Rochester General Hospital

We report a case of severe hypercalcaemia after a single cycle of a combination therapy of ipilimumab and nivolumab. Initial evaluation ruled out common causes, including bone metastases, parathyroid hormone/parathyroid hormone-related protein elevation and paraproteinaemia. Her serum 1,25-dihydroxyvitamin D (calcitriol) levels were significantly elevated following the first immunotherapy cycle. Hypercalcaemia responded only to glucocorticoid therapy, with normalisation of serum calcium and calcitriol levels. Recurrence of hypercalcaemia after glucocorticoid discontinuation and subsequent resolution with glucocorticoid re-initiation strongly supported a calcitriol-mediated mechanism, most likely as an immune-related effect of ipilimumab and nivolumab.

807 Background: Geographic access to clinical trials is critical for equitable cancer care. Gastrointestinal (GI) cancers—including colorectal, pancreatic, liver, gastric, esophageal, and biliary—account for over a quarter of U.S. cancer deaths. Despite this burden, the geographic distribution of active GI cancer trials has not been systematically evaluated, particularly by cancer subtype and population factors such as rurality, socioeconomic status, and race/ethnicity. Methods: All active, interventional Phase I–III GI cancer trials were identified from ClinicalTrials.gov (accessed September 5, 2025), restricted to U.S.-based therapeutic studies. Trial sites were geocoded by ZIP code and mapped to 2020 Census ZIP Code Tabulation Areas (ZCTAs). Geographic access was defined as the proportion of the U.S. population residing within 30 or 60 miles of a site using Haversine distance. Analyses were stratified by cancer subtype, rurality (RUCA codes), income quartile, and race/ethnicity (ACS 2023). Results: We identified 958 active GI cancer trials (287 colorectal, 260 pancreatic, 136 gastric, 86 esophageal, 108 hepatocellular carcinoma [HCC], 81 cholangiocarcinoma) across &gt;4,400 U.S. ZIPs. At 30 miles, population coverage exceeded 80% for colorectal and pancreatic cancers but was lower for HCC (61%) and cholangiocarcinoma (64%). At 60 miles, coverage was &gt;90% for colorectal, pancreatic, and gastric cancers but remained &lt;80% for HCC and cholangiocarcinoma. Subgroup analysis showed 30-mile coverage for HCC was 71.0% among urban vs 9.6% among rural residents, and 42% vs 86% for lowest- vs highest-income quartiles. Hispanic and Black populations had 30-mile coverage of 67% and 70%, respectively. Conclusions: Geographic coverage of GI cancer trials in the U.S. varied by cancer type, with lower access for HCC and cholangiocarcinoma compared with colorectal and pancreatic cancers. Coverage was also reduced in rural, lower-income, and Hispanic and Black populations. These findings highlight geographic and demographic gaps in trial availability and can inform efforts to improve equitable trial access. Population coverage within 30 and 60 miles of GI cancer trial sites, by cancer type and subgroups. Cancer Type No. Trials (NCT IDs) Trial Phase Distribution (I/II/III) No. Sites (ZIPs) Pop Cov (%) (30/60m) Urban Pop Cov (%)(30/60m) Rural Pop Cov (%)(30/60m) Low Income Quartile Cov(%)(30/60m) High Income Quartile Cov(%)(30/60m) Hispanic Pop Cov(%)(30/60m) Black Pop Cov(%)(30/60m) Colorectal 287 123/149/15 1211 83/93 91/96 44/80 65/84 98/99 84/91 85/94 Pancreatic 260 109/132/19 1079 81/92 89/95 42/79 62/83 97/99 81/88 83/92 Gastric 136 59/68/9 966 79/90 87/93 41/75 60/78 96/99 81/87 81/90 Esophageal 86 36/46/4 546 71/84 80/90 24/61 49/69 93/97 74/82 75/85 Liver (HCC) 108 34/67/7 271 61/76 71/83 10/41 42/61 86/93 67/79 70/80 Cholangio 81 24/52/5 398 64/80 74/86 17/50 45/63</