Anus preservation in low rectal adenocarcinoma based on MMR/MSI status (APRAM): a study protocol for a randomised, controlled, open-label, multicentre phase III trial.

BACKGROUND: Anus preservation has been a challenge in the treatment of patients with low rectal adenocarcinoma (within 5 cm from the anal verge) because it is difficult to spare the anus with its functioning sphincter complex under the safe margin of tumour resection. Patients with dMMR/MSI-H can achieve a favourable complete response (CR) rate by using a single immune checkpoint inhibitor. For patients with pMMR/MSS/MSI-L, intensified neoadjuvant three-drug chemotherapy may be the preferred option for anal preservation. In addition, the watch and wait (W&W) strategy has been proven safe and feasible for patients with rectal cancer who achieve a clinical complete response (cCR). Therefore, we initiated this clinical trial to explore the optimal neoadjuvant treatment pattern for patients with low locally advanced rectal cancer (LARC) with different MMR/MSI statuses, aiming to achieve a higher cCR rate with the W&W strategy and ultimately provide more patients with a chance of anus preservation. METHODS: This is a randomised, controlled, open-label, multicentre phase III trial. Patients with clinical stage T2-4 and/or N + tumours located within 5 cm from the anal verge are considered eligible. Based on the results of pathological biopsy, the patients are divided into two groups: dMMR/MSI-H and pMMR/MSS. Patients in the dMMR/MSI-H group will be randomly allocated in a 1:1 ratio to either arm A (monoimmunotherapy) or arm B (short-course radiotherapy followed by monoimmunotherapy). Patients in the pMMR/MSS group will be initially treated with long-term pelvic radiation with concurrent capecitabine combined with irinotecan. Two weeks after the completion of chemoradiotherapy (CRT), the patients will be randomly allocated in a 1:1 ratio to arm C (XELIRI six cycle regime) or arm D (FOLFIRINOX nine cycle regime). The irinotecan dose will be adjusted according to the UGT1A1-genotype. After treatment, a comprehensive assessment will be performed to determine whether a cCR has been achieved. If achieved, the W&W strategy will be adopted; otherwise, total mesorectal excision (TME) will be performed. The primary endpoint is cCR with the maintenance of 12 months at least, determined using digital rectal examination, endoscopy, and rectal MRI or PET/CT as a supplementary method. DISCUSSION: APRAM will explore the best anus preservation model for low LARC, combining the strategies of consolidation chemotherapy, immunotherapy, and short-course radiotherapy, and aims to preserve the anus of more patients using W&W. Our study provides an accurate individual treatment mode based on the MMR/MSI status for patients with low LARC, and more patients will receive the opportunity for anus preservation under our therapeutic strategy, which would transform into long-term benefits. TRIAL REGISTRATION: Clinicaltrials.gov NCT05669092 (Registered 28th Nov 2022).

Primary Surgery Followed by Selective Chemoradiotherapy Versus Preoperative Chemoradiotherapy Followed by Surgery for Locally Advanced Rectal Cancer: A Randomized Clinical Trial.

PURPOSE: The aim of this work was to determine whether locally advanced rectal cancer (LARC) with negative mesorectal fascia (MRF) predicted by magnetic resonance imaging (MRI) can be excluded from preoperative radiation therapy treatment. METHODS AND MATERIALS: This multicenter, open-label, non-inferiority, randomized clinical trial enrolled patients with LARC within 6 to 12 cm from the anal verge and with negative MRI-predicted MRF. Participants were randomized to the intervention group (primary surgery, in which the patients with positive pathologic [CRM] circumferential margins were subjected to chemoradiotherapy [CRT] and those with negative CRM underwent adjuvant chemotherapy according to pathologic staging) or the control group (preoperative CRT, in which all patients underwent subsequent surgery and adjuvant chemotherapy). The primary endpoint was 3-year disease-free survival (DFS). RESULTS: A total of 275 patients were randomly assigned to the intervention (n = 140) and control (n = 135) groups, in which 33.57% and 28.15% patients were at clinical T4 stage and 85.92% and 80.45% patients were at "bad" or "ugly" risk in the intervention and control groups, respectively. There were 2 patients (1.52%) and 1 patient (0.77%) with positive CRM in the intervention and control groups, respectively (P > .05). The non-adherence rates for the intervention and control groups were 3.6% and 23.7%, respectively. After a median follow-up of 34.6 months (IQR, 18.2-45.7), 43 patients had positive events (28 patients and 15 patients in the intervention and control groups, respectively). There were 6 patients (4.4%) with local recurrence in the intervention group and none in the control group, which led to the termination of the trial. The 3-year DFS rate was 81.82% in the intervention group (95% CI, 78.18%-85.46%) and 85.37% in the control group (95% CI, 81.75%-88.99%), with a difference of -3.55% (95% CI, -3.71% to -3.39%; hazard ratio, 1.76; 95% CI, 0.94-3.30). In the per-protocol data set, the difference between 3-year DFS rates was -5.44% (95% CI, -5.63% to -5.25%; hazard ratio, 2.02; 95% CI, 1.01-4.06). CONCLUSIONS: Based on the outcomes of this trial, in patients with LARC and MRI-negative MRF, primary surgery could negatively influence their DFS rates. Therefore, primary surgery was an inferior strategy compared with preoperative CRT followed by surgery and cannot be recommended for patients with LARC.

