Dust transport in a magnetized radio-frequency discharge under microgravity conditions

Dust is found in plasmas used in industrial applications, such as microelectronics and solar cell manufacturing, in fusion plasmas, where it is usually the result of plasma-wall interactions, and in plasmas in space, such as planetary atmospheres, cometary tails, planetary rings, interstellar molecular clouds, and star and planet formation regions. In plasma applications, magnetic fields are occasionally used, mainly to confine the plasma. In space, however, magnetic fields are very often present and they may strongly influence the behavior of dusty plasma, for instance in the formation of stars and planets. We extended a fully self-consistent two-dimensional fluid model for radio-frequency discharges by adding a homogeneous axial magnetic field and the effect it has on the transport of plasma species in a low-temperature dusty discharge. We show that the magnetic field has an important effect on the (ambipolar) diffusion of ions and electrons in the bulk of the discharge. This causes an important change in the force balance of the dust particles and in the time scales of the formation of a dust-free void. Finally, we compare the parameters of the modeled discharge with the parameters of a planet formation region around a young stellar object (YSO). We conclude that a magnetic field in both low-temperature rf discharges under micro-gravity conditions and dusty plasmas around YSO's has an important effect on the transport of dust and must be important for the formation of planets and stars.

Growth factor practice patterns among pediatric oncologists: results of a 1998 Pediatric Oncology Group Survey. Economic Evaluation Working Group the Pediatric Oncology Group

The American Society of Clinical Oncology (ASCO) guidelines on growth factor (GF) use recommend applying adult-derived guidelines in pediatric oncology. An ASCO survey of adult oncology GF use determined the preference for first degree prophylaxis (use of GF when febrile neutropenia [FN] is expected to be high in untreated patients), second-degree prophylaxis (administration of GF after a documented episode of FN on a previous cycle of chemotherapy), and intervention in the treatment of FN. Similar preferences have not been evaluated in pediatrics. The purpose of this study was to (1) characterize GF use in pediatric oncology; (2) correlate use patterns with demographic factors; and (3) compare the Pediatric Oncology Group (POG) and ASCO surveys. The ASCO survey was revised for use within pediatric oncology and was mailed to the physician membership of POG; 341 were returned (86% completion rate). Comparisons were made with the ASCO survey. Most (76%) physicians said GF use was determined by protocol requirements and most (70%) patients were entered on POG protocols. GF use as first-degree prophylaxis was selected 40% of the time, which was significantly greater than in adults; this was most influenced by anticipated duration of neutropenia (> or =7 days). The severity of the initial clinical course (e.g., neutropenia, infection) influenced use in second-degree prophylaxis; dose reduction alone was never selected. For FN, GF use was 45%, with lower preferences in uncomplicated FN (16%-38%) compared with complicated FN (66%). POG respondents endorse greater use of GF for first-and second-degree prophylaxis but less use in uncomplicated FN than do ASCO respondents. These patterns may reflect different strategies, including the role of chemotherapy, value of dose intensity, and perceived toxicity of regimens. Given these differences, adult-based guidelines may not be appropriate for pediatrics.

Significance of commonly used prognostic factors differs for children with T cell acute lymphocytic leukemia (ALL), as compared to those with B-precursor ALL. A Pediatric Oncology Group (POG) study

