Complete pathological response to bevacizumab and chemoradiation in advanced rectal cancer

Identification of CT Values That Could Be Predictive of Necrosis (N-CTav) in Hepatocellular Carcinoma after Lenvatinib Treatment

Purpose: To assess the utility of measurement of the computed tomography (CT) attenuation value (CTav) in predicting tumor necrosis in hepatocellular carcinoma (HCC) patients who achieve a complete response (CR), defined using modified Response Evaluation Criteria in Solid Tumors (mRECIST), after lenvatinib treatment. Method: We compared CTav in arterial phase CT images with postoperative histopathology in four patients who underwent HCC resection after lenvatinib treatment, to determine CTav thresholds indicative of histological necrosis (N-CTav). Next, we confirmed the accuracy of the determined N-CTav in 15 cases with histopathologically proven necrosis in surgical specimens. Furthermore, the percentage of the tumor with N-CTav, i.e., the N-CTav occupancy rate, assessed using Image J software in 30 tumors in 12 patients with CR out of 571 HCC patients treated with lenvatinib, and its correlation with local recurrence following CR were examined. Results: Receiver operating characteristic (ROC) curve analysis revealed an optimal cut-off value of CTav of 30.2 HU, with 90.0% specificity and 65.0% sensitivity in discriminating between pathologically identified necrosis and degeneration, with a CTav of less than 30.2 HU indicating necrosis after lenvatinib treatment (N30-CTav). Furthermore, the optimal cut-off value of 30.6% for the N30-CTav occupancy rate by ROC analysis was a significant indicator of local recurrence following CR with 76.9% specificity and sensitivity (area under the ROC curve; 0.939), with the CR group with high N30-CTav occupancy (≥30.6%) after lenvatinib treatment showing significantly lower local recurrence (8.3% at 1 year) compared with the low (<30.6%) N30-CTav group (p < 0.001, 61.5% at 1 year). Conclusion: The cut-off value of 30.2 HU for CTav (N30-CTav) might be appropriate for identifying post-lenvatinib necrosis in HCC, and an N30-CTav occupancy rate of >30.6% might be a predictor of maintenance of CR. Use of these indicators have the potential to impact systemic chemotherapy for HCC.

11C-Acetate PET for Early Prediction of Sunitinib Response in Metastatic Renal Cell Carcinoma

Sunitinib is an oral multitargeted tyrosine kinase inhibitor with antiangiogenic properties used for treatment of renal cell carcinoma and gastrointestinal stromal tumors at a dose of 50 mg/day consecutively for 4 weeks followed by 2 weeks off per cycle. At present, no data are available on the early prediction of sunitinib response in renal cell carcinoma. We report a clinical case of a patient with metastatic renal cell carcinoma diagnosed with 11C-acetate PET and conventional CT and treated with sunitinib. Partial and complete remission documented by CT was preceded by early functional tumor inhibition shown by 11C-acetate-PET after only 14 days of therapy. This case report highlights some interesting points related to the potential role of a novel non-FDG PET tracer, 11C-acetate, in the early prediction of the response to targeted therapies in metastatic renal cell carcinoma.

Treatment outcomes regarding the addition of targeted agents in the therapeutic portfolio for stage II-III rectal cancer undergoing neoadjuvant chemoradiation

Background

To evaluate the impact of targeted agents in stage II-III rectal cancer undergoing neoadjuvant concurrent chemoradiation therapy (CCRT).

Method

A retrospective study was performed in 124 consecutive patients with clinically T₃N_0-2M₀-staged rectal cancer incorporating targeted agents in CCRT.

Results

Pathologic complete response was detected in 34.2% (n=26) of bevacizumab+FOLFOX-treated patients (n=76), which was significantly higher (p=0.019, post-hoc statistical power =35.87%) than that (n=10, 20.8%) of the cetuximab+FOLFOX-treated patients (n=48). Patients receiving cetuximab+FOLFOX therapy tended to develop severe liver toxicity (91.7%, n=44 versus 17.1%, n=13, p<0.0001), as evaluated by morphologic grading of hepatic steatosis and sinusoidal dilatation in laparoscopy. In the 57 patients with morphologically severe liver toxicity, 36 (63.2%) retained a normal liver function; for the remaining 21 patients with an abnormal liver function, the abnormality was self-limited in 19 patients, whereas 2 cetuximab–treated patients progressed to hepatic failure and mortality. A subset analysis within bevacizumab+FOLFOX-treated patients with either wild-type (n=36) or mutant (n=40) K-ras status indicated K-ras status did not significantly influence the treatment outcomes.

Conclusions

The addition of bevacizumab instead of cetuximab to FOLFOX in the neoadjuvant settings for T₃N_0-2M₀-staged rectal cancer could induce a promising rate of pathologic complete response and lesser hepatotoxicity.

