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Discrete (DTCs) and continuous time crystals (CTCs) are novel dynamical many-body states, that are characterized by robust self-sustained oscillations, emerging via spontaneous breaking of discrete or continuous time translation symmetry. DTCs are periodically driven systems that oscillate with a subharmonic of the external drive, while CTCs are continuously driven and oscillate with a frequency intrinsic to the system. Here, we explore a phase transition from a continuous time crystal to a discrete time crystal. A CTC with a characteristic oscillation frequencyωCTCis prepared in a continuously pumped atom-cavity system. Modulating the pump intensity of the CTC with a frequencyωdrclose to2ωCTCleads to robust locking ofωCTCtoωdr/2, and hence a DTC arises. This phase transition in a quantum many-body system is related to subharmonic injection locking of non-linear mechanical and electronic oscillators or lasers.
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We report the existence of dissipationless currents in bilayer superconductors above the critical temperature T_{c}, assuming that the superconducting phase transition is dominated by phase fluctuations. Using a semiclassical U(1) lattice gauge theory, we show that thermal fluctuations cause a transition from the superconducting state at low temperature to a resistive state above T_{c}, accompanied by the proliferation of unbound vortices. Remarkably, while the proliferation of vortex excitations causes dissipation of homogeneous in-plane currents, we find that counterflow currents, flowing in the opposite direction within a bilayer, remain dissipationless. The presence of a dissipationless current channel above T_{c} is attributed to the inhibition of vortex motion by local superconducting coherence within a single bilayer, in the presence of counterflow currents. Our theory presents a possible scenario for the pseudogap phase in bilayer cuprates.
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We demonstrate the formation of a condensate in a dark state of momentum states, in a pumped and shaken cavity-BEC system. The system consists of an ultracold quantum gas in a high-finesse cavity, which is pumped transversely by a phase-modulated laser. This phase-modulated pumping couples the atomic ground state to a superposition of excited momentum states, which decouples from the cavity field. We demonstrate how to achieve condensation in this state, supported by time-of-flight and photon emission measurements. With this, we show that the dark state concept provides a general approach to efficiently prepare complex many-body states in an open quantum system.
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Time crystals are classified as discrete or continuous depending on whether they spontaneously break discrete or continuous time translation symmetry. Although discrete time crystals have been extensively studied in periodically driven systems, the experimental realization of a continuous time crystal is still pending. We report the observation of a limit cycle phase in a continuously pumped dissipative atom-cavity system that is characterized by emergent oscillations in the intracavity photon number. The phase of the oscillation was found to be random for different realizations, and hence, this dynamical many-body state breaks continuous time translation symmetry spontaneously. Furthermore, the observed limit cycles are robust against temporal perturbations and therefore demonstrate the realization of a continuous time crystal.
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BACKGROUND: Mycosis fungoides (MF), the most common subtype of Cutaneous T-cell lymphomas, is caused by malignant T-cell proliferations in the skin that can invade blood, lymph nodes, or viscera. Currently, data on efficacy of maintenance therapies in MF are lacking. We developed a unique protocol to use chlormethine/mechlorethamine 0.016% gel formulation as maintenance regimen for MF patients in remission. PURPOSE: To determine progression-free survival and efficacy of chlormethine/mechlorethamine as maintenance and active treatment regimens for MF. MATERIALS AND METHODS: A retrospective review of MF patients seen at Thomas Jefferson University from 2012 to 2020 was conducted. Patients of all stages treated with chlormethine/mechlorethamine as maintenance or active treatment with 2 consecutive mSWATs (modified Severity Weighted Assessment Tool) documented were included. Treatment outcomes were assessed by change in mSWAT and progression-free survival. Dermatology Life Quality Index surveys before and after treatment were analyzed. RESULTS: Of 186 MF patients, 44 met inclusion criteria. Patients on maintenance therapy had a 65.22% progression-free survival rate with median time to progression of 29.45 months. By-time analysis for responders on active and maintenance treatment showed an increased response over time. Peak responses were seen at last mSWAT recorded. Both cohorts experienced improved quality-of-life scores from initiation to discontinuation of chlormethine/mechlorethamine. CONCLUSION: Patients on maintenance and active chlormethine/mechlorethamine treatment regimens demonstrated improvement in mSWAT and quality-of-life. Chlormethine/mechlorethamine treatment showed progression-free survival for a median of 29.45 months, indicating this therapy may be an effective maintenance regimen.
