Population-based study on use of chemotherapy in men with castration resistant prostate cancer

Abstract

Background: Chemotherapy prolongs life and relieves symptoms in men with castration resistant prostate cancer (CRPC). There is limited information on a population level on the use of chemotherapy for CRPC.

Material and methods: To assess the use of chemotherapy in men with CRPC we conducted a register-based nationwide population-based study in Prostate Cancer data Base Sweden (PCBaSe) and a nationwide in-patient drug register (SALT database) between May 2009 and December 2010. We assumed that men who died of prostate cancer (PCa) underwent a period of CRPC before they died.

Results: Among the 2677 men who died from PCa during the study inclusion period, 556 (21%) had received chemotherapy (intravenous or per oral) detectable within the observation period in SALT database. Specifically, 239 (61%) of men < 70 years had received chemotherapy, 246 (30%) of men between 70 and 79 years and 71 (5%) men older than 80 years. The majority of men 465/556 (84%) had received a docetaxel-containing regimen. Among chemotherapy treated men, 283/556 (51%) received their last dose of chemotherapy during the last six months prior to death. Treatment with chemotherapy was more common among men with little comorbidity and high educational level, as well as in men who had received curatively intended primary treatment.

Conclusion: A majority of men younger than 70 years with CRPC were treated with chemotherapy in contrast to men between 70 and 79 years of whom half as many received chemotherapy. Chemotherapy treatment was often administered shortly prior to death. The low uptake of chemotherapy in older men with CRPC may be caused by concerns about tolerability of treatment, as well as treatment decisions based on chronological age rather than global health status.

Figure 1.

Inclusion/exclusion in study of chemotherapy use in men with castration resistant prostate cancer (PCa) in PCBaSe Sweden. Study inclusion period is the period during which a case had to die of PCa to be included. Observation period in SALT database is the period prior to death during which data on use of chemotherapy was available. Sjukhusapotekens läkemedelstillverkning (SALT)/Hospital pharmaceutical manufacturing database, an in-hospital medication database. Solid lines represents men followed diagnosed with PCa. Grey and black colors used for time with unknown and known chemotherapy status respectively. The solid lines ends in PCa death (dark grey) or death of other causes (light grey). The inclusion criteria are men dead from PCa within the study inclusion period 21 May 2009 and 31 December 2010. PCa diagnosis recorded in NPCR. Cases included: 1) Men who were diagnosed with PCa, registered in NPCR prior to the observation period in SALT database and died from PCa during the study inclusion period; and 2) Men diagnosed with PCa during the observation period in SALT database and died from PCa during the study inclusion period. Cases excluded: 3) Men who died from PCa prior to the study inclusion period; 4) Men who died from other causes during the study inclusion period; and 5) Men still alive at end of the observation period in SALT database.

Figure 2.

The likelihood of initiation of chemotherapy for various subgroups of men who died from PCa 2009–2010 expressed as odds ratios and 95% confidence intervals. For definition of Charlson Comorbidity Index (CCI) and education, see materials and methods section. Primary treatment; other palliative, e.g. transurethral resection of the prostate, steroids, analgesics. Endocrine treatment – Gonadotropin Releasing Hormone analogues (GnRH).

Figure 3.

Differences between counties in use of intravenous docetaxel chemotherapy treatment, i.e percentage of men dying from prostate cancer who received intravenous docetaxel chemotherapy prior to death. Data from Skåne county is missing (gray).