(See also Gynecologic Tumors.)

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, busulfanSome Trade Names
MYLERAN
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, chlorambucilSome Trade Names
LEUKERAN
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, cyclophosphamideSome Trade Names
CYTOXAN
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, 6-mercaptopurineSome Trade Names
PURINETHOL
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, methotrexateSome Trade Names
RHEUMATREX
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) can cause fetal abnormalities. MethotrexateSome Trade Names
RHEUMATREX
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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 wk, followed by hysterectomy so that the infant can be saved and aggressive cancer treatment 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. Usually, conization can be avoided. If biopsy shows mild dysplasia, normal delivery is possible, and follow-up evaluation can start 6 wk postpartum. Severe dysplasia or carcinoma in situ warrants further evaluation during pregnancy; colposcopy is usually accurate, but sometimes biopsy is necessary.

For carcinoma in situ (Federation of Gynecology and Obstetrics [FIGO] stage 0—see Table 7: Gynecologic Tumors: Clinical Staging of Cervical Carcinoma*) and microinvasive cancer (stage IA1), treatment is often deferred until after delivery because conservative options may be possible then.

If invasive cancer (FIGO stage IA2 or higher) is diagnosed during early pregnancy, immediate therapy appropriate for the cancer is traditionally recommended. If invasive cancer is diagnosed after 20 wk and if the woman accepts the unquantified increase in risk, treatment can be deferred until into the 3rd trimester (eg, 32 wk) to maximize fetal maturity but not delay treatment too long. When hysterectomy is delayed until delivery, some experts recommend that it be done immediately after delivery. Others recommend delaying hysterectomy until 6 wk postpartum because risks due to hysterectomy are thought to be much greater at delivery because of the increased blood supply to the pelvic organs at that time.

In certain cancers, chemotherapy may induce tumor regression, allowing the fetus to mature to a viable stage before definitive treatment (surgery or radiation therapy). Delivery is usually cesarean, but vaginal delivery, although controversial, may be as safe.

Other gynecologic cancers: After 12 wk 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 and fallopian tube cancers rarely occur during pregnancy.

Leukemia and Hodgkin lymphoma: These disorders (see Leukemias and see Lymphomas) are uncommon during pregnancy. Antineoplastic drugs typically used 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 (see Breast Disorders).

Last full review/revision December 2008 by Sean C. Blackwell, MD

Content last modified February 2012