Masaaki Nishi

Additional surgical resection is required to achieve curative treatment in patients with early gastric cancer (EGC) due to the potential risk for lymph nod

Aim: Transanal approaches, such as transanal total mesorectal excision and transperineal abdominoperineal resection, have been developed to improve surgical quality for lower rectal cancer. However, international concerns have been raised about higher local recurrence rates. We investigated the usefulness of the transanal approach with respect to short- and long-term outcomes. Methods: In total, 291 patients who underwent laparoscopic or robotic surgery for rectal cancer were enrolled. Clinical, pathological, surgical, and follow-up data were retrospectively collected. Patients were divided into a transanal approach group (n = 139) and a conventional total mesorectal excision group (n = 152). A 1:1 propensity score-matched analysis was performed to compare surgical outcomes between the two groups. Results: After matching, 65 patients were included in each group. In the transanal group, intersphincteric resection was performed more frequently and abdominoperineal resection was performed less frequently, resulting in a higher rate of anus preservation (72.3% vs. 53.8%). The operative time was shorter (278 [240–343] min vs. 317 [259–373] min, p = 0.030), and blood loss was lower (29 [10–50] mL vs. 50 [10–119] mL, p = 0.033) in the transanal group. Major complications (Clavien–Dindo ≥ III) were less frequent in the transanal group. Overall survival was also better in the transanal group. No significant difference was observed in the total recurrence rate, including local recurrence. Conclusions: The transanal approach may be a promising surgical option for lower rectal cancer, contributing to higher rates of anus preservation and improved short- and long-term outcomes.

Aim: The da Vinci Surgical System (Intuitive Surgical) currently dominates robotic gastrectomy for gastric cancer. The hinotori Surgical Robot System (Medicaroid Corporation) is a newly developed, Japan-made surgical assist robot. This study aimed to introduce the initial experience of robotic gastrectomy using the hinotori and discuss key techniques and challenges. Methods: This single-center retrospective study involved 10 eligible patients who underwent curative robotic distal gastrectomy using the hinotori for primary Stage I to III gastric cancer. Short-term surgical outcomes were evaluated. Lymph node dissection was mainly performed using the conventional double bipolar technique, left-handed double bipolar technique, or laparoscopic coagulation shears from the assist port. Results: No patients developed intraoperative complications, and all procedures were successfully completed without conversion to open or laparoscopic surgery. All patients achieved R0 resection. The median operation time was 275 minutes (range, 252 to 336 min), and the estimated blood loss was 5 mL (range, 3 to 20 mL). The drain amylase content on postoperative day 1 was 220.5 IU/L (range, 66 to 1207 IU/L). The median number of retrieved lymph nodes was 29.5 (range, 11 to 58). No patients developed postoperative Clavien-Dindo grade ≥IIIa complications, and there was no mortality. Conclusion: Robotic gastrectomy using the hinotori shows potential benefits for gastric cancer. Further studies are needed to validate these advantages.

Background/Aim: Neoadjuvant chemoradiation therapy (nCRT) followed by surgery is recommended for patients with locally advanced rectal cancer (LARC). However, because 30%-40% of patients with LARC do not respond to nCRT, better prediction of treatment responses and survival outcomes is required. Therefore, this study aimed to identify apparent diffusion coefficient (ADC) values that predict survival outcomes after nCRT in patients with LARC. Patients and Methods: We analyzed data from 66 patients with LARC who underwent nCRT and evaluated the ADC values pre- and post-nCRT. Cox proportional hazard regression analyses were conducted to assess survival outcomes. Results: There were no significant differences in disease-free survival (DFS) and overall survival (OS) between low and high ADC values pre-nCRT. However, patients classified as low ADC in post-nCRT had a significantly worse prognosis in OS and DFS (OS: p=0.01; DFS: ppp=0.01]. Finally, we identified ADC values that were significantly superior in predicting tumor regression grade, demonstrating remarkable diagnostic accuracy [post-nCRT: area under the curve (AUC)=0.79; alteration-nCRT: AUC=0.85]. Conclusion: We identified the clinical importance of changes in ADC values as a predictor of survival outcomes in patients with LARC. These results highlight the clinical importance of ADC values on improving the treatment strategies of patients.

