Novel drug resistance mechanisms and drug targets in BRAF-mutated peritoneal metastasis from colorectal cancer.

BACKGROUND: Patients with peritoneal metastasis from colorectal cancer (PM-CRC) have inferior prognosis and respond particularly poorly to chemotherapy. This study aims to identify the molecular explanation for the observed clinical behavior and suggest novel treatment strategies in PM-CRC. METHODS: Tumor samples (230) from a Norwegian national cohort undergoing surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) with mitomycin C (MMC) for PM-CRC were subjected to targeted DNA sequencing, and associations with clinical data were analyzed. mRNA sequencing was conducted on a subset of 30 samples to compare gene expression in tumors harboring BRAF or KRAS mutations and wild-type tumors. RESULTS: BRAF mutations were detected in 27% of the patients, and the BRAF-mutated subgroup had inferior overall survival compared to wild-type cases (median 16 vs 36 months, respectively, p < 0.001). BRAF mutations were associated with RNF43/RSPO aberrations and low expression of negative Wnt regulators (ligand-dependent Wnt activation). Furthermore, BRAF mutations were associated with gene expression changes in transport solute carrier proteins (specifically SLC7A6) and drug metabolism enzymes (CES1 and CYP3A4) that could influence the efficacy of MMC and irinotecan, respectively. BRAF-mutated tumors additionally exhibited increased expression of members of the novel butyrophilin subfamily of immune checkpoint molecules (BTN1A1 and BTNL9). CONCLUSIONS: BRAF mutations were frequently detected and were associated with particularly poor survival in this cohort, possibly related to ligand-dependent Wnt activation and altered drug transport and metabolism that could confer resistance to MMC and irinotecan. Drugs that target ligand-dependent Wnt activation or the BTN immune checkpoints could represent two novel therapy approaches.

Navigation-Assisted Surgery for Locally Advanced Primary and Recurrent Rectal Cancer.

BACKGROUND: In some surgical disciplines, navigation-assisted surgery has become standard of care, but in rectal cancer, indications for navigation and the utility of different technologies remain undetermined. METHODS: The NAVI-LARRC prospective study (NCT04512937; IDEAL Stage 2a) evaluated feasibility of navigation in patients with locally advanced primary (LARC) and recurrent rectal cancer (LRRC). Included patients had advanced tumours with high risk of incomplete (R1/R2) resection, and navigation was considered likely to improve the probability of complete resection (R0). Tumours were classified according to pelvic compartmental involvement, as suggested by the Royal Marsden group. The BrainlabTM navigation platform was used for preoperative segmentation of tumour and pelvic anatomy, and for intraoperative navigation with optical tracking. R0 resection rates, surgeons' experiences, and adherence to the preoperative resection plan were assessed. RESULTS: Seventeen patients with tumours involving the posterior/lateral compartments underwent navigation-assisted procedures. Fifteen patients required abdominosacral resection, and 3 had resection of the sciatic nerve. R0 resection was obtained in 6/8 (75%) LARC and 6/9 (69%) LRRC cases. Preoperative segmentation was time-consuming (median 3.5 h), but intraoperative navigation was accurate. Surgeons reported navigation to be feasible, and adherence to the resection plan was satisfactory. CONCLUSIONS: Navigation-assisted surgery using optical tracking was feasible. The preoperative planning was time-consuming, but intraoperative navigation was accurate and resulted in acceptable R0 resection rates. Selected patients are likely to benefit from navigation-assisted surgery.

Drafting in long-track speed skating team pursuit on the ice rink.

