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Val J Gebski

Publications and source records attributed to Val J Gebski.

17 recordsLinked to original sources
PubMed2006

Development of a spreadsheet for the calculation of new tools to improve the reporting of the results of medical research.

PRIMARY OBJECTIVE: Confidence levels, clinical significance curves and risk - benefit contours have recently been developed with the aim of improving the interpretation of clinical studies. It has been suggested that their use may complement traditional methods of result reporting (i.e. p values and 95% confidence intervals), and subsequently improve medical decision-making. These new methods have been used to report study results; however, widespread use may be hampered by the lack of available computer software. Our objective was to design user-friendly software to enable researchers to use these statistical methods. RESEARCH DESIGN: A spreadsheet was designed to calculate these statistics for the assessment of two arm medical studies. The spreadsheet was tested using a wide range of input data and operating systems. User-friendliness was tested by researchers who had no background in statistics. MAIN OUTCOMES AND RESULTS: The confidence calculator was successfully designed, and found to be user-friendly. The spreadsheet is MS Excel-based to allow wide usage. The spreadsheet is freely available from the author and from the web site http://www.primercollaboration.com/Tools/tools.html. CONCLUSIONS: We have successfully designed a spreadsheet that is simple to use and freely accessible for researchers. This is the first such software that calculates confidence levels, clinical significance curves, and risk - benefit contours.

Biomedical Research↗
PubMed2003

Squamous cell carcinoma of the lip: is there a role for adjuvant radiotherapy in improving local control following incomplete or inadequate excision?

BACKGROUND: The treatment of squamous cell carcinoma of the lip with surgery is usually curative but incomplete/inadequate excision may be associated with recurrence and poor outcome. There is no consensus in the literature on the definition of an adequate excision margin. METHODS: Patients treated for squamous cell carcinoma of the lip at Westmead Hospital, Sydney, between 1980 and 2000 were eligible for inclusion. Polytomous logistic regression analysis was undertaken to assess for predictors of recurrence. Recurrence-free and overall survival were calculated using Kaplan-Meier survival curves. RESULTS: A total of 130 patients was identified. Median age at diagnosis was 64 years (23-97 years). Most lesions (90%) were located on the lower lip in 96 (74%) male patients. Median follow-up duration was 54 months (0-189 months). Most patients -presented with T1 lesions (75%). Initial treatment was surgery (39%), radiotherapy (48%) or both (13%). Twenty-seven per cent of excised lesions had a close (< or =2 mm) or positive margin. A total of 40 patients (31%) had recurrence (18% lymph nodes, 11% lip and 2% both). In the surgery group recurrence was significantly more likely with close or positive margins (P = 0.05). The 2 year -recurrence-free survival was 82% and 54% for radiotherapy and surgery, respectively (P < 0.001). The 2 year overall survival was similar (90% radiotherapy vs 100% surgery; P = 0.58). CONCLUSION: Incomplete or inadequate excision of some lip cancers results in local recurrence. If re-excision is not feasible -surgeons should consider the role of adjuvant radiotherapy in improving local control.

Adult↗
PubMed2002

Predicting pregnancy and spermatogenesis by survival analysis during gonadotrophin treatment of gonadotrophin-deficient infertile men.

BACKGROUND: Predictors of fertility or spermatogenesis during gonadotrophin therapy of gonadotrophin-deficient men remain poorly defined. METHODS AND RESULTS: In order to evaluate potential predictors, this study evaluated 29 consecutive gonadotrophin-deficient men all desiring paternity who received 43 courses of therapy in one centre between 1982 and 1998. The Kaplan-Meier survival analysis estimates of median (SE) time to a sperm concentration of >0, >5 and >20 x 10(6)/ml were 5.5 (1.1), 12.4 (2.3) and 29.1 (1.9) months respectively. Conception occurred in 22/43 cycles (with eight men achieving two pregnancies) with a median (SE) Kaplan-Meier estimate of 20.5 (4.7) months. The median sperm concentration at conception was 5.0 (SE 2.0; range 0.0-59.5) x 10(6)/ml. Multivariate correlated Cox proportional hazards models predicting these same sperm thresholds and conception were developed by forward stepwise variable selection with verification of the model by backward stepping. Larger testicular volume, prior gonadotrophin therapy, completion of puberty, older age, the absence of adverse fertility factors and the absence of multiple pituitary hormone deficiency predicted a favourable response. Multivariate modelling suggests that the two most important predictors of sperm output are testicular volume and pubertal status. The most important potentially modifiable predictor was prior gonadotrophin therapy. The efficacy of recombinant and urinary FSH were similar. Prior androgen therapy and partner's age did not appear to be significant. CONCLUSIONS: Since prolonged treatment may be required to induce spermatogenesis, attention to these predictors may allow appropriate early use of advanced reproductive technologies.

Adult↗