My inklings on the inked margin

Positive surgical margins after RP do not predict prostate cancer-specific mortality
By Sarah Guy
28 January 2010
J Urol 2010; Advance online publication

MedWire News: The presence of positive surgical margins (PSMs) after radical prostatectomy (RP) does not indicate an increased risk for cancer-specific mortality, systemic disease progression, or overall mortality in prostate cancer patients, report researchers.

The team also found that PSM incidence has decreased over time; patients treated during the most recent era of prostate-specific antigen (PSA) testing are less than half as likely to experience a PSM as those treated before.

“These results need to be considered when evaluating patients for adjuvant therapy given the potential morbidity and costs of secondary treatment,” suggest Michael Blute, from the Mayo Clinic in Rochester, Minnesota, USA, and co-authors.

The researchers estimated various 10-year survival end-points after a median follow-up of 8.2 years among 11,729 RP patients with and without PSMs.

PSMs, biochemical recurrence (BCR), local recurrence, and systemic progression were defined as tumor extension to the inked surface of the RP specimen, a PSA of 0.4 ng/ml or greater after surgery, cancer on biopsy of the prostatic bed or in the prostatic fossa, and demonstrable metastases on bone scan or biopsy, respectively.

Rates of 10-year BCR were significantly decreased among 3651 patients with at least one PSM compared with men with no PSMs, at 56% versus 77%. The same trend was noted for 10-year local recurrence-free survival, at 89% versus 95%.

Similarly, 10-year systemic progression-free survival, cancer-specific survival, and overall survival rates were worse for 8078 men with PSMs than men without, at 93% versus 97%, 96% versus 99%, and 83% versus 88%, respectively.

Multivariate analysis, adjusted for clinicopathologic variables, showed that presence of PSMs increased the risk for BCR 1.63-fold, local recurrence 1.78-fold, and receipt of salvage therapy 1.79-fold. But PSMs did not significantly predict systemic progression, cancer-specific mortality, or overall mortality.

Finally, the incidence of PSMs significantly decreased from 41.1% in the early PSA era (1990–1995) to 19.6% in the most recent PSA era (2001–2006). This is likely the result of “stage migration in prostate cancer during the PSA era, as well as improvements in [surgical] technique,” write Blute et al.

In response to the research, published in The Journal of Urology, editorialist Mark Mann (SUNY Upstate Medical University, Syracuse, New York) asked: “If surgical margins do not make an impact on survival, is treatment, which is not without morbidity, indicated?”

My thoughts-

It happens often that the prostate specimen’s path report states,”cancer extends to the inked margin.” Pathologists dip the prostate in ink and this makes it easier to see if cancer goes to the “edge” of the prostate. The capsule of the prostate is like the rind of an orange. This finding may or may not mean that the cancer has extended beyond the prostate,or “gotten out.” Because of this I will watch post-operative PSAs and if there is a serial rise in the value, then that is an indication of residual disease and the need for additional therapy, usually external beam radiation.  In the article above the words cancer specific death would relate to capsular extension that did penetrate and resulted in return of disease and its attendant morbidity. This goes back to the truism for all cancers, early detection is the key.

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