Clinical features and outcomes of 20 patients with abdominopelvic desmoplastic small round cell tumor.

INTRODUCTION: Desmoplastic small round cell tumor (DSRCT) is a rare mesenchymal malignancy. We describe our experience with treating DSRCT at a large sarcoma referral center. METHODS: A retrospective chart review was performed on DSRCT patients referred to our institution (1998-2014). Pathology specimens were reviewed to confirm the diagnosis. Clinical and imaging were extracted and summarized with descriptive statistics. Univariate analysis was performed to evaluate the association between patient, tumor, and treatment variables and overall survival (OS). RESULTS: In this study cohort of 20 patients, median age at presentation was 29 y (range 18-43) and 90% were male. Fifty-five percent presented with metastasis. Patients underwent chemotherapy (n = 20), radiation therapy (n = 3), and cytoreductive surgery (CRS) (n = 5). Median OS was 22 m (interquartile range: 12-28 m). Five-year OS rate was 20%. Extra-abdominal metastasis was associated with a higher hazard ratio (HR) of mortality (HR: 3.1, 95% C.I. 1.0-9.4, p = 0.04), while CRS improved OS (HR: 0.1, 95% C.I. 0.03-0.7, p = 0.02). CONCLUSIONS: Despite aggressive treatment, less than half of the patients were dead of DSRCT within 2 years of presentation. Although a select group of patients who underwent CRS had improved OS, novel treatments are urgently needed.

Topotecan and cyclophosphamide in adults with relapsed sarcoma.

UNLABELLED: Background. The combination of topotecan and cyclophosphamide (TC) has activity in pediatric patients with recurrent sarcoma, especially Ewing's sarcoma (EWS). We sought to determine the toxicity of and response to TC in adults with recurrent sarcoma. Patients and Methods. Adults treated with TC from 2005 to 2010 were reviewed who received T = topotecan at 0.75 mg/m(2)/day (days 1-5) and C = cyclophosphamide at 250 mg/m(2)/day (days 1-5) every 21 days. Results. Fifteen patients, median age 31 years (range 17.5-56) had nonpleomorphic rhabdomyosarcoma (RMS, n = 6), EWS, n = 5, synovial sarcoma (SS, n = 2) leiomyosarcoma (LMS, n = 1), and desmoplastic small round cell tumour (DSRCT, n = 1). Median time to progression was 2.5 months (range 1.6-13.0). Partial responses were seen in 2/6 RMS and 1/2 SS. Stable disease was seen in 2/5 EWS, 1/2 SS and 1 DSRCT. The most common reason for stopping treatment was progressive disease 12/15, (80%). Hematologic toxicity was common; 7 (47%) patients required blood product transfusion, 5 (33%) patients had fever/neutropenia. At median follow-up time of 7.7 months, all but 1 patient had died of disease. CONCLUSION: TC combination is tolerable but has only modest activity in adults with recurrent sarcoma. Other regimens deserve exploration for this high-risk group of patients.

Clinical features, treatment, and outcome in 102 adult and pediatric patients with localized high-grade synovial sarcoma.

Background. There remains controversy on the routine use of chemotherapy in localized SS. Methods. The records of 87 adult (AP) and 15 pediatric (PP) patients with localized SS diagnosed between 1986 and 2007 at 2 centres in Toronto were reviewed. Results. Median age for AP and PP was 37.6 (range 15-76) and 14 (range 0.4-18) years, respectively. 65 (64%) patients had large tumours (>5 cm). All patients underwent en bloc surgical resection resulting in 94 (92.2%) negative and 8 (7.8%) microscopically positive surgical margins. 72 (82.8%) AP and 8 (53%) PP received radiotherapy. Chemotherapy was administered to 12 (13.8%) AP and 13 (87%) PP. 10 AP and 5 PP were evaluable for response to neoadjuvant chemotherapy, with response rate of 10% and 40%, respectively. 5-year EFS and OS was 69.3 ± 4.8% and 80.3 ± 4.3%, respectively, and was similar for AP and PP, In patients with tumors >5 cm, in whom chemotherapy might be considered most appropriate, relapse occurred in 9/19 (47%) with chemotherapy, compared to 17/46 (37%) In those without. Conclusions. Patients with localized SS have a good chance of cure with surgery and RT. Evidence for a well-defined role of chemotherapy to improve survival In localized SS remains elusive.

