Characterization of published errors in high-impact oncology journals.

PURPOSE: To assess the frequency and propagation rate of published errors in the oncology literature and to determine possible contributing factors. METHODS: We reviewed 10 major oncology journals to determine variability in the online presentation of errata. Canadian oncologists were surveyed regarding characteristics that may influence error propagation. Errors published during 2004-2007 in the Journal of Clinical Oncology (jco) and the Journal of the National Cancer Institute (jnci) were classified as trivial or serious (that is, whether change in outcome was involved). The frequency of citation and error propagation was determined for serious errors. RESULTS: Of the 10 journals reviewed, 9 present links from the original article to the erratum; in 4 of those 9 journals, at least 1 link was missing. Survey results indicate that 33% of oncologists do not read errata, and 45% have read only the abstract when referencing an article. Although 59% of oncologists have noticed errors in cancer publications, only 13% reported the error. Together, jco and jnci published 190 errata, for an error rate of 4% ± 1% (standard deviation) annually; 26 of 190 errors were serious (14%). The median time from publication of the article to the corresponding erratum was 3.5 months for trivial errors as compared with 8.3 months for serious errors (p = 0.03). Error propagation in citations before and after publication of the erratum was 15% and 2% respectively (p < 0.01). CONCLUSIONS: Error rates in high-impact oncology journals average 4%, which is likely an underestimate, because errors noticed by readers are not consistently reported. Propagation of serious errors decreases, but still continues, after publication of errata.

Decreased dose density of standard chemotherapy does not compromise survival for ovarian cancer patients.

For women diagnosed with ovarian cancer, the standard practice of surgery followed by adjuvant platinum-taxane combination chemotherapy, with cycles administered every 3 weeks, is based on randomized control trials. However, a substantial number of patients require delays or reductions on this schedule. The Cancer Centre of Southeastern Ontario (CCSEO) has historically administered chemotherapy every 4 weeks. We analyzed survival outcomes of our cohort. All ovarian cancer patients treated with chemotherapy at the CCSEO from 1995 to end-2002 were included in this study. Overall survival and progression-free survival were calculated from initiation of chemotherapy using the Kaplan-Meier technique and log-rank tests. Cox regression analysis was used to adjust for age and disease stage. A total of 171 patients were treated with chemotherapy (cisplatin-paclitaxel or carboplatin-paclitaxel), of which 144 received chemotherapy every 4 weeks and 27 every 3 weeks. Median progression-free survival was 19.2 months for the group treated every 4 weeks vs 13.2 months for the 3-weekly group. Median overall survival was 36.5 months compared to 27.1 months, respectively. Trends favored treatment every 4 weeks. In early-stage disease, 5-year overall survival was 74% and 5-year progression-free survival was 68%. Administration of platinum-paclitaxel chemotherapy every 4 weeks did not reduce survival of ovarian cancer patients. Importantly, median survival is favorable compared to results from landmark trials where patients were treated every 3 weeks. These results suggest that decreasing the frequency of chemotherapy cycles does not decrease survival. Prospective trials would be required to compare quality of life and cost-effectiveness.

Assessment of fiberoptic near-infrared raman spectroscopy for diagnosis of bladder and prostate cancer.

OBJECTIVES: To determine whether a fiberoptic Raman system, suitable for in vivo use, is able to differentiate between benign and malignant bladder and prostate pathologic findings in vitro. Raman spectroscopy is an optical technique that provides a measure of the molecular composition of tissue by analyzing the way that tissue scatters laser light. Laboratory studies have shown that the technique can be used to identify and characterize transitional cell carcinoma and prostate adenocarcinoma in vitro. METHODS: A total of 220 Raman spectra were recorded from 29 snap-frozen bladder samples collected at cystoscopic procedures, and 197 Raman spectra were recorded from 38 snap-frozen prostate samples collected at transurethral resection of the prostate. The spectra were correlated with the histologic features and used to construct separate diagnostic algorithms for the bladder and prostate. These algorithms were tested as to their ability to determine the pathologic finding of a sample from its Raman spectrum. RESULTS: The bladder algorithm was able to differentiate benign samples (normal and cystitis) from malignant samples (transitional cell carcinoma), with an overall accuracy of 84%. The prostate algorithm was able to differentiate benign samples (benign prostatic hyperplasia and prostatitis) from malignant samples (prostate cancer), with an overall accuracy of 86%. CONCLUSIONS: The results of this study have demonstrated that the clinical Raman system can provide an accurate and objective method to diagnose prostate and bladder cancer in vitro. Because the Raman probe is suitable for use during endoscopic, laparoscopic, or open procedures, this work paves the way for in vivo studies.

Monitoring of cell and tissue responses to photodynamic therapy by electrical impedance spectroscopy.

Electrical impedance spectroscopic (EIS) monitoring of photodynamic therapy (PDT) was investigated in vivo in rat liver and in vitro in multicellular spheroids. Liver impedance was continuously measured with two needle electrodes before, during and up to 3 hours following Photofrin-PDT. EIS spectra were altered immediately after PDT, with significant changes in conductivity at approximately 10 kHz, and in permittivity at approximately 30 kHz and 1 MHz. The change in permittivity at high frequencies was related to oedema, while low-frequency effects were attributed to cell necrosis and vascular changes. Photofrin-PDT-treated spheroids showed dose-dependent decreases in permittivity and conductivity at frequencies above 10 and 100 kHz, respectively. Histology showed concomitant development of a damaged rim containing sparsely distributed cells with compromised membranes and lightly staining cytoplasm. Different EIS responses to apoptotic versus necrotic modes of cell death further verified the sensitivity of impedance to purely cellular changes in the spheroid model. In conclusion, EIS sensitivity to PDT-induced damage, at both the cell and tissue level, varies with dose and time, and can be correlated qualitatively to biological changes.