You say either, I say either, but let's not call the whole thing off: models for predicting the risk of lymph node involvement in patients with prostate cancer

Radiotherapy in the Management of Clinically Localized Prostate Cancer: Evolving Standards, Consensus, Controversies and New Directions

Major advances have been made in the definitive use of various forms of radiotherapy (RT) in the management of clinically localized prostate cancer (PCa). Despite tremendous gains, the radiation oncology community continues to struggle with several key questions. In general, the areas of controversy pertain to how to improve the therapeutic ratio of RT. Specifically, key issues include dose escalation; the relative benefit of alternative forms of RT (ie, brachytherapy and protons); target localization; the use, timing, and duration of androgen deprivation; and the need for pelvic nodal irradiation. Multiple efforts have been made to address each of these issues; however, there is no consensus on how to resolve them. This review is an evidence-based critique of the available treatment approaches considered for the optimal use of radiotherapy as definitive management of clinically localized PCa.

Eligibility and outcomes reporting guidelines for clinical trials for patients in the state of a rising prostate-specific antigen: recommendations from the Prostate-Specific Antigen Working Group

PURPOSE

To define methodology to show clinical benefit for patients in the state of a rising prostate-specific antigen (PSA).

RESULTS

HYPOTHESIS

A clinical states framework was used to address the hypothesis that definitive phase III trials could not be conducted in this patient population.

PATIENT POPULATION

The Group focused on men with systemic (nonlocalized) recurrence and a defined risk of developing clinically detectable metastases. Models to define systemic versus local recurrence, and risk of metastatic progression were discussed.

INTERVENTION

Therapies that have shown favorable effects in more advanced clinical states; meaningful biologic surrogates of activity linked with efficacy in other tumor types; and/or effects on a target or pathway known to contribute to prostate cancer progression in this state can be considered for evaluation.

OUTCOMES

An intervention-specific posttherapy PSA-based outcome definition that would justify further testing should be described at the outset. Reporting: Trial reports should include a table showing the number of patients who achieve a specific PSA-based outcome, the number who remain enrolled onto the trial, and the number who came off study at different time points. The term PSA response should be abandoned.

TRIAL DESIGN

The phases of drug development for this state are optimizing dose and schedule, demonstration of a treatment effect, and clinical benefit. To move a drug forward should require a high bar that includes no rise in PSA in a defined proportion of patients for a specified period of time at a minimum. Agents that do not produce this effect can only be tested in combination. The preferred end point of clinical benefit is prostate cancer-specific survival; the time to development of metastatic disease is an alternative.

CONCLUSION

Methodology to show that an intervention alters the natural history of prostate cancer is described. At each stage of development, only agents with sufficient activity should be moved forward.

Validation of a biopsy-based pathologic algorithm for predicting lymph node metastases in patients with clinically localized prostate carcinoma

BACKGROUND

The authors validated an algorithm for the preoperative prediction of lymph node (LN) metastases in patients with clinically localized prostate carcinoma. The algorithm was applied to sextant biopsy material and radical retropubic prostatectomy (RRP) stage obtained from a cohort of men who were treated at the authors' institution.

METHODS

Four hundred forty-three patients underwent systematic sextant biopsy and RRP with staging lymphadenectomy. The original algorithm was based on systematic sextant biopsy data and classified patients into three risk groups for LN metastases based on the biopsy result. If > or = 4 of 6 biopsies contained any Gleason Pattern 4 disease, then the patient was at high risk for LN metastases (45%). Patients with > or = 1 of 6 biopsies with dominant Gleason Pattern 4 disease (excluding high-risk patients) had an intermediate predicted risk (19%) of LN metastases. All other patients had a low predicted risk of LN metastases (2.2%). The authors assed the percentage of patients who were positive and negative for LN metastases and calculated the specificity and negative predictive value in the series when patients were classified according to the original algorithm.

RESULTS

Twenty of 443 patients had intraoperative LN metastases. When applied to the current data, the Hamburg algorithm classified 404 patients in the low-risk group, 30 patients in the intermediate-risk group, and 9 patients in the high risk group. The incidence of LN metastases was 2.47% in the low-risk group, 20% in the intermediate-risk group, and 44.4% in the high-risk group. The negative predictive value for the low-risk group was 97.52%, and the specificity was 94.14%.

CONCLUSIONS

The Hamburg algorithm proved a valid tool for the prediction of lymphatic spread in this validation study on data from the authors' institution. The algorithm may serve as a tool to select patients who do not need to undergo pelvic lymphadenectomy at the time they undergo RRP, hence reducing morbidity and expense. More importantly, with the increasing numbers of men undergoing treatment options in whom LN dissection is not performed, this validated algorithm provides an important selection basis regarding the appropriateness of a therapy that does not routinely include LN staging.

