Overcoming immunotherapy resistance and inducing abscopal effects with boron neutron immunotherapy (B-NIT).

Immune checkpoint inhibitors (ICIs) are effective against many advanced malignancies. However, many patients are nonresponders to immunotherapy, and overcoming this resistance to treatment is important. Boron neutron capture therapy (BNCT) is a local chemoradiation therapy with the combination of boron drugs that accumulate selectively in cancer and the neutron irradiation of the cancer site. Here, we report the first boron neutron immunotherapy (B-NIT), combining BNCT and ICI immunotherapy, which was performed on a radioresistant and immunotherapy-resistant advanced-stage B16F10 melanoma mouse model. The BNCT group showed localized tumor suppression, but the anti-PD-1 antibody immunotherapy group did not show tumor suppression. Only the B-NIT group showed strong tumor growth inhibition at both BNCT-treated and shielded distant sites. Intratumoral CD8+ T-cell infiltration and serum high mobility group box 1 (HMGB1) levels were higher in the B-NIT group. Analysis of CD8+ T cells in tumor-infiltrating lymphocytes (TILs) showed that CD62L- CD44+ effector memory T cells and CD69+ early-activated T cells were predominantly increased in the B-NIT group. Administration of CD8-depleting mAb to the B-NIT group completely suppressed the augmented therapeutic effects. This indicated that B-NIT has a potent immune-induced abscopal effect, directly destroying tumors with BNCT, inducing antigen-spreading effects, and protecting normal tissue. B-NIT, immunotherapy combined with BNCT, is the first treatment to overcome immunotherapy resistance in malignant melanoma. In the future, as its therapeutic efficacy is demonstrated not only in melanoma but also in other immunotherapy-resistant malignancies, B-NIT can become a new treatment candidate for advanced-stage cancers.

Laparoscopic Resection Combined with a Transsacral Approach for a Recurrent Tailgut Cyst with a Refractory Fistula.

Tailgut cyst is a rare cystic disease of the anterior sacral surface and the remains of an embryonic tail gut. Tailgut cysts have a potential for malignancy, and complete resection with an adequate surgical margin is necessary. Even if incomplete resection does not result in recurrence of malignant disease, there is a risk of local infection leading to refractory fistulas. The optimal treatment for such refractory recurrent lesions has not been reported. We describe a case in which the combination of laparoscopic and transsacral approaches was effective for resecting a recurrent refractory fistula after incomplete resection of a tail gut cyst.

Perineal Squamous Cell Carcinoma Arising in an Epidermal Cyst.

A 90-year-old Japanese woman who had been aware of a subcutaneous mass on the right perineal region for 5 years was referred to our hospital for further examination and treatment because of the rapid growth of the mass and bleeding that began 3 months earlier. A biopsy of the mass revealed a diagnosis of well-differentiated squamous cell carcinoma. On preoperative examination, the tumor was 90×40 mm in size and was suspected to have partially invaded the levator ani muscle and external sphincter. Since a preoperative cardiac evaluation indicated severe aortic stenosis, we performed transcatheter aortic valve implantation. A radical resection was then performed with general anesthesia. The skin and subcutaneous tissue defects were reconstructed with a posterior gluteal-thigh propeller flap, and a sigmoid colostomy was created. The patient had a good postoperative course and was transferred to a rehabilitation facility 28 days after the surgery. Epidermal cysts are a common benign tumor, and clinicians should keep in mind that these cysts can become malignant.

Definitive S-1/mitomycin-C chemoradiotherapy for stage II/III anal canal squamous cell carcinoma: a phase I/II dose-finding and single-arm confirmatory study (JCOG0903).