Bacteria in Cancer Therapy: Renaissance of an Old Concept

The rising incidence of cancer cases worldwide generates an urgent need of novel treatment options. Applying bacteria may represent a valuable therapeutic variant that is intensively investigated nowadays. Interestingly, the idea to apply bacteria wittingly or unwittingly dates back to ancient times and was revived in the 19th century mainly by the pioneer William Coley. This review summarizes and compares the results of the past 150 years in bacteria mediated tumor therapy from preclinical to clinical studies. Lessons we have learned from the past provide a solid foundation on which to base future efforts. In this regard, several perspectives are discussed by which bacteria in addition to their intrinsic antitumor effect can be used as vector systems that shuttle therapeutic compounds into the tumor. Strategic solutions like these provide a sound and more apt exploitation of bacteria that may overcome limitations of conventional therapies.

Polysilsesquioxane nanoparticles for triggered release of cisplatin and effective cancer chemoradiotherapy

Chemoradiotherapy is a well-established treatment paradigm in oncology. There has been strong interest in identifying strategies to further improve its therapeutic index. An innovative strategy is to utilize nanoparticle (NP) chemotherapeutics in chemoradiation. Since the most commonly utilized chemotherapeutic with radiotherapy is cisplatin, the development of an NP cisplatin for chemoradiotherapy has the highest potential impact on this treatment. Here, we report the development of an NP comprised of polysilsesquioxane (PSQ) polymer crosslinked by a cisplatin prodrug (Cisplatin-PSQ) and its utilization in chemoradiotherapy using non-small cell lung cancer as a disease model. Cisplatin-PSQ NP has an exceptionally high loading of cisplatin. Cisplatin-PSQ NPs were evaluated in chemoradiotherapy in vitro and in vivo. They demonstrated significantly higher therapeutic efficacy when compared to cisplatin. These results suggest that the Cisplatin-PSQ NP holds potential for clinical translation in chemoradiotherapy.

Tumor endothelial cells

The vascular endothelium is a dynamic cellular "organ" that controls passage of nutrients into tissues, maintains the flow of blood, and regulates the trafficking of leukocytes. In tumors, factors such as hypoxia and chronic growth factor stimulation result in endothelial dysfunction. For example, tumor blood vessels have irregular diameters; they are fragile, leaky, and blood flow is abnormal. There is now good evidence that these abnormalities in the tumor endothelium contribute to tumor growth and metastasis. Thus, determining the biological basis underlying these abnormalities is critical for understanding the pathophysiology of tumor progression and facilitating the design and delivery of effective antiangiogenic therapies.

Visualising and quantifying angiogenesis in metastatic colorectal cancer : A comparison of methods and their predictive value for chemotherapy response

PURPOSE

Angiogenesis plays an important role in tumour growth and dissemination. We have recently shown that blood vessel density, determined by image analysis based on microRNA-126 (miRNA-126) in situ hybridization (ISH) in the primary tumours of metastatic colorectal cancers (mCRC), is predictive of chemotherapy response. Here, we evaluated whether more general approaches to determine vessel density in primary tumours are equally predictive of chemotherapy response.

METHODS

This methodological study was carried out using paraffin embedded tissues from primary tumours of 89 patients with mCRC, who had all been treated with first-line chemotherapy (XELOX). Tissue sections from the deepest invasive tumour front were processed for miRNA-126 ISH and CD34 immunohistochemistry (IHC). Estimates of microvessel density (MVD) were obtained for both miRNA-126 and CD34 by quantitative image analyses (MVDi), vascular area per image (μm²) analyses, and manually counting vessels in vascular hot spots (MVDh). Clinical responses were evaluated according to Response Evaluation Criteria In Solid Tumours (RECIST).

RESULTS

The MVDi for miRNA-126 showed a significant correlation with treatment response (p=0.01), with a median value of 2,071 μm² (95% CI, 1,505-3,075 μm²) in the responder group compared to 1,337 μm² (95% CI, 1,038-1,499 μm²) in the non-responder group. This difference translated into a significant difference in progression free survival (p=0.01).

CONCLUSIONS

The methodological assessment of MVD and the molecular vessel marker are both important for the prediction of the chemotherapy response in mCRC. Our findings indicate that MVDi for miRNA-126 represents a powerful estimate and may serve as a clinical biomarker superior to MVDh.

Evaluation of short-course radiotherapy followed by neoadjuvant bevacizumab, capecitabine, and oxaliplatin and subsequent radical surgical treatment in primary stage IV rectal cancer

BACKGROUND

To evaluate the efficacy and tolerability of preoperative short-course radiotherapy followed by capecitabine and oxaliplatin treatment in combination with bevacizumab and subsequent radical surgical treatment of all tumor sites in patients with stage IV rectal cancer.

