Kathleen M Ziegler

Chemotherapy Sensitivity and Resistance Assays: A Systematic Review

PURPOSE This systematic review evaluates evidence comparing therapy guided by chemotherapy sensitivity and resistance assays with empiric chemotherapy, emphasizing survival outcomes. METHODS Prospective studies were sought comparing patients treated contemporaneously by assay-guided chemotherapy and empiric therapy. An initial MEDLINE search and a search performed by a Working Group of the American Society of Clinical Oncology were reviewed with attention to prespecified study selection criteria. RESULTS This review identified 10 studies meeting selection criteria, plus one retrospective study, using seven different assays. Only two studies randomly assigned patients to assay-guided treatment or empiric treatment. Five of nine nonrandomized studies found significantly higher response rates for patients who received assay-guided therapy compared with those treated empirically. One of the two randomized trials found a significantly higher response rate in the assay-guided group. Four additional studies found response rates favoring assay-guided therapy, but comparisons did not achieve statistical significance. Two nonrandomized studies found overall survival to be significantly improved with assay-guided therapy. One randomized study used a cross-over design that made it difficult to determine whether survival differed between groups, while the other randomized trial found no difference in survival. Six studies provided no comparison of groups on baseline patient characteristics. Only one study reported adverse events data. CONCLUSION While higher response rates for assay-guided therapy have been observed, differences may be attributable to bias or confounding. Little evidence on survival is available. These results do not establish the relative effectiveness of assay-guided treatment and empiric treatment. Randomized trials are needed.

Management of small cell lung cancer

OBJECTIVES This is a systematic review of evidence on issues in managing small cell lung cancer (SCLC). Key questions addressed are: the sequence, timing, and dosing characteristics of primary thoracic radiotherapy (TRTx) for limited-stage disease; primary TRTx for extensive-stage disease; effect of prophylactic cranial irradiation (PCI); positron emission tomography (PET) for staging; treatment of mixed histology tumors; surgery; and second- and subsequent-line treatment for relapsed/progressive disease. DATA SOURCES MEDLINE, EMBASE, and the Cochrane Register REVIEW METHODS The review methods were defined prospectively in a written protocol. We sought randomized controlled trials that compared the interventions of interest. Where randomized trials were limited or nonexistent, we sought additional studies. We performed meta-analysis of studies that compared early and late TRTx. RESULTS The strongest evidence available for this report is a patient-level meta-analysis showing that PCI improves survival of SCLC patients who achieved complete response following primary therapy from 15.3 percent to 20.7 percent (p=0.01). No other question yielded evidence so robust. The case for concurrent over sequential radiation delivery rests largely on a single multicenter trial. Support for early concurrent therapy comes from one multicenter trial, but two other multicenter trials found no advantage. Our meta-analysis did not find significant reductions in 2- and 3-year mortality for early TRTx. Favorable results from a single-center trial on TRTx for extensive stage disease need replication in a multicenter setting. For other questions (i.e., management of mixed histology disease; surgery for early limited SCLC), relevant comparative studies were nonexistent. PET may be more sensitive in detecting disease outside the brain than conventional staging modalities, but studies were of poor quality and reliable estimates of performance are not possible. CONCLUSIONS PCI improves survival among those with a complete response to primary therapy. A research agenda is needed to optimize the effectiveness of TRTx and its components. PET for staging may be useful, but its role awaits clarification by rigorous studies. No relevant evidence was available to address management of mixed histology disease or surgery for early limited SCLC.