Sex Linked to Survival Gains After Neoadjuvant Chemoradiotherapy in Resected Pancreatic Cancer
A sex-based survival difference emerged in resected pancreatic ductal adenocarcinoma after gemcitabine-based neoadjuvant chemoradiotherapy. Women treated with nCRT before surgery had a 5-year overall survival rate of 43%, compared with 22% in men.
The finding comes from the PREOPANC randomized controlled trial and places biology at the center of a clinical question that has long been difficult to resolve: why do some patients derive deeper benefit from preoperative treatment than others? In this cohort, the answer appears to involve the interaction between sex, treatment exposure, and the tumour immune microenvironment.
Patients in the analysis came from two surgical pathways. Eighty-two underwent upfront resection, while 66 received neoadjuvant chemoradiotherapy before resection. The investigators assessed overall survival with Cox proportional hazards models and then explored the tumour microenvironment with transcriptomic and spatial proteomic profiling. The result was not just a survival signal, but a biologically coherent pattern that pointed toward enhanced antitumour immunity in women after nCRT.
Survival Diverged Only After Preoperative Treatment
Sex did not function as a simple prognostic marker across all patients. Its effect became clear in the subgroup that received neoadjuvant chemoradiotherapy.
In multivariate analysis, female sex was an independent favourable prognostic factor for overall survival only in the nCRT group, with a hazard ratio of 0.19 and a 95% confidence interval of 0.07 to 0.52. The heterogeneous treatment effects analysis went a step further and identified a significant interaction between sex and treatment, supporting the idea that women experienced greater benefit from nCRT than men.
That pattern matters because it separates baseline prognosis from treatment sensitivity. The operation itself did not appear to explain the difference. The added preoperative exposure to gemcitabine-based chemoradiotherapy did.
Tumour Immunity Looked Different in Women
The immune architecture of the tumours offered a plausible mechanism for the survival gap. After nCRT, women’s tumours contained fewer protumoural CD163+MRC1+ M2 macrophages than men’s tumours. The study supported this observation first through transcriptomic analysis and then through validation with spatial proteomic profiling.
M2 macrophages are classically associated with immunosuppression, tissue repair, and tumour support rather than tumour rejection. Their reduced presence in women after nCRT suggests a microenvironment that was less permissive to immune escape and more hostile to residual cancer cells. In pancreatic cancer, where the stromal and immune milieu often shields malignant cells from effective clearance, even a shift in macrophage polarization can have clinical consequences.
The practical implication is straightforward. Women in this cohort seemed to mount a stronger antitumour response after neoadjuvant treatment, and that immune advantage tracked with better long-term survival.
Why the Immune Microenvironment Matters in Pancreatic Cancer
Pancreatic ductal adenocarcinoma remains one of the most treatment-resistant solid tumours in oncology. Its dense stroma, immune exclusion, and suppressive macrophage populations all conspire to blunt therapeutic effect. For that reason, any factor that reshapes the tumour microenvironment may influence whether preoperative therapy produces a meaningful survival benefit.
This study suggests that sex is one such factor. The female tumours after nCRT carried fewer markers of immunosuppressive macrophage predominance, which may reflect a more effective response to therapy-induced tumour injury or a different baseline immune set point. Either way, the biological readout was consistent: antitumour immunity appeared stronger in women.
The data also raise a clinically relevant possibility. If tumour immune polarization differs by sex, then a one-size-fits-all approach to neoadjuvant treatment may miss a meaningful source of heterogeneity in response. For a disease in which recurrence remains common even after surgery, identifying patients most likely to benefit from preoperative chemoradiotherapy is not an abstract exercise.
It is a route to better selection before a major operation.
What the PREOPANC Cohort Adds to Clinical Decision-Making
The PREOPANC trial already had a central role in evaluating neoadjuvant therapy in pancreatic cancer. This analysis extends that work by asking whether sex modifies the relationship between treatment and survival. The answer was yes, at least in this dataset and with this regimen.
The study did not simply observe a difference in outcomes; it linked the difference to a measurable feature of the tumour microenvironment. That combination of clinical and molecular findings makes the report more useful than a survival comparison alone. It suggests that treatment sensitivity may be shaped by immune contexture, not just by anatomy, tumour burden, or surgical success.
For clinicians, the immediate message is not to alter treatment solely on the basis of sex. The cohort is still limited to a specific trial population, a gemcitabine-based regimen, and a resected PDAC setting. But the findings do argue for closer attention to biological response markers, especially those related to macrophage polarization and immune suppression.
A Sex-Specific Signal With Clear Translational Implications
The strongest signal in the analysis was the interaction between sex and neoadjuvant chemoradiotherapy. Women fared better after nCRT, and their tumours showed fewer protumoural M2 macrophages. Those two observations point in the same direction.
This is a case where the microenvironment is not a side observation. It is part of the explanation for the clinical outcome. A tumour that is less saturated with immunosuppressive macrophages may be less able to recover from chemoradiation-induced damage, less able to protect surviving malignant cells, and less able to seed recurrence after resection.
The study leaves open whether this pattern would hold with other neoadjuvant regimens, modern multi-agent chemotherapy, or different patient populations. It also does not resolve whether sex itself drives the immune differences or whether sex-linked biology interacts with treatment in more complex ways. What it does establish is that, in resected pancreatic cancer, women in this trial derived greater survival benefit from nCRT and showed a tumour immune profile consistent with enhanced antitumour activity.
For a disease where prognosis often remains poor even after surgery, that distinction is clinically consequential.