PATIENTS AND METHODS

Adults with primary metastasized rectal cancer were enrolled. They received radiotherapy (5 × 5 Gy) followed by bevacizumab (7.5 mg/kg, day 1) and oxaliplatin (130 mg/m(2), day 1) intravenously and capecitabine (1000 mg/m(2) twice daily orally, days 1-14) for up to six cycles. Surgery was carried out 6-8 weeks after the last bevacizumab dose. The percentage of radical surgical treatment, 2-year survival and recurrence rates, and treatment-related toxicity was evaluated.

RESULTS

Of 50 included patients, 42 (84%) had liver metastases, 5 (10%) lung metastases, and 3 (6%) both liver and lung metastases. Radical surgical treatment was possible in 36 (72%) patients. The 2-year overall survival rate was 80% [95% confidence interval (CI) 66.3%-90.0%]. The 2-year recurrence rate was 64% (95% CI 49.8%-84.5%). Toxic effects were tolerable. No treatment-related deaths occurred.

CONCLUSIONS

Radical surgical treatment of all tumor sites carried out after short-course radiotherapy, and bevacizumab-capecitabine-oxaliplatin combination therapy is a feasible and potentially curative approach in primary metastasized rectal cancer.

The use of molecular markers as a method to predict the response to neoadjuvant therapy for advanced stage rectal adenocarcinoma

AIM

The response to combined neoadjuvant therapy for advanced stage rectal adenocarcinoma is predictive of outcome. In addition to both clinical and pathological features, the expression of a variety of molecules may provide another method of identifying tumour responsiveness to pre-operative therapy. The aim of this study was to evaluate several markers in the apoptotic pathway as well as expression of Cox-2 and vascular endothelial growth factor (VEGF) to determine their ability to predict response to neoadjuvant therapy.

METHOD

In total, 152 patients with advanced rectal adenocarcinoma were treated with neoadjuvant therapy followed by resection. Paraffin-embedded sections obtained before and after therapy were assessed by immunohistochemical staining for Cox-2, VEGF, p53, p21, p27, Bax, BCL-2 and apoptosis protease-activating factor 1 (APAF-1). These stains were correlated with tumour regression grade, complete pathological response and T-downstaging of the surgical specimen. Clinical and pathological data were also collected. Data were analysed using the χ2 and Spearman's correlation tests.

RESULTS

Pathological complete response was seen in 24.5% of patients. Amongst the apoptosis-associated markers, only APAF-1 expression was found to be significantly associated with tumour regression grade (P<0.001), complete pathological response (P<0.031) and T-downstaging (P<0.004). On multivariate analysis, APAF-1 expression was found to be independently associated with good tumour regression grade. In contrast, overexpression of Cox-2 and VEGF in pretreatment biopsies was related to less tumour regression (P<0.003) and less likelihood of T-downstaging (P<0.03).

CONCLUSION

Immunohistochemical evaluation of initial biopsy specimens of rectal cancer with APAF-1, Cox-2 and VEGF may predict tumour response to neoadjuvant therapy in patients with advanced rectal adenocarcinoma. Those with an expected limited response may be considered for other investigational neoadjuvant protocols.

Complete pathologic response after combined modality treatment for rectal cancer and long-term survival: a meta-analysis

BACKGROUND

Complete pathologic response (CPR) after neoadjuvant chemoradiotherapy (combined modality treatment, CMT) for rectal cancer seems associated with improved survival compared to partial or no response (NPR). However, previous reports have been limited by small sample size and single-institution design.

METHODS

A systematic literature review was conducted to detect studies comparing long-term results of patients with CPR and NPR after CMT for rectal cancer. Variables were pooled only if evaluated by 3 or more studies. Study end points included rates of CPR, local recurrence (LR), distant recurrence (DR), 5-year overall survival (OS), and disease-free survival (DFS).

RESULTS

Twelve studies (1,913 patients) with rectal cancer treated with CMT were included. CPR was observed in 300 patients (15.6%). CPR and NPR patient groups were similar with respect to age, sex, tumor size, distance of tumor from the anus, and stage of disease before treatment. Median follow-up ranged from 23 to 46 months. CPR patients had lower rates of LR [0.7% vs. 2.6%; odds ratio (OR) 0.45, 95% confidence interval (CI) 0.22-0.90, P = 0.03], DR (5.3% vs. 24.1%; OR 0.15, 95% CI 0.07-0.31, P = 0.0001), and simultaneous LR + DR (0.7% vs. 4.8%; OR 0.32, 95% CI 0.13-0.79, P = 0.01). OS was 92.9% for CPR versus 73.4% for NPR (OR 3.6, 95% CI 1.84-7.22, P = 0.002), and DFS was 86.9% versus 63.9% (OR 3.53, 95% CI 1.62-7.72, P = 0.002).

