Prevention of immunization to D+ red blood cells with red blood cell exchange and intravenous Rh immune globulin.

BACKGROUND: Although young women who are D- occasionally receive unintentional transfusions with D+ red blood cells (RBCs), there are little data to assist with management of such an event. Two cases of D- girls transfused with D+ RBCs are reported. In an effort to prevent formation of anti-D, RBC exchange followed by administration of intravenous (IV) Rh immune globulin (RhIg) was used. CASE REPORTS: Patient 1, a 56-kg, 16-year-old D- girl, was involved in a motor vehicle crash. She received 4 units of Group O uncrossmatched D+ RBCs. Thirty-six hours after admission, she underwent RBC exchange with 10 units of D- RBCs, followed by a total of 2718 microg of IV RhIg over 32 hours. Six months later, her antibody screen was negative. Patient 2, a 39-kg, 10-year-old D- girl with aplastic anemia, received 1 unit of D+ RBCs. She underwent RBC exchange on the same day with 5 units of D- RBCs, followed by a total of 900 microg of IV RhIg over 8 hours. Six months later her antibody screen was negative. CONCLUSION: RBC exchange followed by a calculated dose of IV RhIg was successful in preventing allo-immunization to D. Several small studies suggest that both trauma and hematology patients may be less capable of becoming immunized with the transfusion of D+ blood components. Until these findings are more clearly defined, there will be times when prevention of immunization of any D- girl is desired. RBC exchange followed by RhIg appears to be one way to achieve this goal.

Treatment outcome and prognostic factors for infants with acute lymphoblastic leukemia treated on two consecutive trials of the Children's Cancer Group.

PURPOSE: Infants represent a very poor risk group for acute lymphoblastic leukemia (ALL). We report treatment outcome for such patients treated with intensive therapy on consecutive Children's Cancer Group (CCG) protocols. PATIENTS AND METHODS: Between 1984 and 1993, infants with newly diagnosed ALL were enrolled onto CCG-107 (n = 99) and CCG-1883 (n = 135) protocols. Postconsolidation therapy was more intensive on CCG-1883. On both studies, prophylactic treatment of the CNS included both high-dose systemic chemotherapy and intrathecal therapy, in contrast to whole-brain radiotherapy, which was used in earlier studies. RESULTS: Most patients (>95%) achieved remission with induction therapy. The most frequent event was a marrow relapse (46 patients on CCG-107 and 66 patients on CCG- 1883). Four-year event-free survival was 33% (SE = 4.7%) on CCG-107 and 39% (SE = 4.2%) on CCG- 1883. Both studies represent an improvement compared with a 22% (SE = 5.1%) event-free survival for historical controls. Four-year cumulative probabilities of any marrow relapse or an isolated CNS relapse were, respectively, 49% (SE = 5%) and 9% (SE = 3%) on CCG-107 and 50% (SE = 5%) and 3% (SE = 2%) on CCG-1883, compared with 63% (SE = 6%) and 5% (SE = 3%) for the historical controls. Independent adverse prognostic factors were age less than 3 months, WBC count of more than 50,000/microL, CD10 negativity, slow response to induction therapy, and presence of the translocation t(4;11). CONCLUSION: Outcome for infants on CCG-107 and CCG- 1883 improved, compared with historical controls. Marrow relapse remains the primary mode of failure. Isolated CNS relapse rates are low, indicating that intrathecal chemotherapy combined with very-high-dose systemic therapy provides adequate protection of the CNS. The overall unsatisfactory outcome observed for the infant ALL population warrants the future use of novel alternative therapies.

Epidemiology of osteosarcoma and Ewing's sarcoma in childhood: a study of 305 cases by the Children's Cancer Group.

