Residual marrow injury following cytotoxic drugs

[Numbers of early CD34+ progenitors of bone marrow hematopoiesis in patients with diffuse large B-cell lymphoma]

AIM

To estimate the number of early progenitors of bone marrow (BM) hematopoiesis in patients with diffuse large B-cell lymphoma (DLBCL) in the late period after high-dose chemotherapy (HDCT) according to the mNHL-BFM-90 program.

SUBJECTS AND METHODS

The investigators analyzed the results of BM immunophenotypic and histological studies in 40 patients (median age, 57 years) with DLBCL who received HDCT according to the mNHL-BFM-90 program at the Hematology Research Center (HRC), Ministry of Health of the Russian Federation (MHRF), in the period 2002 to 2009. A comparison group consisted of 19 patients (median age, 70 years) treated according to the CHOP/R-CHOP program at HRC, MHRF, in the same period. The median follow-up period was 6 years. The results of BM examination were analyzed before and 5-10 years after the end of HDCT. Immunophenotypic study determined the number of early CD34+ hematopoietic progenitors. BM cellularity, the size of erythroid, granulocytic and megakaryocytic lineages, their ratio, the presence of dysplasia signs, and secondary stromal changes were histologically determined. The BM toxic injury signs found for the first time were evaluated as manifestations of late myelotoxicity.

RESULTS

At 5-to-10-year follow-ups after the end of HDCT according to the mNHL-BFM-90 program, the patients showed a smaller number of early CD34+ progenitors of BM hematopoiesis in 31 (78%) cases than those treated according to the CHOP/R-CHOP-21 program (n=8 (2%)) (p=0.005). Myelopoiesis with decreased CD34+ cell count was characterized by hypocellularity in 8 (26%) patients (p=0.07), the narrowing of megakaryocytic lineage in 14 (45%) (p=0.006), erythroid one in 7 (23%) (p=0.01), and granulocytic one in 8 (26%) (p=0.92), pronounced secondary stromal changes in 15 (48%) (p=0.03), and grade 1 thrombocytopenia in 13 (42%); p=0.02).

CONCLUSION

There is evidence that the number of early CD34+ progenitors of BM hematopoiesis decreased in patients with DLBCL in the late period after HDCT. The investigation shows the relationship of the reduction in the number of early CD34+ progenitors of BM hematopoiesis in the late follow-up period to the presence of pronounced secondary changes in the BM stroma (p=0.02). There was no statistically significant relationship of the decreased number of CD34+ cells to the age younger or older than 60 years, to the period after the end of chemotherapy, to gender or presence of specific BM injury.

[Late myelotoxicity of high-dose chemotherapy according to the modified NHL-BFM-90 program in adult patients with diffuse large B-cell lymphoma]

AIM

to evaluate late myelotoxicity (MT) relate to high-dose chemotherapy (CT) according to the modified NHL-BFM-90 (mNHL-BFM-90) program in adult patients with diffuse large B-cell lymphoma (DLBCL).

SUBJECTS AND METHODS

The results of a complex clinical, laboratory, and instrumental examination, including cytologic, histologic, and routine cytogenetic studies of the bone marrow (BM), were analyzed in 40 DLBCL patients treated according to the mNHL-BFM-90 program in the National Research Center for Hematology (NRCH), Ministry of Health of the Russian Federation (MHRF), in 2002 to 2009; among them, there were 20 men and 20 women (median age, 57 years). A comparison group consisted of 19 patients who had received high-dose СНОР/R-СНОР-21 CT in HRC, MHRF, in the same period of time; out of them, there were 8 men and 11 women (median age, 70 years). The median posttherapy follow-up period was 6 years. The results of BM studies were analyzed before and 5-10 years after treatment in complete remission. The cytological and histological studies of BM determined its cellularity, the sizes of erythroid, granulocytic, and megakaryocytic lineages, their ratios, the signs of dysplasia, and stromal dysplastic changes. Routine BM cytogenetic study was conducted to identify karyological problems. Only myelopoietic changes that had been revealed for the first time 5-10 years after completion of CT were kept in mind as late MT. Cases of baseline and post-CT changes and those of baseline and no post-CT changes were not taken into account.