CONCLUSIONS

CPR after CMT for rectal cancer is associated with improved local and distal control as well as better OS and DFS.

Locally advanced mid/low rectal cancer with synchronous liver metastases

BACKGROUND

Management of patients with T3/4 and/or N+ mid/low rectal cancer with synchronous liver metastases is not codified. The aim of this study was to analyze outcomes of our approach which consists of neoadjuvant chemotherapy or chemoradiotherapy, according to liver disease extension, followed by simultaneous rectal and liver resection.

METHODS

Between 2000 and 2009, 354 patients underwent hepatectomy for synchronous metastases. Thirty-six consecutive patients who underwent rectal and liver resection for metastatic T3/4 and/or N+ mid/low rectal cancer were analyzed.

RESULTS

Liver metastases were multiple in 27 patients, bilobar in 22, and >5 cm in six. Up-front treatment was chemotherapy in 15 patients, chemoradiotherapy in seven, chemotherapy followed by chemoradiotherapy in six, and surgery in eight (five symptomatic tumors). After chemotherapy alone (median number of cycles = 6), primary tumor response was observed in 11 patients (three complete responses). After chemoradiotherapy, only one patient had liver disease progression. Eighty-nine percent of patients underwent simultaneous rectal and hepatic resection. Mortality and morbidity rates were 2.8% (one pulmonary embolism) and 36%, respectively. After a mean follow-up of 39 months, 5-year overall and disease-free survival were 59.3 and 39.6%, respectively. Twenty-one patients had recurrence, including three pelvic recurrences (8.3%). No pelvic recurrence occurred among patients who correctly completed treatment strategy. All patients who received neoadjuvant chemoradiotherapy were alive and disease-free; 5-year overall and disease-free survival of patients receiving neoadjuvant chemotherapy were 59.3 and 25%, respectively.

CONCLUSIONS

For patients with metastatic T3/4 and/or N+ mid/low rectal cancer, the present strategy was safe and effective. Good disease control was achieved by neoadjuvant treatments, low morbidity rates were associated with simultaneous resection, and excellent long-term outcomes with low local relapse rate were obtained.

Customizing systemic therapy in patients with advanced non-small cell lung cancer

Lung cancer is the leading cause of cancer deaths worldwide. Standard chemotherapy has been shown to improve quality of life and has a modest influence on overall survival. This modest improvement in survival is partly due to the choice of chemotherapy regimens that have been based on prognostic factors such as age, performance status and comorbidities of the patient. This underlines the importance of developing a more personalized therapy for patients with non-small cell lung cancer. Such an approach may reduce the variation in how individual patients respond to medications by tailoring therapies to their genetic profile. In this review we focus on several aspects of customized therapy, looking not only at patient characteristics but also to tumor histology and specific tumor biomarkers.

Multicenter, phase II study of axitinib, a selective second-generation inhibitor of vascular endothelial growth factor receptors 1, 2, and 3, in patients with metastatic melanoma

PURPOSE

This multicenter, open-label, phase II study evaluated the safety and clinical activity of axitinib, a potent and selective second-generation inhibitor of vascular endothelial growth factor receptors (VEGFR)-1, 2, and 3, in patients with metastatic melanoma.

EXPERIMENTAL DESIGN

Thirty-two patients with a maximum of one prior systemic therapy received axitinib at a starting dose of 5 mg twice daily. The primary endpoint was objective response rate.

RESULTS

Objective response rate was 18.8% [95% confidence interval (CI), 7.2-36.4], comprising one complete and five partial responses with a median response duration of 5.9 months (95% CI, 5.0-17.0). Stable disease at 16 weeks was noted in six patients (18.8%), with an overall clinical benefit rate of 37.5%. Six-month progression-free survival rate was 33.9%, 1-year overall survival rate was 28.1%, and median overall survival was 6.6 months (95% CI, 5.2-9.0). The most frequently (>15%) reported nonhematologic, treatment-related adverse events were fatigue, hypertension, hoarseness, and diarrhea. Treatment-related fatal bowel perforation, a known class effect, occurred in one patient. Axitinib selectively decreased plasma concentrations of soluble VEGFR (sVEGFR)-2 and sVEGFR-3 compared with soluble stem cell factor receptor (sKIT). No significant association was noted between plasma levels of axitinib and response. However, post hoc analyses indicated potential relationships between efficacy endpoints and diastolic blood pressure of 90 mm Hg or higher as well as baseline serum lactate dehydrogenase levels.

CONCLUSIONS

Axitinib was well tolerated, showed a selective VEGFR-inhibitory profile, and showed single-agent activity in metastatic melanoma. Further evaluations of axitinib, alone and combined with chemotherapy, are ongoing.