BACKGROUND: The Children's Cancer Group conducted a case-control study to determine the role of a broad range of environmental and familial factors in the etiology of Ewing's sarcoma and osteosarcoma in children. These factors included radiation exposure and, for children with osteosarcoma, parental exposure to beryllium. METHODS: The parents of 152 children with osteosarcoma and 153 children with Ewing's sarcoma were interviewed by telephone. Controls were obtained by random digit dialing and were matched to cases by age and race. RESULTS: Female osteosarcoma patients had earlier onset of breast development (age 11.4 vs. 11.8 years, P=0.03) and menarche (age 12.1 vs. 12.5 years, P=0.002) but no significant differences in growth, whereas male osteosarcoma patients were similar in age at the onset of secondary sexual characteristics but reported significantly less weight gain during their growth spurt (6.6 vs. 11.7 kg, P=0.003). For children with Ewing's sarcoma, the growth spurt began earlier (age 12.1 vs. 12.7 years, P=0.12) and resulted in less weight and height gain (5.2 vs. 9.7 kg, P=0.002, and 10.2 vs. 12.7 cm, P=0.02, respectively) for males, but no differences were observed among females. For factors not related to growth and development (including a wide range of occupational, medical, and household exposures), there was little evidence of an etiologic role with respect to either tumor type. CONCLUSIONS: Differences between cases and controls with respect to growth and development showed no consistent pattern. This study did not identify any important risk factors for either type of childhood bone tumor.

Comparison of idarubicin to daunomycin in a randomized multidrug treatment of childhood acute lymphoblastic leukemia at first bone marrow relapse: a report from the Children's Cancer Group.

The outcome of children with acute lymphoblastic leukemia (ALL) and bone marrow relapse has been unsatisfactory largely because of failure to prevent subsequent leukemia relapses. Ninety-six patients were enrolled and received vincristine, prednisone, L-asparaginase, and an anthracycline as reinduction therapy. Ninety-two patients were randomized to receive either daunomycin (DNR) or idarubicin (IDR). After achievement of second complete remission (CR2), maintenance chemotherapy included the same anthracycline, IDR or DNR, high-dose cytarabine, and escalating-dose methotrexate. Compared to DNR (45 mg/m2/week x 3), IDR (12.5 mg/m2/week x 3) was associated with prolonged myelosuppression and more frequent serious infections. Halfway through the study, the dose of IDR was reduced to 10 mg/m2. Overall, second remission was achieved in 71% of patients. Reinduction rate was similar for IDR and DNR. Reasons for induction failure differed; none of 15, 1 of 5, and 5 of 7 reinduction failures were due to infection for DNR, IDR (10 mg/m2), and IDR (12.5 mg/m2), respectively. Two-year event-free survival (EFS) was better among patients who received IDR (12.5 mg/m2) (27 +/- 18%) compared to DNR (10 +/- 8%, P = 0.05) and IDR (10 mg/m2) (6 +/- 12%, P = 0.02). However, after 3 years of follow-up, late events in the high-dose IDR group result in a similar EFS to the lower-dose IDR and DNR groups. In conclusion, IDR is an effective agent in childhood ALL. When used weekly at 12.5 mg/m2 during induction, the EFS outcome during the first 2 years of treatment appears better than lower-dose IDR or DNR (45 mg/m2), although this difference was not sustained at longer periods of follow-up. Increased hematopoietic toxicity seen at this dose might be reduced through the use of supportive measures, such as hematopoietins and intestinal decontamination.

Maternal exposure to potential inhibitors of DNA topoisomerase II and infant leukemia (United States): a report from the Children's Cancer Group.

