The impact of chemotherapy on male fertility: a survey of the biologic basis and clinical aspects

Reproductive Toxicology 15 (2001) 611– 617

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Review

The impact of chemotherapy on male fertility: a survey of the biologic basis and clinical aspects Mark Schrader*, Markus Mu¨ller, Bernd Straub, Kurt Miller Department of Urology, University Hospital Benjamin Franklin, Free University of Berlin, Hindenburgdamm 30, 12200 Berlin, Germany

Abstract The introduction of cisplatin-based polychemotherapy has led to cure rates of up to 90% for the most frequent malignant diseases seen in young men. In view of these high cure rates, increasing clinical importance is now being attached to chemotherapy-induced fertility disorders. Comparative studies examining the impact of cytotoxic chemotherapy on gametogenesis demonstrate significant cytostatic- and dose-specific differences. The extensive literature on possible teratogenic effects of chemotherapy provides no evidence suggesting that offspring of patients with a history of chemotherapy have an increased risk of malformations. However, these studies, the scope and follow-up of which may still be inadequate, have failed to eliminate the fear of such risk. Hormonal protection from chemotherapy-induced testicular damage has thus far succeeded only in animal models pretreated by application of gonadotropin-releasing hormone agonists combined with nonsteroidal antiandrogens or testosterone plus 17␤-estradiol. The same holds true for hormone therapy aimed at stimulating the recovery of spermatogenesis after chemotherapy-induced testicular damage. Cryopreservation of germ cells can be suggested to patients undergoing cytostatic therapy. In some cases, testicular extraction of spermatozoa can also be offered as a novel approach. © 2001 Elsevier Science Inc. All rights reserved. Keywords: Fertility; Chemotherapy; Spermatogenesis; Azoospermia

1. Introduction Cytotoxic chemotherapy for malignant disease has markedly improved the chances of long-term remission or cure in young patients who have not yet started a family. Thus chemotherapy-induced impairment of fertility has gained increasing clinical importance. In the United States, testicular cancer, Hodgkin’s diseases, lymphoma, and leukemia are diagnosed each year in 9,100 males aged 15 to 35 [1]. Approximately 1,400 of these patients are subjected to polychemotherapy and irradiation at doses sufficient to induce prolonged azoospermia. Moreover, cancer is diagnosed and managed by chemotherapy in 4,000 children under the age of 15 each year in the United States [2]. The cure rate of these malignancies is approaching 90% with an upward tendency, and most of these patients receive polychemotherapy and/or irradiation, leading to a rapidly increasing incidence of post-therapy reproductive dysfunction. The aim of this review is to survey the biologic basis and clinical aspects of chemotherapy and * Corresponding author. Tel.: ⫹1-030-8445-2577; fax: ⫹1-030-84454448. E-mail address: [email protected] (M. Schrader).

fertility. Reference is made to publications selected among those we consider most important based on their level of evidence.

2. Parameters for assessing chemotherapy-induced fertility impairment Chemotherapy-induced fertility impairment is difficult to assess. Most studies have evaluated fertility impairment on the basis of laboratory tests, i.e. follicle-stimulating hormone (FSH) [3], luteinizing hormone (LH), and serum testosterone levels [4], sperm-cell concentration and morphology in the ejaculate, or histopathology on testicular biopsy [5–10]. Although sperm concentration and total sperm count correlate with time to pregnancy [11] and are used as the main parameters for postoperative fertility evaluation in most studies, these sperm parameters may only partially describe the impact of chemotherapy on fertility [12]. Trasler et al. have demonstrated in an animal model, for example, that current tests of male reproductive function cannot predict deleterious effects of a paternally administered agent on the offspring [13].

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M. Schrader et al. / Reproductive Toxicology 15 (2001) 611– 617

Table 1 Testicular function before the onset of treatment in patients with testicular germ cell cancer (TGCT) or lymphoma (L) Author

No. of patients with TGCT/L

No. of patients with azoospermia

Total sperm count (106/mL) median (range)

Petersen et al., 1998 [15] Schrader et al.

29 TGCT 9 TGCT 7L 15 TGCT 17 TGCT 33 L 23 L

7/29 3/9 4/7 6/15 4/17 5/33 0/23

41 (0–433) 17 (0–175) 22 (0–229) 20.4 (0–465) 24 (0–68) (?) (?)

