Semen analysis and reproductive hormones in boys with classical Hodgkin lymphoma treated according to the EuroNet-PHL-C2 protocol

Abstract

Study question: What is the impact of the EuroNet-PHL-C2 treatment for boys with classical Hodgkin lymphoma (cHL) on semen parameters?

Summary answer: More than half of the patients (52%, n = 16/31) had oligozoospermia or azoospermia at 2 years from cHL diagnosis; particularly boys treated for advanced-stage cHL had low sperm counts and motility.

What is known already: Chemotherapy and radiotherapy to the inguinal region or testes can impair spermatogenesis and result in reduced fertility. The EuroNet-PHL-C2 trial aims to minimize radiotherapy in standard childhood cHL treatment, by intensifying chemotherapy. The present study aims to assess the (gonadotoxic) impact of this treatment protocol on semen parameters and reproductive hormones in boys aged ≤18 years.

Study design, size, duration: This international, prospective, multi-centre cohort study was an add-on study to the randomized phase-3 EuroNet-PHL-C2 trial, where the efficacy of standard cHL treatment with OEPA-COPDAC-28 (OEPA: vincristine, etoposide, prednisone, and doxorubicin; COPDAC-28: cyclophosphamide, vincristine, prednisone, and dacarbazine) was compared to intensified OEPA-DECOPDAC-21 chemotherapy (DECOPDAC-21: COPDAC with additional doxorubicin and etoposide and 25% more cyclophosphamide). Patients were recruited between January 2017 and September 2021.

Participants/materials, setting, methods: Eligibility criteria included male patients, diagnosed with classical HL before or at the age of 18 years, and treated according to the EuroNet-PHL-C2 protocol in any of the 18 participating sites in the Netherlands, Germany, Belgium, Czech Republic, and Austria. Sperm parameters (sperm concentration, progressive motility, sperm volume, and calculated total motile sperm count) were assessed at diagnosis and 2 years after diagnosis in (post)pubertal boys. Laboratory measurements (serum follicle-stimulating hormone (FSH) and inhibin B) were performed in samples drawn at diagnosis, during treatment (2-3 times), and at 2 years post-diagnosis, and (age-adjusted) analyses were conducted separately for pre-pubertal and (post)pubertal boys. Outcomes were compared between the treatment levels (TL1, TL2, and TL3) and consolidation treatment schemes (COPDAC-28 and DECOPDAC-21).

Main results and the role of chance: In total, 101 boys were included in the present analysis: 73 were (post)pubertal (median age 15.4 years, (IQR 14.4; 16.6), 10 TL1, 29 TL2, 34 TL3, 62% of TL2/3 patients received COPDAC-28) and 28 boys were pre-pubertal (median age 9.6 years (IQR 6.6; 11.4), 4 TL1, 7 TL2, 17 TL3, 38% of TL2/3 patients received COPDAC-28). The study included six boys who had received pelvic radiotherapy; none were irradiated in the inguinal or testicular area. At diagnosis, 48 (post)pubertal boys delivered semen for cryopreservation; 19 (40%) semen samples were oligospermic and 4 (8%) were azoospermic. Low sperm concentration (<15 mil/ml) appeared to be related to the HL disease itself, with a higher prevalence in boys who presented with B symptoms (76% vs 26%, aOR 2.3 (95% CI 1.0; 3.8), P = 0.001) compared to those without such symptoms. At 2 -years post-diagnosis, 31 boys provided semen samples for analysis, of whom 12 (39%) boys had oligozoospermia and 4 (13%) had azoospermia, while 22 boys (71%) had low total motile sperm counts (TMSC) (<20 mil). Specifically, the eight boys in the TL3 group treated with DECOPDAC-21 consolidation had low sperm counts and low progressive motility after 2 years (i.e. median sperm count 1.4 mil/ml (IQR <0.1; 5.3), n = 7 (88%), low sperm concentration, low median progressive motility 16.5% (IQR 0.0; 51.2), respectively). Age-adjusted serum FSH levels were significantly raised and inhibin B levels (and inhibin B:FSH ratios) were decreased during chemotherapy in (post)pubertal boys, with subsequent normalization in 80% (for FSH) and 60% (for inhibin B) of boys after 2 years. Only 4 out of the 14 (post)pubertal boys (29%) with low sperm concentrations after 2 years had elevated FSH (>7.6 IU/l), while 7 (50%) had low inhibin B levels (<100 ng/l). In pre-pubertal boys, reproductive hormones were low overall and remained relatively stable during chemotherapy.

Limitations, reasons for caution: The present analyses included sperm and laboratory measurements up to 2 years post-diagnosis. Long-term reproductive outcomes and potential recovery of spermatogenesis remain unknown, while recovery was reported up to 5- or even 10-year post-chemotherapy in previous studies.Boys who were pre-pubertal at diagnosis were still too young and/or physically not able to deliver semen after 2 years and we could not assess a potential difference in gonadotoxicity according to pubertal state at the time of treatment. Overall, the statistical power of the analyses on sperm concentration and quality after 2 years was limited.