RESULTS

Cytopenic syndromes (having no signs of myelopoietic lineage dysplasia or needing no blood component replacement transfusions) were revealed in 52% of the patients in the high-dose CT; thrombocytopenia amounted to 46%. In the late follow-up period, the patient group after high-dose mNHL-BFM-90 CT were found to have BM hypocellularity in 15 (38%) cases, a narrowing of erythroid and megakaryocytic lineages in 13 (33%) and 19 (48%) cases, respectively, and obvious secondary stromal changes in 17 (43%). The first 6 patients underwent routine BM cytogenetic study; all the patients were ascertained to have a normal karyotype; in this connection further BM study was stopped.

CONCLUSION

The late MT of high-dose mNHL-BFM 90 CT is statistically significantly higher than that of the standard CHOP/R-CHOP-21 therapy. However, signs of myelodysplastic syndromes and those of cytopenia requiring blood component transfusions were observed in none patient.

Antineoplastic Agents and the Associated Myelosuppressive Effects

Bone marrow is a complex organ responsible for the regulation of hematopoietic cell distribution throughout the human body. Patients receiving antineoplastic agents as a therapeutic intervention for hematologic malignancy often experience varying degrees of myelotoxicity. Antineoplastic agents cause hypocellularity in marrow resulting in a reduction in hematopoietic tissue activity and a corresponding decline in cell production. Quantifying the adverse effects on hematopoiesis is based on the properties of a single agent, the use of individual drugs within a combination chemotherapy regimen, and the course, or courses, of chemotherapy designed to treat cancer. The direct or indirect suppression of erythrocytes, granulocytes, and megakaryocytes has potential for multiple negative clinical consequences ranging from increased monitoring of blood counts to life-threatening infection and death. This review will provide an overview of the structure and function of competent adult bone marrow, describe the process of hematopoiesis, and characterize the myelotoxicities associated with common antineoplastic agents currently used in the treatment of cancer.

Haemotoxicity of busulphan, doxorubicin, cisplatin and cyclophosphamide in the female BALB/c mouse using a brief regimen of drug administration

Many anticancer drugs are myelotoxic and cause bone marrow depression; however, generally, the marrow/blood returns to normal after treatment. Nevertheless, after the administration of some anti-neoplastic agents (e.g. busulphan, BU) under conditions as yet undefined, the marrow may begin a return towards normal, but normality may not be achieved, and late-stage/residual marrow injury may be evident. The present studies were conducted to develop a short-term mouse model (a 'screen') to identify late-stage/residual marrow injury using a brief regimen of drug administration. Female BALB/c mice were treated with BU, doxorubicin (DOX), cisplatin (CISPLAT) or cyclophosphamide (CYCLOPHOS) on days 1, 3 and 5. In 'preliminary studies', a maximum tolerated dose (MTD) for each drug was determined for use in 'main studies'. In main studies, mice were treated with vehicle (control), low and high (the MTD) dose levels of each agent. Necropsies were performed, and blood parameters and femoral/humeral nucleated marrow cell counts (FNCC/HNCC) were assessed on six occasions (from days 1 to 60/61 post-dosing). Late-stage/residual changes were apparent in BU-treated mice at day 61 post-dosing: RBC, Hb and haematocrit were reduced, mean cell volume/mean cell haemoglobin were increased and platelet and FNCC counts were decreased. Mice given DOX, CISPLAT and CYCLOPHOS, in general, showed no clear late-stage/residual effects (day 60/61). It was concluded that a brief regimen of drug administration, at an MTD, with assessment at day 60/61 post-dosing was a suitable short-term method/screen in the mouse for detecting late-stage/residual marrow injury for BU, a drug shown to exhibit these effects in man.

Serum FLT-3 ligand in a busulphan-induced model of chronic bone marrow hypoplasia in the female CD-1 mouse