Caroll et al., 1987 [59] Nijman et al., 1987 [60] Tal et al., 2000 [16] Pryzant et al., 1993 [61]

3. Does infertility in cancer patients originate from the treatment, the tumor, or the testis? In 1989, Schilsky questioned whether infertility in testicular cancer patients was due to testicular dysfunction or to the influence of the tumor or the treatment [14]. Important alterations of spermatogenesis can be detected prior to treatment in the majority of young patients with testicular germ cell tumors [15] or lymphoma [16 –18] and are thus unrelated to cytotoxic chemotherapy (Table 1). These abnormalities are reversible in some cases with successful antineoplastic treatment. The changes are hard to predict and thus make it difficult to assess the impact of cytotoxic chemotherapy on fertility. The mechanisms underlying the preexisting impairment of gametogenesis, which is strongest in tumor patients with testicular germ cell tumors [19], are still poorly understood [20]. Possible causes include disorders of urogenital development and/or primary endocrine dysfunction and the presence of contralateral testicular pathology (atrophy or unclassified intratubular germ cell neoplasia) [21]. Possible tumor-related factors include response to ␤-human chorionic gonadotropin, tumor-mediated cytokine production, antisperm autoantibodies, and emotional stress [22,23]. Evidence of a carcinoma-induced alteration in gametogenesis comes from studies demonstrating that the isolated removal or successful treatment of germ cell cancer is associated with an improvement of spermatogenesis [5,16, 24]. When certain cumulative chemotherapeutic doses are exceeded, however, gametogenesis disorders correlate with therapy irrespective of its success [9,25–30]. Infertility is thus clearly due to therapy, at least when the respective threshold doses are exceeded (Table 2).

4. Cytotoxic treatment and gametogenesis The majority of patients develop azoospermia about 8 to 12 weeks after the initiation of cytostatic chemotherapy. This timing is in keeping with the kinetics of human spermatogenesis, because most cytostatics target only cells out-

side the G0 phase and thus destroy mainly the rapidly proliferating type B spermatogonia. Type A dark spermatogonia, which show no proliferative activity under normal conditions, and type A pale spermatogonia, which divide at 16-day intervals [31], are less responsive to cytostatics than the rapidly destroyed type B spermatogonia because these other cells have little or no mitotic activity. If threshold cumulative cytostatic doses are not surpassed, type A spermatogonia survive polychemotherapy and form the basis for the recovery of spermatogenesis. At low cytostatic doses, recovery of spermatogenesis may be expected around 12 weeks after polychemotherapy [9]. The destruction of type A spermatogonia at higher doses leads to a sustained or irreversible loss of sperm cell production. The severity and duration of cytotoxic-agent-induced long-term impairment of spermatogenesis are reflected by the number of type A spermatogonia destroyed [7]. The number of type A spermatogonia detectable in testicular biopsy specimens after therapy is thus highly predictive of the long-term recovery of spermatogenesis following chemotherapy. Aass et al. found that it took up to three years for the majority of patients to reach pretreatment fertility parameters [5]. Petersen showed that, in individual cases, it took patients with testicular germ cell tumors as long as nine years to achieve recovery after therapy [15].

Table 2 Doses of cytotoxic agents causing prolonged azoospermia in 50% of patientsa Agent

Dose

Cyclophosphamide Procarbazine Chlorambucil Lomustineb Cisplatin Carmustineb

7.5 4.0 1.4 1.0 0.6 0.5

a

g/m2 g/m2 g/m2 g/m2 g/m2 g/m2

Based on the data of Meistrich et al. [51]. Based on the treatment of prepubertal males; doses of other agents are based on the treatment of adult men. b

M. Schrader et al. / Reproductive Toxicology 15 (2001) 611– 617

613

Table 3 Testicular function after chemotherapy Reference

No. of patients

Treatment

Cumulative dose of cisplatin (mg/ m2, median (range))

Observation period (mo)

No. with Azoospermia

No. with FSH ⬎ reference value

No. with LH ⬎ reference value

No. with testosterone ⬍ reference value

Hansen et al., 1990 [62]

28

6 ⫻ PVB

487 (346–614)

18/28

22/28

18/28

7/28

Petersen et al., 1996 [29] Palmieri et al., 1996 [63] Bokemeyer et al., 1996 [64] Meistrich et al., 1997 [33] Brennemann et al., 1997 [41]

21 30 28 10 72

3 ⫻ PEB 4 ⫻ PEB 4 ⫻ PE(V)B 6 ⫻ PE(V)B PVB, PEB, PEBV, PE NOVP

618 (486–197) 400 (307–450) (?) (?) 360–1050

15–28 (some cases ⬎54) 31–103 61–103 37–49 31–42 15–159

8/17 5/27 6/28 3/10 (?)

