Minimally invasive vs. open segmental resection of the splenic flexure for cancer: a nationwide study of the Italian Society of Surgical Oncology-Colorectal Cancer Network (SICO-CNN).

BACKGROUND: Evidence on the efficacy of minimally invasive (MI) segmental resection of splenic flexure cancer (SFC) is not available, mostly due to the rarity of this tumor. This study aimed to determine the survival outcomes of MI and open treatment, and to investigate whether MI is noninferior to open procedure regarding short-term outcomes. METHODS: This nationwide retrospective cohort study included all consecutive SFC segmental resections performed in 30 referral centers between 2006 and 2016. The primary endpoint assessing efficacy was the overall survival (OS). The secondary endpoints included cancer-specific mortality (CSM), recurrence rate (RR), short-term clinical outcomes (a composite of Clavien-Dindo > 2 complications and 30-day mortality), and pathological outcomes (a composite of lymph nodes removed ≧12, and proximal and distal free resection margins length ≧ 5 cm). For these composites, a 6% noninferiority margin was chosen based on clinical relevance estimate. RESULTS: A total of 606 patients underwent either an open (208, 34.3%) or a MI (398, 65.7%) SFC segmental resection. At univariable analysis, OS and CSM were improved in the MI group (log-rank test p = 0.004 and Gray's tests p = 0.004, respectively), while recurrences were comparable (Gray's tests p = 0.434). Cox multivariable analysis did not support that OS and CSM were better in the MI group (p = 0.109 and p = 0.163, respectively). Successful pathological outcome, observed in 53.2% of open and 58.3% of MI resections, supported noninferiority (difference 5.1%; 1-sided 95%CI - 4.7% to ∞). Successful short-term clinical outcome was documented in 93.3% of Open and 93.0% of MI procedures, and supported noninferiority as well (difference - 0.3%; 1-sided 95%CI - 5.0% to ∞). CONCLUSIONS: Among patients with SFC, the minimally invasive approach met the criterion for noninferiority for postoperative complications and pathological outcomes, and was found to provide results of OS, CSM, and RR comparable to those of open resection.

Right Colectomy with Intracorporeal Anastomosis: A European Multicenter Propensity Score Matching Retrospective Study of Robotic Versus Laparoscopic Procedures.

BACKGROUND: This study aimed to compare the short- and long-term outcomes of robotic (RRC-IA) versus laparoscopic (LRC-IA) right colectomy with intracorporeal anastomosis using a propensity score matching (PSM) analysis based on a large European multicentric cohort of patients with nonmetastatic right colon cancer. METHODS: Elective curative-intent RRC-IA and LRC-IA performed between 2014 and 2020 were selected from the MERCY Study Group database. The two PSM-groups were compared for operative and postoperative outcomes, and survival rates. RESULTS: Initially, 596 patients were selected, including 194 RRC-IA and 402 LRC-IA patients. After PSM, 298 patients (149 per group) were compared. There was no statistically significant difference between RRC-IA and LRC-IA in terms of operative time, intraoperative complication rate, conversion to open surgery, postoperative morbidity (19.5% in RRC-IA vs. 26.8% in LRC-IA; p = 0.17), or 5-yr survival (80.5% for RRC-IA and 74.7% for LRC-IA; p = 0.94). R0 resection was obtained in all patients, and > 12 lymph nodes were harvested in 92.3% of patients, without group-related differences. RRC-IA procedures were associated with a significantly higher use of indocyanine green fluorescence than LRC-IA (36.9% vs. 14.1%; OR: 3.56; 95%CI 2.02-6.29; p < 0.0001). CONCLUSION: Within the limitation of the present analyses, there is no statistically significant difference between RRC-IA and LRC-IA performed for right colon cancer in terms of short- and long-term outcomes.

HLA-G as a prognostic marker in stage II/III colorectal cancer: not quite there yet.

