Biomedical Engineering Reference
In-Depth Information
11.1
Introduction—Clinical Possibilities for Male
Fertility Preservation
Since the 1970s, oncology patient survival rates have improved as a result of
cooperative protocol-driven clinical research, particularly in young patient categories.
This has propelled the overall event-free survival rate for childhood cancer patients to
79% in 2004 (Ries et al.
2007
), and as a result, research efforts are beginning to shift
towards improving patient quality-of-life after cure. In particular, patients receiving
chemotherapy and radiotherapy for cancer are often at risk for infertility, catapulting
fertility preservation to the forefront of quality-of-life concerns (see Chap. 9). Progress
to minimize the unwanted side effects of current treatment regimens without decreas-
ing their effectiveness against the oncologic disease has allowed many cancer survi-
vors to have children following spontaneous recovery of fertility (van den Berg et al.
2004
). However, some oncological diseases require rigorous treatment regimens,
which will almost always lead to permanent infertility. In addition, ablative conditioning
prior to hematopoietic stem cell transplantation for malignant and non-malignant
disorders is highly gonadotoxic. In particular, treatment regimens that include high-
dose alkylating chemotherapy (e.g., busulfan, melphalan, cyclophosphamide,
nitrosoureas, cisplatin, chlorambucil, carmustine, lomustine, cytarabine, ifosfamide,
and procarbazine) result in the highest risk of long-term infertility [(Wallace et al.
2005
; Lee et al.
2006
; Mitchell et al.
2009
); see Chap. 9]. Recently reported longitu-
dinal male infertility data from the Childhood Cancer Survivor Study indicates that
boys who receive radiation doses greater than 7.5 Gy, high cumulative alkylating
agent doses, and those receiving cyclophosphamide or procarbazine are at highest
risk for future infertility as adults (Green et al.
2010
).
In contrast to the efficient treatment regimens for a patient's primary disease,
very few and limited options are available to prevent the loss of fertility. However,
promising therapies are currently in the research pipeline that may one day offer
these cancer survivors the hope of future fertility. For men, cryobanking of semen
before the initiation of treatment is possible and allows for future
in vitro
fertiliza-
tion (IVF), including intracytoplasmic sperm injection (ICSI), but this is a finite
resource and does not allow for natural conception. Furthermore, some men are not
able to provide an adequate semen sample at the time of diagnosis. For these men,
it is possible to isolate epididymal sperm directly via percutaneous epididymal
sperm aspiration (PESA) or microsurgical epididymal sperm aspiration (MESA)
(Patrizio et al.
1988
; Silber et al.
1990
; Craft et al.
1995
). PESA involves sperm
aspiration through a needle inserted into the cauda epididymis, while MESA is
performed as open surgical procedure under the operating microscope to aspirate
sperm from a single caput epididymal tubule. Alternatively, testicular sperm can be
isolated by fine-needle aspiration via testicular sperm aspiration (TESA) or through
a surgical biopsy for testicular sperm extraction (TESE) (Devroey et al.
1994
). In
the TESE procedure multiple biopsies are obtained surgically from the testicular
parenchyma, biopsies are minced in buffered solutions, and any sperm are identi-
fied by microscopic examination (Tournaye
1999
). Sperm identified using these
techniques can be prospectively isolated by micromanipulation and used for ICSI
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