Variations in committed stem cells (CFU-GM and CFU-TL) in the peripheral blood of cancer patients treated by sequential combination chemotherapy for breast cancer

The present work compared the blood variations in some committed stem cells (CSC), and corresponding differentiated WBC during the first three courses of a 6-day sequential chemotherapy given to 16 breast cancer patients for 28 days each. The granulomonocytic and lymphocytic colony-forming unit levels in blood were significantly lowered in cancer patients before treatment. These CSC appeared to have cyclic variations following each course of chemotherapy. In granulomonocytic colony-forming units, a nadir was observed by Day 15, followed by a sharp rebound above the initial values by Days 22 to 24, which was not affected in magnitude by the continuation of treatment. In lymphocytic colony-forming units, the Day 1 level increased with the continuation of chemotherapy. The initial decrease was less marked, but by Day 15 a minimal level was also observed, followed by a progressive increase to reach a maximum by Day 28. Leukocytes and granulocytes reached a nadir by Days 16 to 17 and recovered by Day 25. The cyclic evolution of monocytes was less apparent as was that of lymphocytes; however, there was less restoration of monocytes and lymphocytes than of granulocytes at the end of the resting period. This study showed: (a) an apparent relationship between the level of CSC in blood, and subsequent variations in the corresponding mature cells of the same lineage; and (b) a weak interval of time between the nadir and peaks of CSC and the corresponding mature cells, which was more evident in the granulocytic lineage. These observations seemed to be of physiological importance, but the possible prediction value of peripheral granulomonocytic colony-forming unit peak magnitude following treatment remains to be established.