Blood, 1960, Vol. 16, No. 2, pp. 1104-1121.
© 1960 American Society of Hematology, Inc.
The Threshold Dose of P32 for Leukemic Cells of the
Lymphocytic and Granulocytic Series
EDWIN E. OSGOOD 1
1 Division of Experimental Medicine, University of Oregon Medical School,
Portland, Oregon.
Analyses of the threshold dose of P32 to control 201 chronic lymphocytic
leukemia patients and 100 chronic granulocytic leukemia patients and of the
P32 dose to maintain 133 chronic lymphocytic leukemia patients for a mean
period of 50.2 months and 49 chronic granulocytic leukemia patients for a
mean period of 33.6 months are analyzed. These threshold doses fit the logarithmic probability distributions given in the tables and figures.
See PDF for Figure
See PDF for Figure
When the dose in mc. to control was plotted against the leukocyte count,
a straight line was obtained on log log paper. The equation for this curve
for the median dose to control chronic granulocytic leukemia is: log mc. P32
per 12 weeks = 0.33 log L - 0.633, where L is the leukocyte count on the
day the first P32 was given. The equation for the log log curve relating median
dose to control chronic lymphocytic leukemia to initial counts above 15,000
is: log mc. P32 per 12 weeks = 0.47 log L - 1.420. But the 40 aleukemic or
subleukemic cases with leukocyte counts below 15,000 had a median P32 requirement and standard deviation that did not differ significantly from that
for the entire group, suggesting that this subleukemic group includes patients
resembling the entire spectrum of cases with elevated initial leukocyte counts.
See PDF for Figure
See PDF for Figure
The median dose of P32 per year to maintain chronic granulocytic leukemia
cases fits the equation: log P32 per year = 0.546 log L - 1.506, and the corresponding equation for chronic leukemic lymphocytic leukemia is: log mc.
P32 per year = 0.45 log L - 1.22. The group of lymphocytic leukemias with
initial counts below 15,000 again showed a median and distribution similar to
that for the entire leukemic group.
The remarkable fact that the dose requirement years later is related to the
initial leukocyte count is discussed. Revised recommendations on dosage
schedule for titrated, regularly spaced P32 therapy of the chronic leukemias
are presented.
For each individual patient with chronic leukemia, there is a threshold
dose of intravenously administered P32 below which no effect is observed. The
dose and interval which will maintain a uniform leukocyte count of about
15,000 may remain unchanged for years or may show abrupt changes at any
time to either a lower or higher requirement.
Submitted on November 6, 1959
Accepted on January 4, 1960
