient experienced an intra-abdominal abscess potentially related to delayed perforation as a postoperative complication. The closed LECS procedure for gastric SMTs can theoretically be applied without contamination and tumor cell dissemination into the abdominal cavity.

Training system for laparoscopy-assisted distal gastrectomy.

PURPOSE: Laparoscopy-assisted distal gastrectomy (LADG) is likely to become a standard procedure for gastric cancer, which highlights the importance of establishing a training system in which even inexperienced surgeons can perform this procedure safely. This study assesses our training system for LADG based on short-term surgical outcomes. METHODS: We evaluated retrospectively the short-term outcomes of 100 consecutive LADGs with curative D1/D1+ lymph node dissection. Our training system was assessed based on the learning curve of trainees, and factors related to achieving good-quality operations were analyzed statistically. RESULTS: Overall, postoperative complications developed in 10 patients (10%), and included one case of anastomotic leakage (1%) and one case of pancreatic fistula (1%). The learning curve of the trainees plateaued after 10 operator cases in terms of operation time. The importance of the trainer's position was also confirmed by the result that the operation time was significantly longer when trainees with ≤10 operator cases performed LADG with a trainer as scopist vs. a trainer as the first assistant. Univariate and multivariate analyses revealed that >10 operator cases were the most important factor for achieving good-quality operations. CONCLUSION: These results show that our current LADG procedure and training system are appropriate and effective.

Management of early gastric cancer that meet the indication for radical lymph node dissection following endoscopic resection: a retrospective cohort analysis.

BACKGROUND: Endoscopic resection (ER) has been widely accepted as the standard treatment for early gastric cancer (EGC). However, in patients considered to have undergone non-curative ER due to their potential risk of lymph node metastasis (LNM), additional gastrectomy is recommended. The aim of the present study was to identify EGC patients after non-curative ER at high risk of LNM. METHODS: A total of 150 patients who had undergone ER for EGC were diagnosed as non-curative ER due to their potential risk of LNM. Clinicopathological data and clinical outcomes were examined retrospectively. RESULTS: Additional gastrectomy with lymph node dissection was performed in 73 patients, and the remaining 77 patients were followed-up without additional gastrectomy. In patients who underwent additional gastrectomy, 8 patients had local residual tumor, and 8 patients had LNM, which were limited in the peritumoral nodes. Only lymphatic invasion (p = 0.012) was a statistically significant factor for LNM. The 5-year overall survival and recurrence-free survival were not significantly different between patients with and without additional gastrectomy. CONCLUSION: Additional gastrectomy with lymph node dissection is recommended for patients who were diagnosed as non-curative ER with lymphatic invasion, and minimizing the extent of lymph node dissection may be allowed for these patients.

[Novel Therapeutic Strategy for Human Epidermal Growth Factor Receptor 2-Positive Gastric Cancer].

Trastuzumab(Tmab), a humanized monoclonal antibody that selectively targets human epidermal growth factor receptor 2(HER2), is currently used in the clinical setting for the treatment of both breast and gastric cancer. While Tmab has shown improvements in patient prognoses, acquired resistance to this agent remains an issue. While some novel HER2-targeted agents have been approved for clinical use in breast cancer, no such agent has shown treatment efficacy for gastric malignancies with Tmab-resistance. Nanotechnology, which has progressed rapidly, has been applied to medical fields in recent years. Gold nanoparticles, which are characterized by their in vivo stability and ease of surface modification, have been reported to show efficacy as the carriers of therapeutic agents, such as drugs, antibodies, peptides, and nucleic acids. In this work, we developed Tmab-conjugated gold nanoparticles and demonstrate their efficacy for the treatment of HER2-positive, Tmabresistant gastric cancer cell lines. Our findings demonstrate that Tmab-conjugated gold nanoparticles have the potential to be a novelHER2 -targeted therapeutic agent.

[Multiple Salvage Radiotherapies for Metachronous Lymph Node Metastasis from Gastric Cancer Contributed to Long-Term Management of Disease].