The concentration of the cytokine fms-like tyrosine kinase-3 ligand (FL) is elevated in the plasma of patients treated with chemotherapy or radiotherapy for malignant conditions. In addition, plasma FL is increased in patients with bone marrow failure resulting from stem-cell defects (e.g. aplastic anaemia). Our goal in the present study was to measure the concentration of serum FL in mice treated with the chemotherapeutic agent busulphan (BU) to induce bone marrow depression and relate changes in FL to effects on haemopoiesis. Female CD-1 mice were treated with BU (9.0 mg/kg) or vehicle by intraperitoneal injection on 10 occasions over 21 days. Animals were autopsied on days 1, 23, 72, 119 and 177 postdosing. A full blood count was performed, and serum prepared for FL analysis. Femoral marrow cell suspensions were prepared to assess the total femoral nucleated cell count (FNCC) and the number of committed haemopoietic progenitor cells (CFU-C). On days 1 and 23 postdosing, significant decreases were evident in many peripheral blood parameters; the FNCC and CFU-C were also reduced in BU-treated mice, in conjunction with increases in serum FL levels. On days 72, 119 and 177 postdosing, several peripheral blood and bone marrow parameters remained reduced and the concentration of serum FL continued to be significantly increased. Linear regression analysis demonstrated significant correlations between the concentration of serum FL in BU-treated mice and peripheral blood and bone marrow parameters; this suggests the possible use of serum FL as a potential biomarker for drug-induced bone marrow injury.

Formaldehyde as a potential human leukemogen: an assessment of biological plausibility

The International Agency for Research on Cancer (IARC, 2004) recently reevaluated the epidemiological data on formaldehyde and concluded that there was "strong but not sufficient evidence for a causal association between leukaemia and occupational exposure to formaldehyde." This conclusion was tempered since a mechanism for leukemia induction could not be identified. Chemically induced leukemia is a well-studied phenomenon with benzene and a number of cancer chemotherapeutic drugs recognized as capable of causing this effect. Abundant in vitro and in vivo data in animals and humans demonstrate that exposure to sufficient doses of these recognized leukemogens can initiate a cascade of events leading to hematopoietic toxicity and the subsequent development of leukemia. This review addresses the biological plausibility that formaldehyde might be capable of causing any type of leukemia by providing a broad overview of the scientific data that must be considered in order to support or refute a conclusion that a particular substance might be leukemogenic. Data on benzene and selected chemotherapeutic cancer drugs are used as examples and are briefly summarized to demonstrate the similar biological events thought to result in leukemogenesis. These data are compared and contrasted with the available data on formaldehyde in order to judge whether they fulfill the criteria of biological plausibility that formaldehyde would be capable of inducing leukemia as suggested by the epidemiological data. Based on the epidemiological data, it is reasonable to expect that if formaldehyde was capable of inducing leukemia, in vivo and in vitro data would offer supporting evidence for biological plausibility. In particular, there is (1) no evidence to suggest that formaldehyde reaches any target organ beyond the site of administration including the bone marrow, (2) no indication that formaldehyde is toxic to the bone marrow/hematopoietic system in in vivo or in vitro studies, and (3) no credible evidence that formaldehyde induces leukemia in experimental animals. As discussed in this review, based on the key biological events that occur in the process of chemically induced leukemia, there is inadequate biological evidence currently available to corroborate existing weak epidemiological associations. This provides an insufficient database to conclude that there is a causal relationship for formaldehyde and leukemia risk.

Further development of a model of chronic bone marrow aplasia in the busulphan-treated mouse

Aplastic anaemia (AA) in man is an often fatal disease characterized by pancytopenia of the peripheral blood and aplasia of the bone marrow. AA is a toxic effect of many drugs and chemicals (e.g. chloramphenicol, azathioprine, phenylbutazone, gold salts, penicillamine and benzene). However, there are no widely used or convenient animal models of drug-induced AA. Recently, we reported a new model of chronic bone marrow aplasia (CBMA = AA) in the busulphan (BU)-treated mouse: eight doses of BU (10.50 mg/kg) were administered to female BALB/c mice over a period of 23 days; CBMA was evident at day 91/112 post-dosing with significantly reduced erythrocytes, platelets, leucocytes and nucleated bone marrow cell counts. However, mortality was high (49.3%). We have now carried out a study to modify the BU-dosing regime to induce CBMA without high mortality, and investigated the patterns of cellular responses in the blood and marrow in the post-dosing period. Mice (n = 64/65) were dosed 10 times with BU at 0 (vehicle control), 8.25, 9.0 and 9.75 mg/kg over 21 days and autopsied at day 1, 23, 42, 71, 84, 106 and 127 post-dosing (n = 7-15); blood and marrow samples were examined. BU induced a predictable bone marrow depression at day 1 post-dosing; at day 23/42 post-dosing, parameters were returning towards normal during a period of recovery. At day 71, 84, 106 and 127 post-dosing, a stabilized, late-stage, nondose-related CBMA was evident in BU-treated mice, with decreased erythrocytes, platelets and marrow cell counts, and increased MCV. At day 127 post-dosing, five BU-treated mice showed evidence of lymphoma. In this study, mortality was low, ranging from 3.1% (8.25 mg/kg BU) to 12.3% (9.75 mg/kg BU). It is concluded that BU at 9.0 mg/kg (or 9.25 mg/kg) is an appropriate dose level to administer (10 times over 21 days) to induce CBMA at approximately day 50-120 post-dosing.