Neoadjuvant Chemotherapy With CAPOX Versus Chemoradiation for Locally Advanced Rectal Cancer With Uninvolved Mesorectal Fascia (CONVERT): Initial Results of a Phase III Trial.

OBJECTIVE: To compare neoadjuvant chemotherapy (nCT) with CAPOX alone versus neoadjuvant chemoradiotherapy (nCRT) with capecitabine in locally advanced rectal cancer (LARC) with uninvolved mesorectal fascia (MRF). BACKGROUND DATA: nCRT is associated with higher surgical complications, worse long-term functional outcomes, and questionable survival benefits. Comparatively, nCT alone seems a promising alternative treatment in lower-risk LARC patients with uninvolved MRF. METHODS: Patients between June 2014 and October 2020 with LARC within 12 cm from the anal verge and uninvolved MRF were randomly assigned to nCT group with 4 cycles of CAPOX (Oxaliplatin 130 mg/m2 IV day 1 and Capecitabine 1000 mg/m2 twice daily for 14 d. Repeat every 3 wk) or nCRT group with Capecitabine 825 mg/m² twice daily administered orally and concurrently with radiation therapy (50 Gy/25 fractions) for 5 days per week. The primary end point is local-regional recurrence-free survival. Here we reported the results of secondary end points: histopathologic response, surgical events, and toxicity. RESULTS: Of the 663 initially enrolled patients, 589 received the allocated treatment (nCT, n=300; nCRT, n=289). Pathologic complete response rate was 11.0% (95% CI, 7.8-15.3%) in the nCT arm and 13.8% (95% CI, 10.1-18.5%) in the nCRT arm ( P =0.33). The downstaging (ypStage 0 to 1) rate was 40.8% (95% CI, 35.1-46.7%) in the nCT arm and 45.6% (95% CI, 39.7-51.7%) in the nCRT arm ( P =0.27). nCT was associated with lower perioperative distant metastases rate (0.7% vs. 3.1%, P =0.03) and preventive ileostomy rate (52.2% vs. 63.6%, P =0.008) compared with nCRT. Four patients in the nCT arm received salvage nCRT because of local disease progression after nCT. Two patients in the nCT arm and 5 in the nCRT arm achieved complete clinical response and were treated with a nonsurgical approach. Similar results were observed in subgroup analysis. CONCLUSIONS: nCT achieved similar pCR and downstaging rates with lower incidence of perioperative distant metastasis and preventive ileostomy compared with nCRT. CAPOX could be an effective alternative to neoadjuvant therapy in LARC with uninvolved MRF. Long-term follow-up is needed to confirm these results.

Computational Dissection of the Role of Trp305 in the Regulation of the Death-Associated Protein Kinase-Calmodulin Interaction.