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Linfoma Cutâneo de Células T , Micose Fungoide , Neoplasias Cutâneas , Humanos , Mecloretamina/efeitos adversos , Mecloretamina/uso terapêutico , Micose Fungoide/tratamento farmacológico , Micose Fungoide/patologia , Estudos Retrospectivos , Neoplasias Cutâneas/tratamento farmacológico , Neoplasias Cutâneas/patologiaRESUMO
BACKGROUND: Vascular endothelial growth factor inhibitors (VEGFi) are compromised by a lack of validated biomarkers. Previously we showed that changes in the concentration of plasma Tie2 (pTie2) was a response biomarker for bevacizumab. Here, we investigated whether pTie2 can predict response and progression cross-tumour for generic VEGFi treatment. PATIENTS AND METHODS: Patients (n = 124) with advanced biliary tract cancer (ABC) received cisplatin/gemcitabine with cediranib or placebo (ABC-03 trial). Concentrations of pTie2 were measured longitudinally from before treatment until disease progression. Data from patients with ovarian cancer (n = 92, ICON7 trial) and patients with colorectal cancer (CRC) (n = 70, Travastin trial) were also included. RESULTS: Cediranib-treated ABC patients were deconvoluted into distinct groups where in one group pTie2 trajectories resembled those seen in placebo-treated patients and in another pTie2 significantly reduced (t-test P = 2.7 × 10-14). Using the 95% confidence interval for these two groups, we defined a vascular complete response (vCR) as a 24% reduction in pTie2 within 9 weeks; vascular no response (vNR) as a 7% increase in pTie2, and a vascular partial response (between these limits). vCR cediranib-treated patients had significantly improved progression-free survival (8.8 versus 7.5 months, restricted mean ratio 0.73, P = 0.012) and overall survival (18.8 versus 12.1 months, hazard ratio 0.49, P = 0.02). By integrating data across ovarian cancer, CRC and ABC, we show that (i) patients with vNR do not benefit from VEGFi and (ii) Tie2-defined vascular progression occurs sufficiently in advance of radiological progressive disease that changes in treatment could be offered to prevent clinical deterioration. CONCLUSION: pTie2 is the first cross-tumour, generic VEGFi, vascular response biomarker to guide optimum use of VEGFi in clinical practice.
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Sistema Biliar , Neoplasias Colorretais , Neoplasias Ovarianas , Sistema Biliar/metabolismo , Biomarcadores Tumorais , Neoplasias Colorretais/tratamento farmacológico , Feminino , Humanos , Neoplasias Ovarianas/tratamento farmacológico , Fator A de Crescimento do Endotélio Vascular/uso terapêuticoRESUMO
We present the first experimental realization of a time crystal stabilized by dissipation. The central signature in our implementation in a driven open atom-cavity system is a period doubled switching between distinct checkerboard density wave patterns, induced by the interplay between controlled cavity dissipation, cavity-mediated interactions, and external driving. We demonstrate the robustness of this dynamical phase against system parameter changes and temporal perturbations of the driving.
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BACKGROUND: Cediranib, an oral anti-angiogenic VEGFR 1-3 inhibitor, was studied at a daily dose of 20 mg in combination with platinum-based chemotherapy and as maintenance in a randomised trial in patients with first relapse of 'platinum-sensitive' ovarian cancer and has been shown to improve progression-free survival (PFS). PATIENTS AND METHODS: ICON6 (NCT00532194) was an international three-arm, double-blind, placebo-controlled randomised trial. Between December 2007 and December 2011, 456 women were randomised, using stratification, to receive either chemotherapy with placebo throughout (arm A, reference); chemotherapy with concurrent cediranib, followed by maintenance placebo (arm B, concurrent); or chemotherapy with concurrent cediranib, followed by maintenance cediranib (arm C, maintenance). Due to an enforced redesign of the trial in September 2011, the primary endpoint became PFS between arms A and C which we have previously published, and the overall survival (OS) was defined as a secondary endpoint, which is reported here. RESULTS: After a median follow-up of 25.6 months, strong evidence of an effect of concurrent plus maintenance cediranib on PFS was observed [hazard ratio (HR) 0.56, 95% confidence interval (CI) 0.44-0.72, P < 0.0001]. In this final update of the survival analysis, 90% of patients have died. There was a 7.4-month difference in median survival and an HR of 0.86 (95% CI: 0.67-1.11, P = 0.24) in favour of arm C. There was strong evidence of a departure from the assumption of non-proportionality using the Grambsch-Therneau test (P = 0.0031), making the HR difficult to interpret. Consequently, the restricted mean survival time (RMST) was used and the estimated difference over 6 years by the RMST was 4.8 months (95% CI: -0.09 to 9.74 months). CONCLUSIONS: Although a statistically significant difference in time to progression was seen, the enforced curtailment in recruitment meant that the secondary analysis of OS was underpowered. The relative reduction in the risk of death of 14% risk of death was not conventionally statistically significant, but this improvement and the increase in the mean survival time in this analysis suggest that cediranib may have worthwhile activity in the treatment of recurrent ovarian cancer and that further research should be undertaken.
