Improving survival in salivary duct cancer with adjuvant androgen deprivation therapy

Wim van Boxtel, Carla van Herpen
2019 OncoTarget  
Salivary gland cancer is a rare cancer, with a global annual incidence of 0.4-2.6/100.000 people [1] . Salivary duct carcinoma (SDC) is an aggressive subtype and represents 9% of salivary malignancies [1] . Median overall survival (OS) of SDC patients is 3-5 years after primary diagnosis [2] . In recurrent and/or metastatic SDC, androgen deprivation therapy (ADT) is first line palliative treatment in most patients, as 67-96% of SDCs is androgen receptor-positive (AR+) and an overall response
more » ... overall response rate of 42% was found in a recently conducted prospective phase 2 trial [3] . We studied as first the added value of adjuvant ADT for poor-risk AR+ SDC patients [4] . In a retrospective cohort study, 22 patients with stage 4a (T4a and/or N2 and M0) AR+ SDC were treated with adjuvant ADT, i.e. bicalutamide, a luteinizing hormone-releasing hormone (LHRH)-analogue or a combination of both after regular curative treatment. This consisted of a tumor resection in all cases, and a neck dissection and postoperative radiotherapy in most cases. Patients were treated in the Radboud university medical center (Nijmegen, the Netherlands) and the Istituto Nazionale dei Tumori (Milan, Italy). Disease free survival (DFS) and OS data were compared to a control group of 111 stage 4a SDC patients that received regular curative treatment only. After a median follow-up of 20 months in the ADT-treated patients and 26 months in the control group, the 3-year DFS was estimated as 48.2% (95% confidence interval [CI] 14.0-82.4%) and 27.7% (95% CI 18.5-36.9%), respectively (P = 0.037). Three-year OS was 77.9% (95% CI 49.7-100%) and 53.9% (95% CI 43.5-64.3%), respectively (P = 0.074). See Figure 1 . A univariable and multivariable Cox regression analysis was performed to correct for potential bias. In the univariable analysis, adjuvant ADT treated patients showed a hazard ratio of 0.49 (95% CI 0.21-1.14, P = 0.098) for DFS and 0.41 (95% CI 0.13-1.33, P = 0.137) for OS. In Figure 1 : Kaplan-Meier survival curves of the overall survival of adjuvant androgen deprivation therapy-treated patients (red) and the control group (blue) (P = 0.074). After correcting for confounders in a multivariable Cox regression analysis, a significant decreased hazard ratio of 0.06 (95% confidence interval 0.01-0.76, P = 0.03) was found. Editorial
doi:10.18632/oncotarget.27004 fatcat:7ogqxxqhwbfnxg4fvuctdplsqe