Is DRE essential for the follow up of prostate cancer patients? A prospective audit of 194 patients

Improving Bacillus Calmette-Guérin (BCG) immunotherapy for bladder cancer by adding interleukin 2 (IL-2): a mathematical model

One of the treatments offered to non-invasive bladder cancer patients is BCG instillations, using a well-established, time-honoured protocol. Some of the patients, however, do not respond to this protocol. To examine possible changes in the protocol, we provide a platform for in silico testing of alternative protocols for BCG instillations and combinations with IL-2, to be used by urologists in planning new treatment strategies for subpopulations of bladder cancer patients who may benefit from a personalized protocol. We use a systems biology approach to describe the BCG-tumour-immune interplay and translate it into a set of mathematical differential equations. The variables of the equation set are the number of tumour cells, bacteria cells, immune cells, and cytokines participating in the tumour-immune response. Relevant parameters that describe the system's dynamics are taken from a variety of independent literature, unrelated to the clinical trial results assessed by the model predictions. Model simulations use a clinically relevant range of initial tumour sizes (tumour volume) and tumour growth rates (tumour grade), representative of a virtual population of fifty patients. Our model successfully retrieved previous clinical results for BCG induction treatment and BCG maintenance therapy with a complete response (CR) rate of 82%. Furthermore, we designed alternative maintenance protocols, using IL-2 combinations with BCG, which improved success rates up to 86% and 100% of the patients, albeit without considering possible side effects. We have shown our simulation platform to be reliable by demonstrating its ability to retrieve published clinical trial results. We used this platform to predict the outcome of treatment combinations. Our results suggest that the subpopulation of non-responsive patients may benefit from an intensified combined BCG IL-2 maintenance treatment.

Is Routine Digital Rectal Examination Required for the Followup of Prostate Cancer?

PURPOSE

With more men being diagnosed and radically treated for prostate cancer there is an increasing number of patients requiring followup. A proportion of radically treated patients have recurrence and require early salvage treatment. Traditionally followup involved physical examination, urinalysis, imaging and biopsy. Since the development of the prostate specific antigen assay, followup has largely consisted of digital rectal examination and prostate specific antigen determination. Although digital rectal examination is routinely used, its efficacy for detecting recurrent cancer in the absence of biochemical evidence of disease progression was questioned in recent studies.

MATERIALS AND METHODS

We performed a literature search using the key words digital rectal examination, per rectal examination, radical prostatectomy and radical radiotherapy, and cross-referenced all results.

RESULTS

The literature that supports digital rectal examination as part of patient followup after radical prostatectomy is based on case studies and it is less applicable with more sensitive prostate specific antigen assays. In almost 5,000 patients after prostatectomy a prostate specific antigen increase reliably preceded disease recurrence, making digital rectal examination superfluous to requirements. No published literature supports repeat digital rectal examination after radical radiotherapy.

CONCLUSIONS

Prostate specific antigen allows the early detection of disease recurrence. Although digital rectal examination is widely used to follow patients, contemporary studies consistently show that disease progression does not occur in the absence of increasing prostate specific antigen. This suggests that remote followup of patients with prostate specific antigen alone is a safe practice, although caution should be exercised in those with higher grade tumors, which may not produce significant amounts of prostate specific antigen.