Development of tertiary hyperparathyroidism after phosphate supplementation in oncogenic osteomalacia.

Oncogenic osteomalacia is a rare paraneoplastic syndrome. It is characterized by bone pain, muscle weakness, gait disturbance, fractures and skeletal deformities. Hypophosphatemia, diminished renal phosphate reabsorption, decreased 1,25 dihydroxy Vitamin D and elevated alkaline phosphatase are the biochemical hallmarks of this disorder. Most tumors are of mesenchymal origin. We report the case of a 39-year-old woman with oncogenic osteomalacia caused by osteosarcoma of the right scapula which was unrecognized for several years. She subsequently developed tertiary hyperparathyroidism after treatment with oral phosphate and Vitamin D. This case illustrates that oncogenic osteomalacia may persist for many years before the tumor is discovered. This is because the tumors are frequently very small and are in obscure locations. The uniqueness of this case is the coexistence of hyperparathyroidism and oncogenic osteomalacia. Five other cases have been reported up to date. All patients had received phosphate supplement, ranging from 10 to 14 years prior to their diagnosis. Interestingly, our patient was on the treatment for only 2 years. The proposed mechanism is that exogenous phosphate stimulates parathyroid activity through sequestration of calcium.

Doxorubicin-cisplatin chemotherapy for high-grade nonosteogenic sarcoma of bone. Comparison of treatment and control groups.

OBJECTIVE: To evaluate the role of chemotherapy with a combination of doxorubicin (adriamycin) and cisplatin in high-grade, nonosteogenic, non-Ewing's sarcoma (non-OSA) of bone. DESIGN: A case series comparison with a literature-derived control group. SETTING: A university-affiliated tertiary care centre. PATIENTS: Thirty patients with a diagnosis of non-OSA. Of these, 8 had low-grade disease (grade 1 or 2) and 22 had high-grade disease (grade 3). Eleven of the 22 with high-grade disease had malignant fibrous histiocytoma. Seventeen patients with nonmetastatic high-grade non-OSA were compared with a literature cohort of 37 patients who met the eligibility criteria of nonmetastatic, high-grade non-OSA treated with surgery, with or without radiotherapy. The mean follow-up was 25.2 months. INTERVENTIONS: Eight patients with low-grade tumour underwent surgery alone; 22 patients with high-grade tumour underwent surgery and 6 courses of adriamycin (75 mg/m2 every 3 weeks) and cisplatin (100 mg/m2 every 3 weeks). MAIN OUTCOME MEASURES: Disease-free survival and overall survival in those with high-grade tumours treated with or without chemotherapy. RESULTS: Of 8 patients who had low-grade tumours and underwent surgery alone, 3 had systemic relapse. Of the 22 having high-grade tumours, 4 did not receive chemotherapy because of age and comorbid conditions. Of the other 18, 13 received 3 courses of chemotherapy preoperatively and 3 courses postoperatively, 4 received all 6 courses postoperatively and 1 received all chemotherapy preoperatively to treat metastatic disease. In the 17-patient cohort used for comparison with the literature control group, disease-free survival was 57% at a mean follow-up of 25.6 months and overall survival was 57% at a mean follow-up of 30.1 months. In the control group, disease-free survival was 16% at a mean follow-up of 20.9 months and overall survival was 26% at a mean follow-up of 29.9 months. These differences are significant: p = 0.0000, chi 2 = 41.61 for disease-free survival and p = 0.0000, chi 2 = 46.49 for overall survival. CONCLUSIONS: The findings of this study support the use of adjuvant chemotherapy in patients with high-grade non-OSA, in whom malignant fibrous histiocytoma was the predominant histologic subtype.

neu/erbB-2 amplification identifies a poor-prognosis group of women with node-negative breast cancer. Toronto Breast Cancer Study Group.

