Metastasis and mortality after treatment for localized prostate cancer
Posted Mar 25 2010 12:00am
A restrospective review of data from Memorial Sloan-Kettering Cancer Center has provided us with some interesting new data on the progression of prostate cancer over time.
In a paper initially available on line and now published in the Journal of Clinical Oncology, Zelefsky et al. have reported data on a total of 2,380 patients initially diagnosed with localized prostate cancer and subsequently treated with either an open radical prostatectomy (RP) by one of two experienced surgeons or with intensity modulated radiotherapy (IMRT) at a dose level of not less than 81 Gy. Unfortunately, the dates of initial treatment of the patients and the lengths of follow-up are not given in the abstract or in the editorial comment on this paper by Evans available on the UroToday web site. We would guess, however, that most of these patients would have received their initial treatment at some time between about 1996 and 2005.
The study was designed to evaluate the effect of first-line treatment with RP or IMRT on risk for distant metastases and risk for prostate cancer-specific death inpatients with localized prostate cancer treated at a single specialized cancer center. All patients included in this retrospective analysis had in itially been diagnosed with clinical stage T1c-T3b disease.
Patient-specific base data from this study can be summarized as follows:
1,318 patients were initially treated with RP.
1,062 patients were initially treated with IMRT.
79/1,318 patients (6 percent) initially treated with RP received immediate adjuvant or salvage radiation therapy.
597/1,062 patients (56 percent) initially terated with IMRT also receive 3 to 6 months of neoadjuvant androgen deprivation therapy (ADT).
107/141 patients with biochemical recurrence after RP went on to receive true salvage radiation therapy with or without ADT or ADT and chemotherapy
48 men were given ADT or chemotherapy without external beam radiation.
88/207 men with a biochemical recurrence after IMRT went on to receive salvage ADT.
Salvage therapy for patientsinitially treated with RP was delivered at median of 13 months after biochemicalfailure.
Salvage therapy for patients initially treated with IMRT was delivered at a median of 69 months after biochemical failure.
The results of the trial showed the following:
The men treated with IMRT (as might be expected) were older than those treated with RP and also had higher PSA levels, clinical stages, and biopsy Gleason scores.
The probabilities of 5-year biochemical recurrence-free survival predicted by the Kattan nomogram was 84 percent for RP patients and 80 percent for IMRT patients.
21/1,318 patients in the RP group (1.6 percent) and 48/1,062 patients in the IMRT group (4.5 percent) developed distant metastases.
The 8-year probability of freedom from metastatic progression was 97 percent for RP patients and 93 percent for IMRT patients.
The adjusted absolute difference in 8-year metastasis-free survival rates was 1.9 percent for men with low-risk disease, 3.3 percent for men with intermediate-risk disease, and 7.8 percent for men with high-risk disease (favoring RP in all cases).
8/1,318 patients in the RP group (0.6 percent) and 22/1062 patients in the IMRT group (2.1 percent) died.
The corresponding 8-year probabilities of prostate cancer-specific survival were 98.6 percent for RP patients and 95.3 percent for IMRT patients.
The 8-year Kaplan-Meier probability of prostate cancer-specific death was 3.8 percent among the RP patients as compared to 9.5 percent among the IMRT patients.
After adjustmentfor case mix, surgery was associated with a reduced risk ofmetastasis (hazard ratio [HR] =, 0.35) and a similarly reduced risk of prostate cancer–specificmortality (HR =0.32).
Zelefsy and his colleagues reach the following conclusions: