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The Oncotype DX 21-gene recurrence score (RS) is widely used to guide adjuvant chemotherapy decisions in early-stage estrogen receptor–positive, HER2-negative breast cancer. However, its high cost and frequent discordance with conventional clinicopathologic risk assessment raise questions regarding whether RS can be substituted by other indicators or selectively omitted in specific clinical settings. In this narrative review, we examined whether RS can be reliably predicted or replaced by clinicopathologic or pathology-derived factors, and whether there are patient groups in whom RS testing has limited impact on treatment decision-making. A comprehensive literature search and structured screening process identified 54 studies that treated RS as an outcome variable, together with additional reports addressing selective testing strategies. Across diverse analytical approaches, RS could not be consistently substituted by existing indicators. Although modest correlations were observed, substantial case-level discordance persisted, particularly within the intermediate RS range, where predictive performance deteriorated near clinically relevant decision thresholds. In contrast, RS testing appeared less influential in treatment decisions for patients with clearly defined low- or high-risk clinicopathologic profiles or favorable special histologic subtypes. Overall, current evidence indicates that RS cannot be reliably replaced by other indicators, while its clinical value varies by context, suggesting that a selective rather than uniform application of RS testing may be reasonable in some settings.
With recent advances in chemotherapy for unresectable pancreatic ductal adenocarcinoma (PDAC) with liver metastasis (LM), attempts have been made to resect the primary tumor in patients showing favorable responses to anti-cancer treatment (so-called “conversion surgery”; CS). This study aimed to clarify the outcomes of CS for PDAC with LM in a nationwide multicenter study. This retrospective, multicenter study was conducted as a project study of the Japan Pancreas Society and included patients with PDAC with LM at initial diagnosis, diagnosed radiologically or intraoperatively (occult LM), who underwent CS after at least 4 months of chemotherapy between 2010 and 2022. Survival outcomes and prognostic factors were analyzed. 90 patients were enrolled from 31 Japanese institutions. Median duration of preoperative chemotherapy was 10.4 (range, 4.2–58.5) months, and gemcitabine plus nab-paclitaxel was the most common first-line regimen, followed by folinic acid, 5-fluorouracil, irinotecan, and oxaliplatin. Liver metastasectomy was performed in 27 patients (30
With the increasing availability of data from historical studies and real-world data sources, hybrid control designs that incorporate external data into the evaluation of current studies are being increasingly adopted. In these designs, it is necessary to pre-specify during the planning phase the extent to which information will be borrowed from historical control data. However, if substantial differences in baseline covariate distributions between the current and historical studies are identified at the final analysis, the amount of effective borrowing may be limited, potentially resulting in lower actual power than originally targeted. In this paper, we propose two sample size re-estimation strategies that can be applied during the course of the blinded current study. Both strategies utilize inverse probability weighting (IPW) based on the probability of assignment to either the current or historical study. When large discrepancies in baseline covariates are detected, the proposed strategies adjust the sample size upward to prevent a loss of statistical power. The performance of the proposed strategies is evaluated through simulation studies, and their practical implementation is demonstrated using a case study based on two actual randomized clinical studies.
