The aim of this study was to investigate the relationship between the collagen type I/III ratio and scarring in patients who underwent immediate reconstruction with the round block technique (RBT) after breast conservation surgery. Seventy-eight patients were included, and demographic and clinical characteristics were recorded. The collagen type I/III ratio was measured using immunofluorescence staining and digital imaging, and scarring was assessed using the Vancouver Scar Scale (VSS). The mean VSS scores were 1.92 ± 2.01 and 1.79 ± 1.89, as assessed by two independent plastic surgeons, with good reliability of the scores. A significant positive correlation was found between VSS and the collagen type I/III ratio (r = 0.552, p < 0.01), and a significant negative correlation was found between VSS and the collagen type III content (r = −0.326, p < 0.05). Multiple linear regression analysis showed that the collagen type I/III ratio had a significant positive effect on VSS (β = 0.415, p = 0.028), whereas the collagen type I and collagen type III content had no significant effect on VSS. These findings suggest that the collagen type I/III ratio is associated with scar development in patients undergoing RBT after breast conservation surgery. Further research is needed to develop a patient-specific scar prediction model based on genetic factors affecting the collagen type I/III ratio.

Background/Objectives: Nipple–areolar complex (NAC) necrosis following nipple-sparing mastectomy (NSM) delays adjuvant therapy and compromises oncological outcomes. This retrospective propensity-matched cohort study compared continuous topical oxygen therapy (cTOT), hyperbaric oxygen therapy (HBOT), and standard care (SOC) in patients with NAC necrosis after NSM. Methods: Between January 2020 and August 2025, 213 patients with NAC necrosis after NSM at a single academic center met eligibility criteria (cTOT, n = 57; HBOT, n = 59; SOC, n = 97). Propensity score matching (1:1:1, 15 covariates, all standardized mean differences < 0.1) yielded 57 matched triplets (171 patients). The primary outcome was time to complete epithelialization, with restricted mean survival time (RMST) at 56 days designated as a co-primary metric. Results: cTOT was associated with the fastest healing (mean 30.5 ± 9.9 days vs. HBOT 36.4 ± 9.0, p = 0.007, vs. SOC 45.1 ± 10.6, p < 0.001). RMST analysis demonstrated a mean gain of 14.0 unhealed days (95% CI, 10.5–17.5) for cTOT versus SOC. Eight-week healing rates were 98.2% (cTOT), 96.5% (HBOT), and 87.7% (SOC). Multivariable Cox regression identified cTOT as an independent predictor of accelerated healing (HR 4.61; 95% CI, 2.99–7.11; p < 0.001), with results stable across incision-type and ptosis-grade sensitivity analyses. The treatment association was most pronounced in larger wounds (≥2.0 cm²; HR 6.85; p for interaction = 0.018). cTOT patients also reported significantly lower pain and higher satisfaction, with no device-related discontinuations (0/57). Conclusions: cTOT was associated with significantly accelerated NAC necrosis healing and, as a portable home-based therapy, may support oncological treatment timelines after NSM. The shorter time to adjuvant initiation observed for cTOT (continuous outcome) was not paralleled by a significant reduction in the >6-week delay endpoint, which requires confirmation in multicenter randomized trials.