Identifying innovative molecules involved in the tumor immune escape process could help refine the survival stratification of colorectal cancer (CRC) patients. HLA-G, a non-classical HLA molecule, physiologically involved in tolerogenic mechanisms, has recently emerged as a relevant prognostic marker in other tumor types, but ambiguous data are reported in the CRC setting. This study aims to evaluate the HLA-G expression and prognostic potential in a series of stage II/III CRCs. HLA-G expression was evaluated in 100 pT3 CRC cases by means of immunohistochemistry using the 4H84 and MEM-G/2 monoclonal antibodies. We observed heterogeneous expression of HLA-G showing different ranges: 4H84 expression ranged from > 1 to 40%-median 7%; MEM-G/2 expression ranged from 20 to 90%-median 50%. HLA-G positivity (any intensity > 1%) varied according to the antibody employed, identifying: 8 4H84 positive, 34 MEM-G/2 positive, 6 double-positive and 52 negative cases. Correlation with clinico-pathologic data showed a significant association with a poor tumor differentiation in stage III right-sided CRC subgroup (p = 0.043), while no other pathologic variable was significantly associated. Survival analysis revealed a reduced disease-free survival rate (HR 4.304613; p = 0.031) in the subgroup of CRC-related death cases, while no correlations were observed considering the whole series and the overall survival. In conclusion, HLA-G is a promising CRC prognostic marker however much work is still required regarding technical aspects and evaluation of expression.

Risk factors for anastomotic leakage after anterior resection for rectal cancer (RALAR study): A nationwide retrospective study of the Italian Society of Surgical Oncology Colorectal Cancer Network Collaborative Group.

AIM: Anastomotic leakage after restorative surgery for rectal cancer shows high morbidity and related mortality. Identification of risk factors could change operative planning, with indications for stoma construction. This retrospective multicentre study aims to assess the anastomotic leak rate, identify the independent risk factors and develop a clinical prediction model to calculate the probability of leakage. METHODS: The study used data from 24 Italian referral centres of the Colorectal Cancer Network of the Italian Society of Surgical Oncology. Patients were classified into two groups, AL (anastomotic leak) or NoAL (no anastomotic leak). The effect of patient-, disease-, treatment- and postoperative outcome-related factors on anastomotic leak after univariable and multivariable analysis was measured. RESULTS: A total of 5398 patients were included, 552 in group AL and 4846 in group NoAL. The overall incidence of leaks was 10.2%, with a mean time interval of 6.8 days. The 30-day leak-related mortality was 2.6%. Sex, body mass index, tumour location, type of approach, number of cartridges employed, weight loss, clinical T stage and combined multiorgan resection were identified as independent risk factors. The stoma did not reduce the leak rate but significantly decreased leak severity and reoperation rate. A nomogram with a risk score (RALAR score) was developed to predict anastomotic leak risk at the end of resection. CONCLUSIONS: While a defunctioning stoma did not affect the leak risk, it significantly reduced its severity. Surgeons should recognize independent risk factors for leaks at the end of rectal resection and could calculate a risk score to select high-risk patients eligible for protective stoma construction.

Impact of operation duration on postoperative outcomes of minimally-invasive right colectomy.

AIM: Operation time (OT) is a key operational factor influencing surgical outcomes. The present study aimed to analyse whether OT impacts on short-term outcomes of minimally-invasive right colectomies by assessing the role of surgical approach (robotic [RRC] or laparoscopic right colectomy [LRC]), and type of ileocolic anastomosis (i.e., intracorporal [IA] or extra-corporal anastomosis [EA]). METHODS: This was a retrospective analysis of the Minimally-invasivE surgery for oncological Right ColectomY (MERCY) Study Group database, which included adult patients with nonmetastatic right colon adenocarcinoma operated on by oncological RRC or LRC between January 2014 and December 2020. Univariate and multivariate analyses were used. RESULTS: The study sample was composed of 1549 patients who were divided into three groups according to the OT quartiles: (1) First quartile, <135 min (n = 386); (2) Second and third quartiles, 135-199 min (n = 731); and (3) Fourth quartile ≥200 min (n = 432). The majority (62.7%) were LRC-EA, followed by LRC-IA (24.3%), RRC-IA (11.1%), and RRC-EA (1.9%). Independent predictors of an OT ≥ 200 min included male gender, age, obesity, diabetes, use of indocyanine green fluorescence, and IA confection. An OT ≥ 200 min was significantly associated with an increased risk of postoperative noninfective complications (AOR: 1.56; 95% CI: 1.15-2.13; p = 0.004), whereas the surgical approach and the type of anastomosis had no impact on postoperative morbidity. CONCLUSION: Prolonged OT is independently associated with increased odds of postoperative noninfective complications in oncological minimally-invasive right colectomy.

