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Abstract Background The follow-up rate, a standard index of the completeness of follow-up, is important for assessing the validity of a cohort study. A common method for estimating the follow-up rate, the “Percentage Method”, defined as the fraction of all enrollees who developed the event of interest or had complete follow-up, can severely underestimate the degree of follow-up. Alternatively, the median follow-up time does not indicate the completeness of follow-up, and the reverse Kaplan-Meier based method and Clark’s Completeness Index (CCI) also have limitations. Methods We propose a new definition for the follow-up rate, the Person-Time Follow-up Rate (PTFR), which is the observed person-time divided by total person-time assuming no dropouts. The PTFR cannot be calculated directly since the event times for dropouts are not observed. Therefore, two estimation methods are proposed: a formal person-time method (FPT) in which the expected total follow-up time is calculated using the event rate estimated from the observed data, and a simplified person-time method (SPT) that avoids estimation of the event rate by assigning full follow-up time to all events. Simulations were conducted to measure the accuracy of each method, and each method was applied to a prostate cancer recurrence study dataset. Results Simulation results showed that the FPT has the highest accuracy overall. In most situations, the computationally simpler SPT and CCI methods are only slightly biased. When applied to a retrospective cohort study of cancer recurrence, the FPT, CCI and SPT showed substantially greater 5-year follow-up than the Percentage Method (92%, 92% and 93% vs 68%). Conclusions The Person-time methods correct a systematic error in the standard Percentage Method for calculating follow-up rates. The easy to use SPT and CCI methods can be used in tandem to obtain an accurate and tight interval for PTFR. However, the FPT is recommended when event rates and dropout rates are high.

Robot-assisted radical cystectomy (RARC) is an emerging operative alternative to open surgery for the management of invasive bladder cancer. Studies from single institutions provide limited data due to the small number of patients. In order to better understand the related outcomes, a world-wide consortium was established in 2006 of patients undergoing RARC, called the International Robotic Cystectomy Consortium (IRCC). Thus far, the IRCC has reported its findings on various areas of operative interest and continues to expand its capacity to include other operative modalities and transform it into the International Radical Cystectomy Consortium. This article summarizes the findings of the IRCC and highlights the future direction of the consortium.

Introduction: While radical retropubic prostatectomy has been the gold standard surgical approach, the explosion of minimally invasive methods has led to the search for less invasive treatment options. We offer an overview of the evolution of laparoscopic radical prostatectomy (LRP) and robot-assisted laparoscopic prostatectomy (RALP) in terms of the landmark publications and recent head-to-head comparisons, and we review our own experience. Materials and Methods: A Medline search was performed using the keywords prostate cancer, prostatectomy, laparoscopic, and robotic. All pertinent articles concerning localized prostate cancer were reviewed. The Montefiore experience consisted of a retrospective review of a prospectively maintained confidential database. Results: Several laparoscopic and robotic series were identified including review articles of each modality as well as studies directly comparing the two. Both LRP and RALP compare very favorably with conventional open surgery in terms of safety and oncologic efficacy. Both minimally invasive approaches offer decreased blood loss, transfusion rate, and length of hospital stay when contrasted with open surgery. When compared directly, LRP and RALP offer similar surgical, oncologic, and functional outcomes. However, RALP likely requires a shorter learning curve. Conclusion: The use of minimally invasive techniques has revolutionized the surgical treatment of prostate cancer. Pure LRP has been shown to be feasible and reproducible. However, it has a steep learning curve and is difficult to learn. In contrast, RALP is easier to learn and is now the surgical treatment of choice in most centers of excellence in the United States. The superior optics with respect to visualization and magnification translates into a procedure that is equivalent, if not superior, with respect to perioperative parameters, oncologic outcomes, and functional outcomes to its open counterpart.