Long Term Survival of a Patient with a Rare Mucinous Carcinoma Arising from Intraductal Papillary Mucinous Neoplasm Status Post R1 Distal Pancreatectomy/Splenectomy and Adjuvant Therapy: A Case Report

Purpose: In 2011, the US Intergroup published the results of the RTOG 97-04 trial, suggesting a local control benefit to adjuvant gemcitabine in combination with 5-FU based chemoradiation (CRT) for patients with pancreas head cancer (PC) adenocarcinoma (ACA) (1). More recently, Conroy published the superior survival of adjuvant FOLFIRINOX alone compared to gemcitabine in the setting of largely pancreatic head ductal ACA. Over 40% of patients in each arm underwent R1 resection (2). The most effective adjuvant regimen for PC ACA remains controversial. Few data report adjuvant outcomes of the rare mucinous carcinoma arising from Intraductal Papillary Mucinous Neoplasm (IPMN) and fewer still report outcomes of the pancreatic body (3,4). This case examines the long-term outcome of a 63-year-old male with this rare tumor.

Methodology: The patient’s case was reviewed as part of an IRB exempt retrospective study. His clinical record, imaging, dosimetry records, treatment plan, and treatment images were reviewed by the study team.

Results: In 2009, initial imaging showed a PET negative 3.0 by 3.4 cm complex cystic mass in the body of the patient’s pancreas. Fine needle aspiration (FNA) revealed IPMN with moderate dysplasia. Given future malignant potential, the tumor board recommended surgical resection. Surgical pathology showed a T3 (3.5cm) N0 (0/16) M0 intestinal type mucinous carcinoma which was well-differentiated and had no lymphovascular invasion or perineural invasion. The closest margin was 0.1 mm. Adjuvant therapy consisting of gemcitabine and 5-FU based CRT to 50.4 Gy as per the RTOG trial with volumetric arc Intensity Modulated Radiation Therapy (IMRT) with daily image guidance was delivered. The patient has been without evidence of disease for over 14 years.

Conclusions: The RTOG 9704 adjuvant regimen was applied to this patient’s rare mucinous tumor status post R1 resection with long term cure. Despite the paucity of literature, the few reported studies do support adjuvant therapy strategies containing CRT for mucinous tumors in the setting of adverse pathologic features such as positive margins.

References: 1. Regine WF, Winter KA, Abrams RA et al. Flurouracil based chemoradiation with either gemcitabine or Fluorouracil chemotherapy following resection of pancreatic adenocarcinoma: 5 year analysis of the US Intergrou /RTOG 9704 Phase III trial. Ann Surg Oncol 2011; 18(5): 1319-26.
2. Conroy T, Hammel P, Hebbar M et al. FOLFIRINOX or Gemcitabine as Adjuvant Therapy for Pancreatic Cancer. N Engl J Med 2018; 379: 2395-2406.
3. Aronsson L, Marinko S, Ansari D et al. Adjuvant therapy in invasive Intraductal Papillary Mucinous Neoplasm (IPMN) of the pancreas: a systematic review. Ann Transl Med 2019; 7(22): 1-6.
4. Seaton M, Hanna A, Boutros C et al. Adjuvant therapy for pancreas body or tail adenocarcinoma: as study from the National Cancer Database. Ther Adv Med Onc 2019; 11: 1-12.