T cell acute lymphocytic leukemia (T-ALL) and B-precursor ALL differ significantly in the clinical characteristics of the patients at presentation and in laboratory-defined characteristics of the leukemic cells. We assessed for pediatric patients with T-ALL the relative importance of prognostic factors previously demonstrated to predict outcome in B-precursor ALL. Presenting clinical and laboratory features were correlated with outcome for 441 children 12 months to 21 years of age with previously untreated T-ALL, registered on the Pediatric Oncology Group (POG) T3 protocol between 1986 and 1992. These T-ALL prognostic factor analyses were then compared to similar analyses for 1993 patients with B-precursor ALL enrolled during the same time period on the POG ALinC 14 protocol. Quantitative interaction between phenotype and each prognostic factor was studied to determine the relative importance of the prognostic factor for each of the two major immunophenotypes. We also analyzed the importance of maturational stage as a T-ALL prognostic factor, using a modified Ludwig definition of maturational stage. We conclude that several of the clinical and laboratory prognostic factors, which are used reliably for B-precursor ALL, are much less predictive in T-ALL (ie age, WBC, consensus risk group, hyperdiploidy, presence of trans- locations and CALLA expression). There was no significant difference between the phenotypes in the prognostic importance of race or gender. Our data demonstrate a significant difference in outcome among the three maturational stages of T-cell ALL, with the intermediate group faring best. Using traditional risk group criteria to stratify patients with T-ALL for therapy may not be appropriate.

Therapy of refractory or recurrent childhood acute myeloid leukemia using amsacrine and etoposide with or without azacitidine: a Pediatric Oncology Group randomized phase II study

PURPOSE

A randomized study compared the combination of amsacrine (100 mg/m2/d on days 1 to 5) and etoposide (200 mg/m2/d on days 1 to 3) with the same two agents plus azacitidine (250 mg/m2/d on days 4 to 50) for the therapy of induction-resistant or relapse childhood acute myeloid leukemia (AML).

PATIENTS AND METHODS

One hundred sixty-seven assessable children with AML who either had failed to respond to primary induction therapy (group 1, n = 41) or had relapsed (group 2, n = 126) were randomized.

RESULTS

Overall, there were 56 complete responses (34%; SE 4%). Among primary refractory patients (group 1), the complete response rate was higher with the three-drug regimen (18% vs 53%, P = .03). In the relapsed patients (group 2), there was no difference in complete response rates related to treatment (31% vs 35%, P = .3). There were 17 early deaths. The major toxicities for both regimens were myelosuppression and infection.

CONCLUSION

The overall complete response rate of 34% in this patient population is indicative of effective antileukemic activity. For patients with relapsed leukemia, the addition of azacitidine to etoposide and amsacrine did not improve response. The suggested advantage of the three-drug regimen for induction failures warrants further investigation.

Leukemic cell growth in SCID mice as a predictor of relapse in high-risk B-lineage acute lymphoblastic leukemia

Mice with severe combined immunodeficiency (SCID) provide a model system to examine the in vivo homing, engraftment, and growth patterns of normal and malignant human hematopoietic cells. The relation between leukemic cell growth in this model and the treatment outcome in patients from whom cells were derived has not been established. Leukemic cells from 42 children with newly diagnosed high-risk B-lineage acute lymphoblastic leukemia were inoculated intravenously into CB.17 SCID mice. Mice were killed at 12 weeks or when they became moribund as a result of disseminated leukemia. All mice were necropsied and subjected to a series of laboratory studies to assess their burden of human leukemic cells. Twenty-three patients whose leukemic cells caused histopathologically detectable leukemia in SCID mice had a significantly higher relapse rate than the 19 patients whose leukemic cells did not (estimated 5-year event-free survival: 29.5% v 94.7%; 95% confidence intervals, 11.2% to 50.7% v 68.1% to 99.2%; P < .0001 by log-rank test). The occurrence of overt leukemia in SCID mice was was a highly significant predictor of patient relapse. The estimated instantaneous risk of relapse for patients whose leukemic cells caused overt leukemia in SCID mice was 21.5-fold greater than that for the remaining patients. Thus, growth of human leukemic cells in SCID mice is a strong and independent predictor of relapse in patients with newly diagnosed high-risk B-lineage acute lymphoblastic leukemia.

Phase I trial of continuous infusion carboplatin and etoposide in children with refractory acute leukemia: a Pediatric Oncology Group study

PURPOSE

The purpose of this phase I study was to determine the toxicities and response to continuous infusion carboplatin in combination with a fixed dose of etoposide (VP-16) in children with refractory acute leukemia.