The haemotoxicity of mitomycin in a repeat dose study in the female CD-1 mouse

Mitomycin (MMC), like many antineoplastic drugs, induces a predictable, dose-related, bone marrow depression in man and laboratory animals; this change is generally reversible. However, there is evidence that MMC may also cause a late-stage or residual bone marrow injury. The present study in female CD-1 mice investigated the haematological and bone marrow changes induced by MMC in a repeat dose study lasting 50 days. Control and MMC-treated mice were dosed intraperitoneally on eight occasions over 18 days with vehicle, or MMC at 2.5 mg/kg, autopsied (n = 6-12) at 1, 7, 14, 28, 42 and 50 days after the final dose and haematological changes investigated. Femoral nucleated bone marrow cell counts and levels of apoptosis were also evaluated and clonogenic assays carried out; serum levels of FLT3 ligand (FL) were assessed. At day 1 post-dosing, MMC induced significant reductions in RBC, Hb and haematocrit (HCT) values, and there were decreases in reticulocyte, platelet, and femoral nucleated cell counts (FNCC); neutrophil, lymphocyte and monocyte values were also significantly reduced. On days 7 and 14 post-dosing, all haematological parameters showed evidence of a return towards normal values, but at these times, and at day 28, values for RBC and FNCC remained significantly reduced in comparison with controls. At days 42 and 50 post-dosing, many haematological parameters in MMC-treated mice had returned to control levels; however, there remained evidence of late-stage effects on RBC, Hb and HCT values, and FNCC also continued to be significantly decreased. Results for granulocyte-macrophage colony-forming units and erythroid colonies showed a profound decrease immediately post-dosing, but a return to normal values was evident at day 50. Serum FL concentrations demonstrated very significant increases in the immediate post-dosing period, but a return to normal was seen at day 50 post-dosing; a relatively similar pattern was seen in the number of apoptotic femoral marrow nucleated cells. The histopathological examination of kidney tissues from MMC animals at day 42 and 50 post-dosing showed evidence of hydronephrosis with cortical glomerular/tubular atrophy and degeneration. It is therefore concluded that MMC administered on eight occasions over 18 days to female CD-1 mice at 2.5 mg/kg induced profound changes in haematological and bone marrow parameters in the immediate post-dosing period with a return to normal levels at day 50 post-dosing; however, there was evidence of mild but significant late-stage/residual effects on RBC and FNCC, and on cells of the erythroid lineage in the bone marrow.

Effect of cumulative etoposide doses on the outcome of autologous peripheral-blood progenitor-cell transplantation for lymphoma

Studies evaluating the effects of previous chemotherapy on stem-cell yield and hematological recovery after autologous peripheral-blood progenitor-cell transplantation (PBPCT) have shown conflicting results. We have retrospectively analyzed 103 consecutive lymphoma patients treated with the BEAM regimen and autologous PBPCT. The impact of the different chemotherapeutic drugs (cumulative doses) on stem-cell yield and transplant-related toxicity was investigated. Highly significant differences in platelet recovery (>20 x 10(9)/l) were observed between patients receiving less or more than 750 mg/m(2) of etoposide before transplant (15 vs 29 days, P=0.001), and between patients receiving less or more than 1.2 x 10(6)/kg CD34(+) cells (27 vs 14 days, P<0.001). Differences in neutrophil engraftment between groups were not clinically significant. Pre-transplant cumulative doses of etoposide >750 mg/m(2) were associated with low CD34(+) cell collections on multivariate analysis. The actuarial incidence of transplant-related mortality (TRM) was 14% at 5 years. Pre-transplant cumulative doses of etoposide >350 mg/m(2) and previous administration of procarbazine were found to be independent prognostic factors for TRM.