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Neoplasias Ovarianas , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Feminino , Humanos , Recidiva Local de Neoplasia/tratamento farmacológico , Neoplasias Ovarianas/tratamento farmacológico , Quinazolinas/uso terapêuticoRESUMO
A periodically driven open three-level Dicke model is realized by resonantly shaking the pump field in an atom-cavity system. As an unambiguous signature, we demonstrate the emergence of a dynamical phase, in which the atoms periodically localize between the antinodes of the pump lattice, associated with an oscillating net momentum along the pump axis. We observe this dynamical phase through the periodic switching of the relative phase between the pump and cavity fields at a small fraction of the driving frequency, suggesting that it exhibits a time crystalline character.
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BACKGROUND: Malignant bowel obstruction is a common complication of ovarian cancer, resulting in limited oral intake. Home parenteral nutrition (HPN) may be offered to patients in this condition to meet nutritional requirements. However, it is not known how they experience being unable to eat. The present study reports how patients related to food when receiving HPN. METHODS: The investigation was a qualitative study underpinned by phenomenology with women with advanced ovarian cancer in bowel obstruction receiving parenteral nutrition. Interview transcripts were analysed thematically guided by the techniques of Van Manen. RESULTS: We recruited 20 women to the study. Participants were interviewed a maximum of four times and a total of 39 in-depth longitudinal interviews were conducted. Participants could tolerate minimal amounts of food, if they had a venting gastrostomy. Not being able to eat engendered a sense of sadness and loss, and most women found it challenging to be in the presence of others eating. They adopted strategies to cope, which included fantasising about food and watching cookery programmes. These approaches were not a long-term solution; either participants came to terms with their loss or the strategies became less effective in providing relief. CONCLUSIONS: Home parenteral nutrition meets the nutritional requirements of patients with malignant bowel obstruction but cannot replace the non-nutritive functions of food. Healthcare professionals can offer a patient-centred approach by acknowledging the difficulties that patients may face and, wherever possible, encourage them to focus on the positive benefits of interacting with people rather than the loss of eating on social occasions.
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Comportamento Alimentar/psicologia , Obstrução Intestinal/psicologia , Neoplasias Ovarianas/psicologia , Nutrição Parenteral no Domicílio/psicologia , Qualidade de Vida/psicologia , Adaptação Psicológica , Idoso , Efeitos Psicossociais da Doença , Feminino , Humanos , Obstrução Intestinal/etiologia , Obstrução Intestinal/terapia , Estudos Longitudinais , Pessoa de Meia-Idade , Neoplasias Ovarianas/complicações , Pesquisa Qualitativa , Comportamento SocialRESUMO
BACKGROUND: The DREAMtherapy (Dual REctal Angiogenesis MEK inhibition radiotherapy) trial is a novel intertwined design whereby two tyrosine kinase inhibitors (cediranib and selumetinib) were independently evaluated with rectal chemoradiotherapy (CRT) in an efficient manner to limit the extended follow-up period often required for radiotherapy studies. PATIENTS AND METHODS: Cediranib or selumetinib was commenced 10 days before and then continued with RT (45 Gy/25#/5 wks) and capecitabine (825 mg/m2 twice a day (BID)). When three patients in the cediranib 15-mg once daily (OD) cohort were in the surveillance period, recruitment to the selumetinib cohort commenced. This alternating schedule was followed throughout. Three cediranib (15, 20 and 30 mg OD) and two selumetinib cohorts (50 and 75 mg BID) were planned. Circulating and imaging biomarkers of inflammation/angiogenesis were evaluated. RESULTS: In case of cediranib, dose-limiting diarrhoea, fatigue and skin reactions were seen in the 30-mg OD cohort, and therefore, 20 mg OD was defined as the maximum tolerated dose. Forty-one percent patients achieved a clinical or pathological complete response (7/17), and 53% (9/17) had an excellent clinical or pathological response (ECPR). Significantly lower level of pre-treatment plasma tumour necrosis factor alpha (TNFα) was found in patients who had an ECPR. In case of selumetinib, the 50-mg BID cohort was poorly tolerated (fatigue and diarrhoea); a reduced dose cohort of 75-mg OD was opened which was also poorly tolerated, and further recruitment was abandoned. Of the 12 patients treated, two attained an ECPR (17%). CONCLUSIONS: This novel intertwined trial design is an effective way to independently investigate multiple agents with radiotherapy. The combination of cediranib with CRT was well tolerated with encouraging efficacy. TNFα emerged as a potential predictive biomarker of response and warrants further evaluation.