Nearly 80 percent of infant leukemias present with an abnormality involving the MLL gene at 11q23. Moreover, secondary acute myeloid leukemias (AML) that occur as the result of chemotherapy agents, which are known to inhibit DNA topoisomerase II, often manifest the same MLL abnormalities. It has been hypothesized that de novo infant leukemias may occur as a result of maternal exposure to agents in diet and medications that inhibit DNA topoisomerase II. Three epidemiologic studies of childhood leukemia with similar methodologies were conducted in the United States and Canada over the past 10 years by the Children's Cancer Group (CCG). Of the total 771 mothers of infants diagnosed at one year of age or less (< 12.5 months) who originally were interviewed (303 infant cases and 468 matched controls) across the three studies, follow-up questionnaire data on maternal exposure to potential DNA topoisomerase II inhibitors during pregnancy were available on 84 cases and 97 matched controls in the US. For maternal diet, a composite variable was created that consisted of 10 foods identified alpha priori as containing DNA topoisomerase II inhibitors. There were no significant trends with increasing maternal consumption for either the overall group, or the acute lymphoblastic leukemia (ALL) stratum. However, within the AML stratum, there was a statistically significant positive association (P trend = 0.04) with increasing consumption of DNA topoisomerase II-inhibitor containing foods (odds ratio [OR] = 9.8, 95 percent confidence interval [CI] = 1.1-84.8; OR = 10.2, CI = 1.1-96.4; for medium and high consumption, respectively). Other potential topoisomerase II inhibitors were explored; no significant findings were found. Results of this preliminary study, in combination with molecular data, should be used in future investigations of childhood leukemia (particularly, infant) to justify the incorporation of a detailed dietary history.

Recommendations for the use of routine bone marrow aspiration and lumbar punctures in the follow-up of patients with retinoblastoma.

PURPOSE: Patients with metastatic retinoblastoma have a poor outcome. Hope that early detection of extraocular spread will improve survival has led to routine monitoring with bone marrow and cerebrospinal fluid (CSF) examinations. In light of cost and patient morbidity, the clinical utility of this practice is questioned. PATIENTS AND METHODS: We have performed 254 serial bone marrow aspirations and 164 lumbar punctures in 60 children with retinoblastoma. RESULTS: Two patients with extensive intraocular disease at diagnosis developed positive bone marrow aspirations, although no patient died of distant metastasis. Three patients developed positive CSF examinations. All had neurologic symptoms at the time of CSF positivity. CONCLUSIONS: We recommend performing staging bone marrow and CSF evaluations only in patients with clinical, histologic, or radiologic evidence of local or systemic extension (Pratt stage III-IV), or in patients presenting with one Reese-Ellsworth group V eye and retrolaminar or extrascleral extension of their tumor. We recommend limiting follow-up bone marrow and CSF evaluations to patients who develop objective signs and symptoms of metastatic or regionally recurrent disease.

Parental alcohol consumption, cigarette smoking, and risk of infant leukemia: a Childrens Cancer Group study.

BACKGROUND: Whether parental drinking and smoking during pregnancy are associated with an increased risk of cancer in offspring is controversial. There are some indications that maternal alcohol consumption is associated with an elevated risk of acute myeloid leukemia (AML) appearing in very young children. Evidence for an association between maternal smoking during pregnancy and risk of leukemia in offspring has been inconsistent. PURPOSE: Using data from a Children's Cancer Group case-control study, we evaluated relationships between infant leukemia risk and parental alcohol consumption and/or cigarette smoking during pregnancy or during the month prior to it. METHODS: Three hundred two leukemia cases (203 acute lymphoid leukemias [ALLs], 88 AMLs, and 11 other leukemia types) diagnosed in children at 18 months of age or younger and 558 individually matched, regional (i.e., same telephone area code and exchange number) controls were included in the analysis. Information concerning parental alcohol consumption and smoking behavior during the index pregnancy and during the month prior to it was collected by telephone interviews with the mothers of all case and control subjects and the fathers of 250 case and 361 control subjects. Odds ratios (ORs) were used to measure the risk of infant leukemia associated with parental smoking and drinking; tests for trend were used to assess dose-response relationships. The data were analyzed further after stratifying the leukemia cases according to histologic and morphologic types. Reported P values are from two-sided tests of statistical significance. RESULTS: Maternal drinking during pregnancy (compared with not drinking) was associated with ORs of 1.43 (95%) confidence interval [CI] = 1.00-2.04) for ALL and 2.64 (95% CI = 1.36-5.06) for AML. A dose-response relationship was observed for total maternal alcohol consumption during pregnancy and risk of AML (P < .01). Alcohol-related risk appeared to be most pronounced for children who developed AML with a morphology of M1 (myeloblastic with minimal maturation) or M2 (myeloblastic with maturation (OR = 7.62; 95% CI = 2.03-28.64). Paternal alcohol consumption did not confer an increased risk of infant leukemia. Maternal smoking during pregnancy (compared with not smoking) was negatively associated with infant leukemia risk (OR = 0.66 and 95% CI = 0.46-0.94 for total leukemia; OR = 0.45 and 95% CI = 0.21-0.96 for AML), whereas paternal smoking 1 month prior to pregnancy (compared with not smoking during the same period) was related to an elevated risk of ALL (OR = 1.56; 95% CI = 1.03-2.36). CONCLUSIONS: Maternal alcohol consumption during pregnancy increases the risk of infant leukemia, especially AML. Maternal smoking, however, does not elevate risk for either AML or ALL. IMPLICATIONS: The data suggest that in utero exposure to alcohol may contribute to leukemogenesis involving myeloid cells.

