Cancer in pregnancy

INTRODUCTION

The simultaneous occurrence of cancer and pregnancy is rare with a reported incidence of 0.07% to 0.1%. When it does so, it may be necessary to perform surgery or to prescribe chemotherapy or radiotherapy. Surgery can, and frequently is, performed without undue difficulty on a pregnant women. This treatment is never withheld from expectant mothers who need it.

Pregnant women with cancer are treated the same way as non-pregnant women with the same conditions. Numerous studies have shown over and over again that the outcome for pregnant women with cancer is no different than that of women who are not pregnant, when matched for age, stage and cancer type.

INCIDENCE OF CANCER

The incidence of women who develop cancer while pregnant is, internationally, increasing. This is partly because more women are having their first baby in their late 30's. Here in Ireland, for example, the number of women under 50 who developed cancer of the breast increased from 451 in 2000 to 600 in 2007. If one accepts international statistics, one would expect 60-70 women to develop cancer while pregnant every year in Ireland. Naturally in such cases concern the outcome for the baby is foremost in parents' minds, and the modern irrational fear of abnormality or imperfection leads some to contemplate euthanasia by abortion. In countries where abortion is freely available, some oncologists will even refuse to treat a pregnant woman before she has had an abortion. We do not want this to happen in Ireland. Availability of abortion could very well do that, where women are forced to have an abortion before they can get treatment.

While large statistically significant medical studies of the outcomes of pregnant women with cancer are not easy to come by, the studies that do exit show that, in cancer cases, abortion will not improve or treat the mothers' outcomes.

One enormous landmark study published in the Clinical Journal of Oncology in 2002 looked at 42,511 women and found no intergroup differences for cause-specific death between pregnant and non-pregnant women. In other words, pregnancy did not make any type of cancer worse. They also found pregnancy a protective factor for women diagnosed with cancer after pregnancy.

Another study looked at a cohort comprised of 185 women diagnosed with melanoma during pregnancy and 5,348 women of the same childbearing age diagnosed with melanoma while not pregnant. There was no statistically significant difference in overall survival between pregnant and non-pregnant groups.

So the real question is how much, if any, harm will be done to the baby in her womb. Once again, we see the constant phenomenon of the morally good being consistent with the temporal good. Studies show that the risk to unborn babies of mothers being treated for their cancers do surprisingly well. In one international collaborative setting, patients with invasive cancer diagnosed during pregnancy between 1998 and 2008 were identified. Clinical data regarding the cancer diagnosis and treatment and the obstetric and neonatal outcomes were collected and analyzed. Of 215 patients, five (2.3%) had a pregnancy that ended in a spontaneous miscarriage and 30 pregnancies were interrupted. Treatment was initiated during pregnancy in 122 patients and postpartum in 58 patients. The most frequently encountered cancer types were breast cancer, hematologic malignancies, and dermatologic malignancies. Delivery was induced in 71.7% of pregnancies, and 54.2% of children were born preterm. In the group of patients prenatally exposed to cytotoxic cancer treatment, the prevalence of preterm labor was increased but there was no increased incidence of congenital malformations.

Another Belgian 2009 study states unequivocally that "cancer complicating pregnancy endangers two lives. Any approach should look at both maternal and foetal safety. Maternal prognosis will not improve by terminating the pregnancy ...Chemotherapy during the second or third trimester can be administered without increasing the incidence of congenital malformations."

The last thing a pregnant woman with cancer needs is pressure on her to have an abortion. She needs the best possible treatment for herself and her unborn baby from an obstetrician also trained in oncology. Or from an oncologist in collaboration with an obstetrician who is concerned for the welfare of her unborn baby. She also needs support from one of the many cancer support groups.

EFFECTS ON THE UNBORN CHILD

Some women will ask to delay some treatments until such a time as the baby is unlikely to be adversely affected by such treatment. The unborn child has developed all its organs and limbs by the 12th week of pregnancy. Hence chemotherapy can be given to a woman in the second and third trimester without causing any abnormality in the unborn child. With judicious selection of chemotherapeutic agents pregnant women can be treated even in the first trimester. Some drugs cannot cross the placental barrier, some others appear not to cause malformations. If the folic acid antagonists are excluded the incidence of congenital malformation is 6% for single agents. Fortunately, methotrexate, the principal folic acid antagonist used, is not part of any curative regimen for which a therapeutically equivalent substitute is lacking.

To optimise the efficacy of radiotherapy for cancer patents who are pregnant, the following factors must be considered: the potential effects of the therapy on the unborn child, the stage and prognosis of the mother's disease and the possible risks to the patient of restricting cancer treatment. The risk to the unborn is negligible if the foetal exposure does not exceed 0.1Gy.