Use of S-100B to evaluate therapy effects during bevacizumab induction treatment in AJCC stage III melanoma

AIM

To investigate the feasibility of using bevacizumab to improve the survival of American Joint Committee on Cancer (AJCC) stage III melanoma patients, we investigated how a single bevacizumab treatment affected nodal disease and a panel of biomarkers in clinically fluorodeoxyglucose positron emission tomography (FDG-PET)/computed tomography (CT)-staged, stage III melanoma patients, prior to therapeutic lymph node dissection (TLND).

METHODS

Four weeks before TLND, nine patients (median age 50, range 28.8-62.1 years; two male, seven female) with palpable lymph node metastases received 7.5 mg/kg bevacizumab. Before and after this treatment, all patients were assessed by measurements of the maximum standardized uptake value (SUVmax) by FDG-PET scan, and serum S-100B and lactate dehydrogenase (LDH). After TLND, the dissection specimen was analyzed for number of removed lymph nodes, number of metastatic lymph nodes, and tumor necrosis.

RESULTS

Median follow-up was 15.5 (2.2-32.9) months. Histopathological analysis revealed tumor necrosis in six patients, of whom five had an S-100B decline and one had an unchanged S-100B level after bevacizumab. The other three patients showed an S-100B increase and no necrosis. Tumor necrosis was correlated with S-100B decrease (P = 0.048). No association was found between necrosis and the markers SUVmax and LDH. No wound healing disturbances were encountered.

CONCLUSION

Tumor necrosis in dissection specimens was associated with declining S-100B levels, while elevated S-100B was only found in cases with no necrosis. Bevacizumab might be useful in treating AJCC stage III melanoma patients prior to TLND, and S100-B appears to be a useful marker for assessment of treatment effects.

Jekyll and Hyde: the role of the microenvironment on the progression of cancer

It is now recognized that the host microenvironment undergoes extensive change during the evolution and progression of cancer. This involves the generation of cancer-associated fibroblasts (CAFs), which, through release of growth factors and cytokines, lead to enhanced angiogenesis, increased tumour growth and invasion. It has also been demonstrated that CAFs may modulate the cancer stem cell (CSC) phenotype, which has therapeutic implications. The altered fibroblast phenotype also contributes to the development of an altered extracellular matrix (ECM), with synthesis of ECM isoforms rarely found in normal tissues, including tenascin-C isoforms and the fibronectin EDA isoform. There is also emerging evidence of how the tensile strength of the tumour-associated ECM may be modified and lead to altered signalling in tumour cells. The hypoxic environment of the tumour stimulates angiogenesis and also impacts on other aspects of cell signalling, including the c-met pathway and lysyl oxidase-mediated signalling, which can directly promote tumour cell invasion. The inflammatory infiltrate associated with many solid tumours also modulates tumour function, having both anti- and pro-tumour effects. All of these components of the microenvironment provide potential targets for therapeutic attack, with a number of molecules already in clinical trials. It is also becoming evident that characterizing the tumour microenvironment can provide important prognostic and predictive information about tumours, independent of the tumour cell phenotype.

Molecular radiobiology meets clinical radiation oncology

BACKGROUND

The 2nd Langendorff Congress in Freiburg in Breisgau (Germany) gathered basic and translational scientists as well as clinicians interested in recent developments in molecular and clinical radiobiology. The topics ranged from the most recent insight into the organisation of the DNA damage response and radiotherapeutically relevant cell death mechanisms to biological imaging for treatment planning and advances in the understanding of the molecular biological effects of particle beams. Clinical aspects of stem cell and tumour stem cell biology as well as of angiogenesis and hypoxia, the search for novel molecular radiosensitisers and potential strategies for exploitation of the immune system to further improve tumour radiotherapy were also discussed.

RESULTS AND CONCLUSION

This report surveys the presentations at the meeting, considering their significance in light of the literature, and documents the increasing importance of molecular radiobiology for clinical radiooncology.

Gene expression profiles of epidermal growth factor receptor, vascular endothelial growth factor and hypoxia-inducible factor-1 with special reference to local responsiveness to neoadjuvant chemoradiotherapy and disease recurrence after rectal cancer surgery

AIMS

To establish a causal relationship between the gene expression profiles of angiogenetic molecular markers, including epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1 (HIF-1), in rectal cancer and the local responsiveness to neoadjuvant chemoradiotherapy and subsequent disease recurrence.

MATERIALS AND METHODS

We examined the pre-treatment tumour biopsies (n=40) obtained from patients with rectal adenocarcinoma (clinical International Union Against Cancer stage ll/III) who were scheduled to receive neoadjuvant 5-fluorouracil-based chemoradiotherapy for EGFR, VEGF and HIF-1 expression by quantitative real-time polymerase chain reaction.