PATIENTS AND METHODS

From January 1989 to February 1992, 20 patients received 28 courses of treatment. Each course of treatment consisted of a 1-hour intravenous (IV) infusion of VP-16 100 mg/m2/d for 5 days, followed by a 23-hour IV infusion of carboplatin each day. The initial, total 5-day dose of carboplatin (1,000 mg/m2) was escalated by 250- to 375-mg increments to a final, total dose of 1,875 mg/m2 over 5 days.

RESULTS

Significant marrow suppression was observed in all patients, with prolonged marrow aplasia at the 1,875-mg/m2 dose level. Grade III diarrhea occurred in three patients; 10 patients experienced life-threatening infection and three had severe thrombocytopenic bleeding. Major marrow responses (two complete remissions and two partial remissions) occurred in four patients (20%).

CONCLUSION

In view of the apparent antileukemic efficacy and minimal extramedullary toxicity, carboplatin deserves further study in a phase II trial.

Transitional pre-B-cell acute lymphoblastic leukemia of childhood is associated with favorable prognostic clinical features and an excellent outcome: a Pediatric Oncology Group study

The presenting characteristics and survival of children with the newly recognized transitional cell pre-B immunophenotype of acute lymphoblastic leukemia (ALL) are compared with those of children with pre-B ALL to determine the clinical significance of the new phenotype. Patients with transitional pre-B ALL (n = 17), defined by lymphoblasts expressing cytoplasmic and surface mu heavy chains without kappa or lambda light chains, have lower initial leukocyte counts (p = 0.02) and a higher frequency of DNA indexes > 1.16 (p < 0.001) than patients with pre-B ALL (n = 501), whether or not cases with the unfavorable prognostic (1;19) translocation are included in the analysis. Patients with transitional pre-B ALL lack FAB L3 morphology, bulky extramedullary disease, surface kappa or lambda chains, and the (8;14), (8;22), and (2;8) translocations, features that characterize the syndrome of B-cell ALL. The 4-year relapse-free survival result for children with transitional pre-B ALL appears better than that for children with pre-B ALL (93.3 +/- 17% versus 72.9% +/- 4.6%), but this difference is not statistically significant. We conclude that patients with transitional pre-B ALL have a very favorable prognosis in the context of the therapy used in this study.

A phase I trial of fazarabine in refractory pediatric solid tumors. A Pediatric Oncology Group study

Fazarabine is a synthetic analog of cytosine arabinoside and 5-azacytidine that incorporates structural features of both compounds. Xenograft studies showed good activity against a variety of transplanted tumors. Initial studies in adults employed both a continuous infusion schedule and a daily bolus x 5 schedule. Myelotoxicity, especially neutropenia, was dose-limiting, with excessive myelotoxicity seen on the daily bolus x 5 at 72 mg/M2/day. Since short infusions may be administered in Ringer's lactate rather than either dimethylsulfoxide or dimethylacetamide required for continuous infusion, this study examined a daily x 5 schedule in children with refractory solid tumors. The initial dosage was 30 mg/M2/day, 80% of the maximum tolerated dosage in adults, with subsequent 30% dosage escalations. A total of 18 patients were enrolled, with a wide spectrum of pediatric solid tumors. Myelosuppression was the only significant toxicity, and was excessive at 78 mg/M2/day. Therefore, on this bolus regimen, 65 mg/M2/day for 5 days was the maximum tolerated dosage. One patient with medulloblastoma had stable disease for 65 days. No other responses were seen.

Ifosfamide with mesna uroprotection and etoposide in recurrent, refractory acute leukemia in childhood. A Pediatric Oncology Group Study

BACKGROUND

Ifosfamide has previously been shown to be active as a single agent and in combination with doxorubicin, etoposide, and teniposide in pediatric solid tumors and adult acute leukemia. The authors performed a dose-escalation trial of ifosfamide with a fixed dosage of etoposide, with mesna uroprotection, in children with multiply recurrent acute leukemia.

