Cancer after Infertility and IVF

Findings from an Australian study

A brief summary for consumers and health professionals
November 1999
Professor David L Healy

Fertility Treatment

Doctors have used fertility drugs in Australia since the 1960s, triggering women's ovaries to produce eggs.  This approach proved successful in assisting many women with fertility problems to become pregnant and have children.

In the past 20 years the use of fertility drugs has increased markedly following the development of IVF and related treatments such as GIFT and ICSI.  (For convenience the term IVF refers to all these recent treatment techniques on this page).

The Study

The growth in the numbers of women seeking help to become pregnant provided an opportunity for this study, the largest of its type anywhere in the world.

The study followed up 29,700 women referred to any of ten participating Australian IVF clinics between 1978 and 1993.  Of this total;

• 20,656 women received fertility drugs during IVF (the 'treated group')
• 9,044 women referred for IVF did not end up having fertility drug treatment (the 'untreated group')

Depending on the year that women joined an IVF program, the duration of follow-up ranged from one to 22 years, with the majority followed up for five to 10 years.

What did the study aim to do?

The designed the study to clarify;

• whether there was any increase in the numbers of cancers of the breast, ovary and uterus in women on IVF compared with the numbers expected among women of the same age followed up over the same period in the general population.
• in the event that there were more of these cancers than predicted, how this might be explained.

What did the study find?

• Cancers of the breast and ovary were no more common in IVF patients overall than in the general population.  Of 29,700 who joined IVF programs, researchers predicted 155 breast cancers and found 143.  for ovarian cancer, 13 cases were predicted and 13 were found.
• Cancers of the uterus were more common than predicted in untreated IVF patients but were no more common than predicted in the treated group.  Among the 9,044 women in the untreated group, three cases were predicted and seven were found.
• More women than predicted in the treated group had a breast cancer diagnosed in the first year after treatment with fertility drugs.  This finding disappeared with time and is discussed below. Among the 20,656 women, 9 breast cancer cases were predicted in the first year after treatment and 17 were found.
• Women with infertility for which a cause could not be found had more cancers of the ovary and uterus than predicted, whether or not they had treatment with fertility drugs.  Out of 3,800 women with unexplained infertility, two cases of ovarian cancer were predicted and five were found.  As regards uterine cancer, one case was predicted and five were found.
• There was no evidence of any link between the number of treatment cycles or type of fertility drug used and increased cancer incidence.  Changes in the types of drugs used in IVF and the amount of ovarian stimulation do not appear to have had an overall impact on cancer in participating women.

What can we conclude?

The findings provide reassurance that the incidence of breast and ovarian cancers in IVF patients is the same as that for women of the same age in the general population when considered over a five to ten year period.

• The evidence of increased numbers of cancers above predicted in small numbers of women in particular sub-groups needs further study.  While there was no overall increase, the occurrence of above expected numbers of breast cancer in the first year after treatment is consistent with other research showing a small increase in diagnoses of breast cancer shortly after women give birth.  The same effect has been seen in recent users of the oral contraceptive pill and hormone replacement therapy.  Possible explanations for this finding after IVF treatment include earlier detection of abnormal breast changes due to close medical supervision, the biological effects of fertility drugs, or both.  Explanations for the relationship between unexplained infertility and the increase in ovarian and uterine cancers are harder to come by.  In a bid to explore such issues, the research team has started a more detailed investigation of about 700 IVF patients, some of whom have cancer and others who do not.
• Notwithstanding future research, this study reinforces the importance for women of medical check-ups at regular intervals after fertility treatment.

What do we recommend?

Cancers of the breast, ovaries and uterus are predominantly diseases of older women, but they do occur in some younger women.

• Women of all ages can become familiar with the normal look and feel of their breasts.  By checking your breasts regularly, you are better able to recognise unusual changes.  While most of these are harmless, breast changes may be a sign of early cancer and should be checked by your doctor.
• The best chance of preventing cancer of the cervix, the neck of the uterus, is to have a Pap smear every two years.  There are no screening tests for the early detection of cancers of the ovaries or for the main part of the uterus.
• Discuss any concerns about your health with your doctor.

The Research Team

Dr Alison Venn
Ms Lynn Watson
Ms Fiona Bruinsma
Centre for the Study of Mothers' & Children's Health
Latrobe University

Professor Graham Giles
Cancer Epidemiology Centre
Anti-Cancer Council of Victoria

Professor David Healy
Monash IVF & Department of Obstetrics & Gynaecology
Monash University

Acknowledgments

The following clinics participated in the study:

• City West IVF
• Concept Fertility Centre
• Flinders Reproductive Medicine
• Lingard Fertility Centre
• Melbourne IVF/Reproductive Biology Unit
• Monash IVF
• Pivet Medical Centre
  Reproductive Medicine Unit (University of Adelaide)
• Tas IVF
• Westmead Fertility Centre

This work was supported by grants from the Kathleen Cuningham Foundation, the Fertility Society of Australia, the Anti-Cancer Council of Victoria, IVF Friends and a research fellowship from the National Health and Medical Research Council.

More Information

About this study
Venn A, Watson L, Bruinsma F, Giles G, Healy D.  Risk of cancer after the use of fertility drugs with in vitro fertilisation.  Lancet 1999;354:1586-90

Contact:
Fiona Bruinsma or Alison Venn
03) 8341 8583 or Professor David Healy on (03) 9429 9188.

About women's health after infertility and IVF

For consumer information on infertility and IVF
Contact ACCESS, Australia's national infertility network on (02) 9670 2380 or at  your IVF clinic.

For information about cancer
Contact the cancer information line on 13 11 20.

For copies of our pamphlet, please contact:
Ms Fiona Bruinsma
Centre for the Study of Mothers' & Children's Health
LaTrobe University
251 Faraday Street, Carlton,  Vic.  3053
(03) 9341 8583

Development of this page has been supported by an unrestricted educational grant from Searle, A Division of Monsanto Australia Ltd.

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