Management of metastatic castration-resistant prostate cancer: Insights from urology experts in Thailand

Abstract

Treatment options for castration-resistant prostate cancer (CRPC) are available, but clear instructions for the selection of appropriate treatment are lacking. A meeting of urology experts based in Thailand was convened with the following objectives: (1) to reach a consensus and share real-life experiences about how to identify CRPC; (2) to choose the appropriate treatment for CRPC patients; (3) to evaluate disease progression using novel inhibitors of the androgen receptor pathway; (4) to identify the frequency of monitoring disease; and (5) to promote rational use of corticosteroids in CRPC patients. This consensus document can provide guidance to other urologists in Thailand to provide appropriate treatment to metastatic CRPC patients in a timely manner.

Keywords: Abiraterone acetate; Androgen receptor; Metastatic castration-resistant prostate cancer; Prostate-specific antigen; Urology expert.

Fig. 1

Urology experts based in Thailand considered the role of chemohormonal therapy in high-tumor volume metastatic hormone-sensitive prostate cancer (HSPC). Sixty percent of urology experts voted to treat HSPC with chemohormonal therapy. The other 40% preferred to treat metastatic HSPC with androgen-deprivation therapy only. ADT, androgen-deprivation therapy.

Fig. 2

Urology experts based in Thailand agreed to treat Thai patients with the same dose of docetaxel in chemohormonal therapy stated in the CHAARTED trial and STAMPEDE trials. CHAARTED, Chemohormonal Therapy Versus Androgen Ablation Randomized Trial for Extensive Disease; STAMPEDE, Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy.

Fig. 3

A total of 58.33% experts voted for novel inhibitors of the androgen receptor pathway (IARP) as subsequent therapy for metastatic castration-resistant prostate cancer (mCRPC). AR, androgen receptor.

Fig. 4

Definition of mCRPC in the European Association of Urology guidelines in 2015. EAU, European Association of Urology; mCRPC, metastatic castration-resistant prostate cancer; PCWG2, Prostrate Cancer Working Group 2; PSA, prostate-specific antigen; RECIST, Response Evaluation Criteria in Solid Tumors.

Fig. 5

Urology experts identified mCRPC patients using various criteria. (A) Serum testosterone <50 ng/dL and increase in PSA level. (B) Serum testosterone <50 ng/dL, increase in PSA level, and radiographic progression. (C) Serum testosterone <50 ng/dL, increase in PSA level, and radiographic and clinical progression. mCRPC, metastatic castration-resistant prostate cancer; PSA, prostate-specific antigen.

Fig. 6

If mCRPC patients had duration of response to initial ADT <12 months and were asymptomatic or mildly symptomatic, treatment can be IARP or chemotherapy. Chemotherapy would be first-line treatment for symptomatic mCRPC patients with duration of response to initial ADT <12 months. ADT, androgen-deprivation therapy; AR, androgen receptor; IARP, inhibitors of the androgen receptor pathway; mCRPC, metastatic castration-resistant prostate cancer.

Fig. 7

Urology experts considered use of novel IARP in mCRPC patients with a high Gleason Score. IARP, inhibitors of the androgen receptor pathway; mCRPC, metastatic castration-resistant prostate cancer.

Fig. 8

Urology experts considered the role of abiraterone acetate in metastatic castration-resistant prostate cancer (mCRPC) patients with viseral metastasis.

Fig. 9

All urology experts agreed that chemotherapy should be given to mCRPC patients who presented with AR splice variant 7. AR, androgen receptor; mCRPC, metastatic castration-resistant prostate cancer.

Fig. 10

Most urology experts agreed to select a novel IARP for mCRPC patients if it was available in their center. IARP, inhibitors of the androgen receptor pathway; mCRPC, metastatic castration-resistant prostate cancer.

Fig. 11

Urology experts considered stopping IARP treatment if mCRPC patients met two of the three criteria of disease progression described by the PCWG2. IARP, inhibitors of the androgen receptor pathway; mCRPC, metastatic castration-resistant prostate cancer; PCWG2, Prostrate Cancer Working Group 2; PSA, prostate-specific antigen.

Fig. 12

Criteria set by the PCWG2 to evaluate disease progression in mCRPC patients. ECOG, Eastern Cooperative Oncology Group; mCRPC, metastatic castration-resistant prostate cancer; PCWG2, Prostrate Cancer Working Group 2; PSA, prostate-specific antigen.

Fig. 13

PSA testing: some urology experts measured serum levels of PSA on average every 3–4 months whereas others did do every 3–4 weeks. PSA, prostate-specific antigen.

Fig. 14

Most urology experts repeated bone scintigraphy in symptomatic patients.