20/21 22/30 11/28 3/10 40/63

9/21 8/30 4/28 6/10 21/63

2/21 1/30 3/28 2/10 6/63

–

–

(?)

(?)

(?)

(?)

12

(?)

65/73

24/73

5/73

⬎96

(?)

18/28

11/28

1/28

22

ⱖ 2 ⫻ PEB, PEBI, CEB, CVBIE Carbo

(?)

12–48

0/22

14/22

(?)

(?)

22

6 ⫻ PVB

(?)

⬎120

4/22

19/22

8/22

1/22

10

ABVD

–

12–93

(?)

2/10

1/10

0/10

9 17

MOPP-ABV MOPP/ABV, COMP, MOPP

– –

⬎120

(?) 8/20

Reiter et al., 1998 [65] Petersen et al., 1999 [66] Tal et al., 2000 [16] Arush et al., 2000 [25]

58 73 28

0/58

8/9 10/20

7/9 (?)

1/10 (?)

A ⫽ adriamycin; B ⫽ bleomycin; Carbo ⫽ carboplatin; D ⫽ dacarbazine; E ⫽ etoposide; I ⫽ ifosfamide; E ⫽ etoposide; P ⫽ cisplatin; V ⫽ Vinblastine; ABVD ⫽ doxorubicin, bleomycin, vinblastine, dacarbazine; MOPP ⫽ mechloretamine, vincristine, procarbazine, prednisone; NOVP ⫽ mitoxantrone, vincristine, vinblastine, prednisone.

5. Cytostatic- and dose-specific impact on gonadal function Comparative studies examining the impact of cytotoxic chemotherapy on gametogenesis have demonstrated significant cytostatic- and dose-specific differences [5,9,16,29, 32– 40]. These studies mainly compared testicular cancer patients who achieved complete remission after cytotoxic chemotherapy with those who were treated by surgery alone or enrolled in a surveillance program. This study design inevitably led to a slight distortion of the results, since tumor stages were not matched in these patients. Thus tumor patients in advanced and less advanced stages were compared without considering cytostatic therapy as an impact factor [5,9,29,32,40].

6. Acute toxicity Studies on acute toxicity have shown that immediate gonadal dysfunction is induced by cisplatin-based chemotherapy (e.g. PEB ⫽ cisplatin, etoposide, bleomycin; PEI ⫽ cisplatin, etoposide, ifosphamide) in testicular germ cell tumor patients as well as by polychemotherapy with nonalkylating compunds such as mitoxantrone, vincristine, vinblastine, prednisone (NOVP) [33], busulfan [34], adriamy-

cin, bleomycin, vinblastine, and dacarbazine (ABVD), or with alkylating treatments such as mechloretamine, vincristine, procarbazine, and prednisone (MOPP) [16] in patients with hematologic malignancies. Azoospermia does not develop immediately after the initiation of chemotherapy but only after about 8 to 12 weeks. The decreased sperm concentration is accompanied by increased serum levels of follicle-stimulating hormone (FSH) in most patients [8,29, 33,35]. Patients with germ cell tumors had the highest mean FSH concentration of 24.4 ⫾ 0.34 standard deviation (range 1.3 to 66.8) about 6 months after chemotherapy [41].

