The Deepest Extent of Acellular Mucin Pools in Resected Locally Advanced Rectal Cancer With Pathological Complete Response After Preoperative Chemoradiotherapy: A Hidden Killer?

For patients with locally advanced rectal cancer (LARC) with pathological complete response (pCR), the clinical significance of the distribution extent of acellular mucin pools (AMP) distribution remains unclear, so this study was conducted to address key unanswered questions. We performed a retrospective analysis of 317 patients with LARC with pCR after preoperative chemoradiotherapy and total mesorectal resection from January 2011 to June 2020. Based on AMP existence and the deepest tissue layer of distribution, patients were assigned new stages. The patient information was recorded, and the main outcome measures included 5-year disease-free survival (DFS) and 5-year overall survival (OS). A total of 83/317 (26.2%) patients exhibited AMP, and disease recurrence occurred in 46/317 (14.5%) patients. Over the 5-year median follow-up period, the patients with AMP showed 5-year DFS rates (75.9% vs. 88.9%, P =0.004) and 5-year OS rates (85.5% vs. 95.7%, P =0.002) statistically lower than those of patients without AMP. Disease recurrence was seen in 15/54 (27.8%) patients with AMP within the subserosa and/or the serosa, or adipose tissue. Univariate and multivariate analysis showed that the existence of AMP within the subserosa and/or the serosa, or adipose tissue was an independent risk factor for DFS [hazard ratio (HR): 2.344; 95% confidence interval (CI): 1.256-4.376; P =0.007] and OS [HR: 3.374; 95% CI: 1.438-7.917; P =0.005]. The new stages based on the deepest extent of AMP were related to worse DFS ( P =0.004) and OS ( P =0.003) rates among patients with pCR. In conclusion, the presence of AMP might reduce the prognosis of LARC patients with pCR after chemoradiotherapy, especially in patients with AMP in deeper tissue layers. Therefore, the influence of the deepest AMP extent might be worth considering in staging. Moreover, the revised staging of patients with pCR according to the deepest extent of AMP, which is unrelated to the clinical T stage, might facilitate postoperative management.

Clinical significance of adjuvant chemotherapy for pathological complete response rectal cancer patients with acellular mucin pools after neoadjuvant chemoradiotherapy.

Background: Approximately 15-30% of locally advanced rectal cancer (LARC) patients achieved pathological complete response (pCR) after neoadjuvant chemoradiotherapy (CRT) and total mesorectal excision, but the clinical significance of adjuvant chemotherapy (ACT) for pCR patients remains unclear. Objectives: To determine whether LARC pCR patients can benefit from the administration of ACT. Design: Single center retrospective study. Methods: This study retrospectively included 280 LARC patients who achieved pCR after CRT and surgery from 2011 to 2019. The information of patients was recorded. Main outcome measures included 5-year disease-free survival (DFS) and 5-year overall survival. Subgroup analysis was conducted on whether pCR patients with acellular mucin pools received ACT or not. Results: A total of 74/280 (26.4%) patients were identified with acellular mucin pools. Disease recurrence occurred in 38/280 (13.6%) patients, and in the subgroup of patients with acellular mucin pools, 15/74 (20.3%) patients developed distant metastases. The existence of acellular mucin pools was associated with worse DFS (79.7% versus 88.8%, P = 0.037). Among pCR patients with acellular mucin pools, 9/25 (36.0%) of non-ACT patients occurred recurrence, and ACT was beneficial for improving DFS (hazard ratio: 0.245; 95% confidence interval: 0.084-0.719; P = 0.010). Conclusions: The existence of acellular mucin pools may represent a sign of invasive tumor biology, which indicated a negative prognosis. ACT can improve the prognosis of patient with acellular mucin pools, so ACT should be considered for them.

Clinical significance of neoadjuvant chemotherapy for locally advanced colorectal cancer patients with deficient mismatch repair: possibly residual value in the era of immunotherapy.

