Role of the mechanical microenvironment on CD-44 expression of breast adenocarcinoma in response to radiotherapy

The biological effects of ionizing radiation are exploited in the clinical practice of radiotherapy to destroy tumour cells while sparing the surrounding normal tissue. While most of the radiotherapy research focused on DNA damage and repair, recently a great attention is going to cells' interactions with the mechanical microenvironment of both malignant and healthy tissues after exposure. In fact, the stiffness of the extracellular matrix can modify cells' motility and spreading through the modulation of transmembrane proteins and surface receptors' expression, such as CD-44. CD-44 receptor has held much interest also in targeted-therapy due to its affinity with hyaluronic acid, which can be used to functionalize biodegradable nanoparticles loaded with chemotherapy drugs for targeted therapy. We evaluated changes in CD-44 expression in two mammary carcinoma cell lines (MCF10A and MDA-MB-231) after exposure to X-ray (2 or 10 Gy). To explore the role of the mechanical microenvironment, we mimicked tissues' stiffness with polyacrylamide's substrates producing two different elastic modulus values (0.5 and 15 kPa). We measured a dose dependent increase in CD-44 relative expression in tumour cells cultured in a stiffer microenvironment. These findings highlight a crucial connection between the mechanical properties of the cell's surroundings and the post-radiotherapy expression of surface receptors.

Impact of inter-observer variability on first axillary level dosimetry in breast cancer radiotherapy: An AIRO multi-institutional study

This study quantified the incidental dose to the first axillary level (L1) in locoregional treatment plan for breast cancer. Eighteen radiotherapy centres contoured L1-L4 on three different patients (P1,2,3), created the L2-L4 planning target volume (single centre planning target volume, SC-PTV) and elaborated a locoregional treatment plan. The L2-L4 gold standard clinical target volume (CTV) along with the gold standard L1 contour (GS-L1) were created by an expert consensus. The SC-PTV was then replaced by the GS-PTV and the incidental dose to GS-L1 was measured. Dosimetric data were analysed with Kruskal-Wallis test. Plans were intensity modulated radiotherapy (IMRT)-based. P3 with 90° arm setup had statistically significant higher L1 dose across the board than P1 and P2, with the mean dose (Dmean) reaching clinical significance. Dmean of P1 and P2 was consistent with the literature (77.4% and 74.7%, respectively). The incidental dose depended mostly on L1 proportion included in the breast fields, underlining the importance of the setup, even in case of IMRT.

Stereotactic body radiotherapy with CyberKnife® System for low- and intermediate-risk prostate cancer: clinical outcomes and toxicities of CyPro Trial

Simple summary

Stereotactic body radiotherapy (SBRT) of 35-36.25 Gy in five fractions with the CyberKnife System yields excellent control with low toxicity in low-intermediate-risk prostate cancer patients. We found no differences in biochemical control and overall survival in relation to dose. There were no significant differences in toxicity or quality of life between the two groups.

Aims

Stereotactic body radiotherapy (SBRT) is an emerging therapeutic approach for low- and intermediate-risk prostate cancer. We present retrospective data on biochemical control, toxicity, and quality of life of CyPro Trial.

Materials and methods

A total of 122 patients with low- and intermediate-risk prostate cancer were treated with the CyberKnife System at a dose of 35 Gy or 36.25 Gy in five fractions. Biochemical failure (BF)/biochemical disease-free survival (bDFS) was defined using the Phoenix method (nadir + 2 ng/ml). Acute/late rectal and urinary toxicities were assessed by the Radiation Therapy Oncology Group (RTOG) toxicity scale. Quality of life (QoL) was assessed by the European Organisation for Research and Treatment of Cancer (EORTC) QLQ C30 and PR25. International Erectile Function Index-5 (IIEF5) and International Prostate Symptom Score (IPSS) questionnaires were administered at baseline, every 3 months after treatment during the first years, and then at 24 months and 36 months.

