Liver resection for colorectal cancer metastases involving the caudate lobe

Sir,

We would like to thank Lawson McClean and Russell for their comments relating to our article “Liver resection for colorectal liver metastases involving the caudate lobe”.

We agree that the non-caudate and caudate groups differ in size and that the caudate-resected group is small (n=25). We agree this could lead to a type II error in the data analysis, particularly where long-term survival is concerned and we have indicated in our results section that due to the small sample size involved in the study, long-term survival results should be interpreted with caution. However, we are confident in our assertion that caudate resection need not incur a greater risk of involved resection margin.

It is estimated that approximately 2-8% of liver resections for colorectal cancer liver metastases involve the caudate lobe. In our series, the proportion is 5.5%, well within the range described in the literature. Our data showed no differences between the groups on comparison of operative blood loss, hospital stay, operative mortality or operative morbidity.

In our series a high proportion of patients underwent neoadjuvant treatment prior to liver resection in order to downstage their tumours prior to liver resection (76% for caudate, 78.2% non-caudate) and on comparison of our entire series with Khan et al (1), our median tumour diameters were markedly less. There can be no dispute that difference in the incidence of involved margins between our series and that of Khan et al is substantial and furthermore the high incidence of involved margins in Khan et al’s series is of some concern. We conclude that the judicious use of neo-adjuvant chemotherapy permits oncologically sound resections of difficult, caudate / caudate involved tumours with clear margins.

The fact that most of these resections were carried out by the senior surgeon in the HPB unit should not be a pointer for criticism as these are difficult resections and it may be reasonable to concentrate them in the hands of the most experienced liver surgeons in each unit.

Yours sincerely

Mr Rhys Thomas
Professor Nariman Karanjia
ndkaranjia@me.com

Reference

1. Khan AZ, Wong VK, Malik HZ, Stiff GM, Prasad KR, Lodge JP et al. The impact of caudate lobe involvement after hepatic resection for colorectal metastases. EJSO 2009; 35: 510-514.

• Commentor: Mr Rhys Thomas, Professor Nariman Karanjia
• Date: Jan 04, 2012

Sir,

We would like to commend Thomas et al for their single-centre study of resection margin involvement after caudate lobe surgery for colorectal cancer liver metastases (CRLM).

While Khan et al found that in patients with CRLM, a higher proportion of caudate versus non-caudate resections had positive resection margins (57% vs 32%, P=0.001) (1), this study concludes there is no such trend. Despite a higher rate of positive margins in caudate lobe resections, this was not statistically significant (4% vs 2.1%, P=0.520). In Khan et al’s study 52 patients had caudate lobe resections, compared with only 25 in this study. We are concerned that the small sample size and lower incidence of margin involvement overall may have resulted in a type 2 error in this study and it may be underpowered to report the outcome of such resections. Further, the fact that almost all resections were performed by the same experienced surgeon may limit the applicability of the findings to other centres.

Significantly, the authors do not clarify the study group’s composition with respect to chronology of the development of metastatic disease. Up to 24% of patients with newly-diagnosed colorectal cancer have synchronous hepatic metastases while Manfredi et al reported a five-year cumulative metachronous liver metastasis rate of 14.5% in their population-wide study (2). It is generally held that synchronicity suggests more aggressive and advanced disease, and is associated with poorer outcomes. It is also true that synchronous CRLM are more often bi-lobar and more numerous (3). These facts may be important in predicting those who will benefit from caudate lobe surgery. Without knowing the composition of the group studied as mentioned previously with respect to chronology, it is difficult to determine the precise clinical relevance of the findings.

A Lawson McLean & CD Russell
Royal Infirmary of Edinburgh, UK
a.lawson-mclean@sms.ed.ac.uk

References:

1. Khan AZ, Wong VK, Malik HZ, Stiff GM, Prasad KR, Lodge JP & Toogood GJ. The impact of caudate lobe involvement after hepatic resection for colorectal metastases. Eur J Surg Oncol. 2009;35(5):510-4.

2. Manfredi S, Lepage C, Hatem C, Coatmeur O, Faivre J, Bouvier AM. Epidemiology and management of liver metastases from colorectal cancer. Ann Surg. 2006;244(2):254-9.

3. Tan EK, Ooi LL. Colorectal cancer liver metastases - understanding the differences in the management of synchronous and metachronous disease. Ann Acad Med Singapore. 2010;39(9):719-15.

• Commentor: A Lawson McLean & CD Russell - Royal Infirmary of Edinburgh, UK
• Date: Oct 22, 2011