METHODS

Chemotherapy was administered daily for 5 days. Etoposide 100 mg/m2 was followed by ifosfamide at an initial dosage of 1.6 g/m2. The ifosfamide was escalated in 20% increments to the maximum tolerated dosage in cohorts of three patients. Mesna 400 mg/m2 was given immediately before the ifosfamide and then at 3 and 6 hours after ifosfamide in the initial patients. Subsequent patients were treated with mesna 400 mg/m2 just before ifosfamide, and then every 2 hours to a total dosage equal to the ifosfamide dosage.

RESULTS

Forty-four heavily pretreated patients were entered on study. Forty were evaluable for toxicity and 36 for response as well. The maximum tolerated dosage of ifosfamide was 4.0 g/m2/d for 5 days (20 g/m2/course). Overall, 10 patients achieved complete remission, and 3 achieved partial remission. Remissions were brief, although four patients went on to bone marrow transplant while in remission. One patient is still alive.

CONCLUSIONS

The combination of etoposide and ifosfamide with mesna uroprotection showed promising activity in children with multiply recurrent acute leukemia.

Extended triple intrathecal chemotherapy trial for prevention of CNS relapse in good-risk and poor-risk patients with B-progenitor acute lymphoblastic leukemia: a Pediatric Oncology Group study

PURPOSE

The Pediatric Oncology Group (POG) acute leukemia in childhood (ALinC) 13 study tested two treatment regimens that used different CNS chemoprophylaxis for children older than 12 months with non-T, non-B acute lymphoblastic leukemia (ALL) and with no demonstrable CNS disease at diagnosis.

PATIENTS AND METHODS

With the first regimen, standard (S), six injections of triple intrathecal chemotherapy (TIC), consisting of methotrexate (MTX), hydrocortisone (HC), and cytarabine (ara-C), were administered during intensification treatment and at every-8-week intervals throughout the maintenance phase for 17 additional doses. The second regimen, standard and MTX pulses (SAM), also specified six TICs during intensification, but substituted every-8-week pulses of intermediate-dose parenteral methotrexate (IDM; 1 g/m2) for the 17 maintenance TIC injections, with a low-dose intrathecal (IT) MTX boost administered with the first four maintenance IDM pulses. Otherwise, systemic therapy on regimen SAM was identical to regimen S. There were 1,152 patients randomized to the S and SAM regimens after stratification by risk group (age/leukocyte count) and immunophenotype.

RESULTS

The 5-year probabilities (+/- SE) of an isolated CNS relapse were regimen S: good risk (n = 381), 2.8% +/- 1.3%; poor risk (n = 196), 7.7% +/- 3.2%; good + poor risk (n = 577), 4.7% +/- 1.5%; regimen SAM: good risk (n = 388), 9.6% +/- 2.2%; poor risk (n = 187), 12.7% +/- 4.2%; good + poor risk (n = 575), 10.9% +/- 2.2%. In poor-risk patients, approximately one third of the isolated CNS relapses occurred before preventive CNS therapy was begun at week 9. Hence, regimen S has provided better CNS preventive therapy for both good- and poor-risk patients (P < .001 overall). The difference is statistically significant for good-risk patients (P < .001), but not for poor-risk patients (P = .20). Neither treatment has shown a significant advantage in terms of general outcome.

CONCLUSION

TIC injections extended throughout the intensification and maintenance periods are superior to IDM pulses for prevention of CNS leukemia. Our results with TIC seem comparable with those achieved with other contemporary methods of CNS preventative therapy. Thus, extended TIC affords a reasonable alternative to CNS irradiation plus upfront IT MTX for patients with B-progenitor ALL.

Treatment of CNS relapse in children with acute lymphoblastic leukemia: A Pediatric Oncology Group study

PURPOSE

To assess the efficacy and toxicity of chemotherapy and cranial radiation for the treatment of children with acute lymphoblastic leukemia (ALL) following first isolated CNS relapse.

