Sreenivasa R. Chandana

Background: Circulating tumor (ct)DNA is a prognostic biomarker in gastrointestinal malignancies. In rectal cancer, its utility to inform perioperative management and predict recurrence, particularly in patients undergoing non-operative management (NOM), remains unclear. Studies are needed to clarify how post-neoadjuvant therapy (NAT) and post-surgical ctDNA status correlate with clinical outcomes in localized rectal cancer. Methods: We retrospectively analyzed ctDNA data from 220 patients with rectal cancer using a personalized tumor-informed assay (Signatera™, Natera, Inc., Austin, TX, USA). Of these, 148 (67.3%) underwent NAT followed by surgery, and 72 (32.7%) underwent NAT followed by NOM. We assessed associations between post-NAT ctDNA status and survival outcomes. In the surgical cohort, we examined associations between post-operative ctDNA status and clinical response, pathological response, survival outcomes, and NAR scores. Results: In the surgical cohort, ctDNA positivity at the post-operative MRD timepoint was a strong predictor of recurrence, with an 88.3% relapse rate compared to 11.5% in ctDNA-negative patients (p < 0.001). Among the 64 NOM patients with post-NAT ctDNA, 21.9% (14/64) were ctDNA-positive, of whom 100% (14/14) relapsed (92.9% local-only), 13 relapsed by the time of data cut-off, and one relapsed 8 months after the cut-off. Only 10% (5/50) of the ctDNA-negative NOM patients experienced local recurrence (p < 0.0001). ctDNA positivity post-NAT was associated with inferior DFS (p = 0.003). Conclusion: ctDNA was a strong predictor of recurrence in rectal cancer, including in NOM settings. In NOM patients, ctDNA detected local recurrences, highlighting its potential to guide post-NAT surveillance and treatment.

Background: Small molecule fibroblast growth factor receptor (FGFR) inhibitors, such as pemigatinib, have been developed for the treatment of cholangiocarcinoma (CCA) with rearrangements or fusions in the FGFR2. FGFR inhibitors (FGFRis) have dermatologic side effects such as dry skin or nail bed damage. However, in very rare instances, a life-threatening vascular calcification disease known as calciphylaxis has been linked to these therapies. Case Description: We report a patient with metastatic CCA, who developed calciphylaxis following the start of their pemigatinib treatment. Calciphylaxis is associated with skin lesions and affects the dermal microvasculature in addition to the vascular calcification. This case focuses on the management strategy used for this rare adverse event (AE) as well as the pathology and complicated mechanism of calciphylaxis. We highlight the unclear pathophysiology behind this disease by identifying key players in the signaling and molecular pathways in the microenvironment that are needed to trigger this pathology. Conclusions: Calciphylaxis is normally associated with advanced renal failure in the setting of high phosphate and calcium. However, the patient we present here did not have advanced renal failure or high calcium levels and calcium dysregulation. As FGFRi use becomes more widespread, the more important it becomes to identify and have a treatment strategy for this rare AE.

The development of novel biomarkers for cancer has exploded over the last decade with advances in novel technologies. Cholangiocarcinoma (CCA), a cancer of the bile ducts, has a dearth of strong disease and pathophysiology biomarkers, making early detection and prognostication a difficult task. In this comprehensive review, we discuss the spectrum of biomarkers for CCA diagnosis and prognostication. We elaborate on novel biomarker discovery through a comprehensive multi-omics approach. We also cover, how certain biomarkers may also serve as unique and potent targets for therapeutic development. Despite the relatively poor diagnostic and prognostic performance of existing biomarkers for CCA, there is a vast range of novel biomarkers with exquisite diagnostic and prognostic performance for CCA in the pipeline. Moreover, these biomarkers may serve as potential targets for precision medicine. Existing strategies to target unique biomolecular classes are discussed, within the context of an overall ‘omics’ focused profiling strategy. Omics profiling will simultaneously allow for enhanced biomarker development and identification of unique subtypes of cholangiocarcinoma and how they are influenced by an individual’s unique context. In this manner, patient management strategy and clinical trial design can be optimized to the individual.

Fibroblast growth factor receptors (FGFR 1–4) are a highly conserved family of receptor tyrosine kinases, involved in several physiological processes. Genetic aberrations of FGFRs and their ligands...