Introduction. Breast cancer is the most frequently experienced malignant neoplasm among women in Poland. The number of new breast cancer cases increases every year. According to the latest report (2009) by the Oncology Centre – Maria Skłodowska-Curie Institute in Warsaw, in 2009 as many as 15752 women developed breast cancer and 5242 of them died. Aim. An attempt to assess the knowledge of female patients hospitalized in the surgical department about the principles of post mastectomy self-care. Material and methods. The study involved 100 consecutive female patients of the Surgical Department of the Regional Specialist Hospital in Radom who underwent a mastectomy there and gave their consent to participate in the survey. This kind of patient selection for the study meets the requirements of a random selection. A diagnostic survey by means of questionnaires was used in the study. Results. 73% of the study participants most often got information on breast cancer prophylaxis from television, radio, and press. For 75% of the respondents the genetic factor was most likely to increase the risk of breast cancer. As many as 83% of the study participants believed that proper treatment was an effective weapon against cancer. 77% of the total were able to perform a breast self-examination. 87% of the respondents said that a doctor was the most reliable source of knowledge of post mastectomy self-care. Conclusions. 1. The study results demonstrated that female patients of the surgical department had insufficient knowledge of the principles of post mastectomy self-care. 2. The level of knowledge of the study participants about breast cancer prophylaxis significantly influenced prevention actions they undertook. 3. Our study results confirmed the thesis that the lack of publicly available publications and a broad-based education campaign on breast cancer prophylaxis and post mastectomy self-care in particular have a great influence on the level of women’s knowledge. 4. According to the study group, doctors and nurses were the most appropriate persons that could provide information on the principles of post mastectomy self-care, but they were not enough engaged in sharing this knowledge.

Key words: knowledge, patients.