Drafting is distinctive for team pursuit races in long-track speed skating. This study aims to compare the impact of drafting on physical intensity (heart rate [HR]) and perceived intensity (ratings of perceived exertion [RPE]) per drafting position. Eighteen skilled male (n = 9) and female (n = 9) skaters (20.0 ± 4.8 years) skated three trials, in first, second or third position, with consistent average velocity (F2,10 = 2.30, p = 0.15, ηp2 = 0.32). Differences in HR and RPE (Borg CR-10 scale) were compared within-subjects (three positions) using a repeated-measures ANOVA (p < 0.05). Compared to the first position, HR was lower in the second (benefit 3.2%) and third (benefit 4.7%) position and lower in third compared to second position (benefit 1.5%), observed in 10 skaters (F2,28 = 28.9, p < 0.001, ηp2= 0.67). RPE was lower when comparing second (benefit 18.5%) and third (benefit 16.8%) position to first (F1.3,22.1 = 7.02, p < 0.05, ηp2= 0.29) and similar for third and second positions., observed in 8 skaters. Even though the physical intensity was lower when drafting in third versus second position, the perceived intensity was equal. There were large interindividual differences between skaters. Coaches are advised to adopt a multidimensional, tailored approach when selecting and training skaters for a team pursuit.

Cancer therapy with isolated limb perfusion. / Kreftbehandling med isolert ekstremitetsperfusjon.

For locally advanced soft tissue sarcomas and metastases from melanoma located in the extremities, mutilating surgery or amputation may be necessary to achieve local control. Isolated limb perfusion with high-dose chemotherapy may represent an alternative to amputation for this patient group.

Higher order genomic organization and epigenetic control maintain cellular identity and prevent breast cancer.

Cells establish and sustain structural and functional integrity of the genome to support cellular identity and prevent malignant transformation. In this review, we present a strategic overview of epigenetic regulatory mechanisms including histone modifications and higher order chromatin organization (HCO) that are perturbed in breast cancer onset and progression. Implications for dysfunctions that occur in hormone regulation, cell cycle control, and mitotic bookmarking in breast cancer are considered, with an emphasis on epithelial-to-mesenchymal transition and cancer stem cell activities. The architectural organization of regulatory machinery is addressed within the contexts of translating cancer-compromised genomic organization to advances in breast cancer risk assessment, diagnosis, prognosis, and identification of novel therapeutic targets with high specificity and minimal off target effects.

Vertical Rectus Abdominis Musculocutaneous Flap Repair Improves Perineal Wound Healing after Abdominoperineal Resection for Irradiated Locally Advanced Rectal Cancer.

BACKGROUND: Radiotherapy (RT) and subsequent abdominoperineal resection (APR) for locally advanced rectal cancer (LARC) is associated with significant perineal wound morbidity. The aim of the present study was to investigate if vertical rectus abdominis musculocutaneous (VRAM) flap repair after APR in LARC patients improves perineal wound healing compared with direct perineal wound closure (non-VRAM). METHODS: LARC patients (n = 329) operated with APR between January 2006 and December 2015 after neoadjuvant RT of ≥ 25 Gy were identified, including 260 and 69 patients in the non-VRAM and VRAM groups, respectively. Perineal wound healing was assessed 3 months postoperatively, and risk factors for perineal wound complications and associations with short- and long-term outcome were analyzed. RESULTS: Delayed perineal wound healing after 3 months was more frequent in the non-VRAM group (31.5%) compared with the VRAM group (10.4%) (p < 0.01). In the non-VRAM group, 26.9% of patients developed pelvic abscess, compared with 10.1% in the VRAM group (p < 0.01). Significant risk factors for perineal wound morbidity were non-VRAM (odds ratio [OR] 3.94, 95% confidence interval [CI] 1.72-9.00; p = 0.02), positive circumferential resection margin (R1; OR 3.64, 95% CI 1.91-6.93; p < 0.01), pelvic abscess (OR 3.27, 95% CI 1.90-5.63; p < 0.01), and short-course RT (OR 3.81, 95% CI 1.75-8.30; p < 0.01). Perineal wound morbidity was not associated with impaired long-term oncologic outcome. CONCLUSIONS: VRAM flap reconstruction of the perineum is associated with an increased wound healing rate and may protect against pelvic abscess development. However, procedure-related long-term morbidity is incompletely studied and the procedure should be reserved for selected patients.

Novel Treatment with Intraperitoneal MOC31PE Immunotoxin in Colorectal Peritoneal Metastasis: Results From the ImmunoPeCa Phase 1 Trial.