7. Long-term toxicity Numerous studies on the long-term effects of chemotherapy have disclosed reduced fertility parameters after polychemotherapy in the majority of cases (Table 3). However, matched-pair analyses of germ cell tumor patients treated with and without cytotoxic chemotherapy reveal that significant differences in serum levels of FSH and LH as well as in the percentage of patients with azoospermia are only detectable above a cumulative cisplatin dose of 400 mg/m2, corresponding to more than 4 cycles of PEB (cisplatin, etoposide, and bleomycin) [9]. On the other hand, some studies have found no significant differences in these pa-

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rameters more than 2 years after chemotherapy in patients who received a cumulative cisplatin dose less than 400 mg/m2 [5,32]. However, permanent azoospermia may be expected in more than 50% of the patients at cumulative cisplatin doses above 600 mg/m2 [9,29]. In a follow-up extending more than 8 years after chemotherapy, some patients achieved a recovery of spermatogenesis even after a dose exceeding 600 mg/m2, which indicates that the time to recovery is dose-dependent and difficult to predict [40]. Replacing cisplatin by carboplatin in the treatment of patients with germ cell tumors reduced gonadal toxicity. However, the therapeutic effect of carboplatin seems to be inferior to that of cisplatin-based polychemotherapy when compared at equitoxic dose levels [35,36]. A comparison of the long-term consequences of polychemotherapy with nonalkylating (e.g. ABVD and NOVP) and alkylating regimens (e.g. MOPP-ABV) in managing Hodgkin‘s disease and non-Hodgkin‘s lymphoma reveals that treatment regimens without alkylating agents are markedly superior with respect to germinal toxicity. In a review of the literature, Marmor et al. reported that MOPP caused azoospermia in 300 of 373 patients [37]. This high degree of testicular toxicity was attributed to alkylating agents such as mechloretamine and procarbazine. Similar results were reported by Viviani et al., who detected azoospermia in 97% of patients after MOPP versus 54% after ABVD [39]. In a comparative study on MOPP-ABV versus ABVD, Tal et al. found azoospermia in 89% of the MOPP-ABV group as opposed to none of the ABVD group more than 1 year after therapy [16]. Azoospermia can be expected in more than 50% of the patients at a procarbazine dose of more than 6 g/m2 [38,39]. However, nearly all reports suggest that the impact of chemotherapy on the specific fertility parameters of individual patients is extremely difficult to predict [42].

8. Fertility Most of the studies mentioned have focussed on the issue of semen quality and FSH serum levels, whereas data on fertility after chemotherapy are sparse. It is difficult to determine the contribution of chemotherapy to infertility in these patients. For one thing, the prevalence of infertility in the age-matched normal population is unclear. Moreover, female fertility factors are not considered, and the influence of cancer itself on the risk of infertility is difficult to estimate. Another problem is that only about one third of the patients seek paternity after treatment [42,43]. The mean rate of couples who remain infertile after chemotherapy ranges between 15 and 30% in the literature [15,30,44 – 47]. Petersen et al. have demonstrated that the cumulative cisplatin dose is of decisive importance in this connection. Paternity after chemotherapy was reported by 5 of 33 men in the group that had received less than 600 mg/m2 and by none of the 21 men treated with higher doses.

It is unclear, however, whether all these couples were actively trying to conceive [29].

9. Drug strategies to protect/stimulate spermatogenesis in men with chemotherapy Hormonal protection from chemotherapy-induced testicular damage by pretreatment with gonadotropin-releasing hormone (GnRH) agonists combined with nonsteroidal antiandrogens [48] or with testosterone plus 17␤-estradiol has thus far only succeeded in animal models [49]. The protective mechanism for spermatogenesis is not entirely clear, since previous assumptions are contradicted by the finding that no changes occur in spermatogonial numbers or suppression of their proliferation [50]. Another approach to stimulating the recovery of spermatogenesis in animals is hormonal treatment with GnRH agonists or continuous testosterone administration after cytotoxic treatment [51]. This strategy was based on the observation that prolonged azoospermia often occurs because the stem spermatogonia survive the toxic insult without being able to differentiate and produce sperm. In the rat, the block appears to be at the differentiation of A spermatogonia. Hormone treatments with testosterone or GnRH agonists, which suppress intratesticular testosterone levels, eliminate this block and enable cells to differentiate [51]. However, clinical studies have not yet been performed in azoospermic men after cytotoxic therapy.

10. Malformations in offspring of patients with a history of chemotherapy The numerous studies that have thus far examined possible teratogenetic effects of chemotherapy provide no evidence for an increased risk of malformations in offspring of patients with a history of chemotherapy [52–56]. Nevertheless, these studies, the scope and follow-up of which may still be inadequate, have not been able to eliminate the fear of an increased risk of malformations among children of chemotherapy patients [54]. Particularly alarming in this connection are the investigations of Trasler et al., who demonstrated in a rat model that paternal cyclophosphamide treatment causes fetal loss and malformations without affecting male fertility [13]. The studies of Sega et al. have shown that paternally mediated effects are due to alkylation of protamines rather than to mutation. DNA damage is believed to result indirectly from chemical binding to sulfhydryl groups in protamine, preventing normal chromatin condensation within the sperm nucleus, thereby destabilizing sperm chromatin structure and causing broken chromosomes and mutations [57, 58].