Results

The 1-, 2-, and 5-year DFS rates were 92.9%, 92.9%, and 92.3%, respectively, while the 1-, 2-, and 5-year bDFS rates were 100%, 100%, and 95.7%, respectively. With regard to risk groups or doses, no statistically significant differences were found in terms of DFS or bDFS. Grade 2 urinary toxicity was acute in 10% and delayed in 2% of patients. No Grade 3 acute and late urinary toxicity was observed. Grade 2 rectal toxicity was acute in 8% and late in 1% of patients. No Grade 3-4 acute and late rectal toxicity was observed. Grade 2 acute toxicity appeared higher in the high-dose group (20% in the 36.25-Gy group versus 3% in the 35-Gy group) but was not statistically significant.

Conclusion

Our study confirms that SBRT of 35-36.25 Gy in five fractions with the CyberKnife System produces excellent control with low toxicity in patients with low-intermediate-risk prostate cancer. We found no dose-related differences in biochemical control and overall survival. Further confirmation of these results is awaited through the prospective phase of this study, which is still ongoing.

Use of Thermoluminescence Dosimetry for QA in High-Dose-Rate Skin Surface Brachytherapy with Custom-Flap Applicator

Surface brachytherapy (BT) lacks standard quality assurance (QA) protocols. Commercially available treatment planning systems (TPSs) are based on a dose calculation formalism that assumes the patient is made of water, resulting in potential deviations between planned and delivered doses. Here, a method for treatment plan verification for skin surface BT is reported. Chips of thermoluminescent dosimeters (TLDs) were used for dose point measurements. High-dose-rate treatments were simulated and delivered through a custom-flap applicator provided with four fixed catheters to guide the Iridium-192 (Ir-192) source by way of a remote afterloading system. A flat water-equivalent phantom was used to simulate patient skin. Elekta TPS Oncentra Brachy was used for planning. TLDs were calibrated to Ir-192 through an indirect method of linear interpolation between calibration factors (CFs) measured for 250 kV X-rays, Cesium-137, and Cobalt-60. Subsequently, plans were designed and delivered to test the reproducibility of the irradiation set-up and to make comparisons between planned and delivered dose. The obtained CF for Ir-192 was (4.96 ± 0.25) μC/Gy. Deviations between measured and TPS calculated doses for multi-catheter treatment configuration ranged from -8.4% to 13.3% with an average of 0.6%. TLDs could be included in clinical practice for QA in skin BT with a customized flap applicator.

Radiation therapy affects YAP expression and intracellular localization by modulating lamin A/C levels in breast cancer

The microenvironment of breast cancer actively participates in tumorigenesis and cancer progression. The changes observed in the architecture of the extracellular matrix initiate an oncogene-mediated cell reprogramming, that leads to a massive triggering of YAP nuclear entry, and, therefore, to cancer cell proliferation, invasion and probably to increased radiation-resistance. However, it is not yet fully understood how radiotherapy regulates the expression and subcellular localization of YAP in breast cancer cells experiencing different microenvironmental stiffnesses. To elucidate the role of extracellular matrix stiffness and ionizing radiations on YAP regulation, we explored the behaviour of two different mammary cell lines, a normal epithelial cell line (MCF10A) and a highly aggressive and invasive adenocarcinoma cell line (MDA-MB-231) interacting with polyacrylamide substrates mimicking the mechanics of both normal and tumour tissues (∼1 and ∼13 kPa). We report that X-ray radiation affected in a significant way the levels of YAP expression, density, and localization in both cell lines. After 24 h, MCF10A and MDA-MB-231 increased the expression level of YAP in both nucleus and cytoplasm in a dose dependent manner and particularly on the stiffer substrates. After 72 h, MCF10A reduced mostly the YAP expression in the cytoplasm, whereas it remained high in the nucleus of cells on stiffer substrates. Tumour cells continued to exhibit higher levels of YAP expression, especially in the cytoplasmic compartment, as indicated by the reduction of nuclear/cytoplasmic ratio of total YAP. Then, we investigated the existence of a correlation between YAP localization and the expression of the nuclear envelope protein lamin A/C, considering its key role in modulating nuclear deformability and changes in YAP shuttling phenomena. As supposed, we found that the effects of radiation on YAP nucleus/cytoplasmic expression ratio, increasing in healthy cells and decreasing in tumour ones, were accompanied by lower and higher lamin A/C levels in MCF10A and MDA-MB-231 cells, respectively. These findings point to obtain a deeper knowledge of the role of the extracellular matrix and the effects of X-rays on YAP and lamin A/C expression that can be used in the design of doses and timing of radiation therapy.