BACKGROUND: MOC31PE immunotoxin was developed to rapidly kill cells expressing the tumor-associated epithelial cell adhesion molecule, which is highly expressed in colorectal cancer. Although cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) may offer long-term survival to patients with peritoneal metastasis from colorectal cancer (PM-CRC), most patients experience disease relapse and novel therapeutic options are needed. On this basis, MOC31PE is being developed as a novel therapeutic principle to target PM-CRC. METHODS: This was a dose-escalating phase I trial to evaluate the safety and toxicity (primary endpoint), pharmacokinetic profile, and neutralizing antibody response (secondary endpoints) upon intraperitoneal administration of MOC31PE in patients with PM-CRC undergoing CRS-HIPEC with Mitomycin C. Fifteen patients received the study drug at four dose levels (3+3+3+6), administered intraperitoneally as a single dose the day after CRS-HIPEC. RESULTS: No dose-limiting toxicity was observed, and the maximum tolerated dose was not reached. There was negligible systemic absorption of the study drug. Drug concentrations in peritoneal fluid samples were in the cytotoxic range and increased in a dose-dependent manner. MOC31PE recovered from peritoneal cavity retained its cytotoxic activity in cell-based assays. All patients developed neutralizing antibodies. CONCLUSIONS: Intraperitoneal administration of MOC31PE was safe and well tolerated, and combined with low systemic uptake, MOC31PE seems ideal for local intraperitoneal treatment. The drug will be further evaluated in an ongoing phase II expansion cohort.

Accuracy of 3D fluoro-navigated anterior transpedicular screws in the subaxial cervical spine: an experimental study on human specimens.

INTRODUCTION: Pedicle screw stabilization, the standard technique in the thoracic and lumbar spine, is increasingly used in the cervical spine. Initial studies on the use of anterior pedicle screws (ATPS) in the cervical spine have been recently published. ATPS use has theoretical advantages over posterior stabilization. We have already established a 3D-fluoroscopy navigation setup in a study of artificial bones. The aim of the current study was to evaluate the positioning quality/accuracy of ATPS introduced to human specimens. METHODS: 36 cannulated screws (3.5 mm) were implanted anteriorly into the C3-C7 segments of four spines (unfixed, frozen, cadaveric specimens) using a 3D-fluoroscopy navigation system. Placement accuracy was evaluated using a recently published classification on postoperative CT scans. Grade 1 is perfect position with pedicle wall perforation <1 mm, grade 2 is perforation <2 mm, etc., and finally grade 5 is cortical perforation of >4 mm and/or transverse foramen entry. RESULTS: 36 anterior pedicle screws were inserted into four human cervical spine specimens. Of these, seven screws were introduced to C3, five to C4 and eight each to C5, C6, and C7. Classified with the modified G&R, 21 of 36 (58.3%) were grade 1. Ten screws (27.8%) were grade 2. Grade 4 was assessed for two screws and grade 5 for three. Customary "good" positioning, combining grades 1 and 2, was thus found in 86.1%. Five screws (13.9%) did not meet this criterion (grade ≥3). CONCLUSIONS: With 86.1% of good positioning (grade 2 or better), a 3D-fluoroscopy navigation of ATPS screws into human c-spine specimens achieved a satisfying results. These are at least comparable to results presented in the literature for posteriorly introduced subaxial pedicle screws.

[The biomechanics of hyperextension injuries of the subaxial cervical spine]. / Biomechanik der Hyperextensionsverletzung der subaxialen Halswirbelsäule.

Hyperextension injuries of the subaxial cervical spine are potentially hazardous due to relevant destabilization. Depending on the clinical condition, neurologic or vascular damage may occur. Therefore an exact knowledge of the factors leading to destabilization is essential. In a biomechanical investigation, 10 fresh human cadaver cervical spine specimens were tested in a spine simulator. The tested segments were C4 to 7. In the first step, physiologic motion was investigated. Afterwards, the three steps of injury were dissection of the anterior longitudinal ligament, removal of the intervertebral disc/posterior longitudinal ligament, and dissection of the interspinous ligaments/ligamentum flavum. After each step, the mobility was determined. Regarding flexion and extension, an increase in motion of 8.36 % after the first step, 90.45 % after the second step, and 121.67 % after the last step was observed. Testing of lateral bending showed an increase of mobility of 7.88 %/27.48 %/33.23 %; axial rotation increased by 2.87 %/31.16 %/45.80 %. Isolated dissection of the anterior longitudinal ligament led to minor destabilization, whereas the intervertebral disc has to be seen as a major stabilizer of the cervical spine. Few finite-element studies showed comparable results. If a transfer to clinical use is undertaken, an isolated rupture of the anterior longitudinal ligament can be treated without surgical stabilization.

