I have a 49-year-old patient who underwent distal subtotal pancreatectomy and splenectomy in 2022 for a pancreatic body adenocarcinoma, stage IIB (pT2N1 G2 R0), with perineural and lymphovascular invasion and tumor involvement in 1/8 regional lymph nodes He had a surgical margin positive for high-grade PIN with negative margins for invasive disease. His preoperative CA19-9 of 140 normalized after surgery. He began adjuvant FOLFIRINOX in 2023. He has a longstanding history of diabetes mellitus and had mild peripheral neuropathy prior to adjuvant chemotherapy. He developed significant worsening of his peripheral neuropathy after his fourth cycle of FOLFIRINOX and declined further oxaliplatin. He has received irinotecan/infusional 5-FU for two additional cycles of treatment with significant ongoing gastrointestinal toxicity. His neuropathy has not improved to this point with gabapentin and holding of oxaliplatin. Germline mutation testing has revealed a PMS2 mutation. Given his neuropathy and poor tolerance of irinotecan-based chemotherapy, would it be reasonable to change him to gemcitabine-capecitabine for the remainder of his adjuvant chemotherapy?
Yes this would be reasonable, especially if appropriate dose reductions have been done for FOFLIRI. considering his increased toxicity for IRI, has his UGT1A1 been checked? as well as DPD(less likely). these patients with UGT1a1 mutations, often need 25-50% dose reduction of irinotecan to proceed with therapy. of all of this has been done, you can switch to gem/xeloda to complete his full 6 months of adjuvant, as he is higher risk with both PNI, LVI and LN+.
