Response to letter "Outcome of second-line chemotherapy for biliary tract cancer"

We read with interest the letter on the retrospective
audit of 63 patients receiving “second-line” chemotherapy
following the ABC02 study. We agree with the
authors that a second line regimen in advanced BTC
may be of benefit in selected patients and that prospective
randomised studies are feasible and warranted in
this population. Survival outcomes of their “second line
platinum regimen” appear modestly active and better
than our data for second-line therapy. However, these
two studies were not comparable and perhaps most
importantly, we did not use the same definition of “second
line chemotherapy” for at least a reasonable proportion
of patients. Indeed, patients in the ABC02
study were by definition well selected, and treatment
with cisplatin and gemcitabine (CisGem) was discontinued
at 24 weeks. Therefore, it is possible that some
patients (how many?) in the author’s study were re-challenged
with the CisGem regimen as it was presumed they
still were platinum sensitive. Moreover, how do you
define platinum resistance in advanced BTC patients?
What delay without progression off platinum used is
accepted a timeline indicating platinum sensitivity? In
contrast, in our study population we continue first line
chemotherapy (sometimes with short chemotherapy holidays)
to progression and start a second line regimen at
the time of disease progression, often symptomatic progression,
and with different drugs. Therefore, in the
absence of other data, we do not recommend the use
of a second line platinum regimen in advanced BTC
clearly progressing on first line chemotherapy, over fluoropyrimidine
alone or a Folfiri regimen, for example.
However, in the absence of early progression, further
studies with more patients may address this question
of re-challenging with platinum regimens as has been
utilised in the treatment of advanced ovarian cancers.