[Type 2 dens fracture in the elderly and therapy-linked mortality : Conservative or operative treatment]. / Typ-II-Densfrakturen des alten Menschen und therapiebedingte Mortalität : Konservative oder operative Behandlung.

BACKGROUND: Type II fractures of the odontoid process of the axis are the most common injury of the cervical spine in elderly patients. Only little evidence exists on whether elderly patients should be treated conservatively or surgically. MATERIAL AND METHODS: The mortality and survival probability of 51 patients were determined in a retrospective study. The range of motion, pain and the neck disability index were clinically investigated. RESULTS: Of the 51 patients 37 were treated surgically and 14 conservatively. The conservatively treated group showed a higher mortality (64 % vs. 32 %). Kaplan-Meier analysis revealed a median survival of the conservatively treated group of 29 months, whereby during the first 3 months of treatment this group showed a higher survival probability and afterwards the surgically treated group showed a higher survival probability. The clinical examination of 20 patients revealed limited range of motion of the cervical spine. Additionally, moderate levels of pain and complaints were recorded using the neck disability index. CONCLUSION: Fractures of the odontoid process pose a far-reaching danger for elderly patients. A balanced assessment of the general condition should be carried out at the beginning of treatment of these patients. In the early phase following trauma no differences were found with respect to survival rates but for long-term survival the operatively treated group showed advantages; however, these advantages cannot be causally attributed to the choice of therapy.

Complete cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for colorectal peritoneal metastasis in Norway: Prognostic factors and oncologic outcome in a national patient cohort.

BACKGROUND AND OBJECTIVES: Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) can offer long-term survival to patients with resectable peritoneal metastasis (PM) from colorectal cancer (CRC), a condition with otherwise dismal prognosis. This study describes short- and long-term outcome in a national patient cohort and aims to identify prognostic factors. METHODS: All patients treated with CRS-HIPEC for non-appendiceal PM-CRC in Norway 2004-2013 were included (n = 119), and outcome and potential prognostic factors were examined using survival- and ROC-curve analysis. RESULTS: Five-year overall survival (OS) and disease-free survival (DFS) were 36% and 14%, respectively, with 45 months median follow-up. The only factor associated with OS in multivariable analysis was peritoneal cancer index (PCI), with HR 1.05 (1.01-1.09) for every increase in PCI-score (P = 0.015). Peritoneal relapse was associated with shorter OS than distant metastasis (P = 0.002). ROC-curves identified PCI > 12 as a marker with 100% specificity for prediction of disease relapse. Severe postoperative complications (Clavien-Dindo ≥ 3) occurred in 15% of patients and there was no 100-day mortality. CONCLUSIONS: Long-term outcome was in line with published results, morbidity was acceptable and there was no 100-day mortality. The results reemphasize CRS-HIPEC as an important treatment option in PM-CRC, with particularly good results in patients with PCI < 12. J. Surg. Oncol. 2016;114:222-227. © 2016 Wiley Periodicals, Inc.

Predicting Clostridium difficile infection in diabetic patients and the effect of metformin therapy: a retrospective, case-control study.