PURPOSE: It remains a challenge to predict which women with axillary node-negative (ANN) breast cancer at greatest risk of relapse may benefit most from adjuvant therapy. Increases in neu/erbB-2 have been implicated in breast cancer prognosis. Although overexpression has been investigated extensively, this study represents the first prospective assessment of the prognostic value of neu/erbB-2 DNA amplification in a cohort of women with newly diagnosed ANN. METHODS: A consecutive series of women was monitored for recurrence (median follow-up duration, 36 months) and tumors from 580 individuals were analyzed for amplification. The association of amplification with risk of recurrence was examined in survival analyses with traditional and histologic markers as prognostic factors. RESULTS: Neu/erbB-2 was amplified in 20% of cases. We found an increased risk of disease recurrence when neu/erbB-2 was amplified > or = twofold that persisted with adjustment for other prognostic factors (relative risk, 2.36; P = .002). We found some evidence that amplification was more important in patients who received chemotherapy compared with untreated patients. CONCLUSION: neu/erbB-2 amplification is an independent prognostic factor for risk of recurrence in ANN breast cancer. Women with tumors without neu/erbB-2 amplification have a good prognosis; aggressive therapy in this group is therefore difficult to justify. On the other hand, even with adjuvant chemotherapeutic treatment, women whose tumors exhibit neu/erbB-2 amplification have an increased risk of recurrence. We encourage a randomized trial to compare more aggressive adjuvant chemotherapy versus standard chemotherapy for ANN women whose tumors exhibit neu/erbB-2 amplification.

Extragonadal germ cell tumors. A 14-year Toronto experience.

BACKGROUND: Extragonadal germ cell tumors (EGCT) represent only 2-5% of adult germ cell malignancies. Because they are rare and biologically distinct from testis cancer, their natural history and optimal management continue to be defined. The clinical characteristics, treatment, and outcome of 40 patients are presented here. METHODS: Patients were identified through the medical records of four University of Toronto teaching hospitals. All patients were treated in specialized oncology units between 1978 and 1993. RESULTS: Thirty-seven males and three females age 16-54 years (median, 24 years) with primary mediastinal (n = 24), retroperitoneal (n = 7), CNS (n = 7), and widespread (n = 2) EGCT were identified. Eight of nine patients (88%) with mediastinal seminoma are alive with no evidence of disease (NED) at 4-132 months (median, 45 months). After combined modality therapy, only 8 of 15 patients (53%) with mediastinal nonseminomas achieved complete remission (CR); 1 experienced relapse and died, resulting in 7 of 15 patients (47%) with NED at 45-86 months (median, 70 months). All three patients with retroperitoneal seminomas achieved CR and all have NED at 77, 103, and 120 months, respectively. Two of four patients with retroperitoneal nonseminomas have died, and the other two are alive at 36 and 54 months. Seven patients with CNS germinomas (seminoma) achieved CR after craniospinal radiation therapy, but one subsequently died after local relapse. The overall survival rate was 87% (median, 74 months). One patient with widespread choriocarcinoma died and the other achieved CR. CONCLUSIONS: Regardless of site of presentation, extragonadal seminomas have a greater than 80% 5-year disease-free survival rate. Mediastinal nonseminomas are biologically distinct, with a poorer prognosis. Treated with cisplatin-based chemotherapy followed by aggressive resection, approximately 50% of patients survive. CNS seminomas have a good prognosis. Nonseminomas of the CNS are extremely rare and were not represented in the current series. These findings concur with other reported series.

Primary non-Hodgkin's lymphoma of bone. A clinicopathologic study.

BACKGROUND: This study relates our experience in the diagnosis and treatment of a rare clinical entity, non-Hodgkin's primary lymphoma of bone. METHODS: Seventeen cases of patients with primary lymphoma of bone diagnosed and treated at a single institution between 1975 and 1992 are reviewed. Ten patients received combined-modality therapy, consisting of an anthracycline-containing combination chemotherapy (CT) regimen, followed by adjuvant radiotherapy (RT) to the primary site of disease. Five patients were treated with CT alone; one patient received RT alone; and one patient was treated with CT after emergency RT for spinal cord compression. RESULTS: Thirteen patients presented with Stage I disease, two with Stage II; and two with Stage IV disease (multiple bony sites only). Thirteen patients had an intermediate-grade diffuse large cell lymphoma; two had an intermediate-grade mixed small and large cell lymphoma; and two had a high-grade lymphoma (one immunoblastic and one small non-cleaved cell lymphoma). The overall response rate was 94% (18% complete response, 58% partial response 1, and 18% partial response 2). Thirteen patients are alive and disease-free at a median of 29 months; 10 of these received CT+RT, and 3 received CT alone. Three patients have died; one of these received CT+RT and one CT alone, and one relapsed immediately after CT. One patient, who was initially treated with RT and then with CT+RT after relapse, was lost to follow-up 40 months from the start of treatment. CONCLUSIONS: Because experience in the literature suggests a 50% distant relapse rate in primary lymphoma of bone treated with RT alone, our policy is to treat all patients with combined-modality therapy (CT+RT). However, only a Phase III randomized, controlled clinical trial will determine whether CT+RT is superior to either modality alone.

