Takeshi Nishikawa

Background: Although methods to overcome difficulties associated with mirror-image conditions have been investigated, the ideal spatial relationship among the operator line of sight, monitor location, and camera location remains unclear. Moreover, the best training method for improving laparoscopic surgical skills under varying operator line of sight, camera, and monitor positions is unknown. We aimed to investigate the role of laparoscopic training under mirror-image conditions in improving surgical efficiency and whether prior surgical experience affects such training. Methods: This prospective study was conducted at the Department of Surgical Oncology, Tokyo University, Japan. Twenty-five surgeons participated. Novice (n=14), trained (n=7), and expert (n=4) participants performed the simulated task in a box trainer while varying the positional relationships among the surgeons, camera, and monitor. Five patterns were repeatedly performed 5 times per day for 4 days over 2 weeks. Results: The most significant differences in terms of the time required to complete the task under mirror-image conditions among the 3 groups were on day 1 (novices: 185.8 s, trained: 79.7 s, and experts: 46.5 s, P=0.009). However, after 4 days of training, the corresponding times did not differ among the 3 groups (26.0, 30.7, and 23.1 s, respectively; P=0.415). Laparoscopic training was sufficiently effective under mirror-image conditions. Conclusions: Mirror-image surgical conditions provided the most difficult setting, because surgeons and assistants often became disoriented, and task performance was most degraded. However, just 4 days of training was found to be sufficient to overcome the difficulties encountered while performing laparoscopic procedures under mirror-image conditions.

Background/Aims: Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis and handsewn anastomosis for ulcerative colitis requires pulling down of the ileal pouch into the pelvis, which can be technically challenging. We examined risk factors for the pouch not reaching the anus.Methods: Clinical records of 62 consecutive patients who were scheduled to undergo RPC with handsewn anastomosis at the University of Tokyo Hospital during 1989–2019 were reviewed. Risk factors for non-reaching were analyzed in patients in whom hand sewing was abandoned for stapled anastomosis because of nonreaching. Risk factors for non-reaching in laparoscopic RPC were separately analyzed. Anatomical indicators obtained from presurgical computed tomography (CT) were also evaluated.Results: Thirty-seven of 62 cases underwent laparoscopic procedures. In 6 cases (9.7%), handsewn anastomosis was changed to stapled anastomosis because of non-reaching. Male sex and a laparoscopic approach were independent risk factors of non-reaching. Distance between the terminal of the superior mesenteric artery (SMA) ileal branch and the anus > 11 cm was a risk factor for non-reaching.Conclusions: Laparoscopic RPC with handsewn anastomosis may limit extension and induction of the ileal pouch into the anus. Preoperative CT measurement from the terminal SMA to the anus may be useful for predicting non-reaching.

Perianal Paget's disease is a rare condition, which is not usually accompanied by cancer. Here, a case of anal canal carcinoma with pagetoid spread and inguinal lymph node metastasis, which exhibited a significant response to preoperative chemoradiotherapy (CRT), is presented. A 58‑year‑old woman was admitted to The University of Tokyo Hospital with a complaint of discomfort around the anus. Physical examination revealed an erythematous inflamed skin lesion in the perianal region and a tumor of 15 mm in diameter detected on palpation in the left inguinal region, which was diagnosed as metastatic adenocarcinoma by excisional biopsy. Colonoscopy revealed moderately differentiated adenocarcinoma of 15 mm in diameter in the anal canal. Skin biopsy of the perianal region revealed an infiltration of pagetoid cells, which were positive for cytokeratin 7, and negative for cytokeratin 20 and gross cystic disease fluid protein 15. Based on these results, the patient was diagnosed as having anal canal adenocarcinoma with pagetoid spread. The patient received preoperative CRT including the bilateral inguinal region. After CRT, robotic‑assisted laparoscopic abdominoperineal resection was performed. The macroscopic findings of the surgical specimen confirmed the formation of a scar as a result of the preoperative CRT. Microscopic examination of the anal tumor revealed no residual carcinoma or lymph node metastasis. In conclusion, this case may suggest the potential applicability of preoperative CRT for the local control of anal canal carcinoma with pagetoid spread.

Most elderly patients with colorectal cancer have comorbidities and reduced functional reserve, which may increase their risks of postoperative morbidity and mortality, and subsequently influence the treatment choice. Therefore, this study aimed to investigate the treatment choice and compare laparoscopic and open surgery in this setting.