Data on risk factors for Clostridium difficile infection (CDI) in diabetic patients are scarce. Recently, it has been shown that metformin increases the Bacteroidetes/Firmicutes ratio; therefore, it may yield a protective effect against CDI. We aimed to assess risk factors for CDI in diabetic patients beyond antibiotic treatment, and to determine the impact of metformin therapy on the development of CDI in these patients. In this retrospective, case-control study, all consecutive CDI diabetic patients, from January 2009 to December 2013, were included and compared to consecutive diabetic patients without CDI, hospitalized during the same period and in the same departments. Of 7,670 patients tested for C. difficile toxins, 486 were diabetics. Of them, 150 (30.8 %) were positive for C. difficile toxins and 336 (69.1 %) were negative. On multivariate analysis, metformin treatment was associated with a significant reduction in CDI [odds ratio (OR) = 0.58; 95 % confidence interval (CI), 0.37-0.93; p = 0.023], while heart failure was associated with significantly higher rates of CDI (OR = 1.654; 95 % CI, 1.007-2.716; p = 0.047), together with poor functional status, previous hospitalization, and abdominal surgery. Our findings suggest that, in diabetic patients, in addition to the well-recognized risk factors, heart failure is an additional risk factor for CDI, while metformin treatment seems to have a protective effect against the development of CDI. The exact mechanisms underlying this protective effect remain to be fully understood.

Nationwide improvement of rectal cancer treatment outcomes in Norway, 1993-2010.

BACKGROUND: The Norwegian Rectal Cancer Project was initated in 1993 with the aims of improving surgery, decreasing local recurrence rates, improving survival, and establishing a national rectal cancer registry. Here we present results from the Norwegian Colorectal Cancer Registry (NCCR) from 1993 to 2010. MATERIAL AND METHODS: A total of 15 193 patients were diagnosed with rectal cancer in Norway 1993-2010, and were registered with clinical data regarding diagnosis, treatment, locoregional recurrences and distant metastases. Of these, 10 796 with non-metastatic disease underwent tumour resection. The results were stratified into five time periods, and the treatment outcomes were compared. Recurrence rates are presented for the 9785 patients who underwent curative major resection (R0/R1). RESULTS: Among all 15 193 patients, relative five-year survival increased from 54.1% in 1993-1997 to 63.4% in 2007-2010 (p < 0.001). Among the 10 796 patients with stage I-III disease who underwent tumour resection, from 1993-1997 to 2007-2010, relative five-year survival improved from 71.2% to 80.6% (p < 0.001). An increasing proportion of these patients underwent surgery at large-volume hospitals; and 30- and 100-day mortality rates, respectively, decreased from 3.0% to 1.4% (p < 0.001) and from 5.1% to 3.0% (p < 0.011). Use of preoperative chemoradiotherapy increased from 6.5% in 1993 to 39.0% in 2010 (p < 0.001). Estimated local recurrence rate after major resection (R0/R1) decreased from 14.5% in 1993-1997 to 5.0% in 2007-2009 (p < 0.001), and distant recurrence rate decreased from 26.0% to 20.2% (p < 0.001). CONCLUSION: Long-term outcomes from a national population-based rectal cancer registry are presented. Improvements in rectal cancer treatment have led to decreased recurrence rates of 5% and increased survival on a national level.

Reactions of the rat musculoskeletal system to compressive spinal cord injury (SCI) and whole body vibration (WBV) therapy.

Traumatic spinal cord injury (SCI) causes a loss of locomotor function with associated compromise of the musculo-skeletal system. Whole body vibration (WBV) is a potential therapy following SCI, but little is known about its effects on the musculo-skeletal system. Here, we examined locomotor recovery and the musculo-skeletal system after thoracic (T7-9) compression SCI in adult rats. Daily WBV was started at 1, 7, 14 and 28 days after injury (WBV1-WBV28 respectively) and continued over a 12-week post-injury period. Intact rats, rats with SCI but no WBV (sham-treated) and a group that received passive flexion and extension (PFE) of their hind limbs served as controls. Compared to sham-treated rats, neither WBV nor PFE improved motor function. Only WBV14 and PFE improved body support. In line with earlier studies we failed to detect signs of soleus muscle atrophy (weight, cross sectional diameter, total amount of fibers, mean fiber diameter) or bone loss in the femur (length, weight, bone mineral density). One possible explanation is that, despite of injury extent, the preservation of some axons in the white matter, in combination with quadripedal locomotion, may provide sufficient trophic and neuronal support for the musculoskeletal system.

