Lymphovascular invasion in prostate cancer - prognostic significance in patients treated with radiotherapy after radical prostatectomy
Review of: Brooks JP, Albert PS, O’Connell J, McLeod DG, Poggi MM. Cancer 2006;106(7):1521-1526.
Lymphovascular invasion (LVI) is found on standard hematoxylin and eosin staining and defined as the unequivocal presence of tumour cells within a vascular or lymphatic, endothelial-lined space. In 1994, the College of American Pathologists recommended reporting LVI using routine brightfield microscopy of prostatectomy specimens. The role of LVI is found in 5% to 53% of specimens after radical prostatectomy and has been associated with aggressive clinical features. The numbers of LVI foci range from 1 to 40 foci per patient, and most patients have 1 or 2 foci.
In the present study, Brooks and collaborators at two military treatment facilities; Walter Reed Army Medical Center and the National Naval Medical Center, assessed the significance of LVI in patients who received adjuvant P-XRT (radiation administered soon after surgery based on clinical or pathologic features) and salvage P-XRT (radiation delayed until laboratory or clinical evidence suggestive of disease progression) after radical prostatectomy. The authors reviewed the medical records of men who received P-XRT from 1991 to 2001 for the presence of LVI in radical prostatectomy specimens and correlated LVI to multiple parameters including time to biochemical recurrence and the time to distant metastases.
LVI was noted in 18 of 160 patients (11%) and was associated significantly with other unfavourable pathologic features, such as seminal vesicle invasion and increasing Gleason score. After a median follow-up of 8.3 years after radical prostatectomy, 16 of 18 patients (89%) with LVI showed biochemical recurrence (rising serum PSA) after P-XRT, 9 of whom developed distant metastases.
The median time to biochemical recurrence in patients with LVI was significantly shorter than in patients without LVI (2.6 vs. 7.8 years). Other significant factors were Gleason score, undetectable post-prostatectomy PSA levels, preradiotherapy serum PSA levels, and the interval from radical prostatectomy to P-XRT. LVI was the only significant factor associated with an increased risk of distant metastases in univariate analysis.
This study is hampered by its retrospective nature, the relatively small numbers of patients, and the lack of a central pathology review. Nevertheless, the authors argue that LVI is a marker for an aggressive variant of prostate cancer but also a marker for reduced efficacy of P-XRT after radical prostatectomy in terms of increased risk of biochemical recurrence and distant metastases. Undoubtedly additional therapy beyond P-XRT may be needed for this group of patients, and we are awaiting the results of other studies to confirm the findings presented here.