Hormone Therapy & Radiation: Survival Benefit for Low-PSA Prostate Cancer?

The question of whether adding hormone therapy to radiotherapy after prostate surgery improves survival for men with prostate cancer, particularly those with low PSA levels, has been a subject of ongoing debate. Recent research, published in The Lancet, suggests that for many men, the addition of hormone therapy may not offer a significant survival benefit, potentially allowing some patients to avoid unnecessary side effects.

Understanding Postoperative Radiotherapy and Androgen Deprivation Therapy

Prostate cancer treatment often involves a combination of approaches. Radiotherapy, or radiation therapy, uses high-energy rays to kill cancer cells. When used after surgery to remove the prostate (radical prostatectomy), it’s known as postoperative radiotherapy (PORT). Androgen deprivation therapy (ADT), often referred to as hormone therapy, aims to lower levels of testosterone, a hormone that can fuel the growth of prostate cancer. ADT works by blocking the production of testosterone or by preventing it from reaching cancer cells. It can be administered in various ways, including injections, pills, or surgical removal of the testicles.

The rationale for combining ADT with PORT is that lowering testosterone levels may make the radiation more effective at killing any remaining cancer cells after surgery. Still, ADT is not without its drawbacks. Common side effects include fatigue, hot flashes, sexual dysfunction, weight gain, and bone loss. More seriously, it can increase the risk of cardiovascular problems and metabolic changes. Given these potential side effects, identifying which patients truly benefit from ADT alongside PORT is crucial.

New Evidence Challenges Conventional Wisdom

The study published in The Lancet analyzed data from a large group of men who underwent PORT after prostate surgery. Researchers found that for men with low PSA levels (0.5 ng/mL or less) before radiotherapy, adding hormone therapy – whether short-term or long-term – did not improve overall survival. This finding is significant since it suggests that a substantial proportion of men may be able to avoid the side effects of ADT without compromising their chances of survival. UCLA Health reports that Dr. Amar Kishan, the lead author of the study, presented these findings at the American Society of Clinical Oncology Genitourinary Cancers Symposium in San Francisco.

However, the study likewise indicated that men with higher PSA levels before radiation may experience modest improvements in survival and metastasis-free survival with the addition of hormone therapy. This suggests that ADT may still be beneficial for a subset of patients – those with more aggressive disease, as indicated by higher PSA levels.

What Does PSA Level Indicate?

Prostate-specific antigen (PSA) is a protein produced by the prostate gland. PSA levels are often measured during prostate cancer screening. Whereas elevated PSA levels can indicate the presence of prostate cancer, they can also be caused by other conditions, such as benign prostatic hyperplasia (BPH) – an enlargement of the prostate – or prostatitis (inflammation of the prostate). A “PSA nadir” refers to the lowest PSA level reached during and after treatment, and tracking this level is crucial for monitoring treatment response. As detailed in research published in Cancer, the PSA nadir and testosterone levels at the time of PSA failure can provide valuable prognostic information.

Limitations and Areas for Further Research

It’s important to acknowledge the limitations of this research. The study focused on men receiving radiotherapy after surgery. The findings may not be generalizable to men receiving radiotherapy as a primary treatment for prostate cancer, or to those whose prostates are still intact. The study did not investigate the potential role of biomarkers – measurable substances in the body – that could help predict which patients are most likely to benefit from ADT. Identifying such biomarkers is an important area for future research.

The authors of the Lancet study emphasize the need to identify biomarkers that can help personalize treatment decisions. This would allow clinicians to tailor therapy to the individual needs of each patient, maximizing the benefits of treatment while minimizing the risk of side effects. The study also highlights the importance of shared decision-making between patients and their doctors, ensuring that patients are fully informed about the potential benefits and risks of ADT before making a treatment decision.

Implications for Clinical Practice and Patient Care

These findings are likely to influence clinical practice, potentially leading to a more selective approach to the utilize of ADT in men undergoing PORT after prostate surgery. For men with low PSA levels, clinicians may be more inclined to forgo ADT, focusing instead on radiotherapy alone. For men with higher PSA levels, ADT may still be considered, but the duration of therapy – short-term versus long-term – should be carefully evaluated based on individual patient characteristics and preferences.

The study reinforces the growing trend towards personalized medicine in cancer care. Rather than applying a one-size-fits-all approach, clinicians are increasingly recognizing the importance of tailoring treatment to the unique characteristics of each patient’s disease. This requires a thorough understanding of the patient’s risk factors, tumor biology, and treatment goals.

What Comes Next: Ongoing Evaluation and Biomarker Discovery

The findings from this study will likely prompt further investigation and refinement of treatment guidelines. Ongoing clinical trials are evaluating the role of ADT in different subsets of prostate cancer patients. Researchers are also actively searching for biomarkers that can predict response to ADT, potentially allowing for more precise patient selection. The process of updating clinical guidance is continuous, informed by new evidence and expert consensus. Patients should discuss their individual circumstances and treatment options with a qualified oncologist to make informed decisions about their care.