Where cure is a realistic goal, therapy should not be modified in such a way as to compromise its achievement. If there is no hope for cure or even significant palliation, the primary goal may become the protection of the foetus from any harmful effects of anticancer therapy and the delivery of a healthy infant. Therapy should be individualised for each patient and patient choice must be respected.

CANCER OF THE WOMB

In the rare case of cervical cancer in pregnancy, it is usually necessary to immediately perform a hysterectomy to remove the cancerous womb of the mother. This hysterectomy is not, and has never been considered by medicine or by the law, as an abortion.

Abortion could do nothing to treat the diseased womb. The desired effect is the removal of the diseased organ; the undesired side effect is the early removal of the baby. The same treatment would be given to a non-pregnant woman with a cancerous womb.

PREGNANCY, ABORTION AND CANCER

A cancer specialist Prof. James Fennelly, stated (Irish Times, 29/6/1992) that "there is no evidence that pregnancy makes cancer worse. There is no evidence that termination of pregnancy makes cancer better. All the necessary treatment can be given under specialised management." He quotes in detail which anti-cancer drugs can be used in different types of cancer (including breast cancer, leukaemia, melanoma and brain tumours) without the risk of producing a deformed baby. There is a possibility that the disease or treatment may cause a miscarriage or lead to an underweight baby, but this is very different from killing the child through abortion.

LANCET REPORTS THAT CHEMOTHERAPY IS SAFE DURING PREGNANCY

As was reported in the Independent, 10 February 2012, women diagnosed with cancer during pregnancy can now be treated and it is possible to save both.

A series of studies published in The Lancet and Lancet Oncology shows that children born to women given chemotherapy while they were growing in the womb developed as well as children in the general population. About one in 1,000 pregnancies is affected by cancer and in the past women have faced a terrible choice: delay treatment until the baby is born, putting their own life at risk, start treatment while pregnant and risk damaging the baby, or terminate the pregnancy.

Now the trend is to preserve pregnancy wherever possible and the evidence shows the outcomes for mother and baby are good. Chemotherapy involves administering toxic drugs to kill the cancer but which also kill healthy cells in the mother's body. Its effects on the foetus have been unclear but a study of 68 women who each had three to four cycles of chemotherapy during pregnancy showed their children were unaffected.

Tests of cognitive ability on the children were "within normal ranges", the researchers from Leuven Cancer Institute in Belgium say. Only those born prematurely had lower scores of cognitive ability but the researchers say this applies in the general population too.

"Our findings do not support a strategy of delay in chemotherapy or [induced] pre-term delivery with [subsequent] chemotherapy to avoid harm to the foetus," the authors write.

In a second paper, researchers from the Institut Gustave Roussy say women must not have chemotherapy in early pregnancy when it can harm the foetus but from the second trimester (12 weeks) onwards evidence shows it is safe. "The use of chemotherapy during pregnancy helps increase the chance of foetal preservation. Children exposed to chemotherapy in utero after the first trimester do not seem to have more congenital abnormalities," the authors say.

Read more of the article in the Independent here

REFERENCES / SOURCES

1. Cancer During Pregnancy: An Analysis of 215 Patients Emphasizing the Obstetrical and the Neonatal Outcomes.
Journal of Clinical Oncology (JCO) Feb 1, 2010:683-689; published online on October 19, 2009; DOI:10.1200/JCO.2009.23.2801

2. Gynaecologic cancer complicating pregnancy: An overview. Best Practice & Research. Clinical Obstetrics & Gynaecology, Sept 7, 2009.

3. Treatment of pregnancy-associated breast cancer. Expert Opinion on Pharmacotherapy, Oct 10, 2009 (14):2259-67.

4. Gynecologic cancers in pregnancy: guidelines of an international consensus meeting.
Division of Gynaecologic Oncology, Department of Obstetrics & Gynaecology, Leuven Cancer Institute (LKI), UZ Gasthuisberg, Katholieke Universiteit Leuven, Belgium.

5. Cause-Specific Survival for Women Diagnosed With Cancer During Pregnancy or Lactation: A Registry-Based Cohort Study.
Journal Clinical Oncology Jan 1, 2009:45-51; published online on November 24, 2008; DOI:10.1200/JCO.2008.17.4110

6. Effect of Pregnancy on Survival in Women With Cutaneous Malignant Melanoma. Journal of Clinical Oncology, Nov 1, 2004:4369-4375; DOI:10.1200/JCO.2004.02.096

 

LINKS

• Consultant Oncologist, John Crown, explains how "there is a high chance of two happy outcomes" for pregnant mothers with cancer

• Tweet by Prof John Crown, Irish Consultant Oncologist, where he states "Must say I don't think I ever had a case where abortion was necessary to save mom." 21st February 2012