Spezielle Therapiesituationen beim metastasierten kolorektalen Karzinom

Specific Treatment Situations in Metastatic Colorectal Cancer As
far as the management of primary resectable liver metastases is
concerned, three approaches are currently competing with each
other: surgery alone, surgery with pre- and postoperative
chemotherapy, and surgery with postoperative chemotherapy alone.
The core of the argument for pre- and postoperative chemotherapy in
these patients is the European Organisation for Research and
Treatment of Cancer (EORTC) 40983 study, which concluded that, in
comparison with surgery alone, perioperative chemotherapy improved
the 3-year progression-free survival (PFS) by 7 months. In contrast
to this, there are two smaller studies - at a somewhat lower
strength of evidence - indicating that adjuvant chemotherapy
extends PFS by 9.1 months compared with surgery alone. In Germany,
the adjuvant approach continues to be favored in many places; this
can also be seen in the formulation of the S3 guideline. In
patients with unresectable liver metastases - with the associated
difficulty of classification due to the lack of clear and
definitive criteria preoperative systemic therapy to induce
`conversion' is indicated, in order to allow secondary resection.
In KRAS wild-type tumors, high response rates ( in terms of a
reduction in size of the metastases, such as according to RECIST (
Response Evaluation Criteria in Solid Tumors)) and a high
conversion rate are achieved using a cetuximab/chemotherapy
combination. Triple chemotherapy combinations with 5-fluorouracil
(5-FU), oxaliplatin and irinotecan also produce high response
rates. Bevacizumab/chemotherapy combinations have led to a high
number of complete and partial pathohistological remissions in
phase II studies; these seem to correlate with long survival times.
In the absence of long-term survival data, it therefore seems to
remain unclear as to what is the best parameter to use in order to
assess the success of preoperative treatment. Lung metastases, too,
or local peritoneal carcinomatosis can nowadays be operated on in
selected patients with a good prospect of long-term remission or
even cure. The surgery should, however, generally only be carried
out in experienced centers, especially in the case of peritoneal
carcinomatosis. For synchronous metastasization, the appropriate
management depends on the size and extent of liver metastases and
of the primary tumor. Small, peripherally lying and safely
resectable liver metastases can be removed before or at the same
time as the primary tumor, especially if a hemicolectomy is being
carried out. If the metastases are unresectable and there is no
bleeding or stenosis, the primary tumor can also be left in situ
and systemic chemotherapy can be carried out first. However, it
should be borne in mind that, according to current data, palliative
resection of the primary tumor combined with systemic therapy leads
to longer overall survival than does chemotherapy alone. Whether
resection or chemotherapy should be done first therefore depends on
the patient's clinical situation.