Prospective validation of an algorithm with systematic sextant biopsy to predict pelvic lymph node metastasis in patients with clinically localized prostatic carcinoma

PURPOSE

We prospectively validate an algorithm to predict pelvic lymph node metastasis in patients with clinically localized prostatic carcinoma.

MATERIAL AND METHODS

A total of 293 patients with prostatic cancer were identified before pelvic lymph node dissection according to an algorithm developed with the classification and regression tree analysis as high-greater than 3 sextant biopsies containing any Gleason grade 4 or 5 cancer, intermediate-at least 1 biopsy dominated by Gleason grade 4 or 5 cancer but not high risk and low risk-all other patients. Observed and predicted frequencies of pelvic lymph node metastasis were compared.

RESULTS

The observed frequencies of lymph node metastasis were remarkably similar to the predicted frequencies, including 2.8% versus 2.2% in 85.7% of patients in the low risk group, 16.7% versus 19.4% in 10.2% intermediate and 41.7% versus 45.5% in 4.1% high, respectively. If patients in the low risk group were considered to have node negative disease the specificity and negative predictive value of the algorithm were 88.4% and 97.2%, respectively.

CONCLUSIONS

Our algorithm is valid as a simple and accurate tool for the prediction of pelvic lymph node metastasis in patients with clinically localized prostatic cancer. Those 85.7% of patients classified by the algorithm to have a low risk of lymphatic spread should not undergo pelvic lymph node dissection before definitive local treatment.

Improved freedom from PSA failure with whole pelvic irradiation for high-risk prostate cancer

PURPOSE

To determine the impact of whole pelvic irradiation on the risk of PSA failure in prostate cancer patients, at high predicted risk for lymph node involvement, receiving definitive radiotherapy.

MATERIALS AND METHODS

Between October 1987 and December 1995, 506 patients with clinically localized prostate cancer were treated with definitive radiotherapy at UCSF and affiliated institutions. Treatment consisted of 4-field whole pelvic irradiation followed by a prostate-only boost, or prostate-only treatment (median follow-up was 35 months and 30 months, respectively). PSA failure was defined as: 1. a PSA value > or = 1 ng/ml; or 2. a PSA value that rose > or = 0.5 ng/ml in < or = 1 year posttreatment on two consecutive measurements, with the first rise defined as the time of failure. The calculated risk of lymph node positivity (%rLN+) was defined as 2/3(iPSA) + 10(GS-6), and high risk was defined as %rLN+ > or = 15%. Univariate and multivariate analyses were performed.

RESULTS

A total of 201 high-risk patients were identified. High-risk patients who received whole pelvic irradiation had significantly improved freedom from PSA failure compared to those who received prostate-only treatment (median PFS = 34.3 months vs. 21.0 months; p = 0.0001). Potential confounding variables, including initial PSA, Gleason score, T stage, radiation dose, year of treatment, use of three-dimensional (3D) conformal techniques, and use of hormone therapy, did not account for the observed difference in time to PSA failure. Multivariate analysis revealed type of radiation treatment to be the most significant independent predictor of outcome.

CONCLUSION

Whole pelvic radiotherapy significantly improves the PSA failure-free survival in patients with a high calculated risk of lymph node positivity.

Systematic sextant biopsies improve preoperative prediction of pelvic lymph node metastases in patients with clinically localized prostatic carcinoma

PURPOSE

An algorithm including the results of systematic sextant biopsies was statistically developed and evaluated to predict the probability of pelvic lymph node metastases in patients with clinically localized carcinoma of the prostate.

MATERIALS AND METHODS

Clinical stage, serum prostate specific antigen concentration, Gleason score, number of positive biopsies, number of biopsies containing any Gleason grade 4 or 5 cancer and number of biopsies predominated by Gleason grade 4 or 5 cancer were recorded in 345 patients undergoing pelvic lymph node dissection and correlated with the incidence of lymph node metastases. Multivariate logistic regression, and classification and regression trees analyses were performed.

RESULTS

In univariate analysis all variables had a statistically significant influence on lymph node status. Logistic regression showed that the amount and distribution of undifferentiated Gleason grade 4 and 5 cancer in the biopsies were the best predictors of lymphatic spread followed by serum prostate specific antigen. Classification and regression trees analysis classified 79.9% of patients who had 3 or fewer biopsies with Gleason grade 4 or 5 cancer and no biopsies predominated by undifferentiated cancer as a low risk group. In this group positive lymph nodes occurred in only 2.2% (95% confidence interval 0.8 to 4.7%).

CONCLUSIONS

Including the results of systematic sextant biopsies substantially enhances the predictive accuracy of algorithms that define the probability of lymph node metastases in prostatic cancer. Patients thus defined as having no lymphatic spread could potentially be spared pelvic lymph node dissection before definitive local treatment.