Induction chemotherapy with mitomycin, vindesine, and cisplatin for stage III unresectable non-small-cell lung cancer: results of the Toronto Phase II Trial.

PURPOSE: The 5-year survival rates with surgical resection for preoperatively identified stage IIIA N2 non-small-cell lung cancer (NSCLC) are less than 10%. A pilot study of mitomycin, vindesine, and cisplatin (MVP) induction chemotherapy was undertaken in an attempt to improve the curative potential of surgery in this group of patients. PATIENTS AND METHODS: Thirty-nine patients with mediastinoscopy stage IIIA N2 NSCLC received two cycles of MVP. Responding patients underwent thoracotomy for resection and two further courses of MVP. RESULTS: The overall response rate was 64% (25 of 39) with three complete and 22 partial responses. Twenty-two patients were resected, which included a radical mediastinal node dissection. Eighteen resections were complete and four were incomplete. Pathologically, three patients (7.7%) had no tumor remaining. Toxicity included two postoperative deaths secondary to a bronchopleural (BP) fistula, mitomycin pulmonary toxicity in two patients, and septic deaths in four patients. Twenty-eight patients have died; 20 have recurrent or progressive disease. Eight of the 18 patients completely resected have recurred, with a median time to recurrence of 20.6 months. Sites of recurrence include two locoregional, five distant (two in brain), and one in both. Median survival of all 39 patients is 18.6 months, with a 3-year survival of 26%. The median survival for those patients completely resected was 29.7 months with a 3-year survival of 40%. CONCLUSIONS: We conclude (1) that MVP is an effective but toxic chemotherapeutic regimen for limited NSCLC; (2) the median survival seems to be prolonged; and (3) the role of induction chemotherapy followed by surgery in stage IIIA N2 NSCLC requires a phase III randomized trial to compare it with other treatment modalities.

DNA content and estrogen receptors in primary carcinoma of the breast.

DNA content and estrogen-receptor status were studied in 54 consecutive patients with primary breast carcinoma. Estrogen-receptor determinations were performed by immunohistochemical assay on frozen sections with a monoclonal antibody against the estrogen-receptor molecule and by biochemical analysis with a dextran-coated charcoal method. Nuclear DNA content was measured by flow cytometry performed on formalin-fixed, paraffin-embedded sections. Seventy-two percent of tumours were positive for estrogen receptors by immunohistochemical assay and 67% by biochemical assay. Comparison of the qualitative results of immunohistochemical and biochemical estrogen-receptor determinations revealed a strong correlation between the two assays, with agreement in 90% of the cases (p less than 0.001). Regression analysis showed only a weak relationship between the quantitative results of the two assays. DNA analysis was performed in 51 cases, and 54% demonstrated aneuploid stemlines by flow cytometry. An association was demonstrated between aneuploidy and low levels of estrogen receptor. The association was highly significant with the immunohistochemical assay but not with the biochemical assay. The authors' results suggest that immunohistologic determinations of estrogen receptor status may better reflect the biologic features of the tumour cells. However, improved standardization in reporting the results is necessary if the test is to have widespread use.

p185neu is phosphorylated on tyrosine in human primary breast tumors which overexpress neu/erbB-2.

A series of primary human breast tumors was analysed by immunoblotting with anti-neu antibodies. Overproduction of the neu protein-tyrosine kinase, p185neu, was observed in 23 of 56 malignant tumor samples. 29 of these tumors were also immunoblotted with antiphosphotyrosine antibodies. A single prominent phosphotyrosine-containing protein, which co-migrated with p185neu was identified in 11 of the 29 tumors examined. There was an exact concordance between the tumors with a 185kDa phosphotyrosine-containing protein, and those with elevated p185neu. These results indicate that overexpressed p185neu in primary human breast cancer is phosphorylated on tyrosine, most likely by autophosphorylation, and by inference is enzymatically activated as a protein-tyrosine kinase. Aberrant tyrosine phosphorylation may therefore be important in the development of a substantial fraction of breast cancers.

