Surgery versus chemotherapy for pulmonary oligometastasis after pancreatectomy: A multicentre observational study

BackgroundSystemic chemotherapy is the standard of care for postoperative recurrence of pancreatic cancer (PC); however, it is sometimes considered an indication for surgical resection in cases of pulmonary oligometastases (PO). In this multicentre study, we aimed to compare overall survival (OS) between surgery and chemotherapy as initial treatments for PO.MethodsThis retrospective observational study involving 32 hospitals included patients (pts) who underwent radical pancreatectomy for PC between January 2009 and December 2019 and began treatment for PO by December 2020. In this study, PO was defined as metastases confined to the unilateral lobe without clinical evidence of other recurrences. OS was defined as survival from the treatment initiation for PO to death. Potential baseline confounders (duration between initial pancreatectomy and manifestation of PO (recurrence-free survival [RFS]), cancer antigen (CA) 19-9 level, number of PO, and performance status [PS]) were adjusted with inverse probability of treatment weighting (IPTW), and we evaluated the hazard ratio (HR) of OS in pts who underwent surgery (group S) compared with pts who received chemotherapy (group C).ResultsIn total, 184 pts were enrolled (107 in group S and 77 in group C). The median RFS, median CA19-9 level, percentage of pts with a single PO lesion, and that of pts with PS of 0 in group S vs. group C were 2.6 vs. 1.4 years, 18.9 vs. 45.7 U/mL, 81.3 vs. 64.9%, and 85.0 vs. 74.0%, respectively. The median OS was 3.6 and 2.0 years in groups S and C, respectively (HR: 0.45, 95% confidence interval [CI]: 0.32–0.65). After adjustment with IPTW, the patient background was well balanced between both groups, and the median OS was 2.9 and 2.1 years in groups S and C, respectively (HR: 0.64, 95% CI: 0.42–0.97). In the subgroup of the IPTW-adjusted cohort, RFS ≥1.5 years and tumour diameter ≤2.0 cm were significantly related to a favourable prognosis for surgery (HR: 0.53, 95% CI: 0.30–0.96; HR: 0.63, 95% CI: 0.40–0.98).ConclusionsSurgery showed more favourable treatment outcomes than chemotherapy as an initial treatment for PO, even after adjustment with IPTW, suggesting that surgery may be a potential initial treatment option.Clinical trial identificationUMIN000046808; Date of disclosure of the study information; 2, Feb, 2022.Legal entity responsible for the studyJapan Oncology Network in Hepatobiliary and Pancreas.FundingHas not received any funding.DisclosureK. Ikezawa: Financial Interests, Personal, Invited Speaker: Taiho Pharmaceutical, Yakult Honsha, MSD, Myriad Genetics, Asahi Kasei Pharma, Incyte Biosciences Japan, Nihon Servier, Chugai Pharmaceutical, AstraZeneca. N. Kato: Financial Interests, Personal, Invited Speaker: Gilead Sciences Inc., AbbVie G.K., Ohtsuka Pharmaceutical Co., Ltd., Chugai Pharmaceutical Co., Ltd., AstraZeneca K.K., Sumitomo Dainippon Pharma Co., Ltd., Takeda Pharmaceutical Co., Ltd., Zeria Pharmaceutical Co., Ltd., Eisai Co., Ltd., Aska Pharmaceutical Co., Ltd., Tsumura & Co., Mochida Pharmaceutical Co., Ltd., Miyarisan Pharmaceutical Co., Ltd., Covidien Japan Inc., Eli Lilly Japan K.K., Nobelpharma Co., Ltd., Kowa