PABC represents a unique clinical scenario that requires a delicate balance of risks and benefits for both maternal and fetal well-being. The most urgent task of the radiologist is to avoid a delayed in diagnosis.
Women with PABC have a higher predisposition to familiar breast cancer [2, 10]. In our study,36% of PABC patients presented a family history of breast cancer and, in line with the most recent published literature, the most frequent onset is the third decade [2, 5, 7, 9, 11, 18]. The diagnostic work up in PABC may be challenging, since all physiological changes that happen during pregnancy may blur those related to breast cancer and delay the diagnosis [6, 8, 9, 11, 12, 16, 17, 19]. In our study, 80% of our patients had a palpable mass and this is in good agreement with what is reported in the literature that breast cancer diagnosed during pregnancy is symptomatic, as a palpable mass [6, 7, 10].
According to clinical guidelines, diagnostic procedures for pregnant patients should not differ from those for non-pregnant women. Ultrasound (US) is the imaging method of first choice in symptomatic pregnant or lactating women, and have a sensitivity of nearly 100%, compared to mammography [12]. However, mammography can be safely performed if an abdominal shield is applied [20–22]. Magnetic Resonance (MR) imaging in the evaluation of pregnant or lactating patients can be considered, but there is no international consensus to the use of gadolinium during pregnancy. The ACR does not recommend the IV administration of gadolinium (Gad) as gadolinium-based contrast agents are known to cross the placental barrier [19]. On the other hand the ACOSOG state that the use of Gad-contrast agents should be considered only if it significantly improves fetal or maternal outcome [23–25].The reported tumor size in PABC patients tend to be greater than 5 cm[3, 5, 6, 11, 13], matching 26% of our cases, and the most frequent size between 2.1-5 cm in 30% of our population.
The imaging features of PABC are like those of non-gestational breast cancer, the most common sonographic finding being a mass [11, 20]. Mammography has a low sensitivity (78 to 100%) due to increased breast density[2, 6, 7, 13, 19]. Nevertheless, mammography plays a complementary role in the evaluation of these patients and must always be performed if cancer is suspected. Mammographic features of PABC do not differ from those of non-PABC and include masses, microcalcifications, asymmetrical density, architectural distortion, and skin thickening[20, 21].
In any suspicious imaging finding, ultrasound-guided core biopsy under local anesthesia should be obtained as histopathology diagnosis based and is the gold standard for PABC diagnosis[8, 20, 21]. Most of our patients (92%) were diagnosed with percutaneous biopsy, even so8% were through surgical biopsy. No complication after biopsy were reported.
In our study, invasive ductal carcinoma was the most common pathological type, accounting for 90% of all cases, 84.6% being histological high grade (G3). This is consistent with the results of similar studies in other populations[2, 8, 10, 13, 15, 24]. The most common molecular subtype found was triple negative in 36%, followed by ER+/PR + Her2 negative in 28%, different from what was previously reported[6, 8, 26–28].
Metastasis to internal organs in literature reaches around 20% of cases. We found a higher percentage with 31%, perhaps secondary of a major incidence of Triple negative breast cancer, presented in the half of these cases[9][8].
Once diagnosis was made, it is important not to delay treatment. Per guidelines surgery, mastectomy or conservative surgery can be safely performed. Breast reconstruction surgery is not recommended during pregnancy[6, 8, 22, 29–31]. Systemic treatment should follow the recommendations that apply to the rest of the breast cancer population [6]. When administered during pregnancy, chemotherapy is usually performed in the middle stage of pregnancy when the safety of mother and fetus can be ensured [2, 6, 22, 26, 27].
The prognosis of early PABC is still controversial with most studies reporting a poor prognosis[2, 7]. Prognosis of metastatic PABC is generally poor and the expected 5-year survival is only about 10% [6, 22, 29]. Recurrences are common and typically appear within 2–3 years of diagnosis[7].