Analogous Cellular Contribution and Healing Mechanisms Following Digit Amputation and Phalangeal Fracture in Mice

Regeneration of amputated structures is severely limited in humans and mice, with complete regeneration restricted to the distal portion of the terminal phalanx (P3). Here, we investigate the dynamic tissue repair response of the second phalangeal element (P2) post amputation in the adult mouse, and show that the repair response of the amputated bone is similar to the proximal P2 bone fragment in fracture healing. The regeneration-incompetent P2 amputation response is characterized by periosteal endochondral ossification resulting in the deposition of new trabecular bone, corresponding to a significant increase in bone volume; however, this response is not associated with bone lengthening. We show that cells of the periosteum respond to amputation and fracture by contributing both chondrocytes and osteoblasts to the endochondral ossification response. Based on our studies, we suggest that the amputation response represents an attempt at regeneration that ultimately fails due to the lack of a distal organizing influence that is present in fracture healing

71 No survival difference in patients receiving radical hysterectomy vs. extrafascial hysterectomy in stage II–IV endometrial cancer patients: a multivariate analysis

Objectives: The objective of this study was to determine whether there is a difference in overall survival (OS) among patients with FIGO Stage II–IV endometrial cancer who have undergone extrafascial hysterectomy (EFH) versus radical hysterectomy (RH). Methods: A retrospective review was performed by utilizing the California Cancer Registry to identify women located in the Central Valley of California (CVR) who had undergone surgery for FIGO stage I–IV endometrial cancer between 2011 and 2021. Minimally invasive and abdominal surgery were both included in the analysis. Demographic data including age, race, residence location, language, and insurance type were collected. We included histologic subtypes and treatment types (surgery, radiation, chemotherapy) as part of the multivariate analysis for 5-year OS. We then determined the percentage of patients who underwent EFH versus RH using Pearson chi square test. Cox regression models were used to create survival curves among women diagnosed with Stage II–IV disease. Results: Over our 10-year study period, a total of 868 women were identified who underwent surgery for endometrial cancer. A total of 737/868 (85%) underwent EFH and 44/868 (5%) underwent RH. Of the patients who underwent RH versus EFH, 56.8% (25/44) compared to 28.1% (207/737) were subsequently diagnosed with Stage II–IV disease on final surgical pathology, respectively (p<0.001). There was no significant difference in OS between patients who underwent RH versus EFH for FIGO stage II–IV (hazard ratio=1.40, p=0.89). For patients with Stage II and above, while controlling for other covariates, the risk of death was significantly higher for patients between the ages 70–80 years (HR=1.92, p=0.049) and for patients ages 80 and older (HR=3.79, p<0.001) compared to their younger counterparts. Conclusions: Among women who underwent surgical staging for endometrial cancer in the CVR, the patients who underwent RH were more likely to be diagnosed with at least Stage II disease compared to those who underwent EFH. However, RH had no improvement in OS in this retrospective review. Additionally, a significant percentage of patients who had radical hysterectomy were ultimately diagnosed at Stage I disease (43.2%). Prospective data is needed for the role of radical hysterectomy in locally advanced endometrial cancer patients