Oncological outcomes of stage I–II breast cancer treatment after subcutaneous/skin-sparing mastectomies with reconstruction

Aim. To study the recurrence of stage I–II breast cancer after subcutaneous/skin-sparing mastectomies with reconstruction with or without radiation therapy. Materials and methods. From 2013 to 2022, 984 patients diagnosed with breast cancer underwent 1020 subcutaneous/skin-sparing mastectomies with reconstruction at the P.A. Herzen Moscow State Medical Institute. Histological types are presented: cancer in situ – 7, invasive cancer without signs of specificity – 818, invasive lobular cancer – 105, combined cancer – 40, rare forms – 50. Subcutaneous mastectomy with reconstruction was performed in 617 (60.5 %), skin-sparing mastectomy in 403 (39.5 %) cases. Reconstruction with own tissues was performed in 5.7 %, expanders/implants in 94.3 % of patients. Patients with diagnosed mutations in the genes ВRCА1, 2, СНЕК2 amounted to 208 (21.1 %), while among patients with primary multiple synchronous cancer, the percentage with mutations was 25 %. Results. In the studied group of patients, recurrence of breast cancer was diagnosed in 40 (4.1 ± 0.1 %) cases, distant metastases – in 52 (5.3 ± 0.1 %) cases. The minimum time to relapse was 36 months, and the maximum was 108 months. In a single-factor analysis of the stage of the disease: at stage I, relapse was diagnosed in 25 (5.8 %) cases, at stage IIA (T2N0M0) – in 5 (2.0 %), at stage IIA (T1N1M0) – in 6 (4.2 %), at stage IIB T2N1M0 – in 4 (2.1 %) (p > 0.05). The recurrence in the group with radiation therapy was 2.5 ± 0.6 (odd ratio 0.98, 95 % confidential interval 1.52–3.48), without radiation therapy 5.1 % (odd ratio 2.13, 95 % confidential interval 0.92–5.18) regardless of the stage of breast cancer (t-criterion >2, p > 0.05). In our study, the recurrence of breast cancer at the edge of R1 was 6.8 ± 2.5 %, at R0 – 3 ± 0.6 % (p > 0.05). When analyzing age and risk of recurrence, we did not identify age dependence, up to 40 years the probability of recurrence is 4.3 ± 1 %, after 40 years – 3.3 ± 0.7 % (t-criterion 0.44, p > 0.05). The dependence of the degree of malignancy of the tumor node and the frequency of recurrence is as follows: G1 – 2. 3 ± 2.3 %, G2 – 3 ± 0.7 %, G3 – 3.9 ± 1 %, when compared G3 c G1 (t-criterion 0.52, p>0.05), when comparing G3 from G2 (t-criterion 0.49, p > 0.05). Recurrence of breast cancer with triple negative type was diagnosed in 2.5 ± 0.9 % relative to other molecular biological types (t-criterion 1.49, p > 0.05). We analyzed the dependence of relapse on the non-luminal and luminal HER2 positive types; the relapse was 5.4 ± 1.5 % (p > 0.05); the dependence on the level of Ki-67; at a level of 40 %, the probability of recurrence is 4 ± 0.8 %, at a level > 40 %, recurrence is 2 ± 0.8 % (t-criterion 1.77, p > 0.05). A statistically significant difference in our study was revealed, in addition to radiation therapy, during neoadjuvant polychemotherapy, so in the group with neoadjuvant polychemotherapy, the recurrence was 2 ± 0.8 %, without neoadjuvant polychemotherapy – 4.1 ± 0.7 % (t-criterion 2.16, р < 0.05). Conclusion. A link between breast cancer recurrence and morphological features (R1 resection margin, lymphovascular invasion, lymphatic tumor emboli, luminal and non-luminal HER2+ subtype, G3) and clinical characteristics (presence of mutations, location of a lesion in the gland, stages) was found. Further search for predictors of breast cancer recurrence after combination or integrated treatment is necessary.