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11. Options of preserving the ability to father a pregnancy The only effective measure for preserving procreative ability is cryopreservation of sperm prior to chemotherapy. Since subsequent intracytoplasmic sperm injection therapy requires only a minimal number of sperm cells, cryopreservation is advisable regardless of the quality of the ejaculate, and can be offered to the patient irrespective of the planned therapy, since the clinical course and response to chemotherapy cannot be predicted in individual cases. Another option is testicular sperm extraction in patients undergoing contralateral biopsy for germ cell tumors or nongonadal malignancies in the presence of azoospermia. We performed this procedure successfully before chemotherapy in 2 of 4 patients with non-Hodgkin’s lymphoma and 1 of 3 testicular germ cell tumor patients with azoospermia.

12. Conclusion It is difficult to individually predict the influence of chemotherapy on testicular function in cancer patients. Critical parameters that significantly increase the risk of posttherapeutic azoospermia are cumulative doses of cisplatin greater than 0.6 mg/m2, cyclophosphamide above 6 g/m2 and procarbazine above 4.0 mg/m2. The individual fertility status of patients after chemotherapy is hard to predict due to marked interindividual variance of pretreatment fertility parameters, cytostatic-related impairment of testicular function, and the influence of the malignant disease itself. The spermatogenesis recovery interval ranging up to 9 years or more causes couples seeking parenthood strong psychologic stress and reduces their quality of life. Current data are not adequate to completely eliminate the fear of an increased rate of congenital abnormalities among offspring of patients with a history of cytotoxic therapy, based on limitations of human studies and on experimental animal research findings. Protection of spermatogenesis during chemotherapy by substances such as GnRH analogues has thus far only succeeded in individual animal experiments and has shown no protective effect in clinical trials. The question of whether gametogenesis will recover after polychemotherapy in cases of azoospermia can be partially estimated, as described above, by analyzing the chemotherapeutic agents applied and their cumulative doses. A testicular biopsy can be helpful in individual patients with azoospermia. Recovery of spermatogenesis after 9 years has been described in cases where spermatogonia were detectable by testicular biopsy. The detection of a Sertoli-cellonly syndrome can be taken as proof of permanent infertility and provides important information for planning donor insemination or adoption.