Reirradiation of Locally Recurrent Prostate Cancer with Cyberknife® System or Volumetric Modulated Arc Therapy (VMAT) and IGRT-Clarity®: Outcomes, Toxicities and Dosimetric Evaluation

The management of prostate cancer recurrence following external beam radiotherapy is not defined yet. Stereotaxic body reirradiation therapy showed encouraging results for local and biochemical control. From April 2017 to December 2020, 29 patients with prostate cancer recurrence were collected, joining the retrospective studies CyPro (prot. 46/19 OSS) and CLARO (Prot. 19/20 OSS) trials. Patients received Cyberknife® treatment (17 pts) or alternatively VMAT (Volumetric Modulated Arc Technique) therapy by IGRT (Image-Guided Radiation Therapy)/Clarity® (12 pts). By comparing the reirradiation of two groups, urinary (GU), rectal (GI) toxicities, and biochemical control were investigated. Further, the two techniques were dosimetrically compared by rival plans. The VMAT-IGRT Clarity® treatments were replanned with an optimized template developed for prostate VMAT-SBRT in FFF mode keeping the same dose and fractionation scheduled for Cyberknife Group (30 Gy in 5 fx, at 80% isodose). In the CK group, 23% of patients experienced grade 2 acute GU, while 6% grade 2 acute GI. In the VMAT-Clarity® group, acute GU toxicity was recorded in 17%, while for 8% grade 2 late toxicity was recorded. The dosimetric analysis shows that the VMAT-FFF allows to deliver a biological equivalent dose to CK, with the advantage of reducing the likelihood of toxicities arising.

Geometric contour variation in clinical target volume of axillary lymph nodes in breast cancer radiotherapy: an AIRO multi-institutional study

OBJECTIVES

To determine interobserver variability in axillary nodal contouring in breast cancer (BC) radiotherapy (RT) by comparing the clinical target volume of participating single centres (SC-CTV) with a gold-standard CTV (GS-CTV).

METHODS

The GS-CTV of three patients (P1, P2, P3) with increasing complexity was created in DICOM format from the median contour of axillary CTVs drawn by BC experts, validated using the simultaneous truth and performance-level estimation and peer-reviewed. GS-CTVs were compared with the correspondent SC-CTVs drawn by radiation oncologists, using validated metrics and a total score (TS) integrating all of them.

RESULTS

Eighteen RT centres participated in the study. Comparative analyses revealed that, on average, the SC-CTVs were smaller than GS-CTV for P1 and P2 (by -29.25% and -27.83%, respectively) and larger for P3 (by +12.53%). The mean Jaccard index was greater for P1 and P2 compared to P3, but the overlap extent value was around 0.50 or less. Regarding nodal levels, L4 showed the highest concordance with the GS. In the intra-patient comparison, L2 and L3 achieved lower TS than L4. Nodal levels showed discrepancy with GS, which was not statistically significant for P1, and negligible for P2, while P3 had the worst agreement. DICE similarity coefficient did not exceed the minimum threshold for agreement of 0.70 in all the measurements.

CONCLUSIONS

Substantial differences were observed between SC- and GS-CTV, especially for P3 with altered arm setup. L2 and L3 were the most critical levels. The study highlighted these key points to address.

