Prostate cancer is one of the most common malignancies in men in China, yet the 5-year survival rate for this type of cancer is not low, with early to mid-stage prostate patients having a 5-year survival rate greater than 99% and late metastatic cases at around 30%.
The annual meeting of the American Society of Clinical Oncology (ASCO), one of the most important meetings in the field of oncology. So, let’s take a look at what new breakthroughs in prostate cancer treatment are being made at this year’s ASCO annual meeting.
Hormone-sensitive prostate cancer
New first-line option for patients with metastases – enzalutamide + testosterone inhibitor ± docetaxel
About 90% of prostate cancer cases are associated with androgen stimulation, and in patients with hormone-sensitive prostate cancer, cancer cell proliferation is stopped primarily with testosterone suppressants (TS), also known as androgen blockade therapy (ADT). For hormone-sensitive prostate cancer that has metastasized, physicians may add docetaxel chemotherapy in addition to testosterone suppression.
A study from this ASCO conference found that for these patients with hormone-sensitive metastatic prostate cancer, there is a better first-line treatment option – adding enzalutamide to the original standard of care (TS±docetaxel) leads to longer survival.
Enzalutamide is an androgen receptor inhibitor, and similar inhibitors to enzalutamide include bicalutamide, nilumide, or flutamide.
In this study, the 3-year survival rate for enzalutamide + standard therapy was 80%, which was significantly better than the other androgen inhibitors (bicalutamide, nilumide, or flutamide) combined with standard therapy. Moreover, enzalutamide also effectively reduced the risk of disease progression. In particular, the use of enzalutamide in combination with a testosterone inhibitor is more effective in patients with a small tumor load (relatively small tumors with few metastases) who cannot tolerate chemotherapy.
With the publication of this result, it is foreseeable that enzalutamide + testosterone inhibitor ± docetaxel will be a new option for first-line treatment in patients with metastatic hormone receptor-positive prostate cancer.
Short comment: This phase III study is clinically significant in that it suggests that – during the period when prostate cancer is hormone-sensitive – the timely combination of androgen-blocking therapy with enzalutamide can extend overall survival by more than 3 years, which is a big step forward. In addition, in the study, androgen blockade therapy combined with enzalutamide prolonged patient survival in both the high-risk group of patients in the high tumor load group and the low-risk patients in the low tumor load group. This result expands the scope of application of combination therapy, allowing patients with low tumor load or low risk to benefit from aggressive treatment, breaking with the previous practice that combination therapy was only indicated for patients with more severe disease and extensive metastases, which is a clinical This is a major advance in clinical understanding.
Destructive-resistant prostate cancer
For metastatic desmoplastic prostate cancer that has failed multiple lines of therapy, the targeted agent olaparib may be an effective option
After a period of endocrine therapy with androgen blockade, almost all patients experience treatment “failure,” which is called “Castration Resistant Prostate Cancer (CRPC). This is called “Castration Resistant Prostate Cancer (CRPC),” which means that the disease progresses despite low testosterone levels.
For patients with metastatic destructive-resistant prostate cancer after failure of multiple lines of therapy, a study at this year’s ASCO meeting confirmed that the PARP inhibitor olaparib is an effective treatment option. The best remission rate of 80% was achieved in patients with BRCA1/2 mutations, followed by patients with PALB2 mutations at 57%. Patients with other mutations were also effectively treated with olaparib, just not as efficacious as these two mutations.
Short comment: This study confirms that olaparib is effective in treating metastatic prostate cancer and warrants a larger study to further validate the efficacy of this drug.