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Understanding the Graphs

Data quality

We have attempted to indicate the quality of data entry for prostatectomy by comparing the returns with Hospital Episode Statistics (HES data) - this is information collected by every NHS hospital after a patient’s discharge from a surgical procedure. Unfortunately, HES data are not 100% reliable but ideally, all procedures recorded on HES will be entered by the surgeon on to the BAUS database for analysis. A coding percentage close to 100% suggests good recording; a percentage higher than this may indicate incorrect HES coding of procedures at the individual surgeon's hospital and a low percentage suggests incomplete recording by the surgeon or, again, poor HES coding.

Number of Operations

The number of operations indicates the number of radical prostatectomy procedures undertaken by each surgeon. There is good evidence that better outcomes are obtained by surgeons who perform more procedures (high-volume surgeons), but this does not mean that low-volume surgeons have poorer outcomes. These data include open, endoscopic, laparoscopic and robotic-assisted procedures for cancer of the prostate.

The data are taken from the BAUS Data and Audit System for procedures performed between 1 January 2015 and 31 December 2017.

The number of operations reported may be lower if a surgeon has only worked through part of the relevant time period. It is not currently possible to risk adjust the data, but this may be possible with subsequent data sets.

Complication rate

The incidence of complications can vary from very minor (which do not alter the length of stay in hospital) to serious (which may require further intervention).  The data presented here indicate all reported post-operative complications labelled Clavien-Dindo III and above (i.e. any complication requiring surgical, endoscopic or radiological intervention, which would result in a prolonged hospital stay).

These results need to be interpreted with caution because there are many factors that can affect outcome which are not immediately apparent from the raw data. The accuracy of capturing and reporting complications can be variable, and surgeons who appear to have more complications may, in fact, be the ones who are most efficient at recording them.

The red vertical lines displayed on the graphs indicate an acceptable amount of variation (99% and 99.9% alerts). If the figures from your surgeon or unit are shown as lying within these inner boundaries (i.e. the dark blue bar is to the left of the red lines), then that surgeon/unit is graded as "acceptable".

We would look closely at surgeons/units if their figures lie beyond the 99% alert. If the blue bar is to the right of the 99.9% line, the surgeon is termed an “outlier”, and further investigation is essential to determine whether there may be a cause for concern.

Length of Stay

The length of stay following the operation can be influenced by the technique employed to carry out the procedure, an individual patient’s general health or complications of surgery, logistical issues (such as the distance they live from where the surgery is carried out) and individual surgeons' practice.

Average patient risk profile

Some risk factors (e.g. the stage and extent of the cancer; other medical problems) can affect the outcome of prostatectomy in terms of complications, length of stay and the likelihood of requiring a transfusion.

The graphs show what percentage of the hospital or surgeon's patients has each (potential) risk factor. This can indicate whether the hospital / surgeon operates on high-risk patients or, in fact, specialises in peforming complicated surgery.

  • Mean pre-operative PSA

​Higher levels of PSA suggest a larger tumour burden in the prostate (i.e. the level usually reflects the size of the tumour and the prostate gland itself). 

  • Gleason score

This measures how aggressive (or developed) a cancer is.  Biopsied cancer cells are graded under the microscope by a pathologist using a score of 1 to 5; 5 being the highest level of aggression.  The two predominant cell patterns are determined, and their scores added together.  Low-grade cancers are those with a sum score of 6 or less; a high percentage of patients with Gleason 3+3 cancers would, therefore, indicate that a surgeon operates mainly on low-grade (less aggressive) cancers. Conversely, a low percentage of patients with Gleason 3+3 cancers indicates that the surgeon operates mainly on higher grade (more aggressive) cancers.

  • Pathological stage T2c or T3

T-staging indicates how advanced the cancer is (i.e. it describes the extent to which it has spread).  Prostate cancers are commonly given four stages (T1 to T4) under a staging system, known as TNM (for Tumour, Nodes and Metastases).  T2c indicates localised (early) cancer which can be detected by feel during a digital rectal examination (DRE) but is confined to the prostate.  T3 is locally advanced cancer which has spread outside the prostate (locally) but is not fixed in the pelvis.

  • Body mass index (BMI)

This is a measure of body mass (i.e. it assesses the presence or absence of obesity). More obese patients have a higher risk of complications following any form of surgery and some heatlh authorities do not sanction surgery in patients with an abnormally high BMI.