No abstract

Situs inversus totalis (SIT) is a rare congenital condition in which the abdominal and thoracic organs are on the opposite sides to their normal anatomic positions. Reports of laparoscopic surgery for colorectal cancer with SIT are very few. Due to the mirror-image transposition of organs and vascular abnormalities, laparoscopic surgery for patients with SIT is technically complicated. Therefore, it has been reported as easier for left-handed surgeons. This report presents that operative procedures can be conducted as usual by changing the positions of the operator and assistants, even if the operator is right-handed. A 71-year-old woman visited our hospital with a 2-month history of hematochezia. Colonoscopy revealed an ulcerative tumor in the sigmoid colon and biopsy confirmed well-differentiated adenocarcinoma. Laparoscopic sigmoidectomy radical lymphadenectomy was performed. The operating time was 189 minutes and blood loss was 13 mL. The patient was discharged on postoperative day 7, without any complications. We report that complicated surgical procedures for patients with SIT can be simplified by changing viewpoints. Due to the altered anatomy in SIT, the positions of the operator and assistants are very important. Location of the pelvis is almost the same as in orthotopic patients, by moving the operator from the left side to the right side of the patient. Changing the position of the operator to the right side seems to be effective for patients with SIT during pelvic procedures.

Background Circulating tumour DNA (ctDNA) is known as a tumour-specific personalised biomarker, but the mutation-selection criteria from heterogeneous tumours remain a challenge. Methods We conducted multiregional sequencing of 42 specimens from 14 colorectal tumours of 12 patients, including two double-cancer cases, to identify mutational heterogeneity to develop personalised ctDNA assays using 175 plasma samples. Results “Founder” mutations, defined as a mutation that is present in all regions of the tumour in a binary manner (i.e., present or absent), were identified in 12/14 tumours. In contrast, “truncal” mutations, which are the first mutation that occurs prior to the divergence of branches in the phylogenetic tree using variant allele frequency (VAF) as continuous variables, were identified in 12/14 tumours. Two tumours without founder and truncal mutations were hypermutators. Most founder and truncal mutations exhibited higher VAFs than “non-founder” and “branch” mutations, resulting in a high chance to be detected in ctDNA. In post-operative long-term observation for 10/12 patients, early relapse prediction, treatment efficacy and non-relapse corroboration were achievable from frequent ctDNA monitoring. Conclusions A single biopsy is sufficient to develop custom dPCR probes for monitoring tumour burden in most CRC patients. However, it may not be effective for those with hypermutated tumours.

We investigated whether early circulating tumor DNA (ctDNA) changes, measured using digital PCR (dPCR), can predict later chemotherapy responses in esophageal squamous cell cancer (ESCC). We compared the dynamics of ctDNA and tumor volumes during chemotherapy in 42 ESCC. The accuracy of predictions of later chemotherapy responses were evaluated by the ratio of the variant allele frequency (VAF) of ctDNA (post-/pre-ctDNA) and the total tumor volume (post-/pre-volume) before and after an initial chemotherapy cycle using a receiver-operating characteristic curve analysis. Total positive and negative objective responses (ORs) were defined as either >50% or ≤50% reductions, respectively, in the total tumor volume at the end of first-line chemotherapy. Mutation screening of 43 tumors from 42 patients revealed 96 mutations. The pretreatment dPCR-ctDNA data were informative in 38 patients, using 70 selected mutations (1–3 per patient). The areas under the curve (AUCs) for the post-/pre-volume and post-/pre-ctDNA levels used in predicting the total OR were 0.85 and 0.88, respectively. The optimal cutoff value of post-/pre-ctDNA was 0.13. In 20 patients with post-/pre-volume ≥50%, the total OR could be predicted by the post-/pre-ctDNA with high accuracy; the AUC by post-/pre-ctDNA was higher than that by post-/pre-volume (0.85 vs 0.76, respectively). Patients with low post-/pre-ctDNA (n = 18) had a significantly better overall survival rate than those with high post-/pre-ctDNA (n = 20; P = 0.03). Early ctDNA changes after an initial cycle of chemotherapy predict later responses to treatment with high accuracy in ESCC patients.

No abstract

We suggest that advanced age should not be a contraindication for LCS, even for complex procedures, such as laparoscopic rectal resection.

Background: Circulating tumor DNA (ctDNA) test has not yet been an established tool for monitoring cancer. Sensitive, yet affordable methods should allow frequent ctDNA monitoring that can assist in clinical management. Patients and Methods: This prospective observational study was conducted in a total of 36 patients with Stage I to IV esophageal squamous cell cancer (ESCC) were enrolled between September 1, 2015 and February 28, 2018. We investigated whether frequent ctDNA monitoring during treatment followed by routine surveillance by digital PCR (dPCR) using tumor-specific mutations offers clinical validity in daily practice for ESCC patients. Results: Mutation screening of tumors from analyzable 35 patients using a specifically-designed "SCC panel" revealed 221 mutations with variant allele frequency (VAF) >2%. VAF of ctDNA was informative in 34 patients surveillance by dPCR using 58 mutations (1-3 per patient). A total of 569 plasma samples at 332 time points for ctDNA testing were evaluated. In pretreatment plasma, the average VAF was higher in advanced stages than earlier stages (P < .0001); tumor volume was also higher for higher VAF (r = 0.71). The ctDNA-positive rate in the pretreatment plasma of stage II or higher was 85.2% (23/27) whereas 85.7% (6/7) stage I were below the detection limit. Ninety-one % (10/11) patients whose ctDNA increased during chemotherapy showed disease progression. Among patients who recurred, ctDNA elevated with a median lead time of 149 days to the imaging diagnosis. Patients with decreased ctDNA within 3 months of initial treatment (n = 10) showed significantly better outcomes than did patients with ctDNA-positive (n = 11; P < .0001, HR 0.10, 95% CI, 0.03-0.30). Conclusions: Our results indicate that frequent tumor burden monitoring using a small number of tumor-specific ctDNAs by dPCR enables prediction of relapse and chemotherapeutic efficacy, as well as relapse-free corroboration in management of ESCC patients.

Background:Anastomotic leakage during laparoscopic low anterior resection (Lap-LAR) for rectal cancer remains challenging for colorectal surgeons. Firing linear staplers multiple times has been reported as a risk factor for iatrogenic anastomotic leakage. Our institute usually performs rectal transection using 2 planned stapler fires followed by anastomosis with the double-stapling technique.Methods:Between November 2009 and September 2016, a total of 272 consecutive patients underwent Lap-LAR with double-stapling anastomosis for rectal cancer. We inserted a linear 45-mm stapler cartridge from a port in the lower right quadrant of the abdomen. The first transection was made up to three-quarters of the rectal wall, and the remaining rectum was completely resected using a second stapler. During this procedure, the intersection of the 2 staple lines, which might otherwise cause anastomotic leakage, was located in the center of the stump of the distal rectum, so the intersection at the rectal stump was able to be easily removed using a circular stapler.Results:None of our patients were converted to open surgery. Among the 272 Lap-LAR procedures for which use of 2 stapler fires was planned, 3 fires occurred in error only once (0.4%). Rectovaginal fistula and anastomotic leakage occurred in 1 patient (0.4%) and 9 patients (3.3%), respectively, and 49 (18.0%) patients required protective diverting stoma.Conclusion:Rectal transection with 2 planned stapler fires appears safe, practical, and straightforward to standardize, and reduces the need for multiple linear fires and the incidence of anastomotic leakage.