Stromal progesterone receptor expression and long-term survival in patients with resected periampullary adenocarcinoma

Background: Early trials have reported a beneficial effect from tamoxifen treatment in patients with unresectable pancreatic cancer, in particular in women. However, the presence and prognostic significance of female hormone receptors in pancreatic or other periampullary cancers has not yet been described. Methods: Immunohistochemical screening of normal and malignant pancreatic tissue revealed that the predominantly expressed female hormone receptor was the progesterone receptor (PgR), in particular in the cancer-associated stroma. The impact of PgR expression on overall survival (OS) was further examined on tissue microarrays with primary tumours from a consecutive retrospective cohort of 175 patients with resected periampullary adenocarcinoma. Results: Median follow-up time was 29.7 (range 1.9–185.1) months. Stromal PgR positivity (PgR+), allover denoted in 31% of the cases, was significantly higher in pancreatobiliary-type than in intestinal-type tumours (38.7% vs 19.0%, p = 0.008), with an equal distribution between sexes. Stromal PgR+ was significantly associated with a prolonged OS in KRAS-mutated tumours, whereas the opposite was seen in KRAS wild-type tumours (p for interaction =0.015). This association was particularly evident in women, with a median OS of 60.5 months for PgR+/KRAS mutated tumours and 9.9 months for PgR+/KRAS wild-type tumours (p for interaction <0.001). PgR expression was not prognostic in male patients. Conclusions: The finding of stromal PgR expression, and its link to clinical outcome in a considerable proportion of pancreatic and other periampullary cancers is novel. The concept of tamoxifen treatment for patients with unresectable disease, in particular elderly women, should be pursued, and PgR and KRAS may be relevant biomarkers for improved patient stratification.