Patients with locally
advanced oesophageal cancer, who are treated with radiotherapy and
chemotherapy, are currently receiving more or less uniform
treatments. However, there are major differences between patients.
During her PhD research radiation oncologist Francine Voncken has
investigated various options to improve patient selection and
optimise radiotherapy. She defends her thesis on November 21st at the Vrije
During her PhD research Francine Voncken investigated ways to
improve patient selection, the technique of PET-CT scans,
image-guided radiotherapy and the response assessment after
With regards to patient selection she determined that elderly
patients (≥70 years) who were carefully selected for
chemoradiotherapy had similar long-term outcomes as younger
patients (<70 years). Age alone should therefore not be a
contraindication for this treatment. She also investigated the
predictive value of tumor markers in the blood (CEA and CA19-9)
before starting chemoradiotherapy. This revealed that patients with
elevated levels of both tumor markers have a 10 times increased
chance of early disease recurrence. Being able to predict this is
important since 1 in 5 patients doesn't profit from an intensive,
combined treatment with chemoradiotherapy and surgery because of
early disease recurrence.
In collaboration with radiotherapists around the Netherlands
Voncken also investigated the role of PET-CT in tumor delineation
for the treatment plan. Although PET did influence the delineation
of the tumor, there was still variation between radiotherapists in
determining the tumor borders, indicating there is room for further
improvement. In addition, she found that compensating for
respiration movement during PET-CT did not improve the demarcation
of the tumor nor the detection of suspicious lymph nodes.
Voncken also investigated several variables that could improve
image-guided radiotherapy and more accurate and individualized
irradiation. In order to irradiate a tumor accurately uncertainty
margins are necessary. She found possible ways to reduce and
individualize those margins.
One in three oesophageal cancer patients has a complete
pathological response following neo-adjuvant chemoradiotherapy,
that is, before surgery. Recognizing a good response is still
challenging though and current techniques to measure that response
(f.e. PET-CT and endoscopy) have limitations. Recent technical
improvements have enabled making high resolution MRI-images of
oesophageal tumors. Vonckens research into response assessment of
oesophageal cancer following chemoradiotherapy by means of
MRI-scans is promising and shows that the assessment could possibly
be improved with those scans.
Practical information about the defense can be found on VU university's website.