RESULTS

Responders (patients with significant tumour regression, i.e. pathological grades 2/3) showed significantly lower VEGF, HIF-1 and EGFR gene expression levels than the non-responders (patients with insignificant tumour regression, i.e. pathological grades 0/1) in the pre-treatment tumour biopsies. The elevated expression level of each gene could predict patients with a low response to chemoradiation. During the median follow-up of all patients (41 months; 95% confidence interval 28-60 months), 6/40 (15%) developed disease recurrence. Although local responsiveness to neoadjuvant chemoradiotherapy was associated with neither local nor systemic disease recurrence, lymph node metastasis and an elevated VEGF gene expression level were independent predictors of systemic disease recurrence. The 3-year disease-free survival rates of the patients with lower VEGF or EGFR expression levels were significantly lower than those of patients with higher VEGF or EGFR expression levels.

CONCLUSIONS

Analysing VEGF expression levels in rectal cancer may be of benefit in estimating the effects of neoadjuvant chemoradiotherapy and in predicting systemic recurrence after rectal cancer surgery.

Evading tumor evasion: current concepts and perspectives of anti-angiogenic cancer therapy

Within three decades, anti-angiogenic therapy has rapidly evolved into an integral component of current standard anti-cancer treatment. Anti-angiogenic therapy has fulfilled a number of its earlier proposed promises. The universality of this approach is demonstrated by the broad spectrum of malignant and benign tumor entities, as well as non-neoplastic diseases, that are currently treated with anti-angiogenic agents. In contrast to tumor cell targeting therapies, the development of acquired drug resistance (e.g., via mutations in growth factor receptor signaling genes) has not been described yet for the principal target of anti-angiogenic therapy--the tumor endothelium. Moreover, the tumor endothelium has emerged as a critical target of conventional cancer therapies, such as chemotherapy and radiotherapy. The presumption that tumor growth and metastasis are angiogenesis-dependent implies that the number of potential targets of an anti-cancer therapy could be reduced to those that stimulate the angiogenesis process. Therefore, the set of endogenous angiogenesis stimulants might constitute an "Achilles heel" of cancer. Direct targeting of tumor endothelium via, e.g., endogenous angiogenesis inhibitors poses another promising but clinically less explored therapeutic strategy. Indeed, the majority of current anti-angiogenic approaches block the activity of a single or at most a few pro-angiogenic proteins secreted by tumor cells or the tumor stroma. Based on our systems biology work on the angiogenic switch, we predicted that the redundancy of angiogenic signals might limit the efficacy of anti-angiogenic monotherapies. In support of this hypothesis, emerging experimental evidence suggests that tumors may become refractory or even evade the inhibition of a single pro-angiogenic pathway via compensatory upregulation of alternative angiogenic factors. Here, we discuss current concepts and propose novel strategies to overcome tumor evasion of anti-angiogenic therapy. We believe that early detection of tumors, prediction of tumor evasive mechanisms and rational design of anti-angiogenic combinations will direct anti-angiogenic therapy towards its ultimate goal--the conversion of cancer to a dormant, chronic, manageable disease.

Multidisciplinary treatment of resectable rectal cancer

This review identifies evidence that influences current practices in the multidisciplinary treatment and shapes future directions in the treatment of resectable rectal cancer. Recent advances in surgery, radiotherapy and systemic chemotherapy have provided measurable improvements in disease control, functional outcomes and quality of life for patients with rectal cancer. However, controversies remain regarding the optimum delivery of adjuvant therapies. Preoperative radiation either with or without concurrent chemotherapy demonstrates lower recurrence, with minimal survival benefit. Currently, the use of neoadjuvant standard fractionation chemoradiation versus short-course radiation without chemotherapy is controversial and under investigation. New combinations of chemotherapeutic agents and targeted therapies are also being evaluated. In addition, criteria for patient selection are being re-evaluated to determine the relative benefit of modern treatments, so that we may better tailor adjuvant therapy recommendations to be patient-specific. Recommendations for adjuvant treatments of rectal cancer are continuing to evolve; however, survival has been only marginally affected despite low incidence of local recurrence. Future trials should aim to address the role of adjuvant therapies utilizing new criteria, such as function, quality of life and impact on development of metastatic disease.

Correlation between tumor growth delay and expression of cancer and host VEGF, VEGFR2, and osteopontin in response to radiotherapy

PURPOSE

To determine the late effects of radiotherapy (RT) on vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR2), and osteopontin (OPN) expression in cancer and stromal cells.

METHODS AND MATERIALS

LS174T xenografted athymic mice were used as a tumor model. Radiation was delivered in two equivalent fractionation schemes: 5 x 7 Gy and 1 x 20 Gy, the latter at two dose rates.

