Breast Cancer During Pregnancy
Cancer is the leading cause of death in women of reproductive age, and cancer during pregnancy is not as uncommon as you would think. It has been estimated that 1 out of every 1,000-1,500 live births are complicated by maternal cancer (breast, ovarian, etc.), causing a significant dilemma for both the patient and her physician.
Nonetheless, a number of recent studies have concluded that cancer treatments can often be delayed until after the child is born, with minimal impact on prognosis. Furthermore, pregnancy after being treated for cancer is generally considered safe, although a minimal waiting period is usually recommended.
In a recent question fielded in the "Ask the Experts" column of Medscape Oncology, Dr. Harold Burstein responded to a query about a 32-year-old woman diagnosed with breast cancer who was 15 weeks pregnant. To complicate matters, her cancer was found to have spread to six lymph nodes. What impact would cancer treatment have on the pregnancy? Should the treatment regimen be altered?
Burstein noted that routine treatment recommendations in the absence of pregnancy would call for definitive surgery, radiation therapy, adjuvant chemotherapy and, if the tumor is hormone-receptor positive, tamoxifen. After numerous caveats depending on the individual medical circumstances and personal issues involved, he said the patient should ultimately be advised to have similar treatments, although the specific timing of various therapies may be affected by her concurrent pregnancy.
Burstein noted the lack of studies focusing on the treatment of women with breast cancer during pregnancy, although he cited a study by researchers at the M.D. Anderson Cancer Center in Houston in which 24 women were treated over an 8-year span using a standardized protocol.
After surgery (modified radical mastectomy), the women received adjuvant chemotherapy until the time of delivery. There were no unexpected antepartum complications; 12% had preterm labor, and 4% had pre-eclampsia. Postpartum lactation was impaired in all patients, and patients were advised not to breast feed on account of chemotherapy exposure.
Importantly, none of the 24 children had congenital abnormalities; 23 of the 24 had birth weights above the 10th percentile. No unusual neonatal complications were noted, although 1 baby had transient leukopenia.
Burstein nonetheless cautioned: "It is hard to overestimate the uncertainties and challenges of managing patients such as the one presented in this case. Ultimately, physicians and patients must acknowledge the potential risks and the potential benefits, and work together to make the best treatment decisions for each individual."
In a study published in the journal Cancer Control, Drs. Mary Gemignani and Jeanne Petrek of Memorial Sloan-Kettering Cancer Center in New York noted that many women are delaying childbearing, whether for educational, professional, or personal reasons. Breast cancer risk increases with age; therefore, women who delay childbearing gradually move into a higher risk category for the disease.
Gemignani and Petrek found that of the 178,700 new cases of breast cancer estimated for 1998, between 10-20 percent occurred in women of childbearing age. They summarized a number of studies which showed that breast cancer patients who subsequently become pregnant have good survival rates, often the same or sometimes better than patients with no subsequent pregnancy. However, they highlighted one study that suggested a wait of at least six months after treatment ends may be warranted.
In that study, 72 percent of the enrolled patients became pregnant within two years of treatment. Those who became pregnant within six months had a comparatively poor prognosis-a 54 percent five-year survival rate compared to a 78 percent five-year survival rate among those who waited six months to two years to become pregnant after breast cancer diagnosis.
They concluded that a wait of at least six months from completion of treatment is recommended.
In response to reports of a higher than expected incidence of pregnancy-related breast cancers among carriers of the BRCA1 and BRCA2 genes, a team of British investigators sought to determine how pregnancy affects the risk of breast cancer in this high-risk population.
Writing in the British medical journal The Lancet, the researchers identified 236 women with BRCA1 or BRCA2 mutations who were diagnosed with breast cancer before age 40 and had not undergone preventive mastectomy, hysterectomy or oophorectomy (removal of the ovaries).
The authors concluded that pregnancy increases the risk of breast cancer by age 40 in carriers of the BRCA1 and BRCA2 mutations and that each subsequent pregnancy is associated with an increased cancer risk. For women in general, an early first pregnancy appears to reduce the risk of breast cancer; however, they noted that this benefit does not seem to hold true for carriers of the BRCA genetic mutations. This could have important implications for women receiving genetic counseling, they added.
SOURCES:
"Ask the Experts on ... Treatment of Breast Cancer During Pregnancy?" Medscape Oncology (http://oncology.medscape.com)
Cancer Control, JMCC, 1999; 6(3):272-276
The Lancet, 1999; 354:1846-1850
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