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References [1] Ries LA HB, Edwards BK. Cancaer Statistics Review, 1973–1987; Bethesda, MD: U.S. Department of Health and Human Services, 1991. [2] Bleyer WA. The impact of childhood cancer on the United States and the world. CA Cancer J Clin 1990;40:355– 67. [3] van Montfrans JM, Hoek A, van Hooff MH, de Koning CH, Tonch N, Lambalk CB. Predictive value of basal follicle-stimulating hormone concentrations in a general subfertility population. Fertil Steril 2000; 74:97–103. [4] Barth V, Schonfelder M. Dependence of serum hormones (T, FSH, LH) on morphometric testicular findings after chemo-, and radiotherapy in patients with malignant testicular tumors. Zentralbl Allg Pathol 1990;136:439 – 42. [5] Aass N, Fossa SD, Theodorsen L, Norman N. Prediction of long-term gonadal toxicity after standard treatment for testicular cancer. Eur J Cancer 1991;27:1087–91. [6] Canellos GP, Anderson JR, Propert KJ, Nissen N, Cooper MR, Henderson ES, et al. Chemotherapy of advanced Hodgkin’s disease with MOPP, ABVD, or MOPP alternating with ABVD. N Engl J Med 1992;327:1478 – 84. [7] Meistrich ML. Relationship between spermatogonial stem cell survival and testis function after cytotoxic therapy. Br J Cancer Suppl 1986;7:89 –101. [8] Meistrich ML, Chawla SP, Da Cunha MF, Johnson SL, Plager C, Papadopoulos NE, et al. Recovery of sperm production after chemotherapy for osteosarcoma. Cancer 1989;63:2115–23. [9] Pont J, Albrecht W. Fertility after chemotherapy for testicular germ cell cancer. Fertil Steril 1997;68:1–5. [10] Kader HA, Rostom AY. Follicle stimulating hormone levels as a predictor of recovery of spermatogenesis following cancer therapy. Clin Oncol (R Coll Radiol) 1991;3:37– 40. [11] Bonde JP, Ernst E, Jensen TK, Hjollund NH, Kolstad H, Henriksen TB, et al. Relation between semen quality and fertility: a populationbased study of 430 first-pregnancy planners. Lancet 1998;352: 1172–7. [12] Liu DY, Baker HW. Tests of human sperm function and fertilization in vitro. Fertil Steril 1992;58:465– 83. [13] Trasler JM, Hales BF, Robaire B. Paternal cyclophosphamide treatment of rats causes fetal loss and malformations without affecting male fertility. Nature 1985;316:144 – 6. [14] Schilsky RL. Infertility in patients with testicular cancer: testis, tumor, or treatment? [editorial]. J Natl Cancer Inst 1989;81:1204 –5. [15] Petersen PM, Giwercman A, Skakkebaek NE, Rorth M. Gonadal function in men with testicular cancer. Semin Oncol 1998;25:224 –33. [16] Tal R, Botchan A, Hauser R, Yogev L, Paz G, Yavetz H. Follow-up of sperm concentration and motility in patients with lymphoma. Hum Reprod 2000;15:1985– 8. [17] Naccache P, Decaudin D, Koscielny S, Bendahmane B, Auger J, Munck JN. Semen preservation, and gonadal toxicity in the treatment of non Hodgkin lymphoma. Experience at the Gustave-Roussy Institute from 1980 to 1993. Bull Cancer 1996:83:307–14. [18] Viviani S, Ragni G, Santoro A, Perotti L, Caccamo E, Negretti E, et al. Testicular dysfunction in Hodgkin’s disease before and after treatment. Eur J Cancer 1991;27:1389 –92. [19] Barth V, Schonfelder M. Fertility studies in malignancy (tumors of the testicle, malignant melanomas, cancer of the thyroid gland). Andrologia 1988;20:75– 82. [20] Morrish DW, Venner PM, Siy O, Barron G, Bhardwaj D, Outhet D. Mechanisms of endocrine dysfunction in patients with testicular cancer. J Natl Cancer Inst 1990;82:412– 8. [21] Skakkebaek NE, Berthelsen JG, von der Maase H, Rorth M, Osterlind A. Prevention of bilateral testicular cancer: significance of detection and treatment of carcinoma in situ. Prog Clin Biol Res 1989;303: 779 – 89.

