External tissue support and fluid-structure simulation in blood flows.

The objective of this work is to address the formulation of an adequate model of the external tissue environment when studying a portion of the arterial tree with fluid-structure interaction. Whereas much work has already been accomplished concerning flow and pressure boundary conditions associated with truncations in the fluid domain, very few studies take into account the tissues surrounding the region of interest to derive adequate boundary conditions for the solid domain. In this paper, we propose to model the effect of external tissues by introducing viscoelastic support conditions along the artery wall, with two-possibly distributed-parameters that can be adjusted to mimic the response of various physiological tissues. In order to illustrate the versatility and effectiveness of our approach, we apply this strategy to perform patient-specific modeling of thoracic aortae based on clinical data, in two different cases and using a distinct fluid-structure interaction methodology for each, namely an Arbitrary Lagrangian-Eulerian (ALE) approach with prescribed inlet motion in the first case and the coupled momentum method in the second case. In both cases, the resulting simulations are quantitatively assessed by detailed comparisons with dynamic image sequences, and the model results are shown to be in very good adequacy with the data.

Molecular imaging and targeted therapies in oncology: new concepts in treatment response assessment. a collection of cases.

The widespread use of several new non-cytotoxic drugs and the significant improvements in functional imaging highlights a number of difficulties in monitoring, interpreting and predicting treatment response in clinical practice. Certain guidelines for disease assessment after therapy are already available: the traditional Response Evaluation Criteria in Solid Tumours guidelines based on tumour size variations using conventional imaging technologies, the recent combined method developed by Choi and colleagues in gastrointestinal stromal tumour treated with tyrosine kinase inhibitors based on tumour density variations using computed tomography (CT), and the European Organization for Research and Treatment of Cancer criteria based on tumour glucose metabolism variations using fluorodeoxyglucose (FDG) positron emission tomography (PET). At the moment combined PET/CT response criteria are still not available. A number of new PET compounds other than FDG are also currently being developed to visualize specific cellular and molecular tumour pathways but their role in assessment and prediction of cancer treatment response has not yet been thoroughly investigated in a large series. However, in clinical practice many oncologists treat cancer patients with targeted therapies or chemotherapy and evaluate the response using conventional or functional imaging without appropriate and standardized guidelines. The aim of this study was to present a selection of clinical cases that illustrate the usefulness of new PET tracers and efficacy evaluation of new drugs. In the era of molecular imaging and molecular therapies, these cases highlight the urgency to develop new criteria for treatment assessment and the exigency of correctly interpreting the biological information obtained from new technologies, and introduce new concepts that require further investigation in clinical trials.

Surgical debulking of gastrointestinal stromal tumors: is it a reasonable option after second-line treatment with sunitinib?

INTRODUCTION: After imatinib treatment, the surgical management of patients affected by gastrointestinal stromal tumor (GIST) has been widely reported and often considered by many oncologists in clinical practice. Surgical results are correlated with disease responsiveness to tyrosine kinase inhibitors and with complete extirpation of all tumor sites. By now, no report specifically addressing surgical management after second-line treatment with sunitinib is still available. Most patients have an unresectable disease and do not have any other therapeutical options except for clinical trials. MATERIALS AND METHODS: We report two clinical cases of patients with metastatic GISTs, who underwent surgery after sunitinib, and discuss the surgical management option in this clinical setting. RESULTS: Both our patients had a long, durable stable disease on sunitinib, but one developed a chronic mild bleeding that does not call for emergency surgical interventions and the other one developed chronic heart toxicity. They were proposed to undergo surgery despite the unresectable diseases and received an incomplete resection because of residual metastatic lesions. They restarted sunitinib after surgery. CONCLUSIONS: The poor prognosis after sunitinib treatment and the absence of alternative validated options open the debate on the assessment of surgical management of metastatic GISTs in this setting. The role of surgery should be investigated in clinical trials; however, the enrollment may be difficult. In clinical practice and after a multidisciplinary case patient discussion, surgery could represent a reasonable choice for advanced GISTs especially if the risk of surgery-related death is not too high.

[Treatment of colorectal cancer liver metastases]. / Il trattamento delle metastasi epatiche da cancro del colon-retto.

Liver is the main target for colorectal cancer (CRC) metastases. About 50% of all patients affected by CRC develop liver metastases. Surgery remains the only potentially curative strategy and indications to surgery and resectability criteria are now less restrictive than before so that a more aggressive attitude in the treatment of metastatic lesions is the rule. However surgery is not possible in the majority of patients. For non resectable patients two options are available: local treatment strategies (Radio-frequency ablation and Cryosurgery: alone or in combination with surgery) and chemotherapy. High rates of objective response achieved with Fluoropyrimidines, Oxaliplatin (OHP) and Irinotecan (CPT-11) based chemo-therapy, enable initially unresectable patients to undergo surgery, with a 5-year survival rate comparable to that observed for primary resectable patients. Therefore chemotherapy has not only a palliative aim, but becomes a fundamental moment of a combined medical and surgical treatment with curative purpose. After surgery two-thirds of patients will relapse in first two years, so that adjuvant therapy has been investigated to reduce recurrence rates, mainly testing hepatic arterial infusion (HAI) schedules. So far no randomized trials have been published on the role of systemic intravenous adjuvant chemo-therapy. Finally we report the results of our monoinstitutional experience, suggesting a possible role of systemic adjuvant chemotherapy in reducing recurrence rates after liver metastasectomy. Probably in the next years new targeted drugs and locoregional therapies will contribute to further improve prognosis of such patients, in a neoadjuvant, adjuvant and palliative setting.