Most guidelines recommend a re-resection in case of insufficient margin width in the pathological specimens [13
]. However, there is no clear scientific basis for this recommendation. In particular, there are no prospective data – especially no data from randomized trials – that demonstrate a benefit of a re-resection in comparison to leaving the situation as it is. The impact of a positive margin status might suggest that changing an R1 status to an R0 status by a re-resection might improve local control. However, the prognostic impact must not necessarily result from the surgery but could be caused by different biological behavior, e.g. the more aggressive tumors are more likely to have an R1 resection. This would mean that an R1 resection is not a mechanistic problem but reflects a biological problem that cannot be solved by surgery alone. Nevertheless, a re-resection with the objective of achieving an R0 situation is justified due to the negative impact of an R1 status.
The situation is more difficult if the tumor has been completely removed with free margins in the initial excision. There are several arguments against a re-resection in these patients:
– In patients with an R0 resection, the difference in local failure rates between patients with close margins and patients with wider margins is small. In a retrospective investigation of 1,046 patients with close (≤ 2 mm free margin) or positive margins after first excision, the local control was 95% in patients with no further excision and 94% in patients with re-excision; residual tumor was found in one-third of re-excision specimens, but this was correlated to other unfavorable prognostic factors such as an extensive intraductal carcinoma component (EIC) and node positivity [15
– In case of a re-resection, residual tumor is found in the re-resection specimen in about 30% of patients, irrespective of where the re-resection has been performed [16
– Multiple resections may increase the uncertainty for optimal definition of the target volume of the radiotherapy boost. As the boost has a clear impact, its quality and efficacy should not be decreased be a less important procedure.