Pancreatic cancer treatment is inherently challenging, largely because the disease is often detected at a late stage and not all patients are candidates for immediate surgical resection. Many patients are diagnosed at the borderline resectable or locally advanced stage, where tumors invade major blood vessels and surgery cannot be performed upfront. While surgery remains the only potentially curative option, whether a tumor can be resected—and whether it can be completely removed—is often determined before the operation. As a result, neoadjuvant or conversion therapy has become increasingly important in recent years, with the goal of shrinking tumors prior to surgery and creating an opportunity for resection.

A Taiwan-Developed Chemotherapy Regimen That Extends Survival
SLOG is a multi-agent chemotherapy regimen combining S-1, leucovorin, oxaliplatin, and gemcitabine. It was developed by Taiwan’s National Health Research Institutes in 2017. Compared with mainstream Western regimens, SLOG demonstrates comparable efficacy while being significantly more tolerable. It does not cause hair loss and can be administered in the outpatient setting.

Because of its high tolerability, patient acceptance is strong, allowing more patients to complete the full treatment course. As a result, the proportion of patients able to continue adjuvant chemotherapy after surgery exceeds 90%. This is critical for improving long-term survival. Experience at Taipei Veterans General Hospital (TVGH) shows a median overall survival of 11 to 12 months, reflecting a balance of effectiveness and tolerability.

Carbon Ion Radiotherapy Precisely Targets the Tumor
Following chemotherapy, carbon ion radiotherapy (CIRT) serves as the second core component of neoadjuvant treatment. TVGH is the only hospital in Taiwan—and one of only a few worldwide—equipped with carbon ion therapy facilities. Carbon ions have a relative biological effectiveness (RBE) two to three times that of photons, along with highly precise dose distribution. This allows energy to be concentrated within the tumor itself, rather than passing through the body as in conventional photon radiotherapy.

These physical and biological properties make CIRT particularly well suited for pancreatic tumors located in anatomically complex regions adjacent to the duodenum, stomach, bile ducts, and major blood vessels. For patients with locally advanced disease who are initially deemed unresectable due to vascular involvement, carbon ion therapy offers a distinct advantage.

Clinical Cases Demonstrate Tumor Control
TVGH has treated more than 110 pancreatic cancer patients with CIRT to date. Among them, eight patients achieved significant tumor shrinkage and regression of vascular invasion through the integrated use of SLOG chemotherapy and CIRT, converting previously unresectable tumors into resectable ones and ultimately enabling successful surgical removal. Throughout treatment, the tumor marker CA19-9 consistently declined—from baseline to post-chemotherapy and further after CIRT—indicating effective tumor control.

One 74-year-old patient presented with upper abdominal discomfort and weight loss and was diagnosed with pancreatic head cancer involving the superior mesenteric artery and vein, rendering the tumor unresectable. After chemotherapy and carbon ion radiotherapy, the original 4 cm tumor shrank to the point of being nearly undetectable on imaging. Six months later, the patient underwent pancreaticoduodenectomy. The surgical specimen showed almost no gross residual tumor, with pathology revealing only a small number of remaining cancer cells. CA19-9 levels dropped from 219 to 12.4 (normal <27). Before the advent of carbon ion therapy, patients with this degree of vascular involvement had virtually no chance of surgical intervention; today, they may gain a realistic opportunity for cure.

Through a precision medicine strategy combining SLOG chemotherapy with carbon ion radiotherapy, Taipei Veterans General Hospital has created new surgical opportunities for patients with previously unresectable pancreatic cancer—offering them a renewed chance at recovery and long-term health.