Breast adenoid cystic carcinoma (BACC) is a rare subtype of breast cancer that accounts for less than 0.1 % of all cases. This study was designed to assess the efficacy of various treatment approaches for BACC and to create the first web-based tool to facilitate personalized treatment decisions. The Surveillance, Epidemiology, and End Results (SEER) database was used for this study's analysis. To identify the prognostic variables, we conducted Cox regression analysis and constructed prognostic models using five Machine Learning (ML) algorithms to predict the 5-year survival. A validation method incorporating the area under the curve (AUC) of the receiver operating characteristic (ROC) curve was used to validate the accuracy and reliability of ML models. We also performed a Kaplan-Meier (K-M) survival analysis. This study included 1212 patients. The median age was 60 years, with most tumors being localized and less than 2 cm in size. The 5-year overall survival (OS) rates were highest for surgery + radiotherapy (RT) (94.9 %) and lowest for surgery + chemotherapy (CTX) + RT (80.1 %). Positive estrogen receptor (ER) status and younger age were associated with better survival outcomes. ML models identified key predictive features for survival, including age, nodal status, and ER status. Age, lymph node metastasis, and ER status are crucial prognostic indicators for BACC. Although postoperative RT enhances survival, the advantages of adjuvant CTX are uncertain, implying that it may be eschewed to avert adverse effects. Our online tool offers essential resources for prognostication and treatment optimization.

Isolated Locoregionally Recurrent Pancreatic Adenocarcinoma (ILRPA) accounts for 25–30% of recurrences after radical resection, yet the role of salvage radiation (RT) in this setting remains controversial due to limited data. We aimed to evaluate the impact of salvage RT on survival outcomes compared with non-salvage RT in patients with ILRPA. We retrospectively analyzed data of patients with ILRPA post-radical resection treated at our centre between 2012 and 2021. Patients were categorized into two cohorts based on whether salvage RT was administered post-recurrence. Patients who received a minimum of 30 Gy in 10 fractions (BED₁₀ ≥ 39 Gy) were included for analysis. The clinical characteristics, treatments, and outcomes were analyzed. The chi-square or Fisher’s exact test for categorical variables and Student’s t-test or Wilcoxon rank sum test for continuous variables were utilized for comparisons. The Kaplan–Meier method and log-rank test were performed to compare overall survival (OS) and progression-free survival (PFS) between the two groups. OS and PFS were calculated from the time of locoregional recurrence until event or loss of follow-up. Thirty-two patients were identified, with sixteen patients in each group. The patients and tumour characteristics were balanced between the two cohorts, except for chemotherapy, where the salvage RT group tended to receive palliative chemotherapy more than the non-salvage group (p = 0.007). The median radiotherapy dose received for the salvage RT cohort was 50.4 Gy (BED₁₀ = 59.5 Gy). Chemotherapy was restarted in 75% either before, after, or during radiation, and only in 31.25% of patients in the non-salvage group (p = 0.013). Patients who received salvage RT had statistically significantly better median OS and PFS than those who did not (25.2 vs. 8.4 months, p = 0.0006, HR 0.25, 95% CI (0.11–0.59)), (15.6 vs. 7.2 months, p = 0.0006, HR 0.26, 95% CI (0.11–0.58), respectively). Ten patients (62.5%) developed distant metastases (DM) at least 3 months post-recurrence in the salvage RT cohort compared to five patients (31.25%) in the non-salvage RT cohort (p = 0.08). In the salvage RT group, 10/16 patients (62.5%) maintained locoregional disease control post-RT. Salvage RT was associated with better OS and PFS in patients with ILRPA, highlighting its potential as an essential treatment modality. While salvage RT appears beneficial, confounding factors like chemotherapy disparities between groups necessitate further investigation in prospective cohorts.