(S014) pN+ Prostate Cancer (CaP) Does Not Imply Incurable Disease

April 30, 2015

When corrected for comorbid conditions in this patient cohort, CaP patients with less than 10% %LN+ have almost 14 years before their disease becomes incurable. Progressively larger %LN+ yields smaller windows of such time. Above 50% LN+, the inflection point is only about 4 years. While better therapies for pN+ CaP must be defined, this patient cadre is not homogenous and should be stratified by %LN+ in future clinical trials.

Jan Poleszcuk, PhD, Heiko Enderling, PhD, Peter Johnstone, MD, FACR; Moffitt Cancer Center

OBJECTIVES: Mathematical modeling of cancer provides mechanisms not simply to predict tumor behavior based on cellular signatures but also to predict patient options based on population dynamics. We have previously reported that populations with cancer die according to an inverse Gompertzian model. Further, we have shown that “incurability” is associated with an inflection point in the Gompertz curve and a nadir in the derivatives of these curves over time. Before reaching this inflection, potential curative interventions may be applied; after this point, reproducible cure is unlikely. Randomized data supporting optimal therapy for pN+ prostate cancer (CaP) patients are frankly nonexistent beyond recommending hormonal therapy. We sought to stratify curability of this cadre of patients by assessing survival by degree of lymph node (LN) positivity (%LN+).

METHODS: Overall or observed survival data in the CaP population are of less utility than in other cancers because of frequent comorbid diagnoses. Thus, national registry-based data were specifically used: relative survival data were retrieved by year postdiagnosis and stratified by the number of positive LNs and by the number of LNs evaluated postoperatively. Data were obtained from the public access Surveillance, Epidemiology, and End Results (SEER) between 1988 and 2011. Observed survival was corrected for an age-, race-, and gender-matched national sample. These data, obtained from a national sample, may be presumed to include hormonal therapy in the disease trajectory. Raw data were then converted to %LN+ and modeled using inverse Gompertzian kinetics. Inflection points were determined for %LN+ values less than 10%, between 10% and 25%, between 25% and 50%, and over 50%.

RESULTS: Data were retrieved from 8,018 pN+ patients. The inflection point varies inversely with increasing %LN+. For patients with less than 10% LN+, the inflection was almost 14 years postoperatively. Patients with 10% to 25% LN+ had an inflection point at almost 10 years; for those with more than 50% LN+, the inflection point was just over 4 years. The difference in time to inflection between cadres was significant.

CONCLUSIONS: When corrected for comorbid conditions in this patient cohort, CaP patients with < 10% %LN+ have almost 14 years before their disease becomes incurable. Progressively larger %LN+ yields smaller windows of such time. Above 50% LN+, the inflection point is only about 4 years. While better therapies for pN+ CaP must be defined, this patient cadre is not homogenous and should be stratified by %LN+ in future clinical trials.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org