On 2017 Nov 21, Samira Vesali commented:

Natural conception and reproductive experiences in cancer survivors who stored reproductive material before their treatment In the October 2017 issue of human reproduction (vol: 17, Page:1-8), Hammarberg K, 2017, published an opinion piece arguing of 301 respondents who had tried to achieve pregnancy since completing cancer treatment almost all had succeeded, in most cases through natural conception,Hammarberg K, 2017. There are some worthwhile points were not considered in this study, even as limitations or reasons for caution, which are bias influencing their findings. First, relatively response rate. It is not possible to know whether people with better or worse survival were more or less likely to participate. Our thoughts on this issue is that cancer patients undergoing advanced stages likely did not tend to participate in the survey. As well, those with malignancy normally get more extensive chemotherapy, which can damage their reproductive system. Evidence has been shown that different chemotherapy regimens can affect the reproductive system differently, Long JP, 2016. However, cancer patients who were on malignant stages have likely lower life expectancy and less hope childbearing after their treatment. It is possible they are less inclined to look for and benefit from fertility preservation options to store their cryopreserved material. Second, we believe that it is important to view the findings within the context of the cancer type, stage and chemotherapy regimens of the participants, because all the mentioned factors can lead to use or not use the frozen reproductive material and are effective in the participants’ ability to get pregnant naturally (possibly mild chemotherapy which can preserve some of the ovarian reserve). Third, the cancer patients studied were recruited from 1995 to 2014, but as we know Human Fertility and Embryology Authority (HFEA) has given permission to the usage of frozen eggs in United Kingdom (UK) from 2000, Wise J, 2000, and American Society of Reproductive Medicine (ASRM) removed the label of “experimental” from oocyte freezing in 2013,Practice Committees of American Society for Reproductive Medicine., 2013 . So, giving single vision to all frozen materials of participants during this time period maybe is not correct. Earlier, the patients only could enjoy form the cryopreserved embryo and sperm, then ovarian tissue and more recently oocytes. Looking at the table II, the pregnancy achievement is presented as “as a result of ART with stored material” but is not presented separately. It is not clear that all usage of stored material are adequately cryopreserved gametes or embryos or not. Fourth, the essential problem we see is that age can be another confounding factor in this survey. Many of the people who have never tried to get pregnant may be in advanced age, but we do not know the age of those who did not respond or never tried to get pregnant. Reza Omani Samani1, Samira Vesali1* 1 Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran Correspondence address: Department of Epidemiology and Reproductive Health, Royan Institute for Reproductive Biomedicine, Tehran, Iran. E-mail: samiravesali@yahoo.com.

On 2017 Nov 21, Samira Vesali commented:

Natural conception and reproductive experiences in cancer survivors who stored reproductive material before their treatment In the October 2017 issue of human reproduction (vol: 17, Page:1-8), Hammarberg K, 2017, published an opinion piece arguing of 301 respondents who had tried to achieve pregnancy since completing cancer treatment almost all had succeeded, in most cases through natural conception,Hammarberg K, 2017. There are some worthwhile points were not considered in this study, even as limitations or reasons for caution, which are bias influencing their findings. First, relatively response rate. It is not possible to know whether people with better or worse survival were more or less likely to participate. Our thoughts on this issue is that cancer patients undergoing advanced stages likely did not tend to participate in the survey. As well, those with malignancy normally get more extensive chemotherapy, which can damage their reproductive system. Evidence has been shown that different chemotherapy regimens can affect the reproductive system differently, Long JP, 2016. However, cancer patients who were on malignant stages have likely lower life expectancy and less hope childbearing after their treatment. It is possible they are less inclined to look for and benefit from fertility preservation options to store their cryopreserved material. Second, we believe that it is important to view the findings within the context of the cancer type, stage and chemotherapy regimens of the participants, because all the mentioned factors can lead to use or not use the frozen reproductive material and are effective in the participants’ ability to get pregnant naturally (possibly mild chemotherapy which can preserve some of the ovarian reserve). Third, the cancer patients studied were recruited from 1995 to 2014, but as we know Human Fertility and Embryology Authority (HFEA) has given permission to the usage of frozen eggs in United Kingdom (UK) from 2000, Wise J, 2000, and American Society of Reproductive Medicine (ASRM) removed the label of “experimental” from oocyte freezing in 2013,Practice Committees of American Society for Reproductive Medicine., 2013 . So, giving single vision to all frozen materials of participants during this time period maybe is not correct. Earlier, the patients only could enjoy form the cryopreserved embryo and sperm, then ovarian tissue and more recently oocytes. Looking at the table II, the pregnancy achievement is presented as “as a result of ART with stored material” but is not presented separately. It is not clear that all usage of stored material are adequately cryopreserved gametes or embryos or not. Fourth, the essential problem we see is that age can be another confounding factor in this survey. Many of the people who have never tried to get pregnant may be in advanced age, but we do not know the age of those who did not respond or never tried to get pregnant. Reza Omani Samani1, Samira Vesali1* 1 Department of Epidemiology and Reproductive Health, Reproductive Epidemiology Research Center, Royan Institute for Reproductive Biomedicine, ACECR, Tehran, Iran Correspondence address: Department of Epidemiology and Reproductive Health, Royan Institute for Reproductive Biomedicine, Tehran, Iran. E-mail: samiravesali@yahoo.com.