Loss of marrow reserve from dose-intensified chemotherapy results in impaired hematopoietic reconstitution after autologous transplantation: CD34(+), CD34(+)38(-), and week-6 CAFC assays predict poor engraftment

Autologous hematopoietic stem cell transplantation (HSCT) is an increasingly successful modality for treating a variety of malignant disorders in the clinic. Experimental and clinical data suggest that prior exposure to cytotoxic agents that damage primitive stem cells results in impaired hematopoiesis after autologous HSCT. To further investigate the ability to predict for impaired hematopoiesis, we measured different stem/progenitor cell populations transplanted and time to engraftment. Patients with previously untreated, advanced-stage follicular lymphoma were treated in sequential prospective protocols with 6-8 cycles of standard-dose (SD) cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP), or four cycles of a higher-dose (HD) CHOP and granulocyte colony-stimulating factor, to induce remission prior to high-dose cyclophosphamide, total body irradiation, and autologous bone marrow transplantation (ABMT). Cryopreserved marrow samples obtained prior to ABMT were assayed for CD34(+), CD34(+)38(-), and cobblestone area-forming cell (CAFC) frequencies. Despite receiving similar numbers of nucleated cells at ABMT, HD-CHOP patients took significantly longer to attain platelet engraftment than the SD-CHOP patients. Marrow from the HD-CHOP patients contained significantly lower CD34(+), CD34(+)38(-), and week 6-8 CAFC frequencies than marrow from SD-CHOP-treated patients. Time to platelet engraftment was plotted against progenitor/stem cell numbers transplanted for each patient and threshold values were developed for all three stem/progenitor cell populations. These values were 0.5 x 10(6) CD34(+) cells/kg, 0.14 x 10(6) CD34(+)38(-) cells/kg, and 9500 week-6 CAFC/kg transplanted. Approximately 50% of patients received marrow progenitor/stem cell numbers above the threshold values and all engrafted without delay. However, transplantation of stem/progenitor cell numbers below threshold values did not uniformly predict for delayed platelet engraftment. These data provide further evidence for the association of low marrow reserve at ABMT, low numbers of stem/progenitor cells transplanted, and delayed hematopoietic recovery. However, there remains a group of patients who have rapid platelet engraftment after ABMT despite low numbers of progenitor/stem cells transplanted. These data suggest the presence of a crucial stem cell population not represented by the stem/progenitor cell populations studied in these experiments.

Stroma-supported progenitor production as a prognostic tool for graft failure following autologous stem cell transplantation

To analyse the involvement of a possible numerical or qualitative stem cell defect in the development of sustained graft failure after autologous transplantation, we have determined the graft content of CD34+ nucleated cells, colony-forming cells and cobblestone area-forming cell subsets, as well as transplant ability to produce progenitors using the long-term culture colony-forming cell (LTC-CFC) assay. We evaluated material from the graft reference ampoules of 13 graft failure patients after bone marrow transplantation (BMT), four graft failure patients and four isolated thrombocytopenia patients after peripheral blood stem cell transplantation (PBSCT). We compared these data with those from six successfully engrafted BMT patients and 20 engrafted PBSCT patients respectively. In the BMT setting, the LTC-CFC 6-week assay represented a highly significant graft failure predictor. In the PBSCT setting, the total number of 2-week and 6-week LTC-CFCs transplanted per kg bodyweight (BW) showed the highest significant difference between the engrafted and the graft failure patients, as well as between the engrafted patients and the patients suffering from isolated thrombocytopenia after transplantation. These data show that the ability of a graft to generate progenitors in vitro rather than the number of primitive progenitors transplanted can have prognostic value for post-transplant haematological reconstitution.

The myelotoxicity of chloramphenicol: in vitro and in vivo studies: II: In vivo myelotoxicity in the B6C3F1 mouse