616

M. Schrader et al. / Reproductive Toxicology 15 (2001) 611– 617

[22] Guazzieri S, Lembo A, Ferro G, Artibani W, Merlo F, Zanchetta R, et al. Sperm antibodies and infertility in patients with testicular cancer. Urology 1985;26:139 – 42. [23] Guo H, Calkins JH, Sigel MM, Lin T. Interleukin-2 (IL-2) is a potent inhibitor of Leydig cell steroidogenesis. Endocrinology 1990;127: 1234 –9. [24] Fossa SD. Influence of lymph node dissection and/or chemotherapy on fertility in patients with testicular cancer. Prog Clin Biol Res 1985;203:687–701. [25] Ben Arush MW, Solt I, Lightman A, Linn S, Kuten A. Male gonadal function in survivors of childhood Hodgkin and non-Hodgkin lymphoma. Pediatr Hematol Oncol 2000;17:239 – 45. [26] DeSantis M, Albrecht W, Holtl W, Pont J. Impact of cytotoxic treatment on long-term fertility in patients with germ-cell cancer. Int J Cancer 1999;83:864 –5. [27] Gerres L, Bramswig JH, Schlegel W, Jurgens H, Schellong G. The effects of etoposide on testicular function in boys treated for Hodgkin’s disease. Cancer 1998;83:2217–22. [28] Stephenson WT, Poirier SM, Rubin L, Einhorn LH. Evaluation of reproductive capacity in germ cell tumor patients following treatment with cisplatin, etoposide, and bleomycin. J Clin Oncol 1995;13: 2278 – 80. [29] Petersen PM, Hansen SW, Giwercman A, Rorth M, Skakkebaek NE. Dose-dependent impairment of testicular function in patients treated with cisplatin-based chemotherapy for germ cell cancer. Ann Oncol 1994;5:355– 8. [30] Bokemeyer C, Schmoll HJ, van Rhee J, Kuczyk M, Schuppert F, Poliwoda H. Long-term gonadal toxicity after therapy for Hodgkin’s and non- Hodgkin’s lymphoma. Ann Hematol 1994;68:105–10. [31] Clermont Y. Kinetics of spermatogenesis in mammals: seminiferous epithelium cycle and spermatogonial renewal. Physiol Rev 1972;52: 198 –236. [32] Pont J, Albrecht W, Postner G, Sellner F, Angel K, Holtl W. Adjuvant chemotherapy for high-risk clinical stage I nonseminomatous testicular germ cell cancer: long-term results of a prospective trial. J Clin Oncol 1996;14:441– 8. [33] Meistrich ML, Wilson G, Mathur K, Fuller LM, Rodriguez MA, McLaughlin P, et al. Rapid recovery of spermatogenesis after mitoxantrone, vincristine, vinblastine, and prednisone chemotherapy for Hodgkin’s disease. J Clin Oncol 1997;15:3488 –95. [34] Jiang FX. Behaviour of spermatogonia following recovery from busulfan treatment in the rat. Anat Embryol (Berl) 1998;198:53– 61. [35] Lampe H, Horwich A, Norman A, Nicholls J, Dearnaley DP. Fertility after chemotherapy for testicular germ cell cancers. J Clin Oncol 1997;15:239 – 45. [36] Bajorin DF, Sarosdy MF, Pfister DG, Mazumdar M, Motzer RJ, Scher HI, et al. Randomized trial of etoposide and cisplatin versus etoposide and carboplatin in patients with good-risk germ cell tumors: a multiinstitutional study [see comments]. J Clin Oncol 1993;11:598 – 606. [37] Marmor D, Duyck F. Male reproductive potential after MOPP therapy for Hodgkin’s disease: a long-term survey. Andrologia 1995;27: 99 –106. [38] Sherins RJ, DeVita VT. Effect of drug treatment for lymphoma on male reproductive capacity. Studies of men in remission after therapy. Ann Intern Med 1973;79:216 –20. [39] Viviani S, Santoro A, Ragni G, Bonfante V, Bestetti O, Bonadonna G. Gonadal toxicity after combination chemotherapy for Hodgkin’s disease. Comparative results of MOPP vs ABVD. Eur J Cancer Clin Oncol 1985;21:601–5. [40] Petersen PM, Skakkebaek NE, Giwercman A. Gonadal function in men with testicular cancer: biological and clinical aspects. Apmis 1998;106:24 –34; discussion 34 –26. [41] Brennemann W, Stoffel-Wagner B, Helmers A, Mezger J, Jager N, Klingmuller D. Gonadal function of patients treated with cisplatin based chemotherapy for germ cell cancer. J Urol 1997;158:844 –50.

