IMRT 2018

Conclusions

1. Conventional RT probably goes with a secondary tumor risk of approximately 1% (High- and Low-dose Areas together). The dose/volume effects for secondary tumor risk are currently completely unclear. 2. Conservative estimates suggest an increase by IMRT to 2%, e.g. the secondary tumor risk doubles when compared to conventional RT.

But: - It is still an overall low number.

- For most diseases, this is negligible in comparison to the risk of local recurrence. - Given the predominantly old age of patients, this is mostly irrelevant anyway - New planning systems create efficient plans, so that the number of monitor units decreases dramatically

3. Realistic estimates suggest a factor of <1.5 between the secondary tumor risk of conventional RT and IMRT.

4. It is not completely improbable, that IMRT reduces the risk of secondary tumors

5. Precise knowledge of the dose at SMN origin is necessary to further refine our knowledge (prospective evaluation necessary!!!!)

6. IMRT for children and breast cancer has to be used with caution, weighing benefits against potential risk, but the same holds true for IORT