Het volume van chirurgische ingrepen en de impact ervan op ... - KCE

112 Volume Outcome KCE reports 113
219, 221, 223
• nodal involvement;
• treatments received: radiotherapy, chemotherapy, hormonal therapy; 221,
222
• location of hospital i.e. rural or urban, teaching or nonteaching; 219
• time period. 221
In our study, patients who were treated in low-volume hospitals were more likely to
undergo mastectomy: 67% in low-volume centres versus 52% in high-volume centres.
Guller et al. mentioned similar statistically significant differences in undergoing BCT
between low- and high-volume hospitals. They pointed out that these differences are
important for patients since BCT is considered equally efficient regarding survival in the
treatment of early-stage breast cancer while it has better results with respect to body
image, sexual function and quality of life. 219 With respect to surgeon volume, on the
other hand, there were no differences in the type of surgery (see Table 5.58). Stefoski
et al. made the same observation in their data. 221
Although the use of adjuvant treatment could not be analyzed in our study, it is
interesting to mention that Stefoski et al. found that chemotherapy rates increased from
12% in very low volume surgeons to 21% in the high category. 221 Remacle et al. found a
similar association between adjuvant chemotherapy and hospital volume in the data of
the Alliance of Christian Sickness Funds. 235 According to Stefoski et al. the increased use
of combined adjuvant therapy by high-volume surgeons strongly suggests a multidisciplinary
approach in the treatment of breast cancer patients. 221
VOLUME OUTCOME ASSOCIATION
A statistically significant inverse association was found between hospital volume and 2year
mortality after breast cancer surgery. Two-year mortality was 8.0% in very low
volume hospitals (150
procedures/yr). Patients operated in low volume hospitals were older, had higher levels
of co morbid illness, were more likely to undergo breast-ablative therapy and had a
more advanced disease stage. Nevertheless, these differences in the case mix could not
explain the survival disadvantage in low volume hospitals.
Bailie et al. reported similar differences in case mix between hospital volume
categories. 222 They found that patients treated in higher volume hospitals were younger,
had smaller tumours, earlier stage disease, and used more conservative surgery and
radiotherapy. Nevertheless, they too found a surgical workload effect on outcome, even
after adjustment for clinical and treatment variables.
With respect to the relationship between surgeon volume and survival, 2-year mortality
is again higher for very small volume surgeons (7.4% for those with less than 3
procedures per year) than for very high volume surgeons (4.1% for surgeons with more
than 51 breast cancer procedures per annum). However, the effect of hospital volume
seems stronger than the one of surgeon volume. There were no differences in case mix
between the surgeon’s volume categories.
We have to note, however, that the extent-of-disease information is missing
differentially across volume groups. This implies that inclusion of information on stage
and grade in the model could have biased the results.
For high-risk cancer surgery such as oesophagectomy and pancreatectomy, it seems
obvious that the attending surgeon has a potential to directly influence mortality; the
surgeon’s volume represents a component of experience which is likely to affect
performance. However, breast cancer surgery is a low-risk procedure where the locoregional
management has limited impact on survival and where patients are unlikely to
die from their cancer surgery. Therefore, some authors argue that the outcome of lowrisk
cancer procedures depends more on the environment and that the relationship
with volume is less obvious. 48, 219 Guller et al. hypothesize that high-volume hospitals
have a better pre-, peri- and postoperative management of patients. 219 They mention the
possibility that the collaboration between physician, nurses, anaesthesiologists, physical
therapists and others is better in high-volume centres. This higher level of collaboration
within the entire team that cares for the patient probably decreases the in-hospital
mortality.