What motivated you to write the Nature Reviews Urology article?
Dr. Crispen: There are still large knowledge gaps regarding the active surveillance of renal masses. The reviewed article by Parker et al [European Urology 2013;63(6):1122-1127; www.sciencedirect.com/science/article/pii/S0302283813001036] is one of the first to evaluate the impact of active surveillance on quality-of-life measures. I feel that this is a critical area of investigation because we employ active surveillance as a potential method of avoiding treatment-related side effects of surgical intervention.
The article provides us with very useful information that can be used for patient counseling and may help us to design and implement measures to improve the quality of life in patients who undergo active surveillance of their renal mass.
Are any of these quality-of-life issues unique to renal patients?
Dr. Crispen: The quality-of-life issues evaluated are applicable to the majority of persons with cancer.
However, in the study by Parker et al, as well as many other series evaluating the active surveillance of renal masses, tumor histology is unknown in the majority of patients. This is an important factor as up to 30% of patients with small renal masses will have benign tumor histology.
Thus, we do not know which patients that we are following actually have cancer. Obviously, the uncertainty of knowing whether they have cancer or not may be very unsettling to patients.
Furthermore, it would be interesting to evaluate how tumor-related anxiety in this population of patients compares to patients undergoing active surveillance for other malignancies.
What reservations do you have about active surveillance over more aggressive treatment?
Dr. Crispen: The greatest reservation is the potential for metastatic progression. With the active surveillance of renal masses we may be allowing a curable malignancy to progress to a lethal disease. The reported rate of progression during active surveillance is approximately 1% to 2%.
However, this rate of progression is based on limited follow-up, with most series following patients for less than three years. Additional risks for active surveillance include increased radiation exposure from repeated CT scans, which may be avoided with the use of MRI or ultrasound during follow-up examinations.
The known risks of active surveillance are important considerations given further improvements in nephron-sparing procedures and other measures implemented to decrease treatment-related morbidity.
Are you planning to do more work in this area?
Dr. Crispen: Ongoing work continues in an attempt to improve our knowledge of small-renal-mass biology and the efficacy of active surveillance. I am still interested in evaluating the biology of renal tumors to potentially identify predictors of aggressive disease that warrant immediate treatment and to identify which tumors may not progress over time.
As part of this I feel that renal-mass biopsy may become standard practice in the evaluation of small renal masses and will help guide treatment decisions. With the known limitations of renal-mass biopsy and standard histologic predictors of malignant potential, the discovery and use of additional molecular markers will likely enhance treatment decisions.