Comprehensive geriatric assessment in older adults with cancer: Recommendations by the Italian Society of Geriatrics and Gerontology (SIGG).

INTRODUCTION: Optimizing the approach to older adults with cancer is now a priority given the increasing frequency of new cancer diagnoses that are made in the older population. The comprehensive geriatric assessment (CGA) represents the gold-standard for (1) defining prognosis and ability to withstand cancer treatments, (2) exploring the multiple aspects that define the complexity of frail older persons, and (3) designing person-tailored interventions. MATERIALS AND METHODS: In this document, based on a comprehensive revision of the literature, the Italian Society for Geriatrics and Gerontology proposes a CGA model (ONCOGER CGA) to be adopted by oncology centers for their routine approach to older patients with cancer. RESULTS AND DISCUSSION: A widespread use of this standardized CGA format will facilitate comparisons across institutions, promote studies based on a multidimensional patient assessment, and foster the inclusion of geriatric endpoints in oncological clinical trials. Furthermore, we predict that the use of a standardized CGA approach will increase the integration of geriatricians into oncology care teams with the final result of improving therapeutic choices and clinical outcomes.

Management and 1-year outcomes of anastomotic leakage after elective colorectal surgery.

PURPOSE: To analyze different types of management and one-year outcomes of anastomotic leakage (AL) after elective colorectal resection. METHODS: All patients with anastomotic leakage after elective colorectal surgery with anastomosis (76/1,546; 4.9%), with the exclusion of cases with proximal diverting stoma, were followed-up for at least one year. Primary endpoints were as follows: composite outcome of one-year mortality and/or unplanned intensive care unit (ICU) admission and additional morbidity rates. Secondary endpoints were as follows: length of stay (LOS), one-year persistent stoma rate, and rate of return to intended oncologic therapy (RIOT). RESULTS: One-year mortality rate was 10.5% and unplanned ICU admission rate was 30.3%. Risk factors of the composite outcome included age (aOR = 1.08 per 1-year increase, p = 0.002) and anastomotic breakdown with end stoma at reoperation (aOR = 2.77, p = 0.007). Additional morbidity rate was 52.6%: risk factors included open versus laparoscopic reoperation (aOR = 4.38, p = 0.03) and ICU admission (aOR = 3.63, p = 0.05). Median (IQR) overall LOS was 20 days (14-26), higher in the subgroup of patients reoperated without stoma. At 1 year, a stoma persisted in 32.0% of patients, higher in the open (41.2%) versus laparoscopic (12.5%) reoperation group (p = 0.04). Only 4 out of 18 patients (22.2%) were able to RIOT. CONCLUSION: Mortality and/or unplanned ICU admission rates after AL are influenced by increasing age and by anastomotic breakdown at reoperation; additional morbidity rates are influenced by unplanned ICU admission and by laparoscopic approach to reoperation, the latter also reducing permanent stoma and failure to RIOT rates. TRIAL REGISTRATION: ClinicalTrials.gov # NCT03560180.

The critical view of safety during laparoscopic cholecystectomy: Strasberg Yes or No? An Italian Multicentre study.