Background: Deficient mismatch repair (dMMR) or microsatellite instability is one of the well-established molecular biomarkers in colorectal cancer (CRC). The efficiency of neoadjuvant chemotherapy (NAC) in locally advanced colorectal cancer (LACC) patients with dMMR is unclear. Objectives: We assessed the tumor response and clinical outcome in LACC patients with dMMR received NAC. Design: Retrospective, single-center analysis. Methods: From 2013 to 2018, a total of 577 LACC patients with dMMR who underwent radical surgery were identified. Among them, 109 patients who received adjuvant chemotherapy were further screened out for analysis. According to whether receiving NAC or not, 109 patients were divided into two groups with the purpose of retrospectively analyzing their characteristics, treatment, and survival results, especially the 5-year disease-free survival (DFS) and 5-year overall survival. Results: Baseline characteristics were matched between the two groups. One of 40 patients in NAC group recurred, while 13 of 69 patients in non-NAC group recurred. Univariate and multivariate analyses showed that NAC (hazard ratio: 0.115; 95% confidence interval: 0.015-0.897; p = 0.039) was independent influence factor for DFS. In NAC group, there were 13/40 (32.5%) patients for tumor regression grade 1 and 27/40 (67.5%) patients converted clinical positive N-stage into negative N-stage. Conclusion: In this study, NAC was associated with better tumor downstaging and longer 5-year DFS in LACC patients with dMMR. Consequently, NAC might be an additional treatment choice when it comes to such patients in the future.

Survival after curative resection for stage I colorectal mucinous adenocarcinoma.

PURPOSE: The prognostic value of the mucinous adenocarcinoma histotype on the early stages especially for stage I colorectal cancer (CRC) is still unclear. This study determined the clinicopathologic characteristics and long-term outcome of stage I colorectal mucinous adenocarcinomas (MAC). METHODS: Among the total of 530 patients with stage I CRC (58 having MAC and 472 having non-MAC) who underwent radical resection, the correlation between clinicopathological factors and MAC was analyzed. Multivariate analysis was performed to determine whether mucinous histotype itself was an independent prognostic impact in stage I patients. RESULTS: MACs were observed more frequently located in the colon than rectum (p = 0.049), more frequently displayed the deficient mismatch repair (dMMR) phenotype (p = 0.001) and had a greater frequency of T2 stage (p = 0.002). The rate of recurrence was 15.3% and the mortality was 9.2% among all stage I CRC patients. There was no difference in disease-free survival and overall survival between MACs and non-MACs. On multivariate analysis, older age (p = 0.009, hazard ratio: 2.22), rectal cancer (p = 0.008, hazard ratio: 3.21), lymphovascular invasion (LVI) (p < 0.001, hazard ratio: 6.28), and deficient mismatch repair (dMMR) phenotypes (p = 0.044, hazard ratio: 2.62) were independently associated to poor survival of stage I CRC. A high carcinoembryonic antigen level (p = 0.034, hazard ratio: 1.86), rectal cancer (p = 0.035, hazard ratio: 1.81), LVI (p = 0.002, hazard ratio: 3.59) and dMMR phenotypes (p = 0.009, hazard ratio: 2.85) were independently related to short disease-free survival of stage I CRC. CONCLUSIONS: Compared with non-MAC, MAC patients had more T2 patients and more dMMR phenotypes in stage I CRC at presentation, but the mucinous histology is not a significant predictor of recurrence and prognosis in stage I CRC.

Distinct Genomic Landscape of Colorectal Mucinous Carcinoma Determined via Comprehensive Genomic Profiling: Steps to a New Treatment Strategy.

Colorectal mucinous carcinoma (MC) is associated with inferior prognosis and response to treatment compared to adenocarcinoma (AC). The molecular landscapes of MC and adenocarcinoma with mucous composition (AMC) are not well-defined. We aimed to describe the genomic landscape of MC and AMC in a large colorectal cancer cohort. Tumor samples from patients with MC, AMC, or AC were analyzed using next-generation sequencing. MC had a molecular signature distinct from that of AC; genomic features were similar between AMC and MC but not between AMC and AC. HER2 amplification and TP53 and APC mutation rates were lower, whereas SMAD4, PIK3CA, ACVR2A, KMT2D, LRP1, TGFBR2, GRIN2A, BRAF V600E, PTEN, and BRCA2 mutation rates were higher in MC than in AC. The mutation frequencies in MAPK, PI3K, and TGF- pathways were higher, whereas those of cell cycle proteins and Wnt were lower in MC and AMC than in AC. The proportion of hypermutated tumors was significantly higher in MC and AMC than in AC. As MC has a distinct molecular signature from AC, immunotherapy can be potentially applied in treating MC. Similar molecular profiles of AMC and MC suggest that treatment strategies for MC, but not AC, can be used for AMC treatment.