ADVANCES IN KNOWLEDGE

The present study compares, by means of validated geometric indexes, manual segmentations of axillary lymph nodes in breast cancer from different observers and different institutions made on radiotherapy planning CT images. Assessing such variability is of paramount importance, as geometric uncertainties might lead to incorrect dosimetry and compromise oncological outcome.

Adhesion and Migration Response to Radiation Therapy of Mammary Epithelial and Adenocarcinoma Cells Interacting with Different Stiffness Substrates

The structural and mechanical properties of the microenvironmental context have a profound impact on cancer cell motility, tumor invasion, and metastasis formation. In fact, cells react to their mechanical environment modulating their adhesion, cytoskeleton organization, changes of shape, and, consequently, the dynamics of their motility. In order to elucidate the role of extracellular matrix stiffness as a driving force in cancer cell motility/invasion and the effects of ionizing radiations on these processes, we evaluated adhesion and migration as biophysical properties of two different mammary cell lines, over a range of pathophysiological stiffness (1-13 kPa) in a control condition and after the exposure to two different X-ray doses (2 and 10 Gy, photon beams). We concluded that the microenvironment mimicking the normal mechanics of healthy tissue has a radioprotective role on both cell lines, preventing cell motility and invasion. Supraphysiological extracellular matrix stiffness promoted tumor cell motility instead, but also had a normalizing effect on the response to radiation of tumor cells, lowering their migratory capability. This work lays the foundation for exploiting the extracellular matrix-mediated mechanism underlying the response of healthy and tumor cells to radiation treatments and opens new frontiers in the diagnostic and therapeutic use of radiotherapy.

Minimizing a Tricky Situation in Breast Irradiation with Helical Tomotherapy

We report on a patient with breast cancer undergoing adjuvant intensity-modulated whole breast and lymph node irradiation with static angle tomotherapy (TomoDirect), who experienced a traumatic ipsilateral humeral fracture and was able to continue radiotherapy with helical tomotherapy and daily dosimetric monitoring by means of the Planned Adaptive module.

Twenty years of radiobiology in clinical practice: the Italian contribution

AIMS AND BACKGROUND

To present the Italian state-of-the-art contribution to radiobiology of external beam radiotherapy, brachytherapy, and radionuclide radiotherapy.

METHODS AND STUDY DESIGN

A survey of the literature was carried out, using PubMed, by some independent researchers of the Italian group of radiobiology. Each paper was reviewed by researchers of centers not comprising its authors. The survey was limited to papers in English published over the last 20 years, written by Italian investigators or in Italian institutions, excluding review articles.

RESULTS

A total of 135 papers have been published in journals with an impact factor, with an increase in the number of published papers over time, for external beam radiotherapy rather than radionuclide radiotherapy. The quantity and quality of the papers researched constitutes a proof of the enduring interest in clinical radiobiology among Italian investigators.

CONCLUSIONS

The survey could be useful to individuate expert partners for an Italian network on clinical radiobiology, addressing future collaborative investigations.

Palliative radiotherapy for painful bone metastases from solid tumors delivered with static ports of tomotherapy (TomoDirect): feasibility and clinical results

PURPOSE

To evaluate the feasibility and response to palliative radiotherapy delivered with static ports of tomotherapy--TomoDirect (TD) in patients affected with painful bone metastases from solid tumors.

METHODS

A prospective cohort of 130 patients (185 osseous lesions) was treated between 2010 and 2013 with TD. Three fractionation schedules were employed according to clinical decision-making (3 Gy × 10; 4 Gy × 5; 8 Gy × 1). Pain response was investigated at 2 weeks and 2 months (for evaluable patients). The Numeric Rating Scale (NRS-11) was used to assess pain. Response rates to radiotherapy were calculated following the criteria of the International Bone Metastases Consensus Group (IBMCG), accounting for the use of concomitant analgesics (response: complete or partial; non-response: stable pain, pain progression or "other"). Analgesic consumption was recalculated into the daily oral morphine-equivalent dose (OMED).