Company, Ltd., Incyte Biosciences Japan GK, Yakult Honsha Co., Ltd., Olympus Marketing, Inc., Taisho Pharmaceutical Co., Ltd., Janssen Pharmaceutical K.K., Daiichi Sankyo Company, Limited, Bayer Yakuhin, EA Pharma, Asahi Kasei Pharma. Financial Interests, Institutional, Research Grant: AbbVie G.K., Ohtsuka Pharmaceutical Co., Ltd., Bayer Yakuhin Ltd., Chugai Pharmaceutical Co., Ltd., Mitsubishi Tanabe Pharma Corporation, Sumitomo Dainippon Pharma Co., Ltd., Shionogi & Co., Ltd., Eisai Co., Ltd., Tsumura & Co., Nippon Kayaku Co., Ltd., JIMRO Co., Ltd., Kowa Company, Ltd. H. Imaoka: Financial Interests, Personal, Invited Speaker: Yakult Honsha, AstraZeneca, Nihon Servier, Kaneka Medix, Sb Kawasumi Laboratories, Boston Scientific, Novartis; Financial Interests, Personal, Advisory Board: Nihon Servier, Kaneka Medix; Financial Interests, Personal, Writing Engagement: Medico's Hirata; Financial Interests, Institutional, Local PI: Ono Pharmaceutical, Novartis, Nihon Servier. C. Morizane: Financial Interests, Personal, Advisory Board: Yakult, MSD, Servier, Boehringer Ingelheim, AstraZeneca, Taiho Pharmaceutical, Merck Biopharma; Financial Interests, Personal, Invited Speaker: Novartis, Myriad Genetics, Guardant, Toray; Financial Interests, Institutional, Coordinating PI: Yakult Honsha, Ono Pharmaceutical, Taiho Pharmaceutical, Eisai, MSD K.K., J-Pharma, AstraZeneca, Merck Biopharma; Financial Interests, Institutional, Funding: Daiichi Sankyo RD Novare, Hitachi; Financial Interests, Institutional, Local PI: Boehringer Ingelheim; Financial Interests, Institutional, Research Grant: Labcorp; Financial Interests, Personal, Steering Committee Member: Boehringer Ingelheim. M. Ueno: Financial Interests, Personal, Invited Speaker: AstraZeneca, Chugai Pharmaceutical, Incyte, MSD, Nihon Servier, Ono Pharmaceutical, Taiho Pharmaceutical, Daiichi Sankyo, Takeda Pharmaceutical, J-Pharma, Eisai, Yakult Honsha; Financial Interests, Personal, Advisory Board: Nippon Boehringer Ingelheim, Novartis; Financial Interests, Institutional, Local PI: Astellas Pharma, AstraZeneca, Chugai Pharmaceutical, DFP, Daiichi Sankyo, Eisai, Incyte, MSD, Merck Biopharma, Ono Pharmaceutical, Taiho Pharmaceutical, Novartis, J-Pharma, Novocure, Chiome Bioscience. J. Furuse: Financial Interests, Personal, Invited Speaker: Ono Pharmaceutical, Bayer, Eisai, Eli Lilly Japan, MSD, Yakult Honsha, Chugai Pharma, Novartis Pharma, AstraZeneca, Pfizer, Takeda, Taiho Pharmaceutical, Sanofi, Mylan EPD, EA Pharma, Kyowa Hakko Kirin, Daiichi Sankyo, Teijin Pharma, Servier Japan, Incyte; Financial Interests, Personal, Advisory Board: Fuji film, Mundi Pharma, Onco Therapy Science, Merck Bio, Ono Pharmaceutical, MSD, Taiho Pharmaceutical, Chugai Pharma, Astellas, AstraZeneca, Takara Bio, Delta-Fly-Pharma, Incyte Japan; Financial Interests, Institutional, Research Grant: Ono Pharmaceutical, MSD, Merck Bio, J-Pharma, Taiho Pharmaceutical, Takeda, Chugai Pharma, AstraZeneca, Yakult Honsha, Eisai, Daiichi Sankyo, Mochida, Sanofi, Sumitomo Dainippon Bayer, Astellas, Incyte Japan; Financial Interests, Personal, Steering Committee Member: Merck Bio, Ono Pharmaceutical, MSD, Taiho Pharmaceutical, Astellas, AstraZeneca, Incyte Japan. All other authors have declared no conflicts of interest.