PATIENTS AND METHODS

One hundred twenty children were treated on Pediatric Oncology Group (POG) protocol 8304. All children had received prophylactic CNS therapy during their initial treatment. The treatment protocol included a four-drug reinduction and six weekly doses of triple intrathecal therapy (TIT). Cranial radiation, 24 Gy, was followed by monthly TIT. Systemic consolidation and maintenance therapy included 6-week cycles of mercaptopurine/methotrexate (6MP/MTX) and vincristine/cyclophosphamide (VCR/CTX), with randomization to intervening pulses of prednisone/doxorubicin (PDN/DOX) or teniposide (VM26)/cytarabine (Ara-C) for a total of 88 weeks.

RESULTS

All 120 patients achieved a second complete remission. There have been 61 protocol failures. Thirty-five patients had a bone marrow relapse, four with simultaneous CNS involvement and one with concurrent testicular leukemia. Thirteen patients had a second isolated CNS relapse, 10 a testicular relapse, and two relapsed in other sites. One patient died in remission. Overall event-free survival (EFS) at 4 years was 46% +/- 7%. The toxicity associated with this protocol was minimal except for leukoencephalopathy, which occurred in 20 (17%) patients. The treatment comparison between VM26/Ara-C or PDN/DOX pulses showed a trend toward superior EFS (P = .12) in favor of VM-26/Ara-C.

CONCLUSION

To date, this represents the largest series of patients with ALL treated uniformly for an isolated CNS relapse. Since marrow relapse remains the primary site of failure, future protocols must intensify systemic therapy.

The non-random dic(9;12) translocation in acute lymphoblastic leukemia is associated with B-progenitor phenotype and an excellent prognosis

A dicentric translocation involving the short arms (p) of chromosomes 9 and 12 was identified in 15 of 2303 successfully banded cases of acute lymphoblastic leukemia (ALL) in children, consecutively entered on protocols of the Pediatric Oncology Group (1986-1990) or St Jude Children's Research Hospital (1984 and 1990). The dic(9;12)(p1?1;p1?2) was seen only in patients with a B progenitor cell immunophenotype: the frequency was 0.8% among pre-B cases (4/508) and 0.9% (11/1177) among early pre-B cases. Laboratory and clinical characteristics were similar to those of the general population of children with ALL, with the exception of a marked male preponderance (12/15 cases). Flow cytometric studies revealed a leukemic cell DNA index of 1.0 in all cases. All fifteen patients are in continuous complete remission at a median follow-up duration of 57+ months (range 9-93+ months). These findings suggest that the dic(9;12) is a recurrent chromosomal translocation in pediatric ALL, occurs exclusively in B-progenitor ALL, and unlike other non-random translocations, is associated with an excellent prognosis.

Philadelphia chromosome and monosomy 7 in childhood acute lymphoblastic leukemia: a Pediatric Oncology Group study

During an 8-year period, 3,638 children from institutions of the Pediatric Oncology Group (POG) were diagnosed with acute lymphoblastic leukemia (ALL). Fifty-seven patients had Philadelphia chromosome-positive (Ph1) ALL. Blast cells obtained at diagnosis from 13 of these 57 cases (23%) were also found to have partial or complete monosomy 7 (-7). This subgroup of children with Ph1/-7 ALL was comprised primarily of older males with early B-lineage ALL. Bone marrow specimens from six Ph1/-7 patients were studied further using the polymerase chain reaction and primers that flank the ALL, and chronic myelogenous leukemia breakpoints to determine the molecular characteristic of the 9;22 translocation. Rearrangements were detected in RNA from bone marrow and/or peripheral blood cells of six patients, although four were in hematologic remission at the time of the analysis. Five cases showed the ALL breakpoint, while one child with Ph1/-7 showed the chronic myelogenous leukemia breakpoint. The induction failure rate was much higher in this subgroup (31%) as compared with Ph1-negative cases, and the projected duration of event-free survival reflected the aggressive nature of this subgroup because no children are projected to remain in remission at 2 years. ALL with both the 9;22 translocation and -7 appears to represent a unique and previously undescribed subgroup of childhood ALL associated with a particularly adverse outcome. Leukemic transformation in such patients may involve the interaction of a dominant oncogene (Ph1) and a tumor suppressor gene (-7).