Transanal and transabdominal combined endoscopic resection of rectal stenosis and anal reconstruction based on transanal endoscopic technique.

OBJECTIVE: To propose a method for the resection of the rectal anastomotic stenosis and anal reconstruction based on the transanal endoscopic technique through a transanal and transabdominal combined endoscopic resection, and to verify its clinical effectiveness. METHODS: Thirty-eight patients with anastomotic stenosis were admitted to the Sixth Affiliated Hospital, Sun Yat-sen University, China, from January 2016 to September 2019. Patients were divided into an experimental group (17 patients) and a control group (21 patients) subjected to the removal of the intestinal stenosis followed by anal reconstruction, they underwent transanal and transabdominal endoscopic surgery and traditional transabdominal surgery, respectively. Data on intraoperative blood loss, operation time, postoperative recovery, and prognosis were collected. RESULTS: (1) The median intraoperative blood loss was approximately 100 ml, without conversion to laparotomy during the surgery and intraoperative complications. The safety of the surgical operation was improved. (2) The operation time was shortened compared to previous reports, and the median operative time was 193 min. The average time of transanal endoscopic dissociation to the retroperitoneal fold was 76 min. (3) Laparoscopic assistance was carried out on 14 of the17 patients, and the incision was reduced. (4) The short-term curative effect was quite satisfactory, without permanent stoma. The average time to recover food intake after the surgery was 1.5 days. The average ambulation time was 3 days. Within 30 days after the surgery, one case suffered anastomotic leakage and then underwent refunctioning stoma through a second surgery. One patient suffered from intestinal obstruction, and the condition was improved through a conservative treatment. One case experienced delayed abdominal wound healing. CONCLUSION: The transanal and transabdominal endoscopic resection of the rectal anastomotic stenosis and anal reconstruction reduced the difficulty of the surgery, improved its safety, shortened the operation time, decreased the operative complications, and enabled patients to recover well after surgery.

Targeting and imaging colorectal cancer by activatable cell-penetrating peptides.

While it has been a great challenge to determine the positive status of metastasis lesions, intraoperative tumor imaging, which can show tumor localization and facilitate intraoperative staging of nodal metastases, have enabled surgeons to quickly and accurately perform radical resections. However, to date, there is no accurate method for evaluating nodal status intraoperatively. In this study, we synthesized activatable cell-penetrating peptides (ACPPs) that can specifically recognize colorectal cancer and their nodal status. ACPPs were labeled with Cy5 dye at the C-terminal, and named ACPP-Cy5. Laser scanning confocal microscopy and flow cytometry were used to measure the change in intracellular fluorescence intensity between cancer cells and normal cells. The results showed while the intracellular Cy5 fluorescent intensity can be visualized in both cancer and normal cells by 8 h after adding ACPP-Cy5, the relative fluorescence intensity of colorectal cancer cells was significantly higher than the normal cells. In addition, IVIS spectrum in vivo imaging system was used to observe the fluorescence intensity of ACPP-Cy5 after tail vein injection of mice with subcutaneous tumor or orthotopic colorectal cancer and liver metastasis. We found in mice with colorectal cancer and liver metastasis the Cy5 fluorescence intensity of cancer was significantly increased compared to the organs including liver, colorectum, lung, spleen, and heart. It is demonstrated here, this ACPPs can target colorectal cancer and liver metastasis, therefore ACPP-Cy5 may be a promising tool used for the diagnoses of colorectal cancer and to assist in tumor localization during surgery.