Wider implications of the findings: Results of the semen analyses conducted among the 31 boys who had provided a semen sample at 2 years post-treatment were generally poor. However, additional long-term and adequately powered data are crucial to assess the potential recovery and clinical impact on fertility. The participating boys will be invited to deliver a semen sample after 5 years. Until these data become available, benefits of intensified chemotherapy in cHL treatment to reduce radiotherapy and lower risk for development of secondary tumours should be carefully weighed against potentially increased risk of other late effects, such as diminished fertility due to the increased chemotherapy burden. Boys with newly diagnosed cHL should be encouraged to deliver sperm for cryopreservation whenever possible. However, patients and clinicians should also realize that the overall state of disease and inflammatory milieu of cHL can negatively affect sperm quality and thereby reduce chance of successful fertility preservation. Furthermore, the measurement of FSH and inhibin B appears to be of low value in predicting low sperm quality at two years from cHL treatment.

Study funding/competing interest(s): This study was funded by the Dutch charity foundation KiKa (project 257) that funds research on all forms of childhood cancer. C.M.-K., D.K., W.H.W., D.H., MC, A.U., and A.B. were involved in the development of the EuroNet-PHL-C2 regimen. The other authors declare no potential conflict of interest.

Trial registration number: N/A.

Keywords: azoospermia; childhood Hodgkin lymphoma; fertility; follicle-stimulating hormone; gonadotoxicity.

Figure 1.

Study flow chart. Flow diagram of the fertility add-on study, depicting enrolment, assigned treatment according to the EuroNet-PHL-C2 protocol with corresponding CED-score, and follow-up/end of study for the present study. According to current PANCARE guidelines (Mulder et al., 2021) treatment with a CED-score ≥4000 mg/m² should be considered high risk of infertility in boys. The depicted CED-score of high-risk treatment is coloured in red, low-risk in orange, and CED-score 0 g/m² is depicted in green. CED, cyclophosphamide equivalent dose; cHL, classical Hodgkin lymphoma; COPDAC-28, cyclophosphamide, vincristine, prednisone, and dacarbazine; DECOPDAC-21, doxorubicin, etoposide, cyclophosphamide, vincristine, prednisone, and dacarbazine; OEPA, vincristine, etoposide, prednisone, doxorubicin; OPPA, vincristine, procarbazine, prednisone, doxorubicin; TL, treatment level; RT, radiotherapy; n, number.

Figure 2.

Sperm parameters at 2 years from childhood classical Hodgkin lymphoma diagnosis, according to assigned treatment level and consolidation treatment. Cumulative distribution figures depicting the cumulative proportion of patients with a specific (A) sperm concentration (B) progressive sperm motility (C) semen volume or (D) total motile sperm count (TMSC) at 2 years from Hodgkin lymphoma diagnosis. Vertical dashed lines indicate WHO reference cutoff values to define abnormal sperm parameters, and the red-marked areas highlight the abnormal range (Cooper et al., 2010). TL, treatment level. Assigned treatment was according to the EuroNet-PHL-C2 protocol. TL1 patients received 2× OEPA±1× COPDAC-28 (CED-score = 0–1 g/m²), TL2 patients received 2× OEPA + 2× (DE)COPDAC (CED-score = 2–2.5 g/m²), TL3 patients received 2× OEPA + 4× (DE)COPDAC (CED-score 4–5 g/m²). OEPA, vincristine, etoposide, prednisone, doxorubicin; COPDAC-28, cyclophosphamide, vincristine, prednisone, and dacarbazine; DECOPDAC-21, doxorubicin, etoposide, cyclophosphamide, vincristine, prednisone, and dacarbazine. Additional explanation on how to read a cumulative distribution figure: each of the cumulative distribution figures illustrates the relationship between the respective assessed sperm parameter on the x-axis and the cumulative probability on the y-axis. Each point on the curve represents the cumulative probability of observing a value less than or equal to the corresponding value on the x-axis. For instance, consider figure A (semen concentration): for a sperm concentration of 15 mil/ml on the x-axis, the cumulative probability is 90% for the red line (indicating the TL3-DECOPDAC-21 treatment arm). This implies that ∼90% of the assessed sperm concentrations in this specific subgroup are ≤15 mil/ml.

Figure 3.

Serum FSH and inhibin B during treatment for childhood Hodgkin lymphoma up to 2 years follow-up in pre- and (post)pubertal boys. (A) FSH, B inhibin. (B) Boxplots depicting the distribution of uncorrected serum FSH or inhibin B from diagnosis up to 2 years post-diagnosis, including the median (centerline), interquartile range (end of the box), and range (end of the whiskers). Separate dots are outliers. Patients who were pre-pubertal at time of diagnosis are shown in orange, and boys who were (post)pubertal at diagnosis (definition testicular volume ≥4 ml or in case of missing Tanner-G ≥2) are shown in blue. The dashed lines in blue highlight applied cut-off scores to define normal (≤7.6 IU/l) or high FSH (>7.6 IU/l), respectively normal (≥100 ng/l) or low inhibin B (<100 ng/l) in (post)pubertal boys. The dashed lines in orange highlight applied cut-off scores to define normal (≤5 IU/l) or high FSH (>5 IU/l), respectively normal- (≥50 ng/l) or low inhibin B (<50 ng/l) in pre-pubertal boys. FSH, follicle-stimulating hormone; N, number. Timing sampling: T0, at diagnosis; T1, after 2× OEPA; T1b, after 1× COPDAC; T2, after 2×(DE)COPDAC; T3, after 4×(DE)COPDAC; T4, 2 years post-diagnosis.