RESULTS

Most of the patients had 1-2 bone metastases (91); those with multiple lesions mostly had a metachronous presentation (60%). Synchronous lesions were mainly approached with multiple plans (63%). Most treatments employed 3-4 fields (77%). Treatment times ranged from 255 to 939 s depending on fractionation, fields, and target lesions number. At 2 weeks, the median self-reported worst pain decreased significantly as median oral morphine-equivalent dose regardless of fractionation used. The response rate according to the IBMCG-based response categories ranged from 45 to 55%. Pain relief duration seems (response at 2 months) slightly inferior with the single fraction approach, with a higher re-treatment rate. At 2 weeks, the median self-reported worst pain and OMED significantly decreased regardless of fractionation (response rate: 49-55%). Pain relief decreased at 2 months, especially for single fraction (higher re-treatment rate).

CONCLUSION

TD is a valid option to deliver palliative radiotherapy for painful bone metastases from solid tumors.

Minimizing a tricky situation in breast irradiation with helical tomotherapy

We report on a patient with breast cancer undergoing adjuvant intensity-modulated whole breast and lymph node irradiation with static angle tomotherapy (TomoDirect), who experienced a traumatic ipsilateral humeral fracture and was able to continue radiotherapy with helical tomotherapy and daily dosimetric monitoring by means of the Planned Adaptive module.

Exposures from nuclear medicine diagnostic procedures: the dose impact on the Aosta Valley population

The present work evaluates the per-procedure, annual collective and per-capita effective doses to the Aosta Valley region population from nuclear medicine (NM) examinations performed from 2005 to 2011 at the regional NM department. Based on its demographical and socioeconomics characteristics, this area can be considered as representative of the level I countries, as defined by the United Nations Scientific Committee on the Effects of Atomic Radiation. The NM per-procedures effective doses were within the range of 0.018-35 mSv. A steady frequency per 10 000 inhabitants has been observed, together with a decrease for thyroid and whole-body bone scintigraphy. Myocardial and bone scintigraphy studies were the major contributors to the total collective effective dose. The mean annual collective and per-capita effective doses to the population were 15 man Sv y(-1) and 120 µSv y(-1), respectively. The NM contribution to the total per-capita effective dose accounts for 5.9 % of that due to the medical ionising radiation examinations overall.

Early PET/CT scan is more effective than RECIST in predicting outcome of patients with liver metastases from colorectal cancer treated with preoperative chemotherapy plus bevacizumab

Markers predictive of treatment effect might be useful to improve the treatment of patients with metastatic solid tumors. Particularly, early changes in tumor metabolism measured by PET/CT with (18)F-FDG could predict the efficacy of treatment better than standard dimensional Response Evaluation Criteria In Solid Tumors (RECIST) response.

METHODS

We performed PET/CT evaluation before and after 1 cycle of treatment in patients with resectable liver metastases from colorectal cancer, within a phase 2 trial of preoperative FOLFIRI plus bevacizumab. For each lesion, the maximum standardized uptake value (SUV) and the total lesion glycolysis (TLG) were determined. On the basis of previous studies, a ≤ -50% change from baseline was used as a threshold for significant metabolic response for maximum SUV and, exploratively, for TLG. Standard RECIST response was assessed with CT after 3 mo of treatment. Pathologic response was assessed in patients undergoing resection. The association between metabolic and CT/RECIST and pathologic response was tested with the McNemar test; the ability to predict progression-free survival (PFS) and overall survival (OS) was tested with the Log-rank test and a multivariable Cox model.

RESULTS

Thirty-three patients were analyzed. After treatment, there was a notable decrease of all the parameters measured by PET/CT. Early metabolic PET/CT response (either SUV- or TLG-based) had a stronger, independent and statistically significant predictive value for PFS and OS than both CT/RECIST and pathologic response at multivariate analysis, although with different degrees of statistical significance. The predictive value of CT/RECIST response was not significant at multivariate analysis.

