Concurrent high-dose intensity-modulated radiotherapy and chemotherapy for unresectable locally advanced and metastatic pancreatic cancer: a pilot study

Aim: To evaluate the efficacy of concurrent chemotherapy and high-dose (≥55 Gy) intensity-modulated radiotherapy (CCIMRT) in comparison with chemotherapy alone and intensity-modulated radiotherapy (IMRT) alone for unresectable locally advanced or metastatic pancreatic cancer. Methods: Forty-six patients with pancreatic cancer undergoing CCIMRT (n = 17), chemotherapy alone (n = 16) or IMRT alone (n = 13) were analysed. Overall survival (OS), locoregional progression-free survival (LRPFS) and gastrointestinal toxicities were evaluated. The median radiation dose was 60 Gy (range, 55–60) delivered in a median of 25 fractions (range, 24–30). Gemcitabine (GEM) alone, GEM + S-1, S-1 alone, FOLFIRINOX and GEM + nab-paclitaxel were used in CCIMRT and chemo-monotherapy. Results: The 1-year OS rate was 69% in the CCIMRT group, 27% in the chemotherapy group and 38% in the IMRT group (p = 0·12). The 1-year LRPFS rate was 73, 0 and 40% in the 3 groups, respectively (p = 0·012). Acute Grade ≥ 2 gastrointestinal toxicity (nausea, diarrhea) was observed in 12% (2/17) in the CCIMRT group, 25% (4/16) in the chemotherapy group and 7·7% (1/13) in the IMRT group (p = 0·38). Late Grade 3 gastrointestinal bleeding was observed in 6·3% (1/16) in the chemotherapy group. Conclusion: High-dose CCIMRT yielded acceptable toxicity and favorable OS and LRPFS.