BACKGROUND: Laparoscopic cholecystectomy is considered the gold standard for the treatment of gallbladder lithiasis; nevertheless, the incidence of bile duct injuries (BDI) is still high (0.3-0.8%) compared to open cholecystectomy (0.2%). In 1995, Strasberg introduced the "Critical View of Safety" (CVS) to reduce the risk of BDI. Despite its widespread use, the scientific evidence supporting this technique to prevent BDI is controversial. METHODS: Between March 2017 and March 2019, the data of patients submitted to laparoscopic cholecystectomy in 30 Italian surgical departments were collected on a national database. A survey was submitted to all members of Italian Digestive Pathology Society to obtain data on the preoperative workup, the surgical and postoperative management of patients and to judge, at the end of the procedure, if the isolation of the elements was performed according to the CVS. In the case of a declared critical view, iconographic documentation was obtained, finally reviewed by an external auditor. RESULTS: Data from 604 patients were analysed. The study population was divided into two groups according to the evidence (Group A; n = 11) or absence (Group B; N = 593) of BDI and perioperative bleeding. The non-use of CVS was found in 54.6% of procedures in the Group A, and 25.8% in the Group B, and evaluating the operator-related variables the execution of CVS was associated with a significantly lower incidence of BDI and intraoperative bleeding. CONCLUSIONS: The CVS confirmed to be the safest technique to recognize the elements of the Calot triangle and, if correctly performed, it significantly impacted on preventing intraoperative complications. Additional educational programs on the correct application of CVS in clinical practice would be desirable to avoid extreme conditions that may require additional procedures.

ICG fluorescence imaging in colorectal surgery: a snapshot from the ICRAL study group.

BACKGROUND: Fluorescence-guided visualization is a recently proposed technology in colorectal surgery. Possible uses include evaluating perfusion, navigating lymph nodes and searching for hepatic metastases and peritoneal spread. Despite the absence of high-level evidence, this technique has gained considerable popularity among colorectal surgeons due to its significant reliability, safety, ease of use and relatively low cost. However, the actual use of this technique in daily clinical practice has not been reported to date. METHODS: This survey was conducted on April 2020 among 44 centers dealing with colorectal diseases and participating in the Italian ColoRectal Anastomotic Leakage (iCral) study group. Surgeons were approximately equally divided based on geographical criteria from multiple Italian regions, with a large proportion based in public (89.1%) and nonacademic (75.7%) centers. They were invited to answer an online survey to snapshot their current behaviors regarding the use of fluorescence-guided visualization in colorectal surgery. Questions regarding technological availability, indications and techniques, personal approaches and feelings were collected in a 23-item questionnaire. RESULTS: Questionnaire replies were received from 37 institutions and partially answered by 8, as this latter group of centers do not implement fluorescence technology (21.6%). Out of the remaining 29 centers (78,4%), fluorescence is utilized in all laparoscopic colorectal resections by 72.4% of surgeons and only for selected cases by the remaining 27.6%, while 62.1% of respondents do not use fluorescence in open surgery (unless the perfusion is macroscopically uncertain with the naked eye, in which case 41.4% of them do). The survey also suggests that there is no agreement on dilution, dosing and timing, as many different practices are adopted based on personal judgment. Only approximately half of the surgeons reported a reduced leak rate with fluorescence perfusion assessment, but 65.5% of them strongly believe that this technique will become a minimum requirement for colorectal surgery in the future. CONCLUSION: The survey confirms that fluorescence is becoming a widely used technique in colorectal surgery. However, both the indications and methods still vary considerably; furthermore, the surgeons' perceptions of the results are insufficient to consider this technology essential. This survey emphasizes the need for further research to reach recommendations based on solid scientific evidence.

A two-step surgery and a multidisciplinary approach in a centenarian patient with an acute presentation of right colon cancer.

BACKGROUND: As surgery remains the cornerstone of colorectal cancer (CRC) treatment, the number of older patients presented for colorectal resection is rapidly increasing. Nevertheless, the choice to operate an oldest-old patient still remain challenging and requires a careful assessment of risk to benefit ratio in order to guarantee appropriate surgical strategies and perioperative management. CASE PRESENTATION: A centenarian patient, acutely admitted to the emergency department, was diagnosed with an ileus caused by stenosing ascending colon cancer with abnormal distension of the right colon at high risk of perforation. Facing with this complex clinical scenario, a lateral decompressive cecostomy as alternative surgical procedure, was performed in local anesthesia in order to avoid the stressful event of an emergency surgery. Thereafter, the patient was admitted to the surgical ward and followed by a geriatrician who performed a comprehensive geriatric assessment (CGA) and daily clinical evaluations. This integrated plan of care was mainly focused on rehabilitation, nutritional interventions and therapeutic reconciliation, maximizing patient's clinical conditions and performance status. Then, the second surgical step, the radical colon surgery with curative intent and bowel continuity reestablishment was performed, demonstrating to be feasible and safety also in a very advanced age patient in term of prolonged survival and preservation of an adequate quality of life. CONCLUSIONS: This is the first case-report that illustrates a successful two step surgery for CRC in a centenarian patient thanks to a multidisciplinary based approach, overwhelming the mere concept of chronological age.