BACKGROUND: Definitive chemoradiotherapy (CRT) with 5-fluorouracil plus mitomycin-C is a standard treatment for stage II/III squamous cell carcinoma of the anal canal (SCCA). We performed this dose-finding and single-arm confirmatory trial of CRT with S-1 plus mitomycin-C to determine the recommended dose (RD) of S-1 and evaluate its efficacy and safety for locally advanced SCCA. METHODS: Patients with clinical stage II/III SCCA (UICC 6th) received CRT comprising mitomycin-C (10 mg/m2 on days 1 and 29) and S-1 (60 mg/m2/day at level 0 and 80 mg/m2/day at level 1 on days 1-14 and 29-42) with concurrent radiotherapy (59.4 Gy). Dose-finding used a 3 + 3 cohort design. The primary endpoint of the confirmatory trial was 3-year event-free survival. The sample size was 65, with one-sided alpha of 5%, power of 80%, and expected and threshold values of 75% and 60%, respectively. RESULTS: Sixty-nine patients (dose-finding, n = 10; confirmatory, n = 59) were enrolled. The RD of S-1 was determined as 80 mg/m2/day. Three-year event-free survival in 63 eligible patients who received the RD was 65.0% (90% confidence interval 54.1-73.9). Three-year overall, progression-free, and colostomy-free survival rates were 87.3%, 85.7%, and 76.2%, respectively; the complete response rate was 81% on central review. Common grade 3/4 acute toxicities were leukopenia (63.1%), neutropenia (40.0%), diarrhea (20.0%), radiation dermatitis (15.4%), and febrile neutropenia (3.1%). No treatment-related deaths occurred. CONCLUSIONS: Although the primary endpoint was not met, S-1/mitomycin-C chemoradiotherapy had an acceptable toxicity profile and favorable 3-year survival and could be a treatment option for locally advanced SCCA. CLINICAL TRIAL INFORMATION: jRCTs031180002.

Locally Advanced Rectal Cancer Invading the Gluteus Maximus Muscle Completely Responded to Total Neoadjuvant Therapy.

A 70-year-old male with anal pain and fever was diagnosed with rectal cancer perforation and abscess in the right gluteus maximus (GM) muscle. He underwent a transverse colon colostomy followed by preoperative capecitabine+oxaliplatin. Some local control was achieved but a residual abscess was observed in the right GM muscle. To secure circumferential resection margin by tumor reduction, he received chemoradiotherapy as total neoadjuvant therapy (TNT) and underwent laparoscopic abdominoperineal resection, D3 lymph node dissection, combined coccyx resection, and partial resection of the right GM muscle. The skin defect and pelvic dead space were filled with a right lateral vastus lateral great muscle flap. Histopathologically, the resected specimen showed no tumor cells in the primary tumor or lymph nodes, indicating a pathological complete response (pCR). This case suggests that TNT might improve the R0 resection and pCR rates and overall survival.

A Case Report of Non-typical Annular Pancreas Diagnosed during Laparoscopic Gastric Surgery.

An annular pancreas is a rare anomaly of the pancreas, defined as pancreatic tissue that totally or partly encircles the duodenum, usually the descending portion. A 76-year-old man who was diagnosed with gastric cancer cT3N0M0 Stage IIB underwent laparoscopic distal gastrectomy with D2 lymph node dissection. Intraoperatively, the dorsal half of the duodenal bulb was seen to be half surrounded by the pancreas, and a non-typical annular pancreas was diagnosed. Because of the risk to the pancreas, it was considered impossible to perform anastomosis by a linear stapler as in the usual laparoscopic procedure. Therefore, we performed laparoscopically assisted distal gastrectomy and Billroth-I reconstruction using a circular stapler, and the surgery was completed without difficulties. His postoperative course was good despite the development of a pancreatic fistula, which was an International Study Group for Pancreas Fistula biochemical leak. Some APs can be diagnosed preoperatively, but the rarer subtypes such as ours are more difficult to visualize on imaging. In gastrectomy, it is both oncologically important and technically challenging to perform lymph node dissection around the pancreas. In this case with an especially proximal pancreas, a circular stapler was considered better suited for gastroduodenal anastomosis and required a broader field than that afforded by laparoscopy. A case of non-typical annular pancreas diagnosed during laparoscopic gastric surgery is described.

Regulatory T cells induce a suppressive immune milieu and promote lymph node metastasis in intrahepatic cholangiocarcinoma.

