Sir Peter MacCallum Department of Oncology - Research Publications
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ItemA multicentre retrospective comparison of central nervous system prophylaxis strategies among patients with high-risk diffuse large B-cell lymphoma(NATURE PUBLISHING GROUP, 2014-09-09)BACKGROUND: Central nervous system (CNS) relapse in diffuse large B-cell lymphoma (DLBCL) is a devastating complication; the optimal prophylactic strategy remains unclear. METHODS: We performed a multicentre, retrospective analysis of patients with DLBCL with high risk for CNS relapse as defined by two or more of: multiple extranodal sites, elevated serum LDH and B symptoms or involvement of specific high-risk anatomical sites. We compared three different strategies of CNS-directed therapy: intrathecal (IT) methotrexate (MTX) with (R)-CHOP 'group 1'; R-CHOP with IT MTX and two cycles of high-dose intravenous (IV) MTX 'group 2'; dose-intensive systemic antimetabolite-containing chemotherapy (Hyper-CVAD or CODOXM/IVAC) with IT/IV MTX 'group 3'. RESULTS: Overall, 217 patients were identified (49, 125 and 43 in groups 1-3, respectively). With median follow-up of 3.4 (range 0.2-18.6) years, 23 CNS relapses occurred (12, 10 and 1 in groups 1-3 respectively). The 3-year actuarial rates (95% CI) of CNS relapse were 18.4% (9.5-33.1%), 6.9% (3.5-13.4%) and 2.3% (0.4-15.4%) in groups 1-3, respectively (P=0.009). CONCLUSIONS: The addition of high-dose IV MTX and/or cytarabine was associated with lower incidence of CNS relapse compared with IT chemotherapy alone. However, these data are limited by their retrospective nature and warrant confirmation in prospective randomised studies.
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ItemT-cell acute leukaemia exhibits dynamic interactions with bone marrow microenvironments(NATURE PUBLISHING GROUP, 2016-10-27)It is widely accepted that complex interactions between cancer cells and their surrounding microenvironment contribute to disease development, chemo-resistance and disease relapse. In light of this observed interdependency, novel therapeutic interventions that target specific cancer stroma cell lineages and their interactions are being sought. Here we studied a mouse model of human T-cell acute lymphoblastic leukaemia (T-ALL) and used intravital microscopy to monitor the progression of disease within the bone marrow at both the tissue-wide and single-cell level over time, from bone marrow seeding to development/selection of chemo-resistance. We observed highly dynamic cellular interactions and promiscuous distribution of leukaemia cells that migrated across the bone marrow, without showing any preferential association with bone marrow sub-compartments. Unexpectedly, this behaviour was maintained throughout disease development, from the earliest bone marrow seeding to response and resistance to chemotherapy. Our results reveal that T-ALL cells do not depend on specific bone marrow microenvironments for propagation of disease, nor for the selection of chemo-resistant clones, suggesting that a stochastic mechanism underlies these processes. Yet, although T-ALL infiltration and progression are independent of the stroma, accumulated disease burden leads to rapid, selective remodelling of the endosteal space, resulting in a complete loss of mature osteoblastic cells while perivascular cells are maintained. This outcome leads to a shift in the balance of endogenous bone marrow stroma, towards a composition associated with less efficient haematopoietic stem cell function. This novel, dynamic analysis of T-ALL interactions with the bone marrow microenvironment in vivo, supported by evidence from human T-ALL samples, highlights that future therapeutic interventions should target the migration and promiscuous interactions of cancer cells with the surrounding microenvironment, rather than specific bone marrow stroma, to combat the invasion by and survival of chemo-resistant T-ALL cells.
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ItemLimited clinical benefit for surveillance PET-CT scanning in patients with histologically transformed lymphoma in complete metabolic remission following primary therapy(SPRINGER, 2014-07)The optimum follow-up of patients with transformed indolent lymphoma (TrIL) is not well defined. We sought to determine the utility of surveillance positron emission tomography-computed tomography (PET-CT) in patients with TrIL achieving complete metabolic remission (CMR) after primary therapy. We performed a retrospective analysis of patients with TrIL treated at Peter MacCallum Cancer Centre between 2002 and 2012 who achieved CMR after primary therapy who had ≥1 subsequent surveillance PET-CT. Of 55 patients with TrIL, 37 (67 %) received autologous stem cell transplantation as consolidation following chemoimmunotherapy. After a median follow-up of 34 (range 3-101) months, the actuarial 3-year progression-free (PFS) and overall survival (OS) were 77 % (95 %CI 62-86 %) and 88 % (75-94 %), respectively. Of 180 surveillance PET-CT scans, there were 153 true negatives, 4 false positives, 1 false negative, 7 indeterminate and 15 true positives. Considering indeterminate scans as false positives, the specificity of PET-CT for detecting relapse was 94 %, sensitivity was 83 %, positive predictive value was 63 % and negative predictive value was 98 %. All seven subclinical (PET detected) relapses were of low-grade histology; in contrast, all nine relapses with diffuse large B cell lymphoma (DLBCL) were symptomatic. In our cohort of patients with TrIL achieving CMR, PET-CT detected subclinical low-grade relapses but all DLBCL relapses were accompanied by clinical symptoms. Thus, surveillance imaging of patients with TrIL achieving CMR is of limited clinical benefit. PET-CT should be reserved for evaluation of clinically suspected relapse.
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ItemLimited role for surveillance PET-CT scanning in patients with diffuse large B-cell lymphoma in complete metabolic remission following primary therapy(NATURE PUBLISHING GROUP, 2013-07-23)BACKGROUND: The usefulness of positron emission tomography with computed tomography (PET-CT) in the surveillance of patients with diffuse large B-cell lymphoma (DLBCL) in complete metabolic remission after primary therapy is not well studied. METHODS: We performed a retrospective review of our database between 2002 and 2009 for patients with de novo DLBCL who underwent surveillance PET-CT after achieving complete metabolic response (CMR) following primary therapy. RESULTS: Four-hundred and fifty scans were performed in 116 patients, with a median follow-up of 53 (range 8-133) months from completion of therapy. Thirteen patients (11%) relapsed: seven were suspected clinically and six were subclinical (all within first 18 months). The positive predictive value in patients with international prognostic index (IPI) <3 was 56% compared with 80% in patients with IPI ≥3. Including indeterminate scans, PET-CT retained high sensitivity 95% and specificity 97% for relapse. CONCLUSION: Positron emission tomography with computed tomography is not useful in patients for the majority of patients with diffuse large B-cell lymphoma in CMR after primary therapy, with the possible exception of patients with baseline IPI ≥3 in the 18 months following completion of primary therapy. This issue could be addressed by a prospective clinical trial.