The number of elderly patients who receive surgical treatment for rectal cancer has gradually increased with aging of the population. In recent years, preoperative chemoradiotherapy, followed by surgical treatment, has been widely used for treating patients with locally advanced rectal adenocarcinoma. The aim of the present study was to evaluate if preoperative chemoradiotherapy is efficacious and safe for the treatment of rectal cancer in patients older than 80 years. A total of 293 patients with rectal cancer, who received preoperative chemoradiotherapy from 2007 to 2017, were studied. Comorbidities and the short‑ and long‑term outcomes in elderly patients (aged ≥80 years old) were investigated and compared to younger patients. The elderly group comprised of 17 patients (5.8%). Pulmonary disease was the most common comorbidity (23.5%). No significant difference between the two groups regarding the rate of completeness of chemoradiotherapy was detected (P=0.26). Curative resection was performed in 14 patients in the elderly group and 252 patients in the younger group. Among 7 patients from both groups who could not receive curative resection due to their poor general condition, 4 patients had decreased lower respiratory function due to pneumonia (3 patients) or chronic obstructive pulmonary disease (1 patient). Morbidity and mortality rates were similar in elderly and younger groups (35.7% vs. 27.0%, 0% vs. 0%, respectively; P=0.54, P=1.00). No significant difference was found regarding recurrence between the two groups (P=1.00). To conclude, preoperative chemoradiotherapy in elderly patients with rectal cancer is safe and well tolerated.

Multivisceral resection for colorectal cancer invading into the adjacent organs may often be difficult and may involve serious complications. Preoperative therapy may facilitate resection with safe margins. Between August 2007 and July 2016, 23 patients with colorectal cancer invading into the adjacent organs treated with preoperative treatment (chemoradiotherpay, chemotherapy, radiotherapy) were retrospectively investigated. All 23 patients received surgery with curative intent. Four patients had distant metastases at the time of diagnosis. Two patients had distant metastasis after preoperative treatment. The mean operative time was 535.3±185.5 min and the median amount of blood loss was 1,050 ml. Histopathological examination revealed malignant infiltration of the adjacent organs in 14 patients (60.9%). R0 resection rate was 73.9%. Postoperative complications were identified in nine patients (39.1%) and a high incidence of infectious complications was observed. Patients with curative resection showed a significantly better survival than patients with R1 or R2 resection (P<0.01). Multivisceral resection for locally advanced colorectal cancer invading into the adjacent organ after preoperative treatment may be performed with acceptable morbidity and minimal mortality. R0 resection improves the prognosis of patients with locally advanced colorectal cancer invading into the adjacent organ after preoperative treatment.

Although systemic chemotherapy has been improved, peritoneal carcinomatosis remains a factor of poor prognosis in patients with colorectal cancer. In order to achieve a higher drug concentration in the peritoneal cavity, intraperitoneal chemotherapy has been performed. However, the optimal regimen for intraperitoneal chemotherapy has not been determined. In this review of intraperitoneal chemotherapy for colorectal cancer, we summarize regimens of hyperthermic intraperitoneal chemotherapy (HIPEC) and other intraperitoneal chemotherapy modalities, such as early postoperative intraperitoneal chemotherapy (EPIC) and sequential postoperative intraperitoneal chemotherapy (SPIC). Mitomycin C and oxaliplatin are the most common chemotherapeutic agents used for HIPEC. Some combination therapies such as those involving bevacizumab, H₂O₂, and amifostine have potential to increase HIPEC efficacy. 5-Fluorouracil is used mainly for EPIC and SPIC. Some new agents such as paclitaxel, melphalan, and various nanoparticles have been developed. These novel chemotherapeutic agents may achieve clinical implementation in the future.

Preoperative chemoradiotherapy has been performed as a standard therapy for advanced low rectal cancer. Cancer stem cells (CSCs) have been reported to contribute to resistance to treatment and patient prognosis. Leucine‑rich repeat‑containing G protein‑coupled receptor 5 (LGR5) and cluster of differentiation (CD133) are putative markers for CSCs. However, their prognostic ability remains unknown, and evaluation of a single marker can be insufficient due to the heterogeneity of cancer. LGR5 and CD133 expression was immunohistochemically evaluated in surgical specimens of 56 patients who received curative resection following chemoradiotherapy for advanced low rectal cancer. In addition, the correlations between their expression levels, and clinicopathological features and patient prognosis were asessed. LGR5 expression was significantly correlated with lymphatic invasion, lymph node metastasis, and tumor node metastasic (TNM) stage. CD133 expression was significantly correlated with vascular invasion and the tumor regression grade. Combined expression was significantly correlated with lymphatic invasion, tumor regression grade and TNM stage, but not with overall, and disease‑free survival. LGR5 and CD133 expressions may represent useful markers associated with tumor progression and resistance to chemoradiotherapy in patients with low rectal cancer. Furthermore, combined expression of these markers may be a more useful marker compared with the expression of each single marker.