Association of paternal diagnostic X-ray exposure with risk of infant leukemia. Investigators of the Childrens Cancer Group.

Whether low level radiation exposure before conception increases the risk of leukemia in offspring has been much debated. No study has specifically evaluated the effect of parental preconception diagnostic X-ray exposure in the development of leukemia among infants. Mothers of 302 infant leukemia cases (diagnosed at < or = 18 months of age) and 558 individually matched regional controls, and fathers of 250 cases and 361 controls, were independently interviewed to obtain information on X-ray exposures. Paternal preconception X-ray exposure was associated with an increased risk of infant leukemia, higher risks being linked to exposures closer to conception. X-ray related leukemia risk varied with exposure site and histopathological type, the highest risk being for acute lymphocytic leukemia related to two or more X-rays of the lower gastrointestinal (GI) tract and lower abdomen (odds ratio, 3.78; 95% confidence interval, 1.49-9.64). A positive association was observed between acute lymphocytic leukemia and number of paternal X-rays of the lower GI and lower abdomen (trend test, P < 0.01), upper GI (P = 0.04), and chest (P = 0.08). Exposures of head and neck and limbs were unrelated to risk. The risk of acute myelogenous leukemia was unrelated to paternal X-ray exposure, except for a marginally significant association (trend test, P = 0.07) for upper GI X-rays. No consistent association between maternal X-ray exposure and infant leukemia was observed. The results of this study suggest that paternal low level radiation exposure before conception is associated with an increased risk of infant leukemia, although the nature of this association needs to be further evaluated.

Visual outcomes of macular retinoblastoma after external beam radiation therapy.

PURPOSE: To determine the risk factors that influence the visual outcomes of patients with macular retinoblastoma who are treated with radiation therapy. METHODS: The medical records of all patients with macular retinoblastoma treated with radiation therapy between 1980 and 1990 were reviewed. Ten patients were entered into the study. Features analyzed included patient age, laterality of eye involvement, location and size of macular tumor(s) at the time of diagnosis, treatment course, and most recent visual acuity. FINDINGS: Ten of 11 eyes (10 patients) were successfully treated with external beam radiation. Eight patients obtained visual acuities ranging from 20/25 to 20/100; two patients had visual acuities of 20/200 or less. The best visual acuities were noted in patients whose tumor(s) did not involve the fovea and were relatively small. The worse visual acuities were noted in patients with binocular vision whose tumors invaded the fovea and were larger in size. In two of three patients in whom both eyes were retained, superimposed amblyopia developed in the eye with macular retinoblastoma. CONCLUSION: The authors' findings indicate that most patients with macular retinoblastoma who are treated with external beam radiation have favorable visual outcomes, but final visual acuity depends on the size of the tumor and involvement of the fovea. Patients in whom both eyes are retained are predisposed to further visual loss from amblyopia.