1. Chloramphenicol continues to be widely used in many parts of the world despite its known haematotoxicity. Until now, elucidation of the mechanisms involved and any attempt at amelioration of the toxic effects have been hampered by the lack of an animal model. 2. In this study neither acute nor chronic administration of chloramphenicol as its succinate ester in the drinking water produced anaemia in mice as assessed by changes in peripheral blood parameters. 3. Chloramphenicol could not be detected in the bone marrow when the antibiotic was administered either in the drinking water or by gavage, although it was detected in the serum. 4. In marrow taken from mice after chloramphenicol succinate administration and cultured in vitro, depression of the differentiation of immature committed erythroid progenitors occurred 15 min after administration of the antibiotic by gavage. However, recovery was beginning to occur at 48 h after administration of chloramphenicol succinate at 50 and 200 mg/kg and this was then followed by an 'overshoot' response at the higher dose. A toxic effect was therefore achieved in the bone marrow but this was probably masked in the peripheral blood by enhanced proliferation. 5. Morphological evidence of apoptosis was seen in erythroid and myeloid precursors in mice treated with 200 mg/kg. 6. The data suggest that the effect of chloramphenicol was at the differentiation stage of the committed marrow progenitor cells rather than at the replication stage of the stem cells and therefore this response appears to mimic the reversible bone marrow depression seen in the treated patient.

A BCNU-containing Regimen, Mini-BEAM, with GM-CSF is a Safe and Effective Mobilizing Regimen Pre-stem Cell Transplantation in Lymphoma Patients

Concern has been raised regarding the quality and engraftment potential of peripheral stem cells obtained from mobilizing regimens containing BCNU. We compared the mononuclear cell (MNC) yields and engraftment times of neutrophils and platelets in twenty-nine patients who received autologous peripheral blood stem cell transplants at our institution. Sixteen patients with either refractory or resistant Hodgkin's disease or non-Hodgkin's lymphoma, were mobilized with a BCNU-containing regimen, mini-BEAM (BCNU 60 mg/m(2) on day 1, etoposide 100 mg/m(2) on days 1-3, cytarabine 150 mg/m(2)q12h on days 1-3, and melphalan 30 mg/m(2) on day 3). Thirteen patients with various malignancies were mobilized with non-BCNU containing priming regimens. All patients received rhGM-CSF (Leukine, Immunex, Seattle, WA) 250μg/m(2) subcutaneously daily from 24 hours after completion of mobilizing chemotherapy through the completion of leukapheresis. The mean mononuclear cell yields in the BCNU versus non-BCNU containing regimens were 2.15 and 1.97 × 10(8) MNC/kg [95% CI -.32 to.68] after a median of 3 and 3 leukaphereses respectively. The median time post-stem cell infusion to an absolute neutrophil count (ANC) of ≥0.5 × 10(9)/1 were 11 days and 13 days [mean 11.7 and 12.2, p = 0.99, 95% CI -2.5, 1.6], days to an ANC of ≥1.0 x 10(9)/1 were 13 and 13 [mean 13.8 and 13.1, p = 0.47, 95% CI-1.8, 3.3], days to a platelet count of ≥20 × 10(9)/1 were 9 and 9 days [mean 11.4 and 9.8, p = 0.10, CI -0.6, 4.0], and days to a platelet count of ≥50 × 10(9)/1 were 14 and 15 days (p = 0.14) respectively. Mini-BEAM, as a mobilizing regimen, is easily administered as an outpatient. Stem cells mobilized with this regimen produces similar mononuclear cell yields as compared to non-BCNU containing regimens. There was no difference in the engraftment times for ANC or platelets from stem cells mobilized with BCNU versus non-BCNU containing regimens.

Hematopoietic stem cell compartment: acute and late effects of radiation therapy and chemotherapy

The bone marrow is an important dose-limiting cell renewal tissue for chemotherapy, wide-field irradiation, and autologous bone marrow transplantation. Over the past 5-10 years a great deal has been discovered about the hematopoietic stem cell compartment. Although the toxicity associated with prolonged myelosuppression continues to limit the wider use of chemotherapy and irradiation, ways are being discovered to circumvent this toxicity such as with the increasing use of cytokines. This review describes what is known of how chemotherapy and irradiation damage stem cells and the microenvironment, how cytokines protect hematopoietic cells from radiation damage and speed marrow recovery after chemotherapy or marrow transplantation, and how various types of blood marrow cells contribute to engraftment and long-term hematopoiesis after high doses of cytotoxic agents and/or total body irradiation.