Short-term results after robot-assisted surgery for primary rectal cancers requiring beyond total mesorectal excision in multiple compartments.

AIM: Rectal cancers requiring beyond total mesorectal excision (bTME) are traditionally operated using an open approach, but the use of minimally invasive robot-assisted procedures is increasing. Introduction of minimal invasive surgery for complex cancer cases could be associated with compromised surgical margins or increased complication rates. Therefore, reporting results both clinical and oncological in large series is important. Since bTME procedure reports are heterogeneous, comparing results is often difficult. In this study, a magnetic resonance imaging (MRI) classification system was used to describe the bTME surgery according to pelvic compartments. METHODS: Consecutive patients with primary rectal cancer operated with laparoscopic robot-assisted bTME were prospectively included for 2 years. All patients had tumors that threatened the mesorectal fascia, invaded adjacent organs, and/or involved metastatic pelvic lateral lymph nodes. Short-term clinical outcomes and oncological specimen quality were registered. Surgery was classified according to pelvic compartments resected. RESULTS: Clear resection margins (R0 resection) were achieved in 95 out of 105 patients (90.5%). About 26% had Accordion Severity Grading System of Surgical Complications grade 3-4 complications and 15% required re-operations. About 7% were converted to open surgery. The number of compartments resected ranged from one to the maximum seven, with 83% having two or three compartments resected. All 10 R1 resections occurred in the lateral and posterior compartments. CONCLUSIONS: The short-term clinical outcomes and oncological specimen quality after robot-assisted bTME surgery were comparable to previously published open bTME surgery. The description of surgical procedures using the Royal Marsden MRI compartment classification was feasible.

Hyperthermic intraperitoneal chemotherapy in colorectal cancer.

BACKGROUND: This study evaluated the efficacy of hyperthermic intraperitoneal chemotherapy (HIPEC) in colorectal cancer with peritoneal metastases (pmCRC) in a large international data set of patients. PATIENTS AND METHODS: Patients with pmCRC from 39 centres who underwent cytoreductive surgery with HIPEC between 1991 and 2018 were selected and compared for the HIPEC protocols received-oxaliplatin-HIPEC versus mitomycin-HIPEC. Following analysis of crude data, propensity-score matching (PSM) and Cox-proportional hazard modelling were performed. Outcomes of interest were overall survival (OS), recurrence-free survival (RFS) and the HIPEC dose-response effects (high versus low dose, dose intensification and double drug protocols) on OS, RFS and 90-day morbidity. Furthermore, the impact of the treatment time period was assessed. RESULTS: Of 2760 patients, 2093 patients were included. Median OS was 43 months (95% c.i. 41 to 46 months) with a median RFS of 12 months (95% c.i. 12 to 13 months). The oxaliplatin-HIPEC group had an OS of 47 months (95% c.i. 42 to 53 months) versus 39 months (95% c.i. 36 to 43 months) in the mitomycin-HIPEC group (P = 0.002), aHR 0.77, 95% c.i. 0.67 to 0.90, P < 0.001. The OS benefit persisted after PSM of the oxaliplatin-HIPEC group and mitomycin-HIPEC group (48 months (95% c.i. 42 to 59 months) versus 40 months (95% c.i. 37 to 44 months)), P < 0.001, aHR 0.78 (95% c.i. 0.65 to 0.94), P = 0.009. Similarly, matched RFS was significantly higher for oxaliplatin-HIPEC versus others (13 months (95% c.i. 12 to 15 months) versus 11 months (95% c.i. 10 to 12 months, P = 0.02)). High-dose mitomycin-HIPEC protocols had similar OS compared to oxaliplatin-HIPEC. HIPEC dose intensification within each protocol resulted in improved survival. Oxaliplatin + irinotecan-HIPEC resulted in the most improved OS (61 months (95% c.i. 51 to 101 months)). Ninety-day mortality in both crude and PSM analysis was worse for mitomycin-HIPEC. There was no change in treatment effect depending on the analysed time period. CONCLUSIONS: Oxaliplatin-based HIPEC provided better outcomes compared to mitomycin-based HIPEC. High-dose mitomycin-HIPEC was similar to oxaliplatin-HIPEC. The 90-day mortality difference favours the oxaliplatin-HIPEC group. A trend for dose-response between low- and high-dose HIPEC was reported.