Determination of the maximum tolerated dose of idarubicin when used in a combination chemotherapy program of reinduction of childhood ALL at first marrow relapse and a preliminary assessment of toxicity compared to that of daunorubicin: a report from the Childrens Cancer Study Group.

An escalating-dose trial of idarubicin, used weekly for 3 doses in combination with vincristine, prednisone, and L-asparaginase (VPLI), to reinduce remission of childhood ALL at first bone marrow relapse was conducted by the Childrens Cancer Study Group (CCSG). The maximum tolerated dose (MTD) of idarubicin, used in the manner, was determined to be 12.5 mg/m2/dose. Twelve of 16 (75%) evaluable patients in first marrow relapse of ALL treated at a dose of 10 or 12.5 mg/m2 entered a second complete remission, compared to 41 of 69 evaluable patients (59%) treated in a comparable way with daunorubicin (30 mg/m2) (VPLD). Prolonged myelosuppression was observed in both groups, but the frequency of documented bacterial sepsis and the duration of required hospitalization were greater among patients treated with idarubicin. No additional toxicity, specifically attributable to idarubicin, was observed at these doses.

Plasma pharmacokinetics and cerebrospinal fluid concentrations of idarubicin and idarubicinol in pediatric leukemia patients: a Childrens Cancer Study Group report.

Idarubicin (4-demethoxydaunomycin) is an anthracycline analogue with striking in vitro and in vivo activity against murine leukemias. Based on activity in adults with acute lymphoblastic leukemia, the Childrens Cancer Study Group initiated studies to evaluate idarubicin in children with leukemia in second or subsequent relapses. As part of those studies, we have characterized the plasma pharmacokinetics of idarubicin and the major circulating metabolite idarubicinol in 21 patients. Idarubicin plasma elimination was described by a three-compartment open model following i.v. infusion (10-15 mg/m2) on a schedule of weekly for 3 weeks and on a schedule of daily for 3 days every 3 weeks (total dose, 30-45 mg/m2). There was substantial variability in idarubicin elimination among patients, but no indication of dose-dependent or of schedule-dependent changes in pharmacokinetic parameters. The mean terminal half-life, total body clearance, and steady state volume of distribution were 17.6 h, 679 ml/min/m2, and 562 l/m2, respectively. Idarubicinol elimination was prolonged compared to that of the parent drug with a terminal half-life of 56.8 h. This metabolite clearly accumulated in plasma during the 3 days of treatment on the schedule of daily for 3 days. Urinary recoveries (48 h) of idarubicin and idarubicinol after a single dose of idarubicin were 2.4 and 10.1%, respectively. Idarubicin was detected in 2 of 21 cerebrospinal fluid samples obtained 18-30 h after administration. In marked contrast, idarubicinol was detected in 20 of those 21 samples. Concentrations in the 20 samples varied from 0.22-1.05 ng/ml with a mean value of 0.51 ng/ml.

Renal involvement in children with lymphoma: comparison of CT with sonography.

In order to determine whether real-time sonography or contrast-enhanced CT was better for detecting renal involvement by lymphoma in children, we retrospectively studied 44 patients (6 months to 19 years of age) in whom lymphoma was diagnosed at our hospital during a 5-year period. In no patient was there any clinical evidence of renal disease at the time of presentation. In 39 patients, sonographic and CT findings were similar (normal in 36 patients and showing extrinsic mass effects on the kidneys in three patients). In five patients with non-Hodgkin lymphoma whose contrast-enhanced CT scans showed low-attenuation renal nodules, renal sonography was normal in two, showed renal enlargement in two, and showed a solitary hypoechoic nodule in one patient with multiple, bilateral nodules on CT. Tissue diagnosis of the renal lesions was not obtained, but in the four patients who had follow-up CT, the renal abnormalities resolved after chemotherapy. Our findings suggest that contrast-enhanced CT is superior to sonography for detection of renal lymphoma in children.