Intraocular lymphoma: report of three cases and review of the literature.

Three cases of intraocular lymphoma are presented. One patient had only ocular involvement, one had involvement of the eye and central nervous system, and in the third patient, ocular lymphoma developed 1 year after the diagnosis of a systemic lymphoma. One patient died before treatment could be initiated, but the other two patients responded well to local radiotherapy. Only one patient who received radiation to both eyes and the whole brain, followed by systemic chemotherapy, remains alive 4 years after diagnosis. Eighty-seven cases of intraocular lymphoma reported in the literature are reviewed. Only 16.7% of cases involved the eyes alone without central nervous system or systemic disease. In more than one-half of the cases (59.7%), the eye was the primary site of involvement. Craniotomy or enucleation was required for diagnosis in 52.7% of patients, and diagnosis frequently followed a significant period of delay during which time patients were treated unsuccessfully for uveitis or iritis. Death for most patients was due to progressive central nervous system involvement. Therefore, we recommend combined modality therapy with radiation to the whole brain and both eyes, followed by systemic chemotherapy with or without intrathecal medications.

Aromatase activity in the breast and other peripheral tissues and its therapeutic regulation.

Studies using [3H]androstenedione (A) demonstrated that this substrate can be aromatized to estrone (E1) in homogenates of breast carcinoma tissue and breast adipose tissue, in breast carcinoma and breast adipose stromal cells in culture, and in cultured adipose stromal cells from sites remote from the tumor. Using cultured breast carcinoma cells, it was shown that estrogen formation was stimulated by cortisol (10(-6) M) and inhibited by endogenous 5 alpha-reduced androgens: 5 alpha-androstene-dione greater than androsterone greater than dihydrotestosterone greater than epiandrosterone greater than 3 alpha- and 3 beta- androstanediol. It was also shown that 19-nortestosterone and 19-norandrostenedione (10(-6) M) inhibited E1 formation by 80%. Progesterone (10(-6) M) had no effect on aromatase activity, while the progestational agent R5020 (10(-6) M) caused a 70% inhibition. These studies emphasize that a variety of compounds can influence aromatase activity and that drugs which are used as aromatase inhibitors in patients with breast carcinoma may have multiple sites of action.

Long-term indwelling silicone catheters: a simple, safe method for venous access.

The increasing long-term use of intravenous chemotherapy has resulted in problems of venous access for a number of reasons, one being the sclerosing action of the drugs used. Silastic catheters were introduced to ameliorate this problem, initially with some caution because of potential complications and the lack of necessary equipment. The purpose of this paper was to show that the procedure is simple, effective and associated with few complications. Ninety-six patients (32 men, 64 women) with lymphoma (25), leukemia (28), metastatic breast cancer (28) or other malignant lesions (15) were referred for insertion of a Silastic permanent indwelling catheter into the superior vena cava. The catheter was inserted through a subclavian vein using a Cordis Vein Dilator Kit, itself introduced over a guide wire inserted initially under fluoroscopic control. Local sepsis at the insertion site occurred in 6 of the first 43 patients treated but in none of the remainder. Six catheters became thrombosed and required revision. There were no instances of bleeding, air embolism or pulmonary complications. Patient acceptance of this method of venous access was high compared with that for peripheral, repeated venepuncture.

Hepatic arterial infusion of mitoxantrone in the treatment of primary hepatocellular carcinoma.