Myeloproliferation in long-term plasmacytoma-regressor mice

MOPC-315 plasmacytoma-bearing BALB/c mice were treated with high doses of melphalan, causing a permanent and complete regression of the tumor. In the present study we analyzed plasmacytoma-regressor mice (PRM) 3-6 months after plasmacytoma regression. A second group of otherwise untreated normal mice was treated with melphalan (M--control group). A third group of mice remained untreated and served as an age- and sex-matched control group. PRM were cachectic and had an increased mortality rate compared to the M and the C control groups. Histopathological examination indicated that the spleen of PRM showed pronounced abnormalities, primarily in the red pulp. These abnormalities consisted of extramedullary hematopoiesis and myeloid-granulocytic hyperplasia. Spleens of M mice showed similar abnormalities but to a much lesser extent. Flow cytometric analysis of cellular surface markers of PRM splenocytes indicated a high number of large MAC-I- and GR-I-positive cells compared to splenocytes of M or C controls. These large cells also expressed Fc tau receptors (Fc tau RII), stained positively with non-specific esterase and adhered to plastic dishes; a certain percentage expressed MAC-2 and MAC-3 antigens. A quantitative suppression of CD4+ T cells and of B cells was also shown. Circulating levels of TNF were higher in PRM than in M or C mice. The capacity of splenocytes from PRM to secrete factors that stimulated CFU-GM colony formation in soft agar by bone-marrow cells from normal mice was significantly up-regulated compared to that of splenocytes from M or C mice.(ABSTRACT TRUNCATED AT 250 WORDS)

SWOG 8825: melphalan GM-CSF: a phase I study

The use of intravenous melphalan at higher doses is limited by severe myelosuppression. It was postulated that GM-CSF would permit the use of higher dose melphalan with only moderate myelosuppression easily manageable in an outpatient setting. Therefore, a phase I study of intravenous melphalan utilizing GM-CSF (recombinant granulocyte-macrophage colony-stimulating factor) support was initiated. Intravenous melphalan at doses of 15-45 mg/m2 was administered every 28 days. GM-CSF was utilized at doses of 10-20 micrograms/kg/day subcutaneously Days 2-21 on a 28-day cycle. Twenty-five patients received 53 courses of therapy. The dose-limiting toxicities were severe or life-threatening granulocytopenia and thrombocytopenia. Utilizing 20 micrograms/kg/day GM-CSF, the maximum tolerated dose (MTD) of melphalan is 30 mg/m2 and, with 10 mg/kg/day GM-CSF, the maximum tolerated melphalan dose is only 20 mg/m2. One patient with ovarian cancer achieved a partial response. Because the reported MTD of intravenous melphalan without GM-CSF is 30 mg/m2, GM-CSF has not allowed sufficient escalation of the intravenous melphalan dose for routine outpatient use.

Second malignancies and Hodgkin's disease--the Royal Marsden Hospital experience

The frequency of secondary malignant neoplasms occurring in patients treated for Hodgkin's disease at the Royal Marsden Hospital between 1963 and 1978 is reported and the literature is reviewed. 730 patients were reviewed and 583 patients permanently resident in the United Kingdom were included in the analysis. The frequency of leukaemia and solid tumors was determined from age- and sex-corrected data from the South Thames Cancer Registry. Thirty-seven malignancies were recorded in 36 patients including 9 leukaemias, 10 lung cancers, 6 skin cancers and 2 non-Hodgkin's lymphoma, all of which were observed in significant excess. When all remaining sites are combined, there was a slight excess but no one site is individually significant.

Drug-induced aplastic anaemia and agranulocytosis. Incidence and mechanisms

Aplastic anaemia and agranulocytosis are uncommon but serious adverse effects of drug therapy. They result from an adverse interaction between the drug and the haemopoietic pathway in certain susceptible individuals. The nature of this idiosyncratic interaction differs for different drugs and possibly for different individuals. In some instances an immune mechanism might be implicated, in others the patient's cells might carry a genetic susceptibility to the drug, while yet other patients might metabolise the drug abnormally. The idiosyncratic nature of these effects has made their investigation difficult, but experimental studies have allowed some progress in our understanding. In a practical sense, however, responsibility for preventing these problems will remain with clinicians, who should be alert to the risks and revise their prescribing habits accordingly.

