Zumsteg et al. searched the database at Memorial Sloan
Kettering Cancer Center (MSKCC) to
determine the risk factors associated with cancer progression after primary
radiation treatment, and the timing of progression. Their retrospective
analysis looked at records of 2,694 patients treated at MSKCC with radiation
doses between 76 Gy to 86 Gy. The median follow-up was 83 months for all
patients and 122 months for those who experienced biochemical failure (defined
as nadir+2). They did not report what, if any, salvage treatment was used. The
researchers found:
- · 23% of patients experienced biochemical failure.
- · The median time from biochemical failure to detection of distant metastases was 5.4 years.
- · The median time from biochemical failure to prostate cancer-specific mortality was 10.5 years, 5.1 years after metastases were detected.
- · Risk of clinical progression following biochemical failure were independently associated with:
o Shorter PSA doubling time
o Higher clinical stage
o Higher Gleason score
o Shorter time to biochemical failure
John Hopkins reported that for men treated with surgery, 19%
experienced biochemical failure. Some of the difference may be attributable to
the inadequate dose of radiation (76 Gy) used on some patients, or that those
patients were diagnosed with more aggressive disease. The median time from
biochemical recurrence to detection of distant metastases was 8 years, 3 years
among those who did not have salvage
radiation after biochemical recurrence (Antonarakis et al.), The shorter time in the radiation study
may reflect the fact that patients choosing radiation have historically been
older and further progressed at time of diagnosis. The median time to death after
metastases were detected was 5 years – identical in both studies. They all
report the same risk factors for clinical progression.
The numbers
reported for initial radiation therapy are similar, at first blush, to those
reported for initial prostatectomy. Because there will probably never be a
randomized clinical trial of surgery vs. radiation, it is tempting for the
patient faced with the choice of initial therapy after diagnosis to compare
these datasets, both from top institutions in their respective specialty. While
I would very much like to see the patient characteristics and the data
stratified by risk group and salvage treatment, if any, there does seem to be a
similar overall pattern. Some patients will have already experienced undetected
micrometastases before treatment, and they will not be cured by either therapy
using current methods. Other patients, most in fact, will be cured by either
therapy.