Death-associated protein kinase 1 (DAPK1), as a calcium/calmodulin (CaM) regulated serine/threonine kinase, functions in apoptotic and autophagy pathways and represents an interesting drug target for inflammatory bowel disease and Alzheimer's disease. The crystal structure of the DAPK1 catalytic domain and the autoregulatory domain (ARD) in complex with CaM provides an understanding of CaM-dependent regulation of DAPK1 activity. However, the molecular basis of how distinct Trp305 (W305Y and W305D) mutations in the ARD modulate different DAPK1 activities remains unknown. Here, we performed multiple, µs-length molecular dynamics (MD) simulations of the DAPK1-CaM complex in three different (wild-type, W305Y, and W305D) states. MD simulations showed that the overall structural complex did not change significantly in the wild-type and W305Y systems, but underwent obvious conformational alteration in the W305D system. Dynamical cross-correlation and principal component analyses revealed that the W305D mutation enhanced the anti-correlated motions between the DAPK1 and CaM and sampled a broader distribution of conformational space relative to the wild-type and W305Y systems. Structural and energetical analyses further exhibited that CaM binding was unfavored in response to the W305D mutation, resulting in the decreased binding of CaM to the W305D mutant. Furthermore, the hydrogen bonds and salt bridges responsible for the loss of CaM binding on the interface of the DAPK1-CaM complex were identified in the W305D mutant. This result may provide insights into the key role of Trp305 in the regulation of CaM-mediated DAPK1 activity.

Low prevalence of mismatch repair deficiency in Chinese colorectal cancers: a multicenter study.

BACKGROUND: Although universal testing for mismatch repair deficiency (dMMR) has been recommended to all colorectal cancer (CRC) patients, related evidence for the Chinese population is lacking. Here, we investigated the prevalence and clinicopathological features of dMMR patients in a large Chinese CRC cohort. METHODS: We included 7,373 CRC patients treated at four Chinese medical centers between August 2010 and September 2016. Patients' baseline characteristics and pathological features were recorded. The clinicopathological features were compared between patients with MLH1/PMS2 deficiency (dMLH1/PMS2) and MSH2/MSH6 deficiency (dMSH2/MSH6). RESULTS: Among the investigated patients, 654 (8.9%) were identified with dMMR CRCs and, of them, 401 (61.3%) were males, with a median age of 55 years (range, 22-87 years); 355 (54.3%) had stage II CRC based on American Joint Committee on Cancer 8th edition. The prevalence of the dMLH1/PMS2 group and the dMSH2/MSH6 group were 51.5% (337/654) and 25.1% (164/654), respectively. Compared with dMSH2/MSH6 patients, those with dMLH1/PMS2 were older (57 vs 52 years, P < 0.001), more likely to be female (45.7% vs 31.5%, P = 0.004), prone to having tumors located in the right-hand side of the colon (59.0% vs 47.6%, P = 0.015), and less likely to have a family history of tumors (29.7% vs 43.3%, P = 0.003). CONCLUSIONS: The prevalence of dMMR in Chinese CRC patients was low, especially in the dMLH1/PMS2 group. The clinicopathological features were different between dMMR subgroups.

Circulating guanylyl cyclase C (GCC) mRNA is a reliable metastatic predictor and prognostic index of colorectal cancer.

BACKGROUND: Currently, few specific biomarkers or standard cutoff values are available for circulating tumor cells (CTCs) detection and survival prediction in patients with early stage colorectal cancer (CRC). Guanylyl cyclase C (GCC) presents as a specific expression in intestinal tumor cells and during their metastases, indicating its potential application as a metastatic predictor of CRC. METHODS: The circulating GCC mRNA of 160 colorectal cancer patients at stage I-III was detected via quantitative real-time (qRT)-PCR in our study, and the correlation of GCC mRNA level with tumor metastasis and long-term survival was explored. RESULTS: GCC mRNA was found to be positive in 43 out of 160 CRC patients and negative in ten healthy controls. It was found that GCC mRNA over the baseline (>100 copies/µL and 200 copies/µL) showed a significant correlation with disease-free survival (DFS) and overall survival (OS) in the stage II subgroup. It was further revealed that GCC mRNA over 300 copies/µL or higher than the median value of copy numbers was significantly correlated with reduced OS and DFS in CRC patients. A nomogram model based on variables including GCC mRNA copy number was established for predicting the OS of CRC patients (AUC =0.98). CONCLUSIONS: Circulating GCC mRNA over baseline is a reliable predictor for tumor metastasis and can be a prognostic index in CRC patients.

Brain-derived neurotrophic factor involved epigenetic repression of UGT2B7 in colorectal carcinoma: A mechanism to alter morphine glucuronidation in tumor.