Twenty-three patients (16 male, seven female) with hepatocellular carcinoma (HCC) were treated by hepatic arterial infusion (HAI) of mitoxantrone every 4 weeks. At each treatment, a catheter was inserted percutaneously into the main hepatic artery via the femoral artery under image intensification. Treatment consisted of a 24-hour continuous HAI of mitoxantrone, 6 mg/m2/d X 3 (eight patients) or 10 mg/m2/d X 3 (14 patients) without heparin. Eight patients had only one infusion, nine patients four infusions, five patients three infusions, two patients two infusions, and one patient five infusions. A partial response was seen in six patients, with a median duration of 20 weeks (range, 18 to 38 weeks). Five patients achieved stable disease, with a median duration of 20 weeks (range, 11 to 42 weeks). The median survival of the overall group was 22 weeks. Survivals of responding, stable, and nonresponding patients were 32 weeks, 24 weeks, and 9 weeks, respectively. Complications of catheter placement included asymptomatic dissection of the hepatic artery (one patient), and asymptomatic thrombosis of the hepatic artery (five patients). Three patients experienced mild nausea and vomiting, and six patients had mild to moderate alopecia. Granulocytopenia was frequent at both dose schedules. The granulocyte nadir was greater than 1,000/microL in 34% of evaluable courses, 500 to 1,000/microL in 32%, and less than 500/microL in 34% of courses. Two patients developed neutropenia-associated fever. A platelet nadir below 100,000/microL was seen after only 10% of courses, and only two patients had platelets below 50,000/microL. Seven patients received doxorubicin after progression on mitoxantrone. Four received systemic doxorubicin, 50 mg/m2, and three HAI of doxorubicin, 25 mg/m2, for three days. Two patients achieved partial response (18 weeks and 32 weeks) to HAI doxorubicin. Mitoxantrone has activity in HCC and is well tolerated when administered by HAI. It is not entirely cross-resistant with doxorubicin.

The relationship between growth and androstenedione metabolism in four cell lines of human breast carcinoma cells in culture.

The conversion of androstenedione (A) to estrogens, testosterone (T) and 5 alpha-reduced metabolites was studied in different phases of cell growth in 4 lines of cultured human breast carcinoma cells. Aromatase activity was 10-fold greater in MD and DM than in MCF7 cells and was undetectable in ZR75 cells. Estrogen formation in MD and DM lines increased during the phase of exponential growth and decreased to 20% of maximum during confluence. 5 alpha-Reductase activity was determined by the formation of 5 alpha-androstane-3,17-dione (5 alpha-A-dione) and androsterone (AND), and was 5-fold greater in ZR75 cells than MD cells and 2-fold greater than in MCF7 cells. This activity was relatively constant during exponential growth and decreased during confluence. T accumulation was inversely related to 5 alpha-reductase activity. The MCF7 and ZR75 cells which contain estrogen receptors had the highest levels of 5 alpha-reductase activity while the MD line which lacks estrogen receptors had the lowest 5 alpha-reductase activity. The assessment of aromatase and 5 alpha-reductase activity in addition to estrogen and progesterone receptors may be helpful in predicting hormone sensitivity in human breast tumours.

Multi-imaging demonstration of distant metastases from ovarian carcinoma.

An unusual case of ovarian carcinoma is presented with extra-abdominal soft tissue metastasis. These demonstrate calcification on plain films and CT, as well as avid uptake of Tc-99m MDP.

The intracellular control of aromatase activity by 5 alpha-reduced androgens in human breast carcinoma cells in culture.

Four cell lines, each derived from a primary tumor from a patient with breast carcinoma, were grown to confluence in alpha-Minimum Essential Medium with 15% fetal calf serum and incubated for 24 h with [3H]androstenedione. The two lines (SA and PP) with the lowest formation of estrone and estradiol (less than 0.1% conversion) were the most active in the formation of the 5 alpha-reduced androgen metabolites androsterone (AND), 5 alpha-androstanedione (5 alpha-A-dione), and dihydrotestosterone (DHT). The two lines with the highest aromatase activity (DM and MD) had the lowest formation of 5 alpha-reduced metabolites. To determine if the 5 alpha-reduced androgen metabolites formed within the breast carcinoma cells could influence aromatase activity, the MD line was further studied. After 24-h preincubation with AND, DHT, or 5 alpha-A-dione at concentrations of 10(-6), 10(-7), and 10(-8) M, [3H]androstenedione was added to the culture medium, and aliquots were removed at 0, 4, 8, and 24 h. An 8-h incubation period was found to be optimum for inhibition studies. In comparison to control levels of estrone (2.5%) and estradiol (0.35%) formation, inhibition of aromatization was evident with all three compounds at 10(-8) M, with 5 alpha-A-dione producing the greatest inhibition (50%). At 10(-7) M, inhibition ranged from 45% (AND) to 70% (5 alpha-A-dione), and at 10(-6) M, inhibition was greater than 90% for each compound. 5 alpha-A-dione produced slightly greater inhibition than AND or DHT at each concentration tested. Since each of these compounds was capable of inhibiting aromatization, the cumulative effect of these 5 alpha-reduced metabolites could be an important factor in the intracellular regulation of aromatase activity.