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LBA3503 Background: Promising results have been obtained during the last decade using cytoreductive surgery (CRS) plus HIPEC for selected patients with colorectal PC who are amenable to complete macroscopic resection. This is the first trial to evaluate the specific role of HIPEC, after CRS, for the treatment of PC of colorectal origin. Methods: Prodige 7 is a randomized phase III, multicenter trial. Patients with histologically proven and isolated PC, peritoneal cancer index (PCI) ≤25 were eligible. Randomization (1:1) was stratified by center, complete macroscopic resection (R0/1 vs R2), and neoadjuvant systemic chemotherapy. Patients were treated with CRS plus HIPEC with oxaliplatin or CRS alone, in association with systemic chemotherapy. The primary endpoint was the overall survival (OS). Secondary endpoints were relapse-free survival (RFS) and toxicity. 264 patients were required to show a gain in median OS from 30 to 48 months (HR = 0.625) with a two-sided α = 0,046 and 80% power. Results: 265 patients from 17 centers were included between February 2008 and January 2014: 132 in Arm without HIPEC and 133 in Arm with HIPEC. The median age was 60 years (range: 30-74). Baseline characteristics were well balanced. The overall post-operative mortality rate was 1.5% and was not different between the two arms. The morbidity rates did not differ statistically at 30 days. At 60 days, the grade 3-5 morbidity rate was significantly higher with HIPEC (24.1% vs. 13.6%, p= 0.030). After a median follow up of 63.8 months (95% CI: 58.9-69.8), the median OS was 41.2 months (95% CI 35.1-49.7) in the non-HIPEC Arm and 41.7 months (95% CI: 36.2-52.8) in the HIPEC Arm, HR = 1.00 (95% CI: 0.73-1.37) p = 0.995. The median RFS was 11.1 months (95% CI: 9-12.7) in non-HIPEC Arm and 13.1 months (95% CI: 12.1-15.7) in HIPEC Arm, HR = 0.90 (95% CI: 0.69-1.90) (p = 0.486), whilst the 1-year RFS rates were 46.1% in non-HIPEC Arm and 59 % in the HIPEC Arm. Conclusions: The therapeutic curative management of PC from colorectal cancer by CRS shows satisfactory survival results. While the addition of HIPEC with oxaliplatin does not influence the OS. Clinical trial information: NCT00769405.

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Background: Rectal cancer surgery is technically challenging and depends on many factors. This study evaluated the ability of clinical and anatomical factors to predict surgical difficulty in total mesorectal excision. Conclusion: This simple morphometric score may assist surgical decision-making and comparative study by defining operative difficulty before surgery.

Microtubule dynamics rely on the properties of tubulin and are regulated by microtubule-associated proteins. GTP-tubulin assembles into hollow polymers, which can depolymerize upon GTP hydrolysis. Depolymerizing microtubules may stop shrinking and resume growth. Such rescues are regulated by microtubule-associated proteins like CLIP-170 and the CLASPs [1, 2]. Microtubule domains prone to rescues contain discrete regions (previously termed "GTP islands") that retain a GTP-tubulin-like conformation in the main body of the microtubule [3]. However, the exact nature of these domains and the mechanisms controlling their occurrence and distribution are largely unknown. Here we show that collisions between growing microtubules and mechanical obstacles (including other microtubules) in vitro result in the higher abundance of GTP-like islands in stressed microtubule regions. Furthermore, these islands were found to be efficiently generated by both lateral contacts and mechanical constraints applied to the main body of the microtubules. They were also particularly prominent where shifts in the number of protofilaments occur in the microtubule lattice. GTP-like islands and rescues frequently co-occurred at microtubule intersections in vitro and in living cells, both in crossing and in crossed microtubules. We also observed that CLIP-170 recognizes GTP-like islands in vivo and is retained at microtubule crossings. Therefore, we propose that rescues occur via a two-stage mechanism: (1) lattice defects determine potential rescue-promoting islands in the microtubule structure, and (2) CLIP-170 detects these islands to stimulate microtubule rescue. Our results reveal the interplay between rescue-promoting factors and microtubule architecture and organization to control microtubule dynamics.

The small GTP-binding protein ADP-ribosylation factor 6 (ARF6) controls the endocytic recycling pathway of several plasma membrane receptors. We analyzed the localization and GDP/GTP cycle of GFP-tagged ARF6 by total internal reflection fluorescent microscopy. We found that ARF6-GFP associates with clathrin-coated pits (CCPs) at the plasma membrane in a GTP-dependent manner in a mechanism requiring the adaptor protein complex AP-2. In CCP, GTP-ARF6 mediates the recruitment of the ARF-binding domain of downstream effectors including JNK-interacting proteins 3 and 4 (JIP3 and JIP4) after the burst recruitment of the clathrin uncoating component auxilin. ARF6 does not contribute to receptor-mediated clathrin-dependent endocytosis. In contrast, we found that interaction of ARF6 and JIPs on endocytic vesicles is required for trafficking of the transferrin receptor in the fast, microtubule-dependent endocytic recycling pathway. Our findings unravel a novel mechanism of separation of ARF6 activation and effector function, ensuring that fast recycling may be determined at the level of receptor incorporation into CCPs.

R-TME is less likely to be converted to open surgery than L-TME; operative time and curative pathologic criteria are equivalent. Future prospective trial should compare standardized procedures performed by experienced surgeons for subgroups of high-risk patients.