[Learning curve of transanal total mesorectal excision for rectal cancer].

OBJECTIVE: To explore the learning curve of transanal total mesorectal excision (taTME) for rectal cancer. METHODS: Clinical data of 60 rectal cancer patients undergoing taTME from July 2014 to April 2016 were retrospectively analyzed. According to the sequence of operation date, 60 patients were divided into four groups (A, B, C, D) with 15 cases in each group. General information and perioperative, especially the operative indexes were compared among four groups. RESULTS: There were no significant differences in age, sex, preoperative staging, BMI, tumor size among four groups (all P>0.05). The distance from tumor to anal verge in A group was(6.7±2.5) cm, which was significantly different with B group (4.6±1.2) cm, C group (4.5±1.0) cm and D group (4.0±1.0) cm (P=0.000, P=0.000, P=0.001). Ratio of receiving neoadjuvant therapy was 0, 60.0%(9 cases), 26.7%(4 cases) and 26.7%(4 cases) in A, B, C, D groups respectively with significant difference (P=0.004). Ratio of receiving complete taTME was 73.3%(11/15) in A group, 26.7%(4/15) in B group, 13.3%(2/15) in C group and 26.7%(4/15) in D group, while other patients underwent laparoscopy-assisted procedures. This ratio of A group was significantly higher as compared to B, C, D groups (P=0.003). The operation time was significantly different among four groups [A group (223.0±105.2) minutes, B group (299.0±131.0) minutes, C group(278.0±44.8) minutes, D group (246.0±34.0) min, P=0.035]. Fluctuation of operation time was more common in A and B groups, which became stable in C and D groups. Though intra-operative blood loss was not significantly different among four groups [A group (249.0±559.6) ml, B group (288.0±568.1) ml, C group (87.0±43.3) ml, D group (69.0±64.5) ml, P=0.225], but it presented a decline trend in C and D groups. Number of harvested lymph node from postoperative pathological specimen was 10.9±5.9 in A group, 9.6±2.7 in B group, 15.8±4.8 in C group, and 14.2±5.1 in D group, with significant difference among groups (P=0.008; A group vs. C group, P=0.010; B group vs. C group, P=0.002; B group vs. D group, P=0.021). There were no significant differences in specimen length, postoperative complication rate, distal margin distance and hospital stay. CONCLUSION: A well-skilled laparoscopic colorectal surgeon, by following the standard surgical procedures, are likely to overcome the learning curve smoothly after performing approximately 30 cases of taTME for rectal cancer.

Remarkable preservation of Ca(2+) homeostasis and inhibition of apoptosis contribute to anti-muscle atrophy effect in hibernating Daurian ground squirrels.

The underlying mechanisms that hibernators deviated from muscle atrophy during prolonged hibernating inactivity remain elusive. This study tested the hypothesis that the maintenance of intracellular Ca(2+) homeostasis and inhibition of apoptosis would be responsible for preventing muscle atrophy in hibernating Daurian ground squirrels. The results showed that intracellular Ca(2+) homeostasis was maintained in soleus and extensor digitorum longus (EDL) in hibernation and post-hibernation, while cytosolic Ca(2+) was overloaded in gastrocnemius (GAS) in hibernation with a recovery in post-hibernation. The Ca(2+) overload was also observed in interbout arousals in all three type muscles. Besides, the Bax/Bcl-2 ratio was unchanged in transcriptional level among pre-hibernation, hibernation and interbout arousals, and reduced to a minimum in post-hibernation. Furthermore, the Bax/Bcl-2 ratio in protein level was reduced in hibernation but recovered in interbout arousals. Although cytochrome C was increased in GAS and EDL in post-hibernation, no apoptosis was observed by TUNEL assay. These findings suggested that the intracellular Ca(2+) homeostasis in hibernation might be regulated by the cytosolic Ca(2+) overload during interbout arousals, which were likely responsible for preventing muscle atrophy via inhibition of apoptosis. Moreover, the muscle-specificity indicated that the different mechanisms against disuse-induced atrophy might be involved in different muscles in hibernation.