Uridine diphosphate-glucuronosyltransferase (UGT) 2B7, as one of significant drug enzymes, is responsible on the glucuronidation of abundant endobiotics or xenobiotics. We here report that it is markedly repressed in the tumor tissues of colorectal carcinoma (CRC) patients. Accordingly, morphine in CRC cells will stimulate the expression of its main metabolic enzyme, UGT2B7 during tolerance generation by activating the positive signals in histone 3, especially for trimethylated lysine 27 (H3K4Me3) and acetylated lysine 4 (H3K27Ac). Further study reveals that brain-derived neutrophilic factor (BDNF), a secretory neurotrophin, enriched in CRC can interact and inhibit UGT2B7 by primarily blocking the positive signals of H3K4Me3 as well as activating H3K27Ac on the promoter region of UGT2B7. Meanwhile, BDNF repression attributes to the sensitizations of main core factors in poly-comb repressive complex (PRC) 1 rather than PRC2 as the reason of the depression of SUZ12 in the later complex. Besides that, the productions of two main morphine glucuronides are both increased in the BDNF deficient or TSA and BIX-01294 treated morphine tolerance-like HCT-116 cells. On the same condition, active metabolite, morphine-6-glucuronide (M6G) was accumulated more than inactive M3G. Our findings imply that enzymatic activity enhancement and substrate regioselective catalysis alteration of UGT2B7 may release morphine tolerance under the cure of tumor-induced pain.

Efficacy and safety of bevacizumab in Chinese patients with metastatic colorectal cancer.

OBJECTIVE: To evaluate the efficacy and safety of bevacizumab in the treatment of patients with metastatic colorectal cancer (mCRC). METHODS: In a single-center, observational study of 91 Chinese patients with mCRC who received bevacizumab in combination with chemotherapy was conducted. OBJECTIVE response rates (ORRs), progression-free survival (PFS), overall survival (OS) and adverse events were recorded, and the relationships between various clinical factors and PFS or OS were evaluated by Cox proportional hazards models. RESULTS: Treatment with bevacizumab and chemotherapy was effective and tolerable. Univariate analysis showed that PFS and OS were significantly associated with the Eastern Cooperative Oncology Group performance status (ECOG- PS) score, duration of bevacizumab exposure, and whether chemotherapy was continued after discontinuation of bevacizumab treatment. A multivariate analysis showed that the duration of bevacizumab exposure and whether chemotherapy was continued after discontinuation of bevacizumab were independent prognostic factors for PFS and OS. CONCLUSION: In Chinese mCRC population, the shorter the duration of exposure to bevacizumab and chemotherapy, the worse the prognosis is.

[Detection of guanylate cyclase C mRNA and cytokeratin 20 mRNA in peripheral blood and analysis of prognosis in early to moderate colorectal cancer patients].

OBJECTIVE: To investigate the associations of guanylate cyclase C (GC-C) mRNA and cytokeratin 20 (CK20) mRNA with metastasis and prognosis in early to moderate colorectal cancer patients. METHODS: GC-C mRNA and CK 20 mRNA in peripheral blood of 74 colorectal cancer patients without distant metastasis were detected by fluorescent quantitative PCR (FQ-PCR). Based on their clinicopathological and postoperative follow-up data, the relationship and clinical significance of these data with metastasis hazards and prognosis factors were analyzed. RESULTS: The positive rate of GC-C mRNA in 74 colorectal cancer patients was 33.8% (25/74), and CK20 mRNA was 31.1% (23/74). The 1-, 2-, 3- year disease-free survival rates of patients were 94.6%, 82.4% and 78.4% respectively. There were significant differences in positive rates of GC-C mRNA and CK20 mRNA, tumor differentiation, mesentery lymph node metastasis, tumor embolus in vessel and postoperative chemotherapy associated with 3-year disease free survival rate by Kaplan-Meier analysis (all P<0.05). While mesentery lymph node metastasis and tumor embolus in vessel were independent risk factors of 3-year disease-free survival (P<0.05). CK20 mRNA and tumor embolus in vessel were independent risk factors of 3-year disease-free survival by analysis stratified with clinical stage (P<0.05). CONCLUSIONS: Detection of CK20 mRNA and GC-C mRNA in peripheral blood may be important for early detection of early metastasis of colorectal cancer.

