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Treating a pregnant woman diagnosed with breast cancer is a difficult clinical scenario facing a variety of clinicians, obstetricians, radiologists, surgeons, medical oncologists, and radiation oncologists, just to name a few. Unfortunately, there is a paucity of randomized, clinical trial data to guide the treating physicians.1,2 Thus the clinicians must rely on retrospective data and clinical experience to determine an individual patient's treatment plan. This chapter will summarize the best currently available evidence for treating a pregnant woman with breast cancer.
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The traditional definition of pregnancy-associated breast cancer (PABC) is that the diagnosis of breast cancer is made during pregnancy or within 1 year afterwards. Using this definition, epidemiologic data demonstrate that a breast cancer is diagnosed once in every 3000 pregnancies.3 The median age of pregnant women affected with breast cancer is 33 years (range, 23-47 years).2,4 As more and more women are delaying motherhood until their 30s or even 40s,5 PABCs should be increasing, but convincing epidemiologic data are not yet available.
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Historically, PABC patients had a dismal prognosis. Kilgore and Bloodgood6 reported no survivors, whereas Haagensen and Stout7 reported an 8.6% overall 5-year survival rate, and White8 reported a 17% 5-year survival rate.
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Harrington9 is credited with reviving at least a bit of optimism for these patients in 1937 by demonstrating a 61% 5-year survival rate among patients with negative lymph nodes. However, the majority of PABC patients present with metastatic disease in the regional nodal basin.10 When compared with age-matched, nonpregnant peers, the node-negative and node-positive 5-year survival is quite similar.11 Petrek et al11 reported that patients with PABC with tumor-free lymph nodes had an 82% 5-year survival rate, compared with an 82% rate for their nonpregnant counterparts. The pregnant patients with tumor-involved lymph nodes had a 47% 5-year survival rate compared with a 59% rate in the control patients; the difference was not statistically significant. This similar survival rate between pregnant breast cancer patients and their nonpregnant peers has been confirmed by others12-15 (Table 89-1).
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