Clinico-pathological associations and concomitant mutations of the RAS/RAF pathway in metastatic colorectal cancer.

BACKGROUND: Over the past few years, next-generation sequencing (NGS) has become reliable and cost-effective, and its use in clinical practice has become a reality. A relevant role for NGS is the prediction of response to anti-EGFR agents in metastatic colorectal cancer (mCRC), where multiple exons from KRAS, NRAS, and BRAF must be sequenced simultaneously. METHODS: We optimized a 14-amplicon NGS panel to assess, in a consecutive cohort of 219 patients affected by mCRC, the presence and clinico-pathological associations of mutations in the KRAS, NRAS, BRAF, and PIK3CA genes from formalin-fixed, paraffin-embedded specimens collected for diagnostics and research at the time of diagnosis. RESULTS: We observed a statistically significant association of RAS mutations with sex, young age, and tumor site. We demonstrated that concomitant mutations in the RAS/RAF pathway are not infrequent in mCRC, and as anticipated by whole-genome studies, RAS and PIK3CA tend to be concurrently mutated. We corroborated the association of BRAF mutations in right mCRC tumors with microsatellite instability. We established tumor side as prognostic parameter independently of mutational status. CONCLUSIONS: To our knowledge, this is the first monocentric, consecutively accrued clinical mCRC cancer cohort tested by NGS in a real-world context for KRAS, NRAS, BRAF, and PIK3CA. Our study has highlighted in clinical practice findings such as the concomitance of mutations in the RAS/RAF pathway, the presence of multiple mutations in single gene, the co-occurrence of RAS and PIK3CA mutations, the prognostic value of tumor side and possible associations of sex with specific mutations.

Elevated platelet count is a negative predictive and prognostic marker in locally advanced rectal cancer undergoing neoadjuvant chemoradiation: a retrospective multi-institutional study on 965 patients.

BACKGROUND: In patients with locally advanced rectal cancer treated by neoadjuvant chemoradiation, pathological complete response in the surgical specimen is associated with favourable long-term oncologic outcome. Based on this observation, nonoperative management is being explored in the subset of patients with clinical complete response. Whereas, patients with poor response have a high risk of local and distant recurrence, and appear to receive no benefit from standard neoadjuvant chemoradiation. Therefore, in order to develop alternative treatment strategies for non responding patients, predictive and prognostic factors are highly needed. Accumulating clinical observations indicate that elevated platelet count is associated with poor outcome in different type of tumors. In this study we investigated the predictive and prognostic impact of elevated platelet count on pathological response and long-term oncologic outcome in patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiation. METHODS: A total of 965 patients were selected from prospectively maintained databases of seven Centers within the SICO Colorectal Cancer Network. Patients were divided into two groups based on a pre-neoadjuvant chemoradiation platelet count cut-off value of 300 × 109/L identified by receiver operating characteristic curve considering complete pathological response as the outcome. RESULTS: Complete pathological response rate was lower in patients with elevated platelet count (12.8% vs. 22.1%, p = 0.001). Mean follow-up was 50.1 months. Comparing patients with elevated platelet count with patients with not elevated platelet count, 5-year overall survival was 69.5% vs.76.5% (p = 0.016), and 5-year disease free survival was 63.0% vs. 68.9% (p = 0.019). Local recurrence rate was higher in patients with elevated platelet count (11.1% vs. 5.3%, p = 0.001), as higher was the occurrence of distant metastasis (23.9% vs. 16.4%, p = 0.007). At multivariate analysis of potential prognostic factors EPC was independently associated with worse overall survival (HR 1.40, 95% CI 1.06-1.86), and disease free survival (HR 1.37, 95% CI 1.07-1.76). CONCLUSIONS: In locally advanced rectal cancer elevated platelet count before neoadjuvant chemoradiation is a negative predictive and prognostic factor which might help to identify subsets of patients with more aggressive tumors to be proposed for alternative therapeutic strategies.