BACKGROUND: Emerging evidence indicates that immunogenicity plays an important role in intrahepatic cholangiocarcinoma (ICC). Herein, we systematically evaluated the clinical relevance of immunogenicity in ICC. METHODS: Highly immunogenic ICCs identified in the public dataset and the Cancer Immunome Atlas (TCIA) were assessed to determine the prognostic impact of immunogenicity in ICC and key components after curative resection. We also investigated the clinical relevance of the immune milieu in ICC. RESULTS: Using the Gene Expression Omnibus dataset 89749 and TCIA, we identified CD8+/forkhead box P3 (FoxP3)+ tumour-infiltrating lymphocytes (TILs), T-cell immunoglobulin and mucin domain 3 (TIM-3) and human leukocyte antigen-A (HLA-A) in highly immunogenic ICCs. Immunohistochemical analysis of the in-house cohort showed that intratumoral FoxP3+ TILs correlated with CD8+ TILs (P = 0.045, Fisher's exact test) and that high FoxP3+/CD8+ ratio (FCR) was an important marker for poor survival (P < 0.001, log-rank test). Furthermore, the FCR was higher in tumour-free lymph nodes in ICCs with lymph node metastases than in those without lymph node metastases (P = 0.003, Mann-Whitney U test). CONCLUSIONS: FCR should be considered an important biomarker that represents the immune environment of ICC based on its potentially important role in tumour progression, especially lymph node metastasis.

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.

Descending Colon Cancer Coincident with Schistosoma japonicum in an 89-year-old Male.

An 89-year-old male came to the hospital with a complaint of abdominal distension. Abdominal computed tomography showed wall thickening in the descending colon and marked dilatation of the proximal colon, and lower gastrointestinal endoscopy demonstrated a stenosis in the descending colon. Although a biopsy from the stenotic lesion showed calcified eggs of Schistosoma japonicum with no malignant findings, we suspected malignant involvement, so we performed a descending colectomy with regional lymph node dissection. Pathological examination revealed a moderately differentiated adenocarcinoma. The colon cancer was diagnosed as pT4bN0M0, Stage IIc. The patient's history as a resident of one of the formerly endemic areas of Japan suggests that he may have carried S. japonicum for a long time, and that it may have contributed to carcinogenesis.

Surgical Resection for Local and Lateral Lymph Node Recurrence of MSI-high Cecal Cancer with the BRAF V600E Mutation.

An 84-year-old female underwent open right hemicolectomy with D3 lymph node dissection for cecal cancer, pathologically identified as pT4aN2M0 Stage IIIc and BRAF mutation-positive. Due to early recurrence of abdominal wall and right lateral lymph nodes, the patient was treated with FOLFOXIRI+Bevacizumab. Imaging after 5 courses of chemotherapy found tumor shrinkage and no new metastases. The patient did not tolerate chemotherapy well, and tumor resection was performed. Microsatellite instability (MSI) testing using multiplex polymerase chain reaction (PCR) fragment analysis revealed MSI-high status. The patient is currently recurrence-free without chemotherapy at 1 year postoperatively. BRAF-mutated colorectal cancer has a poor prognosis, and may require resection of the metastatic or recurrent tumor after comprehensive evaluation.

Heterogeneous distribution of Fusobacterium nucleatum in the progression of colorectal cancer.

BACKGROUND AND AIM: Fusobacterium nucleatum (Fn) is involved in colorectal cancer (CRC) growth and is a biomarker for patient prognosis and management. However, the ecology of Fn in CRC and the distribution of intratumoral Fn are unknown. METHODS: We evaluated Fn and the status of KRAS and BRAF in 200 colorectal neoplasms (118 adenomas and 82 cancers) and 149 matched adjacent normal mucosas. The differentiation status between "surface" and "deep" areas of cancer tissue and matched normal mucosa were analyzed in 46 surgical samples; the Ki-67 index was also evaluated in these samples. RESULTS: Fusobacterium nucleatum presence in the tumor increased according to pathological stage (5.9% [adenoma] to 81.8% [stage III/IV]), while Fn presence in normal mucosa also increased (7.6% [adenoma] to 40.9% [stage III/IV]). The detection rates of Fn on the tumor surface and in deep areas were 45.7% and 32.6%, while that of normal mucosa were 26.1% and 23.9%, respectively. Stage III/IV tumors showed high Fn surface area expression (66.7%). Fn intratumoral heterogeneity (34.8%) was higher than that of KRAS (4.3%; P < 0.001) and BRAF (2.2%; P < 0.001). The Ki-67 index in Fn-positive cases was higher than that in negative cases (93.9% vs 89.0%; P = 0.01). CONCLUSIONS: Fusobacterium nucleatum was strongly present in CRC superficial areas at stage III/IV. The presence of Fn in the deep areas of adjacent normal mucosa also increased. The intratumoral heterogeneity of Fn is important in the use of Fn as a biomarker, as Fn is associated with CRC proliferative capacity.

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.