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Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Quimiorradioterapia/métodos , Neoplasias Retais/terapia , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/farmacocinética , Benzimidazóis/administração & dosagem , Biomarcadores Tumorais , Estudos de Coortes , Feminino , Seguimentos , Humanos , Masculino , Dose Máxima Tolerável , Pessoa de Meia-Idade , Prognóstico , Quinazolinas/administração & dosagem , Neoplasias Retais/patologia , Distribuição TecidualRESUMO
BACKGROUND: The use of home parenteral nutrition (HPN) for palliative indications is increasing internationally and is the leading indication in some countries. Discharge on HPN can be complex in metabolically unstable patients and requires intestinal failure expertise. METHODS: Between 2012 and 2018, we performed a retrospective analysis aiming to assess the impact of a novel remote discharge pathway for palliative HPN patients. This was evaluated using a quality improvement approach. RESULTS: One hundred and twenty-five patients with active malignancy [mean (range) age 58 (25-80) years] were referred to the intestinal failure unit (IFU) for remote discharge. Of 82 patients were discharged from the oncology Centre on HPN using the pathway. The remaining 43 patients either declined HPN or the Oncology team felt that the patient became too unwell for HPN or died prior to discharge. There was an increase in patients referred for remote discharge from 13 in 2012 to 43 in 2017. The mean number of days between receipt of referral by the IFU to discharge on HPN from the oncology centre reduced from 29.4 days to 10.1 days. Following remote discharge, the mean number of days on HPN was 215.9 days. Catheter-related blood stream infection rates in this cohort were very low at 0.169 per 1000 catheter days. CONCLUSIONS: This is the first study to demonstrate the remote safe, effective and rapid discharge of patients requiring palliative HPN between two hospital sites. This allows patients with a short prognosis more time in their desired location.
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Procedimentos Clínicos , Neoplasias/terapia , Nutrição Parenteral no Domicílio/métodos , Alta do Paciente , Telemedicina/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cuidados Paliativos/métodos , Estudos RetrospectivosRESUMO
We demonstrate a light-induced formation of coherence in a cold atomic gas system that utilizes the suppression of a competing density wave (DW) order. The condensed atoms are placed in an optical cavity and pumped by an external optical standing wave, which induces a long-range interaction mediated by photon scattering and a resulting DW order above a critical pump strength. We show that the light-induced temporal modulation of the pump wave can suppress this DW order and restore coherence. This establishes a foundational principle of dynamical control of competing orders analogous to a hypothesized mechanism for light-induced superconductivity in high-T_{c} cuprates.
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We demonstrate dynamical control of the superradiant transition of cavity-BEC system via periodic driving of the pump laser. We show that the dominant density wave order of the superradiant state can be suppressed, and that the subdominant competing order of Bose-Einstein condensation emerges in the steady state. Furthermore, we show that additional, nonequilibrium density wave orders, which do not exist in equilibrium, can be stabilized dynamically. Finally, for strong driving, chaotic dynamics emerge.