[42] Fossa SD, Aass N, Molne K. Is routine pre-treatment cryopreservation of semen worthwhile in the management of patients with testicular cancer? Br J Urol 1989;64:524 –9. [43] Hansen PV, Glavind K, Panduro J, Pedersen M. Paternity in patients with testicular germ cell cancer: pretreatment and post-treatment findings. Eur J Cancer 1991;27:1385–9. [44] Fossa SD, Ous S, Abyholm T, Norman N, Loeb M. Post-treatment fertility in patients with testicular cancer. II. Influence of cis-platinbased combination chemotherapy and of retroperitoneal surgery on hormone and sperm cell production. Br J Urol 1985;57:210 –14. [45] Fossa SD, Aass N, Ous S, Waehre H. Long-term morbidity and quality of life in testicular cancer patients. Scand J Urol Nephrol Suppl 1991;138:241– 6. [46] Redman JR, Bajorunas DR, Goldstein MC, Evenson DP, Gralla RJ, Lacher MJ, et al. Semen cryopreservation and artificial insemination for Hodgkin’s disease. J Clin Oncol 1987;5:233– 8. [47] Sanger WG, Olson JH, Sherman JK. Semen cryobanking for men with cancer– criteria change. Fertil Steril 1992;58:1024 –7. [48] Kangasniemi M, Wilson G, Huhtaniemi I, Meistrich ML. Protection against procarbazine-induced testicular damage by GnRH- agonist and antiandrogen treatment in the rat. Endocrinology 1995;136:3677– 80. [49] Meistrich ML, Wilson G, Ye WS, Kurdoglu B, Parchuri N, Terry NH. Hormonal protection from procarbazine-induced testicular damage is selective for survival and recovery of stem spermatogonia. Cancer Res 1994;54:1027–34. [50] Meistrich ML, Wilson G, Zhang Y, Kurdoglu B, Terry NH. Protection from procarbazine-induced testicular damage by hormonal pretreatment does not involve arrest of spermatogonial proliferation. Cancer Res 1997;57:1091–7. [51] Meistrich ML. Hormonal stimulation of the recovery of spermatogenesis following chemo- or radiotherapy. Review article. Apmis 1998;106:37– 45; discussion 45–36. [52] Bajnoczky K, Khezri S, Kajtar P, Szucs R, Kosztolanyi G, Mehes K. No chromosomal instability in offspring of survivors of childhood malignancy. Cancer Genet Cytogenet 1999;109:79 – 80. [53] Blatt J. Pregnancy outcome in long-term survivors of childhood cancer. Med Pediatr Oncol 1999;33:29 –33. [54] Byrne J. Long-term genetic and reproductive effects of ionizing radiation and chemotherapeutic agents on cancer patients and their offspring. Teratology 1999;59:210 –5. [55] Green DM, Fiorello A, Zevon MA, Hall B, Seigelstein N. Birth defects and childhood cancer in offspring of survivors of childhood cancer. Arch Pediatr Adolesc Med 1997;151:379 – 83. [56] Levy MJ, Stillman RJ. Reproductive potential in survivors of childhood malignancy. Pediatrician 1991;18:61–70. [57] Evenson DP, Jost LK, Baer RK. Effects of methyl methanesulfonate on mouse sperm chromatin structure and testicular cell kinetics. Environ Mol Mutagen 1993;21:144 –53. [58] Sega GA. Adducts in sperm protamine and DNA vs. mutation frequency. Prog Clin Biol Res 1991;372:521–30. [59] Carroll PR, Whitmore WF, Herr HW, Morse MJ, Sogani PC, Bajorunas D, et al. Endocrine and exocrine profiles of men with testicular tumors before orchiectomy. J Urol 1987;137:420 –3. [60] Nijman JM, Schraffordt Koops H, Kremer J, Sleijfer DT. Gonadal function after surgery and chemotherapy in men with stage II and III nonseminomatous testicular tumors. J Clin Oncol 1987;5:651– 6. [61] Pryzant RM, Meistrich ML, Wilson G, Brown B, McLaughlin P. Long-term reduction in sperm count after chemotherapy with and without radiation therapy for non-Hodgkin’s lymphomas [published erratum appears in J Clin Oncol 1993 May;11(5):1007]. J Clin Oncol 1993;11:239 – 47. [62] Hansen SW, Berthelsen JG, von der Maase H. Long-term fertility and Leydig cell function in patients treated for germ cell cancer with

M. Schrader et al. / Reproductive Toxicology 15 (2001) 611– 617 cisplatin, vinblastine, and bleomycin versus surveillance. J Clin Oncol 1990;8:1695– 8. [63] Palmieri G, Lotrecchiano G, Ricci G, Spiezia R, Lombardi G, Bianco AR, et al. Gonadal function after multimodality treatment in men with testicular germ cell cancer. Eur J Endocrinol 1996;134:431– 6. [64] Bokemeyer C, Berger CC, Kuczyk MA, Schmoll HJ. Evaluation of long-term toxicity after chemotherapy for testicular cancer. J Clin Oncol 1996;14:2923–32.

617

[65] Reiter WJ, Kratzik C, Brodowicz T, Haitel A, Pokorny A, Zielinski CC, et al. Sperm analysis and serum follicle-stimulating hormone levels before and after adjuvant single-agent carboplatin therapy for clinical stage I seminoma. Urology 1998;52: 117–9. [66] Petersen PM, Hansen SW. The course of long-term toxicity in patients treated with cisplatin- based chemotherapy for non-seminomatous germ-cell cancer. Ann Oncol 1999;10:1475– 83.