Role of biomarkers to predict outcomes and response to therapy

Salvage combination intravesical immunotherapy with Bacillus Calmette-Guérin and interferon-α2B: impact on recurrence, progression, and survival

BACKGROUND

The population of patients with bladder cancer who have recurrence following an initial instillation of Bacillus Calmette-Guérin (BCG) is critical to study, as treatment delay with repeated courses of intravesical therapy may yield poor prognosis in patients with disease progression.

OBJECTIVE

To evaluate our institution's experience with use of BCG alone and in combination with interferon (INF)-α2B in regard to the rates of bladder cancer recurrence, disease progression, need for eventual cystectomy, and survival in patients with initial BCG failure.

STUDY DESIGN

We identified a combined series of 139 patients who had undergone intravesical instillations of BCG alone (n = 114) or in combination with INF-α2B (n = 25) performed at Brigham and Women's Hospital, Boston, between 2002 and 2007. All patients previously received an initial 6-week course of BCG therapy and subsequently had BCG failure on follow-up cystoscopy. Study outcome measures included: time to cancer recurrence in patients, progression of disease, eventual cystectomy, and patient mortality.

RESULTS

At a median follow-up of 64.7 months from initial BCG administration, 84% of patients treated with BCG + INF-α2B had disease recurrence. The average time to recurrence was < 1 year, and 63% of patients had recurrence on the first post-treatment biopsy. Among patients with a positive first biopsy, 52% had disease progression on initial surveillance. Overall, disease progression was seen in 48% of patients receiving BCG + INF-α2B therapy, and 28% of all patients eventually underwent radical cystectomy. All outcomes occurred more frequently in patients undergoing combination intravesical therapy compared with patients given BCG monotherapy.

CONCLUSIONS

Patients with bladder cancer undergoing salvage intravesical BCG + INF-α2B at our institution had a > 50% chance of disease recurrence and progression, and > 25% of patients eventually proceeded to radical cystectomy. Randomized trials are needed to clarify the issues present in our findings and to determine the appropriate role for concomitant INF therapy in patients when BCG monotherapy has failed.

Prognostic role of cell cycle and proliferative biomarkers in patients with clear cell renal cell carcinoma

PURPOSE

Cell cycle regulatory molecules are implicated in various stages of carcinogenesis. In this proof of principle study we systematically evaluate the association of aberrant expression of cell cycle regulators and proliferative markers and their effect on oncologic outcomes of patients with clear cell renal carcinoma.

MATERIALS AND METHODS

Immunohistochemistry for Cyclin D, Cyclin E, p16, p21, p27, p53, p57 and Ki67 was performed on tissue microarray constructs of 452 patients treated with extirpative therapy for clear cell renal cell carcinoma between 1997 and 2010. Clinical and pathological data elements were collected. A prognostic marker score was defined as unfavorable if more than 4 biomarkers were altered. The relationship between marker score and pathological features and oncologic outcomes was evaluated.

RESULTS

Median age was 57 years (range 17 to 85) and median followup was 24 months (range 6 to 150). An unfavorable marker score was found in 55 (12.2%) patients and was associated with adverse pathological features. A significant correlation between unfavorable marker score and disease-free survival (HR 26.62, 95% CI 43.38-100.04, p=0.000) and with cancer specific survival (HR 8.15, 95% CI 74.42-101.56, p=0.004) was demonstrated on Kaplan-Meier survival analysis. On multivariate analysis an unfavorable marker score was an independent predictor of disease-free survival (HR 2.63, 95% CI 1.08-6.38, p=0.033).

CONCLUSIONS

The cumulative number of aberrantly expressed cell cycle and proliferative biomarkers correlates with aggressive pathological features and inferior oncologic outcomes in patients with clear cell renal cell carcinoma. Our findings indicate that interrogation of cell cycle and proliferative markers is feasible, and further prospective pathway based exploration of biomarkers is needed.

Statistical consideration for clinical biomarker research in bladder cancer

OBJECTIVE

To critically review and illustrate current methodological and statistical considerations for bladder cancer biomarker discovery and evaluation.

METHODS

Original, review, and methodological articles, and editorials were reviewed and summarized.

RESULTS

Biomarkers may be useful at multiple stages of bladder cancer management: early detection, diagnosis, staging, prognosis, and treatment; however, few novel biomarkers are currently used in clinical practice. The reasons for this disjunction are many and reflect the long and difficult pathway from candidate biomarker discovery to clinical assay, and the lack of coherent and comprehensive processes (pipelines) for biomarker development. Conceptually, the development of new biomarkers should be a process that is similar to therapeutic drug evaluation-a highly regulated process with carefully regulated phases from discovery to human applications. In a further effort to address the pervasive problem of inadequacies in the design, analysis, and reporting of biomarker prognostic studies, a set of reporting recommendations are discussed. For example, biomarkers should provide unique information that adds to known clinical and pathologic information. Conventional multivariable analyses are not sufficient to demonstrate improved prediction of outcomes. Predictive models, including or excluding any new putative biomarker, need to show clinically significant improvement of performance in order to claim any real benefit. Towards this end, proper model building, avoidance of overfitting, and external validation are crucial. In addition, it is important to choose appropriate performance measures dependent on outcome and prediction type and to avoid the use of cutpoints. Biomarkers providing a continuous score provide potentially more useful information than cutpoints since risk fits a continuum model. Combination of complementary and independent biomarkers is likely to better capture the biological potential of a tumor than any single biomarker. Finally, methods that incorporate clinical consequences such as decision curve analysis are crucial to the evaluation of biomarkers.

CONCLUSIONS

Attention to sound design and statistical practice should be delivered as early as possible and will help maximize the promise of biomarkers for patient care. Studies should include a measure of predictive accuracy and clinical decision-analysis. External validation using data from an independent cohort provides the strongest evidence that a model is valid. There is a need for adequately assessed clinical biomarkers in bladder cancer.