Sampling clinicians' activities using electronic pagers.

Pager-based activity sampling (PAS) is described as a cost-effective and unobtrusive method for sampling residents' activities in clinical settings. A sample program evaluation is presented using residents in an urban children's hospital resident-training program. The purposes of the program evaluation were: (a) to establish a behavioral baseline that would help clinical faculty understand how residents were using their time, and (b) to determine whether alterations in the way residents were assigned within the hospital resulted in desired changes to time spent. The primary rationale for changing resident-assignment policies were: (a) to decrease the time residents were spending in transit between various locations within the hospital, and (b) to increase the time spent by residents in educational activities and in direct contact with patients and their families. This PAS application demonstrates that the technique can produce statistically supportable conclusions, at minimal cost, without unduly disrupting either the residents or their patients. PAS is compared with other time-sampling methods, its limitations are discussed, and suggestions for future applications are provided.

Eight drugs in one day chemotherapy in children with brain tumors: a critical toxicity appraisal.

The toxicity of a new chemotherapeutic regimen for CNS tumors using eight anticancer agents administered in a 12-hour period was evaluated in 34 children with newly diagnosed and recurrent tumors treated at the Children's Hospital and Medical Center in Seattle. The chemotherapy included methylprednisolone, vincristine, lomustine (CCNU), procarbazine, hydroxyurea, cisplatin (CDDP), and either cyclophosphamide or imidazole carboximide (DTIC). The first five patients additionally received high-dose methotrexate (HDMTX), but because of excessive toxicity this was replaced by cytarabine. Of 125 courses administered without HDMTX, red cell transfusions were required in 15% of the courses and platelet transfusions were required in 8%. Hospitalization for empiric treatment of fever associated with neutropenia occurred in 6% of courses. Three episodes of documented sepsis occurred. Virtually all hematologic toxicity occurred in patients with recurrent disease. Renal toxicity occurred in 14% of patient courses. One patient died of renal failure and sepsis following therapy. Neurologic and hepatic complications were infrequent. High-frequency hearing loss above the voice range was common, but clinically significant hearing loss occurred in only three patients. Severe nausea and vomiting were infrequent. Overall, the toxicity of "eight in one" chemotherapy in newly diagnosed patients was minimal; toxicity was greater in patients with recurrent disease.

The incidence and epidemiologic characteristics of neuroblastoma in the United States.

The incidence of neuroblastoma in the United States is described in relation to age, sex, race, and anatomic site, as well as population-derived indicators of socioeconomic levels, degree of urbanization, and farming activity. Incidence data were obtained for the years 1973-1978 from the Surveillance, Epidemiology and End Results Program of the National Cancer Institute. Based upon 265 cases, the overall incidence of neuroblastoma was 2.26 per million person-years. Approximately 60% of the cases were diagnosed under age two years, 75% under age five years and 84% under age 10 years. The incidence among males was 1.3 times that among females, but the male predominance was observed only among persons diagnosed under age five years. Although no difference in overall incidence was observed by race, the rate among whites was 1.6 times that among blacks and 1.5 times that among other nonwhites under age five years. Approximately 50% of all cases were diagnosed with tumors arising from the adrenals or soft tissues. No clear pattern of area-to-area variation in incidence was identified. Neuroblastoma incidence was inversely related to socioeconomic level as measured by per capita income (p = 0.05), as well as the proportion of county land devoted to farming (p = 0.034). No association was observed in relation to urbanization or population density.

Eight drugs in one day chemotherapy for brain tumors: experience in 107 children and rationale for preradiation chemotherapy.