CONCLUSION

PET/CT response was significantly predictive of long-term outcomes during preoperative treatment of patients with liver metastases from colorectal cancer, and its predictive ability was higher than that of CT/RECIST response after 3 mo of treatment. Such findings need to be confirmed by larger prospective trials.

Intensity-modulated adjuvant whole breast radiation delivered with static angle tomotherapy (TomoDirect): a prospective case series

PURPOSE

To report the 2-year outcomes of whole breast intensity-modulated radiotherapy (IMRT) after conserving surgery for early breast cancer (EBC) delivered with static angle tomotherapy (TomoDirect) (TD).

METHODS

A prospective cohort of 120 EBC patients underwent whole breast IMRT with TD between 2010 and 2012. Radiation was delivered to a conventionally fractionated whole breast total dose of 50 Gy with TD, followed by a sequential conventionally fractionated tumor bed boost dose of 10-16 Gy with helical tomotherapy (HT). Clinical endpoints include acute and late toxicity, cosmesis, quality of life and local control.

RESULTS

Median follow-up was 24 months (range 12-36 months); maximum detected acute skin toxicity was G0 22 %; G1 63 %; G2 12 % and G3 3 %. Predictors of acute dermatitis were as follows: volume of the whole breast minus boost volume receiving 105, 110 and 115 % of prescription dose, whole breast and boost volume, breast thickness and soft tissue thickness. Late skin toxicity was mild with no >G2 events. Cosmesis was good/excellent in 91.7 % of patients and fair/poor in 8.3 %. Quality of life was preserved over time, but for fatigue, transiently increased.

CONCLUSION

Adjuvant whole breast IMRT delivered sequentially with both TD and HT provides consistent clinical results. An observed unintended excessive dose outside the tumor bed might increase acute toxicity and eventually affect long-term clinical endpoints. The incorporation of the boost dose within the whole breast phase employing a simultaneous integrated boost (SIB) approach might mitigate this issue.

Early PET/CT scan compared with RECIST to predict long-term outcome of patients with liver metastases from colorectal cancer treated with preoperative chemotherapy plus bevacizumab

11008

Background: Early changes in tumor metabolism measured with positron-emission-tomography/computerized tomography (PET/CT) could predict the long-term efficacy of treatment better than dimensional RECIST response. Methods: We performed PET/CT before and after 1 cycle of treatment in patients with resectable liver metastases from colorectal cancer, within a phase II trial of preoperative FOLFIRI plus bevacizumab. For each lesion, the maximum SUV (SUVmax) and the total lesion glycolisis (TLG) were determined. For both, based on previous studies, a ≤-50% change from baseline was used as threshold for significant response. Metabolic response was categorized no/yes by using three different methods that enter into the calculation (i) the largest observed value (highest SUVmax/TLG), or (ii) the sum of all the observed values (Total SUVmax/TLG), or (iii) each observed values (SUVmax/TLG-by-lesion). Standard RECIST response was assessed after 3 months of treatment. The association between metabolic and RECIST response was tested with the Mc Nemar’s test and their agreement was expressed as Kappa statistics; the ability to predict progression-free (PFS) and overall (OS) survival was tested with Log-rank test and a multivariable Cox model. Results: 33 patients were analyzed. After treatment, there was a notable decrease of all PET/CT parameters, with a median change of -33.9% for the highest SUVmax, -61.5% for the highest TLG, -34.9% for the total SUVmax, and -65.5% for the total TLG. The association of SUV-based metabolic response (but not the TLG-based) with RECIST was statistically significant. However, the agreement between RECIST and PET/CT responses was consistently small. PFS and OS were significantly longer among PET/CT responding patients, whichever the measure used. On the contrary, no significant outcome difference was evident according to RECIST response. Conclusions: Early PET/CT response was significantly predictive of long-term outcomes during preoperative treatment of patients with liver metastases from colorectal cancer and its predictive ability was higher than that of RECIST response. Clinical trial information: 2006-006572-38.