Preoperative chemoradiotherapy versus surgery alone for advanced low rectal cancer: a large multicenter cohort study in Japan.

PURPOSE: To clarify the usefulness of chemoradiotherapy (CRT) for low rectal cancer, we investigated the current status of CRT in Japan and its short- and long-term outcomes versus surgery alone for low rectal cancer in a large multicenter cohort study. METHODS: Between January 2010 and December 2011, data from 1608 patients with clinical Stage II-III rectal adenocarcinoma were collected from 69 specialized centers. Of these 1608 patients, 923 were diagnosed with clinical stage III low rectal cancer, 838 were enrolled in this study, divided into the surgery-alone group (n = 649) and preoperative CRT group (n = 189), and analyzed. RESULTS: The following parameters were significantly lower in the CRT versus surgery-alone group: blood loss (210 vs. 431.5 mL), postoperative complications (27.5% vs 39.0%), and the incidence of anastomotic leakage (3.7% vs. 8.8%). The 3-year overall survival, relapse-free and local recurrence-free survival rates did not between the two groups to a statistically significant extent (91.2% vs. 87.4%, 68.8% vs. 66.4%, and 88.2% vs. 88.4%, respectively). CONCLUSIONS: The present study revealed the current status of CRT for low rectal cancer in Japan. The results showed that CRT could be safely performed for advanced low rectal cancer in comparison to surgery alone.

Surgical Management in Patients with Gastrointestinal Stromal Tumors: A Single-Center Experience.

BACKGROUND: We have revisited prognostic outcomes and recurrence patterns in patients with gastrointestinal stromal tumors (GISTs) who underwent complete surgical resection at a single institution. PATIENTS AND METHODS: Patients who underwent curative surgical treatment were divided into two groups: those with high-risk GISTs (high-risk group) and those with very low-, low-, and intermediate-risk GISTs (lower-risk group). RESULTS: A total of 109 patients who underwent surgery as an initial treatment for GIST were studied. The overall 5- and 10-year survival rates after surgery were 90.3 and 71.1%, respectively. The 5-year survival rate in high-risk group patients was 88.1%, and their overall survival rate did not vary significantly from that of the lower-risk group (5-year survival rate, 91.3%). The recurrence rate in patients with high-risk GISTs gradually increased without reaching a plateau, with a cumulative rate of GIST recurrence of 26.4 and 48.9% at 5 and 10 years after surgical treatment, respectively. CONCLUSIONS: Our data suggest that the repeat surgical management in metastatic GIST is of clinical usefulness whatever the risk and improves survival.

[A Case Report of a Pathological Complete Response of Rectal Cancer to Preoperative Chemoradiotherapy with Tegafur].

We report the case of a patient with advanced rectal cancer who achieved a pathological complete response to preoperative chemoradiotherapy (CRT). A 65-year-old man was diagnosed as having a two-thirds circumferential well-to moderately differentiated tumor (Rb-P, type 2). To control local recurrence, we treated the patient with CRT. Radiotherapy was administered in fractions of 2 Gy/day (total, 40 Gy). Concurrently, S-1 was administered orally at a fixed daily dose of 80 mg/m2 for 20 days. Withdrawal and/or dose reduction of S-1 was not necessary in spite of Grade 1 or 2 toxic effects, including diarrhea and periproctitis, occurring on day 7. Laparoscopic abdominoperineal resection was performed 6 weeks after the final dose of chemotherapy was administered. The histopathological regression grade was Grade 3. No recurrence was detected on enhanced CT more than 5 years after surgery. This case suggests that the regimen was both effective and tolerated, and that preoperative chemoradiotherapy may be effective for tumor suppression to prevent local recurrence.

Rare case of rectal carcinoid with synchronous primary carcinoid tumors of the lung misdiagnosed as lung metastases.