The development of a new multidrug chemotherapy regimen for primary brain tumors was based upon the cellular heterogeneity within individual tumors, the Goldie-Coldman and Price-Goldie-Hill hypotheses, and known agonistic effects of certain drug combinations and sequences. Eight drugs (vincristine [VCR], hydroxyurea, procarbazine, CCNU, cisplatin, cytosine arabinoside [Ara-C] high-dose methylprednisolone, and either cyclophosphamide or dacarbazine) were administered within 12 hours in an attempt to minimize myelosuppression. Courses were repeated at 2- to 4-week intervals. The regimen was devised to include lipid and water soluble drugs, polar and nonpolar agents, phase-specific and cell-cycle independent agents, and antineoplastics with different mechanisms of action. More than 330 courses of the regimen were administered to 107 children with brain tumors whose tumor had recurred or had been incompletely resected at diagnosis. Tumor response according to protocol-specified criteria and independent review was evaluable in 78% of the patients. After just two cycles of chemotherapy and within a 4- to 6-week interval, 50% had an objective tumor response including 15.5% who had a complete response (CR). Nephrotoxicity and high-frequency hearing losses were noted after three to five courses of therapy in approximately half of the patients. Transfusions with red cells or platelets and use of antibiotics for fever and neutropenia were required in 10% to 25% of patients. The regimen appears satisfactory for preradiation chemotherapy in newly diagnosed patients with residual tumor after surgery, but it must be compared with standard therapeutic approaches in prospective controlled trials before its relative value can be established.

Systemic responses to tourniquet release in children.

The hemodynamic and metabolic effects of deflation of pneumatic tourniquets were assessed in 15 children, seven of whom had bilateral tourniquets applied. Systemic acidosis from release of lactate and PaCO2 after tourniquet deflation did not cause adverse effects in these healthy children. Larger increases in lactate were seen with longer tourniquet inflation times (greater than 75 min) or with bilateral tourniquets. The greatest decrease in pH was seen with simultaneous deflation of bilateral tourniquets. Heart rate did not change with tourniquet deflation, whereas systolic blood pressure decreased 8-10 mm Hg with deflation. Blood pressure returned to control values within 5-10 min; no arrhythmias were seen. Recommendations to minimize the systemic metabolic effects after release of tourniquets in children under general anesthesia include the following: 1) attempt to limit tourniquet inflation times to less than 75 min; 2) use controlled ventilation prior to and after tourniquet deflation to remove the respiratory component of acidosis; 3) check blood gas tensions within 5 min of tourniquet deflation in children with long tourniquet inflation times (greater than 75 min), and where bilateral tourniquets are deflated simultaneously or within 30 min of each other.

Canine cryptorchism and subsequent testicular neoplasia: case-control study with epidemiologic update.

A retrospective study of 2,912 cryptorchid dogs identified 14 breeds with significantly high risk. Among six distinct closely interrelated breed groups (e.g., toy, miniature, and standard poodles), the risk in the smaller breed was always greater than that in the larger relative, suggesting that genetically influenced maldescent could be, in part, related to physical size or the rate of growth of the involved structures. Testicular tumors were diagnosed in 5.7% of the cryptorchid dogs; half had only Sertoli cell tumors, one-third had only seminomas. The relative risk for Sertoli cell tumor or seminoma was not directly related to a familial risk for cryptorchism. Using the health experience of a control population composed of male dogs with anal sac disease (N = 4,184), there is an estimated relative risk of 9.2 in cryptorchid dogs to develop a testis tumor (95% confidence interval, 5.9-14.3) and 4.2 in dogs with inguinal hernia (95% confidence interval, 1.8-9.5). Considering that the anatomical development of the genital tract, testis descent, and tunic relationships in dog are very similar to that in man, and that the associations of cryptorchism and inguinal hernia with testis neoplasms are also similar, the dog should be an excellent model system to further investigate the causes of human cryptorchism.