Background: CHOP is considered to be the gold standard for patients with hi
stologically aggressive non-Hodgkin's lymphoma both in limited and advanced
stages. In order to determine the maximum tolerable dose of an intensified
CHOP regimen, a dose-escalation study of CHOP (cyclophosphamide, doxorubic
in, vincristine, and prednisone) in patients with non-Hodgkin's lymphoma (N
HL) was started.
Patients and methods: With an increased fixed dose of doxorubicin at 75 mg/
m(2) instead of 50 mg/m(2) on day 1 and standard doses of vincristine (1.4
mg/m(2) on day 1) and prednisone (100 mg day 1 through 5), cyclophosphamide
dose was escalated by increments of 250 mg/m(2) in consecutive cohorts of
at least three patients starting from 1000 mg/m(2). Granulocyte-colony stim
ulating factor (G-CSF) support was added to the regimen starting from the d
ose-level inducing grade 4 neutropenia lasting more than five days in two p
atients. Dose limiting toxicity was defined as either the dose inducing gra
de 4 neutropenia lasting more than seven days despite the use of G-CSF, or
grade 3-4 thrombocytopenia lasting more than seven days, or any grade 4 non
-hematological toxicity other than alopecia. The dose-level below the one i
nducing dose-limiting toxicity was defined as maximum tolerable dose. All p
atients were treated on an outpatient basis. Dose-intensity parameters for
single agent doxorubicin and cyclophosphamide as well as for the whole regi
men were evaluated.
Results: Eighty-seven patients are evaluable over a four-year study period.
At 1750 mg/m(2) dose-level, G-CSF was added to the regimen according to de
scribed criteria. At the cyclophosphamide dose of 3000 mg/m(2), dose-limiti
ng hematological toxicity occurred in two patients, with one grade 4 thromb
ocytopenia and neutropenia and one grade 4 neutropenia lasting more than se
ven days. Thus, cyclophosphamide dose of 2750 mg/m(2) was defined as maximu
m tolerable dose.
Conclusions: CHOP intensification of approximately 1.8 times that of the st
andard regimen is feasible and safely administered on an outpatient basis w
ith G-CSF support. Further investigation on the role of dose-intensity in t
he outcome of NHL should focus on the comparison of intensified CHOP regime
n and standard CHOP or high-dose chemotherapy.