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Cancer in Pregnancy


Lara A. Friel

, MD, PhD, University of Texas Health Medical School at Houston, McGovern Medical School

Last full review/revision Jun 2021| Content last modified Jun 2021
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Pregnancy should not delay treatment of cancer. Treatment is similar to that in nonpregnant women except for rectal and gynecologic cancers.

Because embryonic tissues grow rapidly and have a high DNA turnover rate, they resemble cancer tissues and are thus very vulnerable to antineoplastic drugs. Many antimetabolites and alkylating drugs (eg, busulfan, chlorambucil, cyclophosphamide, 6-mercaptopurine, methotrexate) can cause fetal abnormalities. Methotrexate is particularly problematic; use during the 1st trimester increases risk of spontaneous abortion and, if the pregnancy continues, multiple congenital malformations. Although pregnancy often concludes successfully despite cancer treatment, risk of fetal injury due to treatment leads some women to choose abortion.

Rectal cancer

Rectal cancers may require hysterectomy to ensure complete tumor removal. Cesarean delivery may be done as early as 28 weeks, followed by hysterectomy so that aggressive cancer treatment can be started.

Cervical cancer

Pregnancy does not appear to worsen cervical cancer.

Cervical cancer can develop during pregnancy, and an abnormal Papanicolaou (Pap) test should not be attributed to pregnancy. Abnormal Pap tests are followed by colposcopy and directed biopsies when indicated. Colposcopy does not increase risk of an adverse pregnancy outcome. Expert colposcopic evaluation and consultation with the pathologist are recommended before doing a cervical biopsy because the biopsy may cause hemorrhage and preterm labor. If the examination suggests that lesions are low-grade, a biopsy may not be done, particularly if cervical cytology also suggests that lesions are low-grade.

For carcinoma in situ (Federation of Gynecology and Obstetrics [FIGO] stage 0—see table FIGO Clinical Staging of Cervical Cancer Carcinoma) and microinvasive cancer (stage IA1), treatment is often deferred until after delivery because at these stages, cancer progresses very slowly and pregnancy can be completed safely without affecting the woman's prognosis.

If invasive cancer (FIGO stage IA2 or higher) is diagnosed, pregnancy should be managed in consultation with a gynecologic oncologist. If invasive cancer is diagnosed during early pregnancy, immediate therapy appropriate for the cancer is traditionally recommended. If invasive cancer is diagnosed after 20 weeks and if the woman accepts the unquantified increase in risk, treatment can be deferred until into the 3rd trimester (eg, 32 weeks) to maximize fetal maturity but not delay treatment too long. For patients with invasive cancer, cesarean delivery with radical hysterectomy is done; vaginal delivery is avoided.

Other gynecologic cancers

After 12 weeks gestation, ovarian cancer is easily missed; then, the ovaries, with the uterus, rise out of the pelvis and are no longer easily palpable. If very advanced, ovarian cancer during pregnancy may be fatal before completion of the pregnancy. Affected women require bilateral oophorectomy as soon as possible.

Endometrial cancer and fallopian tube cancer rarely occur during pregnancy.

Leukemia and Hodgkin lymphoma

Leukemia and Hodgkin lymphoma are uncommon during pregnancy.

Antineoplastic drugs typically used to treat lymphoma increase risk of fetal loss and congenital malformations.

Because leukemias can become fatal rapidly, treatment is given as soon as possible, without any significant delay to allow the fetus to mature.

If Hodgkin lymphoma is confined to above the diaphragm, radiation therapy may be used; the abdomen must be shielded. If lymphoma is below the diaphragm, abortion may be recommended.

Breast cancer

Breast engorgement during pregnancy may make recognizing breast cancer difficult. Any solid or cystic breast mass should be evaluated. Usually, breast cancer should be treated immediately.

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