A 68-year-old woman was referred to our hospital for rectal surgery after a pathological diagnosis of rectal carcinoid with venous invasion following endoscopic submucosal dissection of a 5 mm-sized submucosal tumor in the lower rectum. Chest CT showed nodules in the left upper lobe and right lower lobe, but positron emission tomography and somatostatin receptor scintigraphy showed no hyperaccumulation in the lung nodules. CT-guided needle biopsy was performed on the nodular lesion in the left upper lobe, which showed focal growth of tumor cells with a high N/C ratio and positive synaptophysin, leading to a diagnosis of pulmonary metastasis of rectal carcinoid. Since the patient was asymptomatic and did not wish to undergo surgery or chemotherapy, she was followed up strictly with sufficient informed consent. Three years have passed since the diagnosis, and there is no tendency for the lung metastasis to increase, and no other new lesions have been observed. The disease had not progressed and remained stable. Therefore, immunohistological analysis of the lung biopsy specimen was performed again, which was positive for TTF-1 and negative for CDX2. Consequently, the diagnosis was changed to primary lung carcinoid tumors, and the patient remains under follow-up with no disease progression.

Robot-assisted laparoscopic surgery for rectal cancer in a patient with a horseshoe kidney: A case report.

A 52-year-old, Japanese man presented to the hospital with a complaint of anal bleeding, and detailed examination resulted in a diagnosis of locally advanced rectal cancer. The patient underwent total neoadjuvant therapy followed by short-course radiation therapy and consolidation chemotherapy, which provided a partial response. After preoperative contrast-enhanced computed tomography showed a horseshoe kidney, robot-assisted, precise, laparoscopic, low anterior resection with D3 dissection and ileostomy construction was performed. The horseshoe renal isthmus was elevated surrounding the inferior mesenteric artery, and the left ureter and seminal vessels ran in front of the kidney. The hypogastric nerve traveled ventral to the horseshoe kidney. With robotic surgery, it was possible to perform more precise surgery while recognizing vascular and nerve anatomy in a rectal cancer patient with a horseshoe kidney due to good three-dimensional visibility and articulated forceps manipulation.

Endoscopic lavage for an infected pelvic hematoma in a patient with pelvic sepsis after anterior pelvic exenteration.

Anastomotic leakage and subsequent pelvic sepsis are serious complications after surgery for pelvic malignancies, particularly challenging due to the large pelvic cavity dead space post-exenteration. We report a 47-year-old man treated for a severely infected pelvic hematoma and sepsis following anastomotic leakage after anterior pelvic exenteration. Post robot-assisted exenteration for locally advanced sigmoid colon cancer treated with neoadjuvant chemotherapy, a pelvic abscess from anastomotic dehiscence was identified. Initial CT-guided drainage and subsequent laparoscopic drainage were performed. On postoperative day 22, a bleeding left internal iliac pseudoaneurysm required embolization. Despite these efforts, the sepsis worsened due to an enlarged, infected hematoma. Endoscopic lavage, in collaboration with skilled endoscopists, successfully removed the hematoma, leading to an improved inflammatory response, and the patient was discharged. Endoscopic lavage proved to be the safest and most effective treatment for pelvic sepsis with an infected hematoma after various attempted interventions.

Primary ileal myeloid sarcoma presenting with bowel obstruction: a case report.

BACKGROUND: Myeloid sarcoma (MS) is an extramedullary tumor constituted by myeloid blasts or immature myeloid cells. It frequently occurs in conjunction with acute myeloid leukemia (AML); however, it can exceptionally manifest in patients without leukemia. Here, we present a rare case of primary MS originating in the small bowel without evidence of bone marrow involvement. CASE REPRESENTATION: A 33 year-old female with no relevant medical history was admitted to our hospital with recurrent abdominal pain. Computed tomography (CT) revealed bowel obstruction due to thickening of the ileum wall, which was suspected to be an ileal tumor. Initially, ectopic endometriosis was suspected because of abdominal pain associated with the menstrual cycle and changes observed on a follow-up CT scan. The lesion could not be detected by double-balloon endoscopy. Despite conservative treatment, the obstruction persisted, and laparoscopic partial ileal resection was performed, which revealed extensive involvement of the ileum and mesentery. Additionally, the mesentery of the resected ileum was extremely thickened. Histopathological and immunohistochemical examinations of the surgical specimen indicated ileal MS. Bone marrow aspiration after discharge was negative for cytological findings of leukemia, leading to a final diagnosis of primary ileal MS. Her postoperative course was uneventful, and she is currently undergoing systemic chemotherapy tailored to AML at another hospital. CONCLUSIONS: Even though MS of the small bowel is rare and may not be considered preoperatively, similar surgical treatment to that of other small bowel malignancies can ensure proper postoperative diagnosis and appropriate chemotherapy. Given the potential need for chemotherapy, ensuring surgical safety that allows for its rapid initiation is critical.