Therapeutic Advances in Medical Oncology (Sep 2022)

Survival benefit of HER2-targeted or androgen deprivation therapy in salivary duct carcinoma

  • Daisuke Kawakita,
  • Toshitaka Nagao,
  • Hideaki Takahashi,
  • Satoshi Kano,
  • Yoshitaka Honma,
  • Hideaki Hirai,
  • Natsuki Saigusa,
  • Kohei Akazawa,
  • Kaori Tani,
  • Hiroya Ojiri,
  • Kiyoaki Tsukahara,
  • Hiroyuki Ozawa,
  • Kenji Okami,
  • Takahito Kondo,
  • Takafumi Togashi,
  • Chihiro Fushimi,
  • Tomotaka Shimura,
  • Akira Shimizu,
  • Isaku Okamoto,
  • Takuro Okada,
  • Yorihisa Imanishi,
  • Yoshihiro Watanabe,
  • Kuninori Otsuka,
  • Akihiro Sakai,
  • Koji Ebisumoto,
  • Yuichiro Sato,
  • Keisuke Yamazaki,
  • Yushi Ueki,
  • Toyoyuki Hanazawa,
  • Yuki Saito,
  • Mizuo Ando,
  • Takashi Matsuki,
  • Masato Nakaguro,
  • Yukiko Sato,
  • Makoto Urano,
  • Yoshitaka Utsumi,
  • Shinji Kohsaka,
  • Takashi Saotome,
  • Yuichiro Tada

DOI
https://doi.org/10.1177/17588359221119538
Journal volume & issue
Vol. 14

Abstract

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Background: The efficacy and safety of human epidermal growth factor receptor 2 (HER2)-targeted therapy and androgen deprivation therapy (ADT) for locally advanced or recurrent or metastatic (LA/RM) salivary duct carcinoma (SDC) have been reported in prospective studies. However, the survival benefit of these therapies to conventional therapy remains controversial, and whether HER2-targeted therapy or ADT should be chosen in HER2- and androgen receptor (AR)-positive SDC patients remains unknown. Methods: Overall, 323 LA/RM SDC patients treated at seven institutions between August 1992 and June 2020 were retrospectively enrolled. The primary aim was to analyze the effect of HER2-targeted therapy and ADT on overall survival from the diagnosis of LA/RM disease to death from any cause (OS1). The secondary indicators included the overall response rate (ORR), clinical benefit rate (CBR), overall survival from therapy initiation for LA/RM disease (OS2), progression-free survival (PFS), time to second progression (PFS2), duration of response (DoR), and duration of clinical benefit (DoCB) of HER2-targeted therapy or ADT as first-line therapy for HER2-positive/AR-positive SDC. Results: Patients treated with HER2-targeted therapy or ADT had longer OS1 than those treated without these therapies (Median OS1: historical control, 21.6 months; HER2-targeted therapy, 50.6 months; ADT, 32.8 months; HER2-targeted therapy followed by ADT, 42.4 months; and ADT followed by HER2-targeted therapy, 45.2 months, p < 0.001). Among HER2-positive/AR-positive SDC patients, although HER2-targeted therapy had better ORR, CBR, and PFS than those of ADT as first-line therapy, we found no significant differences between HER2-targeted therapy and ADT regarding OS2, PFS2, DoR, and DoCB. Conclusion: Patients treated with HER2-targeted therapy and ADT showed longer survival in LA/RM SDC. HER2-targeted therapy can be recommended prior to ADT for HER2-positive/AR-positive SDC. It is warranted to establish a biomarker that could predict the efficacy of clinical benefit or better response in ADT.