RESULTS

Tumor growth arrest was similar in all treatment groups, with the exception of a better response of small-size tumors in the 5 x 7-Gy group. The host VEGF and OPN levels were directly proportional to the tumor doubling time and were independent of the fractionation scheme. The host and cancer cell VEGFR2 levels in tumor were also directly related to the tumor response to RT.

CONCLUSION

Upregulated VEGFR2 in cancer cells suggest paracrine signaling in the VEGFR2 pathway of cancer cells as the factor contributing to RT failure. The transient activation of the host VEGF/VEGFR2 pathway in tumor supports the model of angiogenic regeneration and suggests that radiation-induced upregulation of VEGF, VEGFR2, and downstream proteins might contribute to RT failure by escalating the rate of vascular repair. Coexpression of host OPN and VEGF, two factors closely associated with angiogenesis, indicate that OPN can serve as a surrogate marker of tumor recovery after RT. Taken together, these results strongly support the notion that to achieve optimal therapeutic outcomes, the scheduling of RT and antiangiogenic therapies will require patient-specific post-treatment monitoring of the VEGF/VEGFR2 pathway and that tumor-associated OPN can serve as an indicator of tumor regrowth.

Portal venous gas following chemotherapy for colorectal cancer liver metastasis

The standard of care for patients with colorectal liver metastases is a combination of chemotherapy and surgery. New chemotherapy regimens with biologic agents (cetuximab, bevacizumab) have been shown to increase tumor response rates. Although this might be beneficial and this is an expected endpoint, it should be noted that patients with synchronous colorectal and liver metastases are at risk of septic complications. We recently encountered a case of hepatic portal venous gas after two cycles of chemotherapy in a patient with right colon cancer liver metastases. Complete necrosis of the liver metastasis subsequently turned into a liver abscess, which fistulized in the right portal vein. Infection of the necrotized metastasis was thought to be promoted by the colic tumor. Although this is a dramatic situation, it does not contraindicate a curative surgical resection.

Clinical biomarkers of angiogenesis inhibition

INTRODUCTION

An expanding understanding of the importance of angiogenesis in oncology and the development of numerous angiogenesis inhibitors are driving the search for biomarkers of angiogenesis. We review currently available candidate biomarkers and surrogate markers of anti-angiogenic agent effect.

DISCUSSION

A number of invasive, minimally invasive, and non-invasive tools are described with their potential benefits and limitations. Diverse markers can evaluate tumor tissue or biological fluids, or specialized imaging modalities.

CONCLUSIONS

The inclusion of these markers into clinical trials may provide insight into appropriate dosing for desired biological effects, appropriate timing of additional therapy, prediction of individual response to an agent, insight into the interaction of chemotherapy and radiation following exposure to these agents, and perhaps most importantly, a better understanding of the complex nature of angiogenesis in human tumors. While many markers have potential for clinical use, it is not yet clear which marker or combination of markers will prove most useful.

Lessons from multidisciplinary translational trials on anti-angiogenic therapy of cancer

The importance of multidisciplinary translational clinical trials is obvious; however, making them work is complex and challenging. Here I present an argument for designing and implementing multidisciplinary mechanistic trials and present the lessons our team at the Massachusetts General Hospital Cancer Center has learned from two such trials in cancer patients with locally advanced rectal carcinomas and recurrent glioblastomas.

Current status of antivascular therapy and targeted treatment in the clinic

Antivascular and targeted therapy are now an integrated part of the treatment of myelogenous leukemias, GIST tumours, B-cell lymphomas and breast cancer. In various malignancies improved responses and prolongation of survival for several months is regularly reported. The progress in this field is relevant for hyperthermia. Heat has among other effects documented antivascular effects, and can be considered as one of the established methods in the field based on several randomised phase III studies. Hyperthermia should be considered for combination with other antiangiogenic agents.

Combined analysis of VEGF and EGFR predicts complete tumour response in rectal cancer treated with preoperative radiotherapy