Residual adriamycin (AdR)-induced hematopoietic damage: a consideration for subsequent radiotherapy

The long-term effect of adriamycin (AdR) on the radiation response of hematopoietic marrow was studied at 16 weeks after treatment with a MTD (10 mg/kg) for the BDF1 mouse. The radiation response was monitored in both the "stem cell" (CFUs-8) and myeloid (CFU-gm, granulocyte, WBC) compartments, as well as the erythroid (BFUe, CFUe, HcT) compartments of the marrow for 14 days following a whole body dose (TBI) of 4.5 Gy X ray. At the time of irradiation, animal and spleen weight of AdR treated animals were reduced while HcT and WBC remained at control levels. At the same time the granulocyte and CFUs-8d compartments were depressed, while the BFUe compartment was expanded. The CFUe and CFU-gm compartments remained at control levels. For all marrow compartments, treatment with AdR 16 weeks prior to 4.5 Gy resulted in a radiation response deficit determined from the temporal recovery curves. The data suggest that manifestation of long-term AdR injury, at least through 16 weeks following treatment, is dependent on a subsequent stress of sufficient magnitude to enhance the proliferative activity associated with hematopoietic cell production and differentiation. A comparison is made between these observations and previously reported long-term drug-induced hematopoietic injury.

Second cancers following antineoplastic therapy

The occurrence of metachronous malignancies has long been a phenomenon of interest to physicians. The problem of treatment-related malignancies has added to that interest and has contributed to the understanding of carcinogenesis. Prolonged survival of patients with previously lethal diseases is now allowing the expression of long-term toxicities of the intensive therapies being used in many disease settings. Although the oncogenic potential of the various alkylating agents may not be equivalent, they have all been implicated as causing cancer in man. Procarbazine also appears to be highly carcinogenic in man. The intensity of treatment (duration and total dose) is a significant factor in the carcinogenesis of these agents. The dose-response relationship between radiation and cancer induction is less clear, but most believe that increasing radiation exposure increases the risk of cancer in a linear fashion. The combination of intensive chemotherapy and intensive radiotherapy yields the greatest risk for treatment-related hematologic and solid malignancies. To replace effective therapy with less carcinogenic therapy of unproved effectiveness would be difficult since survival curves have not been significantly affected by the evolution of treatment-related cancers. Whether that will hold true for the adjuvant use of intensive therapy remains to be seen. Where feasible, the design of such adjuvant trials should keep the dose-response relationship in mind. If the virtual absence of metachronous leukemia in Hodgkin's disease patients treated with ABVD holds true over time, the search for noncarcinogenic combination therapy will be well worth the effort. Therapeutic options in cancer treatment currently are few, and the benefits of potentially carcinogenic chemotherapy and radiotherapy continue to outweigh the risks.

Acute nonlymphocytic leukemia after therapy with alkylating agents for ovarian cancer: a study of five randomized clinical trials

We evaluated the occurrence of acute nonlymphocytic leukemia (ANL) among 1399 women with ovarian cancer who were treated in five randomized clinical trials. Of the 1399 women, 998 had been treated with alkylating agents, and among these, 12 cases of ANL were observed; the expected number was 0.11. Ten patients with ANL had received melphalan, and two chlorambucil. ANL was not observed in 401 women who had been treated with surgery or radiation or both, without alkylating agents. The excess risk of ANL that was associated with alkylating-agent therapy was 5.8 cases per 1000 women per year, and the cumulative seven-year risk of ANL among patients who were treated with chemotherapy alone was indistinguishable from that observed in patients receiving both radiation and chemotherapy. A positive correlation between initial drug dose and the risk of ANL was suggested. These data underscore the need to assess other cytotoxic agents and regimens of drug administration to identify those that do not have harmful late effects.

Haematopoietic late effects of prolonged bleomycin treatment in mice

In two studies, haematopoietic late effects of prolonged bleomycin treatment were evaluated in mice given serial injections of 21 mg bleomycin/m2 weekly for 31 and 44 weeks, respectively. Femoral bone marrow cellularity measured at 43, 45, and 49 weeks after discontinuation of the drug in the first and after 20 weeks in the second study was found to be significantly (P less than 0.05) lower in the treated mice than in the controls. CFU-S, BFU-E, and CFU-C contents were also reduced in the treated bone marrow, but with the exception of CFU-S in the second study, differences from control values were not significant. Additional long-term bone marrow cultures performed in the second study revealed no marked changes in the marrow proliferative activity and the self-renewal of stem cells to explain the reduced marrow cellularity and stem cell content. These last findings might, therefore, be due to a decrease in femoral size with less marrow content in the treated mice, since measurements of the tibial weights in both groups showed that the bones in the treated animals were significantly (P less than 0.05) lighter than those in the controls.