Editing Chemotherapy (section)

=== Infertility ===
Some types of chemotherapy are gonadotoxic and may cause [[infertility]].<ref name=Brydoy>{{cite journal | vauthors = Brydøy M, Fosså SD, Dahl O, Bjøro T | title = Gonadal dysfunction and fertility problems in cancer survivors | journal = Acta Oncologica | volume = 46 | issue = 4 | pages = 480–9 | year = 2007 | pmid = 17497315 | doi = 10.1080/02841860601166958 | s2cid = 20672988 }}</ref> Chemotherapies with high risk include procarbazine and other alkylating drugs such as cyclophosphamide, ifosfamide, busulfan, melphalan, chlorambucil, and chlormethine.<ref name=Brydoy /> Drugs with medium risk include doxorubicin and platinum analogs such as cisplatin and carboplatin.<ref name=Brydoy /> On the other hand, therapies with low risk of gonadotoxicity include plant derivatives such as vincristine and vinblastine, [[antibiotic]]s such as bleomycin and dactinomycin, and antimetabolites such as methotrexate, mercaptopurine, and 5-fluorouracil.<ref name=Brydoy />

[[Female infertility]] by chemotherapy appears to be secondary to [[premature ovarian failure]] by loss of [[primordial follicles]].<ref name=Morgan2012>{{cite journal | vauthors = Morgan S, Anderson RA, Gourley C, Wallace WH, Spears N | title = How do chemotherapeutic agents damage the ovary? | journal = Human Reproduction Update | volume = 18 | issue = 5 | pages = 525–35 | year = 2012 | pmid = 22647504 | doi = 10.1093/humupd/dms022 | doi-access = free | hdl = 1842/9543 | hdl-access = free }}</ref> This loss is not necessarily a direct effect of the chemotherapeutic agents, but could be due to an increased rate of growth initiation to replace damaged developing follicles.<ref name=Morgan2012 />

People may choose between several methods of [[fertility preservation]] prior to chemotherapy, including [[cryopreservation]] of semen, ovarian tissue, oocytes, or embryos.<ref>{{cite journal | vauthors = Gurgan T, Salman C, Demirol A | title = Pregnancy and assisted reproduction techniques in men and women after cancer treatment | journal = Placenta | volume = 29 Suppl B | pages = 152–9 | date = October 2008 | pmid = 18790328 | doi = 10.1016/j.placenta.2008.07.007 }}</ref> As more than half of cancer patients are elderly, this adverse effect is only relevant for a minority of patients. A study in France between 1999 and 2011 came to the result that embryo freezing before administration of gonadotoxic agents to females caused a delay of treatment in 34% of cases, and a live birth in 27% of surviving cases who wanted to become pregnant, with the follow-up time varying between 1 and 13 years.<ref>{{cite journal | vauthors = Courbiere B, Decanter C, Bringer-Deutsch S, Rives N, Mirallié S, Pech JC, De Ziegler D, Carré-Pigeon F, May-Panloup P, Sifer C, Amice V, Schweitzer T, Porcu-Buisson G, Poirot C | title = Emergency IVF for embryo freezing to preserve female fertility: a French multicentre cohort study | journal = Human Reproduction | volume = 28 | issue = 9 | pages = 2381–8 | date = September 2013 | pmid = 23832792 | doi = 10.1093/humrep/det268 | doi-access = free }}</ref>

Potential protective or attenuating agents include [[GnRH analog]]s, where several studies have shown a protective effect ''[[in vivo]]'' in humans, but some studies show no such effect. [[Sphingosine-1-phosphate]] (S1P) has shown similar effect, but its mechanism of inhibiting the [[Sphingomyelin#Apoptosis|sphingomyelin apoptotic pathway]] may also interfere with the [[apoptosis]] action of chemotherapy drugs.<ref name="RonessKalich-Philosoph2014">{{cite journal | vauthors = Roness H, Kalich-Philosoph L, Meirow D | title = Prevention of chemotherapy-induced ovarian damage: possible roles for hormonal and non-hormonal attenuating agents | journal = Human Reproduction Update | volume = 20 | issue = 5 | pages = 759–74 | year = 2014 | pmid = 24833728 | doi = 10.1093/humupd/dmu019 | doi-access = free }}</ref>

In chemotherapy as a [[conditioning regimen]] in hematopoietic stem cell transplantation, a study of people conditioned with cyclophosphamide alone for severe aplastic anemia came to the result that ovarian recovery occurred in all women younger than 26 years at time of transplantation, but only in five of 16 women older than 26 years.<ref>{{cite journal | vauthors = Tichelli A, Rovó A | title = Fertility issues following hematopoietic stem cell transplantation | journal = Expert Review of Hematology | volume = 6 | issue = 4 | pages = 375–88 | date = August 2013 | pmid = 23991924 | doi = 10.1586/17474086.2013.816507 | s2cid = 25139582 }}
<br />In turn citing: {{cite journal | vauthors = Sanders JE, Hawley J, Levy W, Gooley T, Buckner CD, Deeg HJ, Doney K, Storb R, Sullivan K, Witherspoon R, Appelbaum FR | title = Pregnancies following high-dose cyclophosphamide with or without high-dose busulfan or total-body irradiation and bone marrow transplantation | journal = Blood | volume = 87 | issue = 7 | pages = 3045–52 | date = April 1996 | pmid = 8639928 | doi = 10.1182/blood.V87.7.3045.bloodjournal8773045 | doi-access = free }}</ref>