Abdominal drainage after elective colorectal surgery: propensity score-matched retrospective analysis of an Italian cohort.

BACKGROUND: In Italy, surgeons continue to drain the abdominal cavity in more than 50 per cent of patients after colorectal resection. The aim of this study was to evaluate the impact of abdominal drain placement on early adverse events in patients undergoing elective colorectal surgery. METHODS: A database was retrospectively analysed through a 1:1 propensity score-matching model including 21 covariates. The primary endpoint was the postoperative duration of stay, and the secondary endpoints were surgical site infections, infectious morbidity rate defined as surgical site infections plus pulmonary infections plus urinary infections, anastomotic leakage, overall morbidity rate, major morbidity rate, reoperation and mortality rates. The results of multiple logistic regression analyses were presented as odds ratios (OR) and 95 per cent c.i. RESULTS: A total of 6157 patients were analysed to produce two well-balanced groups of 1802 patients: group (A), no abdominal drain(s) and group (B), abdominal drain(s). Group A versus group B showed a significantly lower risk of postoperative duration of stay >6 days (OR 0.60; 95 per cent c.i. 0.51-0.70; P < 0.001). A mean postoperative duration of stay difference of 0.86 days was detected between groups. No difference was recorded between the two groups for all the other endpoints. CONCLUSION: This study confirms that placement of abdominal drain(s) after elective colorectal surgery is associated with a non-clinically significant longer (0.86 days) postoperative duration of stay but has no impact on any other secondary outcomes, confirming that abdominal drains should not be used routinely in colorectal surgery.

The effect of preoperative chemoradiotherapy on lymph nodes harvested in TME for rectal cancer.

BACKGROUND: Adequate lymph nodes resection in rectal cancer is important for staging and local control. This retrospective analysis single center study evaluated the effect of neoadjuvant chemoradiation on the number of lymph nodes in rectal carcinoma, considering some clinicopathological parameters. METHODS: A total of 111 patients undergone total mesorectal excision for rectal adenocarcinoma from July 2005 to May 2012 in our center were included. No patient underwent any prior pelvic surgery or radiotherapy. Chemoradiotherapy was indicated in patients with rectal cancer stage II or III before chemoradiation. RESULTS: One-hundred and eleven patients were considered. The mean age was 67.6 yrs (range 36 - 84, SD 10.8). Fifty (45.0%) received neoadjuvant therapy before resection. The mean number of removed lymph nodes was 13.6 (range 0-39, SD 7.3). In the patients who received neoadjuvant therapy the number of nodes detected was lower (11.5, SD 6.5 vs. 15.3, SD 7.5, p = 0.006). 37.4% of patients with preoperative chemoradiotherapy had 12 or more lymph nodes in the specimen compared to the 63.6% of those who had surgery at the first step (p: 0.006).Other factors associated in univariate analysis with lower lymph nodes yield included stage (p 0.005) and grade (p 0.0003) of the tumour. Age, sex, tumor site, type of operation, surgeons and pathologists did not weight upon the number of the removed lymph nodes. CONCLUSION: In TME surgery for rectal cancer, preoperative CRT results into a reduction of lymph nodes yield in univariate analisys and linear regression.

The experience of the COMRE group (REctal COMmittee): can magnetic resonance imaging and endosonography really help the clinical pathway after NCRT in rectal cancer?