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INTRODUCTION: Treatment on a clinical trial is considered to be beneficial to oncology patients. However, supportive evidence for this is scarce. Trial effect describes the phenomenon of improved health outcomes in patients treated with standard of care (SOC) on trial compared to those receiving SOC outside of a clinical trial. We evaluated trial effect in patients with ovarian cancer treated at our tertiary cancer centre. METHODS: We performed a retrospective cohort study of patients with ovarian cancer treated at The Christie National Health Service Foundation Trust. Patients treated on one of three first-line clinical trials: (SCOTROC-4, ICON-5, ICON-7) were matched (for age, International Federation of Gynaecology and Obstetrics stage, surgical status and performance status) with individuals receiving the same SOC off trial. Survival was calculated using Kaplan-Meier methodology. RESULTS: 60 patients were evaluated; 30 on trial and 30 on SOC off trial. The median progression-free survival (PFS) was 21.8â months (control group) and 25.9â months (trial group), median overall survival (OS) was 64.3â months (control group) and 68.9â months (trial group). There was no difference in PFS (log-rank test: HR 0.87 (95% CI 0.48 to 1.54), p=0.6) or OS (log-rank test: HR 0.87 (95% CI 0.46 to 1.64), p=0.7) between groups. CONCLUSIONS: Patient survival was similar regardless if treated on trial or as SOC. Our findings do not support trial effect, at least in a tertiary cancer centre. Clinical trial participation in specialised cancer centres promotes best practice to the benefit of all patients. These findings may impact discussions round consent of patients to trials and organisation of oncology services.
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AIMS: Ovarian cancer is the principal cause of gynaecological cancer death in developed countries, yet overall survival in the UK has been reported as being inferior to that in some Western countries. As there is a range of survival across the UK we hypothesised that in major regional centres, outcomes are equivalent to the best internationally. MATERIALS AND METHODS: Data from patients treated in multicentre international and UK-based trials were obtained from three regional cancer centres in the UK; Manchester, University College London and Leeds (MUL). The median progression-free survival (PFS) and overall survival were calculated for each trial and compared with the published trial data. Normalised median survival values and the respective 95% confidence intervals (ratio of pooled MUL data to trial median survival) were calculated to allow inter-trial survival comparisons. This strategy then allowed a comparison of median survival across the UK, in three regional UK centres and in international centres. RESULTS: The analysis showed that the trial-reported PFS was the same in the UK, in the MUL centres and in international centres for each of the trials included in the study. Overall survival was, however, 45% better in major regional centre-treated patients (95% confidence interval 9-73%) than the median overall survival reported in UK trials, whereas the median overall survival in MUL centres equated with that achieved in international centres. CONCLUSION: The data suggest that international survival statistics are achieved in UK regional cancer centres.
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Neoplasias Ovarianas/mortalidade , Neoplasias Ovarianas/terapia , Idoso , Intervalo Livre de Doença , Feminino , Humanos , Pessoa de Meia-IdadeRESUMO
Relatively few Chinese patients access tertiary cancer services in North West England. We investigated the reasons behind this using a culturally sensitive questionnaire. The questionnaire, completed by 214 Chinese people in English, Cantonese or Mandarin, evaluated the Chinese population's access and satisfaction with primary care, understanding of cancer and awareness of local cancer services. Ninety-five per cent of respondents were registered with a general practitioner (GP) and 75% had accessed primary care in the last year. Satisfaction with GP consultations was high but a third of respondents reported a lack of confidence in local National Health Service (NHS) services. Only 57% of eligible women had attended cervical screening programmes. The overall understanding of the causes and treatment of cancer and cancer services in the North West was poor. Despite registration with primary healthcare, the Chinese population under-utilise cancer prevention programmes and tertiary cancer services because of a lack of awareness and understanding of cancer services in the North West. A significant proportion of the population is dissatisfied with the perceived slow service and lack confidence in services, with 41% considering using healthcare abroad. These data highlight the critical need to engage with, educate and support the Chinese population if they are to access NHS cancer services.