FOLFIRI plus bevacizumab (B) as neoadjuvant treatment for potentially resectable colorectal cancer patients (pts) with liver metastasis: A phase II trial

e14130

Background: Irinotecan-based chemotherapy plus B was shown to be effective and safe in both first- and second-line treatment for metastatic colorectal cancer (mCRC) pts.We designed this trial to assess whether the combination of FOLFIRI + B given to untreated, potentially resectable mCRC pts was feasible and active. Methods: Phase II, single arm trial with 1-year progression-free rate (PFR) as primary end-point. A sample size of 39 pts was calculated to detect a 70% ± 12% 1-year PFR. The treatment was FOLFIRI q2w (irinotecan 180 mg/m2, leucovorin 200 mg/m2, 5FU 2400 mg/m2 iv in 46 hrs) plus B 5mg/kg q2w. Last cycle before surgery was without B. Potentially resectable, untreated mCRC pts, with liver as unique site of metastases, were eligible. Normal organ function and no contraindications to B were required. Pts were reevaluated for surgery after 6 cycles. PET-Scan were performed at baseline and at the second cycle. Results: Overall 39 pts were enrolled. Median age was 58 (range 30-75), male/female were 24/15. Twenty seven pts (69.2%; 95%CI 52.4% – 83.0%) were progression-free at 1-year. Thirty seven pts (94.9%) underwent surgery. One complete and 22 partial responses were observed (response rate 59.0%; 95% CI 42.1% – 74.4%); 5 pts had disease progression (4 resectable and 1 unresectable). Early PET-scan was assessed according PERCIST criteria [Wahl RL, J Nucl Med 2009] in 29 pts and showed metabolic response (SUV-max decrease > 30%) in 17 (58.6%; 95% CI: 38.9%- 76.5%).Severe toxicity includes grade 3 neutropenia (3 pts, 7.7%) and grade 3 diarrhea (1 pt, 2.6%). Other toxicities include grade 1-2 diarrhea (15.4%), grade 2 nausea (7.8%), grade 2 leucopenia (5.1%), grade 2 asthenia (5.1%), grade 1 anemia (2.6%), grade 2 thrombosis (2.6%). Overall, 16 pts out of 37 experienced surgical complications (43.2%; 95%CI 27.1% - 60.5%): biliary leak (11 pts, 29.7%), biliary fistula (1 pt, 2.7%), other complications (4 pts, 10.8%). All complications were reversible. No peri-operative bleeding was observed. Conclusions: The trial yielded its primary aim and shows that FOLFIRI plus B is feasible and active as neo-adjuvant treatment in patients with resectable liver metastases of CRC.

Cohesin promotes the repair of ionizing radiation-induced DNA double-strand breaks in replicated chromatin

The cohesin protein complex holds sister chromatids together after synthesis until mitosis. It also contributes to post-replicative DNA repair in yeast and higher eukaryotes and accumulates at sites of laser-induced damage in human cells. Our goal was to determine whether the cohesin subunits SMC1 and Rad21 contribute to DNA double-strand break repair in X-irradiated human cells in the G2 phase of the cell cycle. RNA interference-mediated depletion of SMC1 sensitized HeLa cells to X-rays. Repair of radiation-induced DNA double-strand breaks, measured by gammaH2AX/53BP1 foci analysis, was slower in SMC1- or Rad21-depleted cells than in controls in G2 but not in G1. Inhibition of the DNA damage kinase DNA-PK, but not ATM, further inhibited foci loss in cohesin-depleted cells in G2. SMC1 depletion had no effect on DNA single-strand break repair in either G1 or late S/G2. Rad21 and SMC1 were recruited to sites of X-ray-induced DNA damage in G2-phase cells, but not in G1, and only when DNA damage was concentrated in subnuclear stripes, generated by partially shielded ultrasoft X-rays. Our results suggest that the cohesin complex contributes to cell survival by promoting the repair of radiation-induced DNA double-strand breaks in G2-phase cells in an ATM-dependent pathway.