BACKGROUND: MRI and rectal endosonography (EUS) are routinely used for preoperative tumor staging and assessment of response to therapy in patients with rectal cancer. This study aimed to evaluate the accuracy of the two techniques in predicting the pathological response compared to the resected specimen and the agreement between MRI and EUS and to define the factors that could affect the ability of EUS and MRI to predict pathological responses. MATERIALS AND METHODS: This study included 151 adult patients with middle or low rectal adenocarcinoma treated with neoadjuvant chemoradiotherapy, followed by curative intent elective surgery in the Oncologic Surgical Unit of a hospital in the north of Italy between January 2010 and November 2020. All patients underwent MRI and rectal EUS. RESULTS: The accuracy of EUS to evaluate the T stage was 67.48%, and for the N stage was 75.61%; the accuracy of MRI to evaluate the T stage was 75.97%, and that for the N stage was 51.94%. The agreement in detecting the T stage between EUS and MRI was 65.14% with a Cohen's kappa of 0.4070 and that for the evaluation of the lymph nodes between EUS and MRI was 47.71% with a Cohen's kappa of 0.2680. Risk factors that affect the ability of each method to predict pathological response were also investigated using logistic regression. CONCLUSIONS: EUS and MRI are accurate tools for rectal cancer staging. However, after Radiotherapy - Chemotherapy RT-CT, neither method is reliable for establishing the T stage. EUS seems significantly better than MRI for assessing the N stage. Both methods can be used as complementary tools in the preoperative assessment and management of rectal cancer, but their role in the assessment of residual rectal tumors cannot predict the complete clinical response.

SB202190 Predicts BRAF-Activating Mutations in Primary Colorectal Cancer Organoids via Erk1-2 Modulation.

The p38 inhibitor SB202190 is a necessary component of the medium used for normal colorectal mucosa cultures. Sato et al. suggested that the primary activity of SB202190 may be EGFR signaling stabilization, causing an increased phosphorylation of Erk1-2 sustaining organoid proliferation. However, the growth of some colorectal cancer (CRC)-derived organoid cultures is inhibited by this molecule via an unknown mechanism. We biochemically investigated SB202190 activity on a collection of 25 primary human CRC organoids, evaluating EGFR, Akt and Erk1-2 activation using Western blot. We found that Erk1-2 phosphorylation was induced by SB202190 in 20 organoid cultures and inhibited in 5 organoid cultures. A next-generation sequencing (NGS) analysis revealed that the inhibition of p-Erk1-2 signaling corresponded to the cultures with BRAF mutations (with four different hits, one being undescribed), while p-Erk1-2 induction was apparently unrelated to other mutations involving the EGFR pathway (Her2, KRAS and NRAS). We found that SB202190 mirrored the biochemical activity of the BRAF inhibitor Dabrafenib, known to induce the paradoxical activation of p-Erk1-2 signaling in BRAF wild-type cells. SB202190 was a more effective inhibitor of BRAF-mutated organoid growth in the long term than the specific BRAF inhibitors Dabrafenib and PLX8394. Overall, SB202190 can predict BRAF-activating mutations in patient-derived organoids, as well as allowing for the identification of new BRAF variants, preceding and enforcing NGS data.

Impact of formalin fixation on mismatch repair protein evaluation by immunohistochemistry.

Mismatch repair/microsatellite instability (MMR/MSI) status in colorectal cancer (CRC) has become fundamental as a diagnostic, prognostic, and predictive factor. MMR immunohistochemistry (IHC) is considered a simple and reliable approach; however, its effectiveness depends on pre-analytic factors. Aim of this study was to investigate the impact of different fixation times/protocols on MMR protein IHC quality. Left over tissue from surgically resected CRC samples (cold ischemia time < 30 min) where fixed as follows: standard formalin fixation (24-48 h); hypo-fixation (<20 h); hyper-fixation (>90 h); cold (4°C) fixation (24-48 h); standard fixation for small sample size (0.5×0.5 cm). Samples for each group were collected from 30 resected CRC and the following parameters were evaluated on 600 immunohistochemical stains: intensity of expression; patchiness of staining; presence of central artefact. Forty-six immunoreactions were inadequate (score 0 intensity), the majority regarding MLH1 or PMS2 in the hypo-fixation group (47.8%), followed by the hyper-fixation group (28.1%); cold formalin fixation showed the least inadequate cases. Patchiness and central artefact were more frequent in hypo-fixation and standard fixation group compared to the others. MLH1 (closely followed by PMS2) performed worse with regard to immunostaining intensity (p=0.0002) in the standard and in the hypo-fixation group (p< 0.00001). Using a small sample size improved patchiness/central artefacts. This is the first study specifically created to evaluate the impact of fixation on MMR protein IHC, showing that both formalin hypo- and hyper-fixation can cause problems; 24-h formalin fixation as well as cold (4°C) formalin fixation are recommended for successful IHC MMR evaluation.