Detection of circulating tumor cells in peripheral blood of colorectal cancer patients without distant organ metastases.

PURPOSE: Recently, the detection of circulating tumor cells (CTCs) in peripheral blood has become an important tool for the non-invasive assessment of micrometastases and to predict clinical outcome. The objective of this study was to investigate if the presence of CTCs in peripheral blood influences the prognosis in colorectal cancer (CRC) patients without distant organ metastases. METHODS: The GCC mRNA and CK20 mRNA levels in peripheral blood and the serum levels of CEA of 92 CRC patients without distant organ metastasis were analyzed by quantitative RT-PCR and ELISA, respectively. Its associations with overall survival (OS) and disease-free survival (DFS) rates were analyzed. RESULTS: Univariate analyses showed that lower OS and DFS rates were significantly associated with GCC and CK20 mRNA levels, the presence of lymph node metastases, the presence of mesenteric root lymph node metastases, and the presence of tumor emboli in vessels (p < 0.05), but not with CEA levels. Multivariate analyses showed a significant association between 1) OS and GCC mRNA levels and differentiation types and 2) DFS and the presence of tumor emboli in the vessels. Kaplan-Meier curves showed that DFS was significantly associated with the presence of poorly differentiated cells, the presence of mesenteric root lymph node metastases having received prior chemotherapy, and the presence of tumor emboli in vessels. CONCLUSION: The detection of CTCs in peripheral blood may be useful for the prediction of clinical outcome in CRC patients without distant organ metastases.

[Detection and clinical significance of apoptosis related protein in local advanced rectal cancer patients with preoperative neoadjuvant therapy].

OBJECTIVE: To discuss the mechanism of rectal cancer apoptosis induced by preoperative chemoradiotherapy and evaluate its effect by detection of apoptosis related proteins in locally advanced colorectal cancer patients who had received preoperative chemoradiation. METHODS: To detect Bcl-XL and Bax expression in rectal cancer before and after chemoradiotherapy by EnVision method, combined with patients clinical and pathological index, statistically analysis and evaluation their relationship and clinical significance. RESULTS: Patients with or without tumor shrinkage after preoperative chemoradiotherapy was 13 cases and 21 cases. While the positive rate of Bcl-XL in rectal cancer before and after chemoradiotherapy were 58.8% (20/34) and 52.9% (18/34), respectively. There were significant difference between Bcl-XL change before and after chemoradiation with tumor size, tumor cells shrinkage and operation pattern. The positive rate of Bax in rectal cancer before and after chemoradiotherapy were 32.4% (11/34) and 44.1% (15/34), respectively. There were no significant difference between Bax change before and after chemoradiotherapy with tumor cells shrinkage. There were statistically significant difference between Bax ratio (χ(2) = 9.607, P = 0.048) before and after chemoradiation while there were no significant difference between Bcl-XL/Bax ratio before and after chemoradiation with tumor shrinkage. According to layered analysis with preoperative therapy, there were statistically significant difference (χ(2) = 13.964, P = 0.007) between Bcl-XL change with operation pattern while the same of significant difference between Bax change with tumor infiltration and tumor shrinkage (χ(2) = 10.806 and 10.455, both P < 0.05). CONCLUSIONS: Preoperative chemoradiation can influence rectal cancer cell's apoptosis and treatment effect by changing Bcl-XL and Bax expression. Bcl-XL downregulation and Bax upregulation have shown important function in colorectal cancer cell apoptosis which induced by preoperative chemoradiation, it can also improve the effection of chemoradiation in rectal cancer.

Distinct profiles of epigenetic evolution between colorectal cancers with and without metastasis.