Favorable prognosis associated with hyperdiploidy in children with acute lymphocytic leukemia correlates with extra chromosome 6. A Pediatric Oncology Group study

Pretreatment bone marrow cytogenetic studies were included for 1664 patients with acute lymphoblastic leukemia (ALL) accrued to Pediatric Oncology Group (POG) 8035 laboratory classification study from May 1981 through January 1986. There was a significant difference (P = 0.0001) in distribution of stem-line karyotype (normal, hypodiploid, pseudodiploid, or hyperdiploid) among children with early pre-B, pre-B, or T-cell ALL, with early pre-B patients demonstrating a higher proportion of hyperdiploid karyotypes with modal chromosome numbers greater than 51. Cytogenetic classification of 1216 patients with early pre-B or pre-B ALL evaluable for duration of event-free survival (EFS), with median follow-up of 42 months, showed a significant prolongation of five-year EFS associated with hyperdiploidy greater than 51 (75%; standard error [SE] = 5%) compared with hyperdiploidy 47 to 51 (46%; SE = 7%), hypodiploidy (55%; SE = 11%), and pseudodiploidy (45%; SE = 7%) (P = 0.0001). Five-year EFS was intermediate for patients with normal (58%), constitutionally abnormal (66%), or unsuccessful analyses (66%). The breakpoint defining hyperdiploidy associated with better prognosis was best defined as greater than 51 (P = 0.0002). Of 239 children with hyperdiploid karyotypes, analysis of the contribution of each chromosome to EFS duration showed a significant association between improved EFS and additional chromosome(s) six (P = 0.02). Chromosome translocation was associated with shorter EFS (P = 0.0001).

Histopathology and prognosis in childhood hepatoblastoma and hepatocarcinoma

To determine the relationship between outcome and histologic type, the authors examined data from 168 cases of hepatoblastoma (HB) and 28 cases of hepatocarcinoma (HC) accrued from children over a 14-year period. After adjustment for stage of disease, there was no significant difference in median survival between HB and HC. Mitotic activity was associated with poor prognosis. Necrosis or vascular invasion did not influence prognosis. In 55 cases of completely resected HB, pure fetal histologic type (PFH) was associated with improved survival when compared with all other histologic patterns of HB (92% versus 57% 24 months' survival; P = 0.02). A prognostic effect of PFH was not demonstrable in incompletely resected HB, but the absence of mitoses and the presence of differentiated mesenchymal elements improved survival. The fibrolamellar pattern of HC demonstrated survival similar to that of the typical pattern of HC. The authors conclude that features consistent with differentiation in HB convey improved prognosis for survival. These observations may be important in designing future therapy for children with hepatic tumors.

Circulating immune complexes in childhood malignancies: a Pediatric Oncology Group study

Pretreatment serum samples obtained at diagnosis from 89 children with various pediatric malignancies were examined for circulating immune complexes (CIC) using the [125I]Clq binding assay. The study population consisted of 35 children with acute lymphocytic leukemia (ALL), 22 children with acute non-lymphocytic leukemia (ALL), 24 with neuroblastoma (NB), and eight with osteosarcoma (OS). Concomitant quantitation of immunoglobulins was performed in 55 patients, revealing normal values for age. Increased levels of CIC at diagnosis were found in 9%, 22%, 42%, and 50% of children with ALL, AML, NB, and OS, respectively. Except for a higher proportion of CIC-positive patients observed in stage IV NB (nine of 17) compared to stage I-III NB (one of seven), no correlation was observed between initial CIC level and presenting clinical features, response to treatment, prognosis, or presence of infection. Longitudinal sampling of six NB and two OS patients did not reveal a clear relationship between disease activity and quantity of CIC. For the pediatric malignancies studied, these data demonstrate minimal value in quantitating CIC as a means of assessing disease activity or predicting response to treatment and are in contrast to the apparently adverse effect of elevated pretreatment CIC on response to therapy and survival observed in adults with ALL, AML, and OS.