The ability to predict complete pathologic response or sensitivity to radiation before treatment would have a significant impact on the selection of patients for preoperative radiotherapy or chemo-radiation therapy schedules. The aim of this study was to determine the value of epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), p53, Bcl-2 and apoptosis protease-activating factor-1 (APAF-1) as predictors of complete pathologic tumour regression in patients undergoing preoperative radiotherapy for advanced rectal cancer. Pretreatment tumour biopsies from predominantly cT3 patients undergoing a preoperative high-dose-rate brachytherapy protocol were immunostained for EGFR, VEGF, p53, Bcl-2 and APAF-1. Immunoreactivity was evaluated by three pathologists. Cut-off scores for tumour marker positivity were obtained by receiver-operating characteristic (ROC) curve analysis. The association of marker expression with complete pathologic response was analysed in univariate and multivariable analysis. Multi-marker phenotypes of the independent protein markers were evaluated. In multivariable analysis, loss of VEGF (P-value=0.009; odds ratio (OR) (95% CI)=0.24 (0.08–0.69)) and positive EGFR (P-value=0.01; OR (95% CI)=3.82 (1.37–10.6)) both demonstrated independent predictive value for complete pathologic response. The odds of complete response were 12.8 for the multi-marker combination of VEGF-negative and EGFR-positive tumours. Of the 34 EGFR-negative- and VEGF-positive cases, 32 (94.1%) had no complete pathologic response. The combined analysis of VEGF and EGFR is predictive of complete pathologic response in patients undergoing preoperative radiotherapy. In addition, the findings of this study have identified a subgroup of simultaneous EGFR-negative and VEGF-positive patients who are highly resistant to radiotherapy and should perhaps be considered candidates for innovative neoadjuvant combined modalities.

Conventional and novel PET tracers for imaging in oncology in the era of molecular therapy

In the last ten years, the development of several novel targeted drugs and the refinement of state of the art technologies such as the genomics and proteomics and their introduction to clinical practice have revolutionized the management of patients affected by cancer. However, everyday practice points out several clinical questions: the difficulty of response assessment to new drugs especially using standard RECIST criteria that do not provide information on biological, vascular or metabolic variations; the inadequate selection of patients who are likely to benefit from a targeted therapy excluding those with breast cancer and gastrointestinal stromal tumours; the need to know the global biological background of diseases especially in metastatic setting using repeatable non-invasive procedures. Molecular imaging could provide information on in vivo distribution of biological markers in response to targeted therapy and could improve the selection of patients before therapies. The aim of this review is to analyze the current role of conventional and innovative positron emission tomography (PET) radiotracers in clinical practice and to explore the promising perspectives of molecular imaging in cancer research.

Antiangiogenics: the potential role of integrating this novel treatment modality with chemoradiation for solid cancers

Although still in very early stages of clinical development, the combination of antiangiogenics with contemporary chemoradiotherapy regimens has emerged as a feasible and promising approach to many cancers. We review the rationale and the current understanding of antiangiogenics and their therapeutic potential in combination with chemoradiotherapy. Finally, we offer a perspective on future research directions aimed at making this complex therapeutic approach successful in the clinic.

Targeted therapy in rectal cancer

Epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) are often overexpressed in colorectal cancer and are associated with inferior outcomes. Based on successful randomized phase III trials, anti-EGFR and anti-VEGF therapeutics have entered clinical practice. Cetuximab (Erbitux), an EGFR-specific antibody, is currently approved in the United States in combination with irinotecan (Camptosar) for patients with metastatic colorectal cancer refractory to irinotecan or as a single agent for patients unable to tolerate irinotecan-based therapy. In retrospective analyses, patients with EGFR-expressing rectal cancer undergoing neoadjuvant radiation therapy had a significantly inferior disease-free survival and lower rates of achieving pathologic complete response. Based on the positive data in metastatic colorectal cancer and synergy with radiation therapy seen in preclinical models, there is a strong rationale to combine cetuximab with neoadjuvant radiation therapy and chemotherapy in rectal cancer. Bevacizumab (Avastin), a VEGF-specific antibody, was the first antiangiogenic agent to be approved in the United States for use in combination with standard chemotherapy in the first- and second-line of treatment in metastatic colorectal cancer. VEGF-targeted therapy may lead to indirect killing of cancer cells by damaging tumor blood vessels, and may increase the radiosensitivity of tumor-associated endothelial cells. VEGF blockade can also "normalize" tumor vasculature, thereby leading to greater tumor oxygenation and drug penetration. This review will address completed and ongoing trials that have established and continue to clarify the effects of these agents in rectal cancer.

VEGF-targeted cancer therapy strategies: current progress, hurdles and future prospects

Despite setbacks, the clinical development of antiangiogenic agents has accelerated remarkably over the past 3-4 years. Consequently, there are currently three direct inhibitors of the VEGF pathway approved for use in cancer therapy. Other agents that block the VEGF pathway are in advanced stages of clinical development and have shown promising results. With these exciting developments come crucial questions regarding the use of these new molecular-targeted agents, alone or in combination with standard cytotoxic or targeted agents. Importantly, the mechanisms of action of anti-VEGF therapy remain unknown. Here, we discuss several potential mechanisms of action such as tumor vascular normalization, bone marrow-derived cell recruitment blockade and cytostatic effects of anti-VEGF therapy. We review the current progress, the major stumbling blocks and the future directions for anti-cancer therapy using anti-VEGF agents, emphasizing clarification of the underlying molecular mechanisms of action and biomarker identification and validation.