Liver metastasis is a fatal step in the progression of colorectal cancer (CRC); however, the epigenetic evolution of this process is largely unknown. To decipher the epigenetic alterations during the development of liver metastasis, the DNA methylation status of 12 genes, including 5 classical CpG island methylator phenotype (CIMP) markers, was analyzed in 62 liver metastases and in 78 primary CRCs (53 stage I-III; 25 stage IV). Genome-wide methylation analysis was also performed in stage I-III CRCs and in paired primary and liver metastatic cancers. Methylation frequencies of MGMT and TIMP3 increased progressively from stage I-III CRCs to liver metastasis (P = 0.043 and P = 0.028, respectively). The CIMP-positive cases showed significantly earlier recurrence of disease than did CIMP-negative cases with liver metastasis (P = 0.030), whereas no such difference was found in stage I-III CRCs. Genome-wide analysis revealed that more genes were methylated in stage I-III CRCs than in paired stage IV samples (P = 0.008). Hierarchical cluster analysis showed that stage I-III CRCs and stage IV CRCs were clustered into two distinct subgroups, whereas most paired primary and metastatic cancers showed similar methylation profiles. This analysis revealed distinct methylation profiles between stage I-III CRCs and stage IV CRCs, which may reflect differences in epigenetic evolution during progression of the disease. In addition, most methylation status in stage IV CRCs seems to be established before metastasis.

[Detection of chromosomal aberration in sporadic colorectal cancer with comparative genomic hybridization].

OBJECTIVE: To investigate the chromosomal aberration in sporadic colorectal carcinoma and its association with clinicopathological features. METHODS: Comparative genomic hybridization(CGH) was used to screen the changes in the number of DNA sequence copies in 40 sporadic colorectal cancer patients in order to identify regions that contain genes important for the development and progression of colorectal cancer. RESULTS: In 40 sporadic colorectal cancer, frequent gain at 20 q, 12 q, 13 q, 7 p, 7 q and 16 q were found, while loss was also found at 18 q, 5 q, 4 q, 8 pand 17 p. The number of chromosomal aberration was closely associated with tumor stage(P<0.05). No significant association was found between the number of chromosomal aberration and tumor site, histopathologic type and histologic grade. CONCLUSIONS: Chromosomal aberration exists generally in sporadic colorectal carcinoma. The number of chromosomal aberration and gain of 20q are closely associated with tumor stage.

[Efficacy assessment of preoperative radiochemotherapy and analysis of associated factors in rectal cancer].

OBJECTIVE: To evaluate the efficacy of preoperative radiochemotherapy and investigate the influencing factors in rectal cancer. METHODS: Fifty-three patients with locally advanced rectal cancer were treated with radiochemotherapy before surgery. Three-field technique of radiation therapy was administered with 46 Gy, 2 Gy per fraction, five times a week. Two cycles of chemotherapy were carried out at day 1, 2 and day 21, 22 during the radiation course. Surgery was performed 4-6 weeks after the radiochemotherapy. Response of preoperative radiochemotherapy was evaluated in all the patients by endoscopic ultrasonography (EUS), spiral computed tomography (SCT) and pathology. Influencing factors of the efficacy of radiochemotherapy were evaluated by univariate and Logistic analysis. RESULTS: Univariate analysis revealed that tumor size and histological grading were associated with the efficacy of preoperative radiochemotherapy. Logistic regression analysis showed that only tumor size was the significant predictive factor for response to preoperative radiochemotherapy. All patients underwent surgical resection after preoperative radiochemotherapy. The tumor was reduced by an average of 32.1%. T-level down-staging was 64.2%. Nodal negativity was 58.1%. Complete pathologic remission occurred in 11 patients. CONCLUSIONS: Preoperative radiochemotherapy can shrink the primary tumor and decrease lymph node metastasis rate. Patient with small tumor may have better response to preoperative radiochemotherapy.

[Comparative study of endoluminal ultrasonography and spiral computed tomography in preoperative staging of rectal carcinoma].

OBJECTIVE: To compare the efficacy of endoluminal ultrasonography (EUS) and spiral computed tomography (SCT) in preoperative staging of rectal carcinoma. METHODS: Both EUS and SCT were performed prior to surgery in 68 patients with rectal carcinoma. After radical surgery, the preoperative findings were compared with histologic findings of the operative specimens, and the efficacy of EUS and SCT in staging the rectal carcinoma were evaluated. RESULTS: For T stage, EUS accuracy was 86.8%, while SCT was 70.6%. The difference was significant (P<0.05). For N stage, EUS accuracy was 67.6% and SCT was 63.2%. The difference was not significant (P>0.05). CONCLUSION: EUS is superior to SCT for the judgement of tumor infiltration depth, but neither is able to provide satisfactory assessment of lymph node metastases.