Perioperative chemotherapy in colorectal cancer with peritoneal metastases: A global propensity score matched study.

Background: There is a paucity of studies evaluating perioperative systemic chemotherapy in conjunction with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with colorectal cancer peritoneal metastases (CRCPM). The aim was to evaluate neoadjuvant and/or adjuvant systemic therapy in CRCPM. Methods: Patients with CRCPM from 39 treatment centres globally from January 1, 1991, to December 31, 2018, who underwent CRS+HIPEC were identified and stratified according to neoadjuvant/adjuvant use. Crude data analysis, propensity score matching (PSM) and Cox-proportional hazard modelling was performed. Findings: Of 2093 patients, 1613 were included in neoadjuvant crude evaluation with 708 in the PSM cohort (354 patients/arm). In the adjuvant evaluation, 1176 patients were included in the crude cohort with 778 in the PSM cohort (389 patients/arm). The median overall survival (OS) in the PSM cohort receiving no neoadjuvant vs neoadjuvant therapy was 37.0 months (95% CI: 32.6-42.7) vs 34.7 months (95% CI: 31.2-38.8, HR 1.08 95% CI: 0.88-1.32, p = 0.46). The median OS in the PSM cohort receiving no adjuvant therapy vs adjuvant therapy was 37.0 months (95% CI: 32.9-41.8) vs 45.7 months (95% CI: 38.8-56.2, HR 0.79 95% CI: 0.64-0.97, p = 0.022). Recurrence-free survival did not differ in the neoadjuvant evaluation but differed in the adjuvant evaluation - HR 1.04 (95% CI: 0.87-1.25, p = 0.66) and 0.83 (95% CI: 0.70-0.98, p = 0.03), respectively. Multivariable Cox-proportional hazard modelling in the crude cohorts showed hazard ratio 1.08 (95% CI: 0.92-1.26, p = 0.37) for administering neoadjuvant therapy and 0.86 (95% CI: 0.72-1.03, p = 0.095) for administering adjuvant therapy. Interpretation: Neoadjuvant therapy did not confer a benefit to patients undergoing CRS+HIPEC for CRCPM, whereas adjuvant therapy was associated with a benefit in this retrospective setting. Funding: None.

Bicalutamide-induced hypoxia potentiates RUNX2-mediated Bcl-2 expression resulting in apoptosis resistance.

BACKGROUND: We have previously shown that hypoxia selects for more invasive, apoptosis-resistant LNCaP prostate cancer cells, with upregulation of the osteogenic transcription factor RUNX2 and the anti-apoptotic factor Bcl-2 detected in the hypoxia-selected cells. Following this observation, we questioned through what biological mechanism this occurs. METHODS: We examined the effect of hypoxia on RUNX2 expression and the role of RUNX2 in the regulation of Bcl-2 and apoptosis resistance in prostate cancer. RESULTS: Hypoxia increased RUNX2 expression in vitro, and bicalutamide-treated LNCaP tumours in mice (previously shown to have increased tumour hypoxia) exhibited increased RUNX2 expression. In addition, RUNX2-overexpressing LNCaP cells showed increased cell viability, following bicalutamide and docetaxel treatment, which was inhibited by RUNX2 siRNA; a range of assays demonstrated that this was due to resistance to apoptosis. RUNX2 expression was associated with increased Bcl-2 levels, and regulation of Bcl-2 by RUNX2 was confirmed through chromatin immunoprecipitation (ChIP) binding and reporter assays. Moreover, a Q-PCR array identified other apoptosis-associated genes upregulated in the RUNX2-overexpressing LNCaP cells. CONCLUSION: This study establishes a contributing mechanism for progression of prostate cancer cells to a more apoptosis-resistant and thus malignant phenotype, whereby increased expression of RUNX2 modulates the expression of apoptosis-associated factors, specifically Bcl-2.