The interval between courses of high-dose chemotherapy with stem cell rescue: therapeutic hypotheses

Can we negotiate with a tumor?

Recent progress in deciphering the molecular portraits of tumors promises an era of more personalized drug choices. However, current protocols still follow standard fixed-time schedules, which is not entirely coherent with the common observation that most tumors do not grow continuously. This unpredictability of the increases in tumor mass is not necessarily an obstacle to therapeutic efficiency, particularly if tumor dynamics could be exploited. We propose a model of tumor mass evolution as the integrated result of the dynamics of two linked complex systems, tumor cell population and tumor microenvironment, and show the practical relevance of this nonlinear approach.

High-dose chemotherapy with autologous stem cell transplantation in the first line treatment of aggressive non-Hodgkin lymphoma (NHL) in adults

BACKGROUND

High-dose chemotherapy with autologous stem cell support (HDT) has been proven effective in relapsed aggressive non-Hodgkin lymphoma (NHL). However, conflicting results of HDT as part of first-line treatment have been reported in randomised controlled trials (RCTs). We undertook a systematic review and meta-analysis to assess the effects of such treatment.

OBJECTIVES

To determine whether high-dose chemotherapy with autologous stem cell transplantation as part of first-line treatment improves survival in patients with aggressive non-Hodgkin lymphoma.

SEARCH STRATEGY

MEDLINE, EMBASE, Cancer Lit, the Cochrane Library and smaller databases, Internet-databases of ongoing trials, conference proceedings of the American Society of Clinical Oncology and the American Society of Hematology were searched. We included full-text, abstract publications and unpublished data.

SELECTION CRITERIA

Randomised controlled trials comparing conventional chemotherapy versus high-dose chemotherapy in the first-line treatment of adults with aggressive non-Hodgkin lymphoma were included in this review.

DATA COLLECTION AND ANALYSIS

Eligibility and quality assessment, data extraction and analysis were done in duplicate. All authors were contacted to obtain missing data and asked to provide individual patient data.

MAIN RESULTS

Fifteen RCTs including 3079 patients were eligible for this meta-analysis. Overall treatment-related mortality was 6.0% in the HDT group and not significantly different compared to conventional chemotherapy (OR 1.33 [95% CI 0.91 to 1.93], P=0.14). 13 studies including 2018 patients showed significantly higher CR rates in the group receiving HDT (OR 1.32, [95% CI 1.09 to 1.59], P=0.004). However, HDT did not have an effect on OS, when compared to conventional chemotherapy. The pooled HR was 1.04 ([95% CI 0.91 to 1.18], P=0.58). There was no statistical heterogeneity among the trials. Sensitivity analyses underlined the robustness of these results. Subgroup analysis of prognostic groups according to IPI did not show any survival difference between HDT and controls in 12 trials (low and low-intermediate risk IPI: HR 1.41[95% CI 0.95 to 2.10], P=0.09; high-intermediate and high risk IPI: HR 0.97 [95% CI 0.83 to 1.13], P=0.71. Event-free survival (EFS) also showed no significant difference between HDT and CT (HR 0.93, [95% CI 0.81 to 1.07], P=0.31). Other possible risk factors such as the proportion of patient with diffuse large cell lymphoma, protocol adherence, HDT strategy, response status before HDT, conditioning regimens and methodological issues were analysed in sensitivity analyses. However, there was no evidence for an association between these factors and the results of our analyses.

AUTHORS' CONCLUSIONS

. Despite higher CR rates, there is no benefit for high-dose chemotherapy with stem cell transplantation as a first line treatment in patients with aggressive NHL.

Recent translational research: computational studies of breast cancer

The combination of mathematics – queen of sciences – and the general utility of computers has been used to make important inroads into insight-providing breast cancer research and clinical aids. These developments are in two broad areas. First, they provide useful prognostic guidelines for individual patients based on historic evidence. Second, by suggesting numeric tumor growth laws that are correlated to clinical parameters, they permit development of biologically relevant theories and comparison with patient data to help us understand complex biologic processes. These latter studies have produced many new ideas that are testable in clinical trials. In this review we discuss these developments from a clinical perspective, and ask whether and how they translate into useful tools for patient treatment.

Telomere dynamics determine episodes of anticancer drug resistance in rat hepatoma cells

Clinical and experimental observations indicate that resistance to anticancer drugs may be spontaneously reversible over time, but the mechanisms of this reversal are unknown. The resistance of cultured hepatoma cells to methotrexate (MTX) and cisplatin was followed for 9 months. Cells were exposed to three treatments: MTX 200 nM for 24 h or 15 nM continuously and cisplatin 50 microM for 2 h. We investigated the relation between the temporal pattern of cell resistance and the previously reported fluctuations in cell proliferation rate, telomere length and telomerase activity. Spontaneous major peaks in resistance to each drug fell in time windows of 2-3 months (60-70 population doublings) and were at different times for each drug. The frequency of the fluctuations in drug resistance was the same as that of variations in cell growth rate, but amplitudes were unrelated. By contrast, resistance was directly related to telomere length dynamics in the same cells. MTX resistance occurred when telomeres shortened and cisplatin resistance when they were elongated. Furthermore, peaks of resistance to the continuous treatment with MTX were observed at 350-bp intervals of mean telomere length (9.06, 9.41, and 9.76 kbp) during the two 2-month phases of telomere shortening. Statistical analysis demonstrates the sinusoidal relationship between intermittent MTX resistance and telomere length. Possibly, erosion of telomeres encroaches on periodically spaced nucleosomal proteins, defining the onset of resistance phases. This evidence that resistance of tumoral cells to anticancer drugs may be intermittent and that onset of resistance is dictated by telomere length has major implications for clinical practice.

A short course of induction chemotherapy followed by two cycles of high-dose chemotherapy with stem cell rescue for chemotherapy naive metastatic breast cancer: sequential phase I/II studies

Two cycles of high-dose chemotherapy with stem cell support (HDC) may increase the total dose delivered and dose intensity. A brief induction phase and different non-cross-resistant agents for each HDC cycle were used to avoid drug resistance. Twenty-six women with metastatic BC had induction and stem cell mobilization with two cycles of doxorubicin/G-CSF given every 14 days. Patients with stable disease or better after induction received HD CTCb followed by HD melphalan and dose-escalated paclitaxel. At 475 mg/m(2) of paclitaxel by 24-h infusion, dose-limiting transient peripheral sensory neuropathy was encountered. No toxic deaths occurred. Complete and near complete response after completion of therapy was achieved in 22 (85%) of 26 patients. The median EFS was 38 months. The median OS has not yet been reached. At a median follow-up of 33 (25-43) months, actuarial EFS and OS were 54% (95% confidence interval (CI), 39-69%) and 69% (95% CI, 56-79%), respectively. This double transplant approach lasts only 14 weeks and is feasible, safe, and tolerable. Whilst selection biases may in part contribute to favorable EFS and OS, a randomized comparison of standard therapy vs double transplant in both metastatic and locally advanced breast cancer is warranted.