Growth in children with acute lymphocytic leukemia: a Pediatric Oncology Group study

We have studied 127 children from 5 participating institutions as to the effect of acute lymphoblastic leukemia (ALL) or the therapy used in the treatment of ALL on growth, growth hormone concentrations, and somatomedin activity. The study (SWOG No. 7581) was initiated in December 1975 and was closed to new entry in September 1979 and to data collection in February 1981. Heights, weights, and blood samples for growth hormone and somatomedin activity were obtained at the time of initial diagnosis and at intervals during the 55 months of observation. The percentage of boys less than 4 years of age below the 50th percentile is significantly greater than the expected 50% for both initial and final height (P less than 0.01). Girls less than 4 years appeared to have significantly different percentile height distribution from the normal for their final height measurement (P less than 0.05) but not for their initial height measurement. No other significant differences in the percentile height distribution were found. When growth rate, since time of diagnosis of ALL, is compared to the expected growth of normal children of the same age by linear regression analysis, there is a difference in the slope of the lines. Children with ALL are significantly shorter. The mean initial growth hormone and somatomedin concentration, 6.2 ng/ml and 1.3 micrograms/ml, respectively, vs mean remission growth hormone and somatomedin of 2.5 ng/ml and 1.1 micrograms/ml, respectively, were different. This was significant at P less than 0.01. The slope of the computed regression lines for multiple analysis of growth hormone and somatomedin were negative for more than 60% of the patients when compared to the initial concentration. These data suggest that a significant number of the children less than 4 years of age are short prior to the onset of therapy, and this persists throughout the course of their disease. Second, there is a reduction in growth rate during intensive therapy or the first year of the disease, with a normal growth rate thereafter. Third, growth hormone and somatomedin concentrations appear to be higher at the time of onset of the disease and decrease while on therapy.

Radiotherapy (2500 rad) for testicular leukemia: local control and subsequent clinical events: a Southwest Oncology Group study

The effectiveness of radiotherapy, 2500 rad over two weeks, in treating leukemic infiltrates of the testicles was studied in 38 boys who met the requirements for tissue conformation of testicular involvement and examination of the bone marrow. The study group was heterogeneous with respect to specific histology and prior therapy. Complete regression of testicular infiltrates was confirmed by repeated biopsy examinations of 32 of 33 patients undergoing the procedure. The single treatment failure occurred in a boy with acute myelogenous leukemia. In all other patients, local disease control following radiotherapy persisted throuthout the remainder of the clinical course. Three of 5 children, however, showed evidence of reseeding of the testicle as a part of the relapse process at post-mortem examination. Statistical analysis of data from the 35 patients with acute lymphocytic leukemia showed the subsequent course of the disease with respect to next relapse, involving either bone marrow (BM) or the central nervous system (CNS), to be dependent on the acute leukemia prognostic group, as determined by age and peripheral white blood cell count (WBC) at the time of diagnosis, and timing of extramedullary disease (EMD). Patients with poor prognosis at the time of diagnosis and EMD afterward had a 3.8 times greater risk of a subsequent BM or CNS relapse than did patients with good or average prognosis and no EMD at any time (P = 0.07). Of the candidate prognostic factors examined with repect to survival, only the number of prior BM relapses was of statistical significance (P = 0.044). Children with two or more prior BM relapses had the worst prognosis for survival from testicular relapse, with a death risk of 3.6 times greater per unit of time than that of children with no or one prior BM relapse. Protective BM and CNS rescue therapy was recommended for those otherwise in complete remission (CR) at the time of testicular relapse. The median times to next relapse for patients receiving both BM and CNS recue therapy and for patients given CNS recue only were 42+ and seven weeks, respectively ( P = 0.09). The type of rescue received did not appear to affect survival time following testicular CR.