Background: The concepts examined in tumor metabolism research have been moving away from cancer cells themselves and the tumor microenvironment has become a focus of investigation. Epigenetic changes affecting glucose metabolism in cancer‐associated fibroblasts (CAFs) in the tumor microenvironment regulate the malignancy of cancer cells. Light‐emitting diode (LED) have several functional effects, including anti‐tumor effects, through a variety of mechanisms. We previously reported that blue LED irradiation had an anti‐tumor effect via Opsin 3 that suppress CAF function in vivo and in vitro. However, the detailed mechanism by which LED affect CAF regulation remained unclear.Methods: CAFs were induced from human intestinal fibroblasts co‐cultured with colon cancer cells. Using lactate assays and reverse transcription‐quantitative PCR, the effects of LED irradiation on glycolysis in CAFs were investigated. The effects of LED irradiation for metabolic coupling were evaluated in vitro.Results: Reverse transcription‐quantitative PCR showed higher expression of CAF marker genes in induced CAFs. Blue LED irradiation of induced CAFs suppressed their ability to promote characteristics of tumor malignancy of colon cancer cell line. LED treatment decreased expression of glycolysis markers, including phosphofructokinase and monocarboxylate transporter 4, indicating inhibition of glycolytic activity in CAFs. Extracellular secretion of lactate from CAFs was decreased by LED irradiation.Conclusions: Blue LED irradiation targeted metabolic coupling between CAFs and colon cancer cells, thereby reducing the promotion of tumor progression by CAFs. Blue LED targeting glucose metabolism in CAFs is a promising anti‐cancer treatment option.

The pro-tumor effects of mast cell (MC) in the tumor microenvironment (TME) are becoming increasingly clear. Recently, MC were shown to contribute to tumor malignancy by supporting the migration of tumor-associated macrophages (TAMs), suggesting a relationship with tumor immunity. In the current study, we aimed to examine the correlation between MC infiltration and neoadjuvant chemoradiotherapy (nCRT) response for locally advanced rectal cancer (LARC). Ninety-five LARC patients who recieved nCRT were enrolled in this study. Protein levels of the MC marker tryptase and TAM marker CD206 were evaluated with immunohistochemistry (IHC). The correlation between MC infiltration and prognostic factors was evaluated. The effects of MCs on the malignant potential were examined using in vitro proliferation and invasion assays with a colorectal cancer (CRC) cell line (HCT-116). Following nCRT, 31.6% of resected LARC patient specimens were positive for MC infiltration by tryptase IHC analysis. MC infiltration was significantly correlated with nCRT response. The 5-year disease-free survival (DFS) rate was significantly lower in the MC-positive group compared with the MC-negative group (52.3% vs. 76.8%). Univariate and multivariate analyses revealed that MC infiltration was the independent prognostic indicator for DFS. MC infiltration was significantly correlated with CD206 expression, and therefore TAMs. In vitro experiments suggested that tumor activated mast cells could promote CRC cell malignant behavior via production of macrophage inhibitory factor. MC infiltration in LARC patients was positively correlated with TAM infiltration and resistance to nCRT, and was also an independent poor prognostic indicator.

Background: The use of robotic surgery (RS) for gastric cancer (GC) has been rapidly increasing. However, the utility of RS for advanced GC (AGC), especially T3 or more AGC, is unclear. Methods: Ninety patients who underwent curative upfront minimally invasive surgery (MIS) (D2 lymph node dissection) for fStage II or III GC were enrolled in this study. Among these patients, 68 underwent MIS for T3 or more AGC. Thirty‐six patients underwent RS, and 32 patients underwent laparoscopic surgery (LS). The short‐term and long‐term surgical outcomes were compared between the two groups. Results: In the T3 or more AGC cohort, there were no significant intergroup differences in the operative time or blood loss volume. The number of retrieved lymph nodes tended to be higher in the RS than LS group (38.5 vs. 33.0, p = .11). The drain amylase content on postoperative day 1 was significantly lower in the RS than LS group (243.5 vs. 521.0 IU/L, p < .01). The morbidity rate (Clavien–Dindo grade ≥2) was similar between the groups. There were no significant differences between the LS and RS groups in the 3‐year overall survival rate (80.7% vs. 74.5%, respectively; p = .95) or 3‐year disease‐free survival rate (75.0% vs. 69.7%, respectively; p = .95). Conclusions: RS for primary T3 or more AGC was safe and contributed to similar short‐term and long‐term outcomes compared with LS.