To the Editor:
We read with interest the recent report by Pawlik et al.1 In their article, the authors describe the effect of positive surgical margin status on survival and site of recurrence in patients after hepatic resection for colorectal metastases. The results of this study give rise to some comments.
First, it is well known that surgical margin of less than 1 cm is risk factor for recurrence and death following liver resection. However, it is very difficult for the pathologist to assess the exact distance between the tumor and the end of the liver with great accuracy. Liver section can cause liver fractures along the line of the cut, completely changing the distance to be measured. Moreover, the positive ink margin can sometimes make the definition of a positive margin quite subjective (as Dr. Choti mentions in the discussion section of the article). The definition of positive margin is imperative. In our opinion, the exact surgical margin is the piece of liver that becomes aspirated by the cavitational ultrasonic surgical aspirator. This should be the real definition of liver surgical margin. The effect of surgical margin after hepatic resection should include the study of this aspirated tissue. In our experience (unpublished data), in 2 of 18 last hepatectomies, microscopic analysis showed a positive margin. However, none of them has the cavitational ultrasonic surgical aspirator line affected in the initial pathologic study. Currently, both patients are free of disease. The analysis of this aspirated hepatic material has been completed with molecular analysis techniques.
Second, the growth of liver metastases is important in understanding local recurrence. The rounding zone for liver metastasis should also be analyzed because it is an important area in the formation of new vessels.2 A classification of liver metastases found differences, depending on the characteristics of the cut surface of the tumor. Nodular liver metastases had a better prognosis than confluent nodular3 ones. This discovery suggests that tumor growth is centered in the rounding zone, and oncologic and prognostic studies may also be included in this.
Third, recently published data suggest that surgical margin is being overestimated.4 Experienced liver surgeons plan the hepatic section line preserving a safety zone. However, the position of the tumor involving hepatic veins or its size can impose changes in the section line, reducing the margin. The significance of surgical margin status in long-term survival after resection of colorectal metastases remains controversial.
Finally, our congratulations to the authors for their extensive study, which will help toward understanding the progress of colorectal cancer patients. The usefulness of performing pathologic studyof the margin has been very thoroughly reviewed.
Juli Busquets
Nuria Pelaez
Sandra Alonso
Luís Grande
Hospital del Mar
Barcelona, Spain
jbusquets@imas.imim.es
REFERENCES
- 1.Pawlik TM, et al. Effect of surgical margin status on survival and site of recurrence after hepatic resection for colorectal metastases. Ann Surg. 2005;241:715–722 , discussion 722–724. [DOI] [PMC free article] [PubMed]
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