Is pregnancy not protective against breast cancer?Pregnancy at an early age is protective against breast cancer in the long term due to the positive effect of hormones on the development of breast tissue. It is known that the risk of developing breast cancer in women who have had their second birth before the age of 30 is reduced by 30%. However, in late pregnancy, cells with breast cancer potential may rapidly differentiate and multiply by the effect of pregnancy hormones. Breastfeeding increases the resistance to breast cancer and has a protective effect.Is breast cancer frequent in pregnancy?Breast cancer is the second most common cancer in pregnancy after cervical cancer. However, it is not common.Is breast cancer worse when seen during pregnancy?Most of the time, growth caused by pregnancy hormones and milk accumulation prevents the early detection of breast masses and patients present in the late period. Due to the late stage of breast cancers seen in pregnancy being in higher stage and not being able to apply standard treatments in pregnancy due to the concern that it may harm the baby, these cancers are known to have a worse course. However, survival is the same as in breast cancer of the same stage in non-pregnant women.What are your recommendations for early diagnosis?It is important that the patient is under the control of the gynecologist from the beginning of pregnancy. In addition to the general examination, breast examination is performed at doctor visits. When a persistent mass in the breast is noticed, the patient is referred to the general surgeon and further examination is performed. Approximately 90% of the patients have a first breast mass. However, it should be remembered that approximately 80% of the masses during pregnancy are benign lesions such as milk cyst, sebaceous gland, fibroadenoma. In case of discoloration, blistering, shrinkage, edema and nipple discharge, the surgeon should also evaluate the patient.Which radiological tests can be performed in pregnant women?Ultrasonography is the safest pregnancy during pregnancy, it does not give radiation to the baby, it can also evaluate the lymph nodes under the armpit and biopsy can be performed in suspicious lesions. However, changes in breast tissue during pregnancy decrease the sensitivity of ultrasonography. If necessary, mammography can be performed using plates that prevent radiation transmission to the abdominal region. It should be kept in mind that the contrast agent given in magnetic resonance imaging is transmitted to the child and should not be used for this reason. Ultrasonography should be preferred for the evaluation of abdominal distension. Computed tomography should not be used in pregnant women.What kind of treatment is applied to a woman diagnosed with breast cancer during pregnancy?The treatment depends on which stage of the disease diagnosis is made. Surgical intervention can be performed at any stage of pregnancy without damaging the baby. Breast sparing surgery requires radiotherapy after 16 weeks. However, radiotherapy causes developmental disorders in the unborn baby. Therefore, in cases diagnosed early in pregnancy, the entire breast should be removed. If the diagnosis is made after the 5th month of pregnancy, breast-conserving surgery can be applied by leaving radiotherapy to the postnatal period. Use of blue dye in the evaluation of armpit spread is not recommended in pregnant women. It is noted that low-dose radioactive material may be used instead. However, nowadays, the standard approach in pregnant women is the axillary dissection procedure in which the breast-related part of the axillary lymph nodes are cleaned. Chemotherapy can be started from the 5th month of pregnancy by selecting the appropriate drugs.