A 70-year-old man who underwent gastrectomy for Stage III C gastric cancer developed lymph node(LN)metastasis posterior to the pancreatic head 3 years after the radical surgery.He was first treated with radiotherapy(RT)followed by chemotherapy.The irradiated tumor regressed completely.However, the cancer relapsed in a single para-aortic LN and he was treated with RT to the lesion followed by chemotherapy.Although it completely regressed, later, lung metastasis was observed.The lung lesions were well suppressed by switching to docetaxel; however, the cancer relapsed again in a mediastinal LN, and it was not responsive to docetaxel.The growing mediastinal lesion was irradiated again, which resulted in stable disease.The patient has been treated for 4 years and 7 months with all lesions being well-managed, and chemotherapy is being continued.Recurrent gastric cancer after surgery tends to present as multiple lesions; therefore, the principle therapy is systemic chemotherapy and RT is unlikely to be suitable.However, especially in cases of a solitary lesion that is chemo-resistant, RT could be an optimal option and contribute to long-term survival even in patients with recurrent gastric cancer.

[A Case of Goblet Cell Carcinoid of the Appendix Treated by Laparoscopic Ileocecal Resection after Diagnosis by Colonoscopic Examination for Positive Occult Blood].

A79 -year-old woman underwent colonoscopic examination for positive occult blood. Aneoplastic lesion was seen in the orifice of the vermiform appendix. She was referred to our hospital and underwent colonoscopic examination again. The biopsy revealed poorly differentiated adenocarcinoma or mixed adenoneuroendocrine carcinoma(MANEC), and she was diagnosed with carcinoma of the appendix. She was treated by laparoscopic ileocecal resection with lymph node dissection (D3). Histopathological examination revealed goblet cell carcinoid(GCC)of the appendix with serosal invasion. No metastasis was detected in the dissected lymph nodes. This patient has been followed-up for 6 months after surgery and no recurrences have been detected.

[Radical Thoracoscopic Esophagectomy for Elderly Patients with Advanced Esophageal Cancer].

We report a case of an elderly patient with advanced esophageal cancer who underwent multidisciplinary treatment. An 86-year-old male consulted our hospital with complaints of pharynx discomfort and difficulty in swallowing. He was preoperatively diagnosed with esophageal cancer, T3N2M0, Stage III . We performed 2 courses of cisplatin plus 5-FU therapy as neoadjuvant chemotherapy. The primary tumor and metastatic lymph nodes reduced in size, and thoracoscopic esophagectomy in the prone position was performed. Pathological findings were esophageal cancer, pT3-Ad, INF b, ly2, v1, IM0, pPM0, pDM0, pRM1, pN3, pStage III . As the radical margin was positive, chemoradiotherapy was performed. We continued postoperative chemotherapy for approximately 1 year, and the patient has survived without relapse for 4 years from esophagectomy. Even in patients over 80 years old, long-term prognosis can be expected by performing radical surgery and chemoradiotherapy.

Biological ablation of sentinel lymph node metastasis in submucosally invaded early gastrointestinal cancer.

Currently, early gastrointestinal cancers are treated endoscopically, as long as there are no lymph node metastases. However, once a gastrointestinal cancer invades the submucosal layer, the lymph node metastatic rate rises to higher than 10%. Therefore, surgery is still the gold standard to remove regional lymph nodes containing possible metastases. Here, to avoid prophylactic surgery, we propose a less-invasive biological ablation of lymph node metastasis in submucosally invaded gastrointestinal cancer patients. We have established an orthotopic early rectal cancer xenograft model with spontaneous lymph node metastasis by implantation of green fluorescent protein (GFP)-labeled human colon cancer cells into the submucosal layer of the murine rectum. A solution containing telomerase-specific oncolytic adenovirus was injected into the peritumoral submucosal space, followed by excision of the primary rectal tumors mimicking the endoscopic submucosal dissection (ESD) technique. Seven days after treatment, GFP signals had completely disappeared indicating that sentinel lymph node metastasis was selectively eradicated. Moreover, biologically treated mice were confirmed to be relapse-free even 4 weeks after treatment. These results indicate that virus-mediated biological ablation selectively targets lymph node metastasis and provides a potential alternative to surgery for submucosal invasive gastrointestinal cancer patients.