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Acessibilidade aos Serviços de Saúde , Necessidades e Demandas de Serviços de Saúde , Neoplasias/terapia , Atenção Primária à Saúde , Atenção Terciária à Saúde , Adulto , Idoso , China/etnologia , Detecção Precoce de Câncer , Inglaterra , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias/prevenção & controle , Adulto JovemRESUMO
BACKGROUND: Thrombotic events are common in cancer patients and have been associated with an adverse prognosis in large registry-based studies. METHODS: A retrospective cohort of 417 patients with ovarian cancer treated at a tertiary cancer centre between 2006 and 2009 was studied to identify the incidence and risk factors for thrombotic events and the prognostic impact of thrombosis. Patient outcomes were evaluated against a matched control group without thrombosis. RESULTS: Ninety-nine thrombotic events occurred in 90 patients (21.6%) from 8 months before diagnosis to 56 months following diagnosis, peaking in the 4 months following diagnosis. Patients with thrombosis were older (mean 65 vs 61 years, P=0.007), had a worse performance status (PS ≥2: 29.9% vs 9.5%, P<0.0001) and had a more advanced FIGO stage (FIGO III/IV 75.6% vs 56.9%, P<0.0001) than patients without thrombosis. Shorter overall survival was seen in patients with pulmonary embolism and pelvic/lower limb deep vein thrombosis than without thrombosis (P=0.001). When the control group was matched for stage and PS, no survival difference was seen (P=0.91). CONCLUSION: Ovarian cancer patients with thrombotic events had a shorter survival. However, when matched for prognostic factors (PS and FIGO stage), thrombosis did not impact upon prognosis.
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Neoplasias Ovarianas/sangue , Trombose/etiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Feminino , Humanos , Incidência , Pessoa de Meia-Idade , Projetos Piloto , Prognóstico , Estudos Retrospectivos , Fatores de Risco , Adulto JovemRESUMO
Ovarian cancer presents at advanced stage in around 75% of women, and despite improvements in treatments such as chemotherapy, the 5-year survival from the disease in women diagnosed between 1996 and 1999 in England and Wales was only 36%. Over 80% of patients with advanced ovarian cancer will relapse and despite a good chance of remission from further chemotherapy, they will usually die from their disease. Sequential treatment strategies are employed to maximise quality and length of life but patients eventually become resistant to cytotoxic agents. The expansion in understanding of the molecular biology that characterises cancer cells has led to the rapid development of new agents to target important pathways but the heterogeneity of ovarian cancer biology means that there is no predominant defect. This review attempts to discuss progress to date in tackling a more general target applicable to ovary cancer-angiogenesis.
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Inibidores da Angiogênese/uso terapêutico , Terapia de Alvo Molecular , Neovascularização Patológica/tratamento farmacológico , Neoplasias Ovarianas/irrigação sanguínea , Neoplasias Ovarianas/tratamento farmacológico , Angiopoietinas/antagonistas & inibidores , Angiostatinas/biossíntese , Anticorpos Monoclonais Humanizados/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Bevacizumab , Bibenzilas/uso terapêutico , Feminino , Fatores de Crescimento de Fibroblastos/antagonistas & inibidores , Flavonoides/uso terapêutico , Humanos , Neoplasias Ovarianas/mortalidade , Trombospondinas/biossíntese , Resultado do Tratamento , Fatores de Crescimento do Endotélio Vascular/antagonistas & inibidoresRESUMO
BACKGROUND: There is limited evidence that imaging biomarkers can predict subsequent response to therapy. Such prognostic and/or predictive biomarkers would facilitate development of personalised medicine. We hypothesised that pre-treatment measurement of the heterogeneity of tumour vascular enhancement could predict clinical outcome following combination anti-angiogenic and cytotoxic chemotherapy in colorectal cancer (CRC) liver metastases. METHODS: Ten patients with 26 CRC liver metastases had two dynamic contrast-enhanced MRI (DCE-MRI) examinations before starting first-line bevacizumab and FOLFOX-6. Pre-treatment biomarkers of tumour microvasculature were computed and a regression analysis was performed against the post-treatment change in tumour volume after five cycles of therapy. The ability of the resulting linear model to predict tumour shrinkage was evaluated using leave-one-out validation. Robustness to inter-visit variation was investigated using data from a second baseline scan. RESULTS: In all, 86% of the variance in post-treatment tumour shrinkage was explained by the median extravascular extracellular volume (v(e)), tumour enhancing fraction (E(F)), and microvascular uniformity (assessed with the fractal measure box dimension, d(0)) (R(2)=0.86, P<0.00005). Other variables, including baseline volume were not statistically significant. Median prediction error was 12%. Equivalent results were obtained from the second scan. CONCLUSION: Traditional image analyses may over-simplify tumour biology. Measuring microvascular heterogeneity may yield important prognostic and/or predictive biomarkers.