Surgical results after downstaging of initially marginal or non-resectable liver metastases

How to increase the resectability of initially unresectable colorectal liver metastases: A surgical perspective

Although surgical resection is the only treatment of choice that can offer prolonged survival and a chance of cure in patients with colorectal liver metastases (CRLM), nearly 80% of patients are deemed to be unresectable at the time of diagnosis. Considerable efforts have been made to overcome this initial unresectability, including expanding the indication of surgery, the advent of conversion chemotherapy, and development and modification of specific surgical techniques, regulated under multidisciplinary approaches. In terms of specific surgical techniques, portal vein ligation/embolization can increase the volume of future liver remnant and thereby reduce the risk of hepatic insufficiency and death after major hepatectomy. For multiple bilobar CRLM that were traditionally considered unresectable even with preoperative chemotherapy and portal vein embolization, two-stage hepatectomy was introduced and has been adopted worldwide with acceptable short- and long-term outcomes. Recently, ALPPS (associating liver partition and portal vein ligation for staged hepatectomy) was reported as a novel variant of two-stage hepatectomy. Although issues regarding safety remain unresolved, rapid future liver remnant hypertrophy and subsequent shorter intervals between the two stages lead to a higher feasibility rate, reaching 98%. In addition, adding radiofrequency ablation and vascular resection and reconstruction techniques can allow expansion of the pool of patients with CRLM who are candidates for liver resection and thus a cure. In this review, we discuss specific techniques that may expand the criteria for resectability in patients with initially unresectable CRLM.

The local efficacy and influencing factors of ultrasound-guided percutaneous microwave ablation in colorectal liver metastases: a review of a 4-year experience at a single center

PURPOSE

To investigate the clinical effectiveness and safety of ultrasound (US)-guided percutaneous microwave ablation (MWA) for colorectal liver metastasis (CRLM) and evaluate the influencing factors of local efficacy.

METHODS

From January 2013 to January 2017, 137 CRLM patients accepting US-guided percutaneous MWA were included. The 2450-MHz microwave ablation system and a cooled-shaft antenna were used. All patients were regularly followed up for at least 6 months. Technical success, complete ablation, local tumor progression (LTP), complications and side effects were assessed. Logistic regression analysis was used to identify the independent prognostic factors for LTP.

RESULTS

In total, 411 lesions (mean diameter 15.4 ± 7.2 mm, range 5-67 mm) were treated. Complete ablation was achieved in 99.27% (408/411) of lesions and 97.81% (134/137) of patients. LTP occurred in 5.35% (22/411) of lesions and 16.06% (22/137) of patients. LTP was more likely to occur in lesions larger than 3 cm in diameter (OR: 14.71; p < .001; 95% CI: 3.7 3-57.92), near a large vascular structure (OR: 7.04; p < .001; 95% CI: 2.41-20.60), near the diaphragm (OR: 4.02; p = .049; 95% CI: 1.05-16.11) and in patients with no response to chemotherapy before MWA (OR: 3.25; p = .032; 95% CI: 1.14-15.30). MWA was well tolerated, with a major complication rate of 3.65%, a minor complication rate of 8.03% and a mortality rate of 0%. Fever and pain were the most common side effects after MWA.

CONCLUSIONS

US-guided percutaneous MWA of CRLM is a safe and effective method that is expected to become a routine treatment for local tumor control of CRLM.

Local tumor progression patterns after radiofrequency ablation of colorectal cancer liver metastases

PURPOSE

We aimed to evaluate patterns of local tumor progression (LTP) after radiofrequency ablation (RF ablation) of colorectal cancer liver metastases (CRCLM) and to highlight the percentage of LTP not attributable to lesion size or RF ablation procedure-related factors (heat sink or insufficient ablation margin).

METHODS

CRCLM treated by RF ablation at a single tertiary care center from 2004-2012, with a minimum of six months of postprocedure follow-up, were included in this retrospective study. LTP morphology was classified as focal nodular (<90° of ablation margin), circumferential (>270°), or crescentic (90°-270°). Initial metastasis size, minimum ablation margin size, morphology of LTP, presence of a heat sink, and time to progression were recorded independently by two radiologists.

RESULTS

Thirty-two of 127 RF ablation treated metastases (25%) with a mean size of 23 mm (standard deviation 12 mm) exhibited LTP. Fifteen of 32 LTPs (47%) were classified as focal nodular, with seven having no procedure-related factor to explain recurrence. Ten of 32 LTPs (31%) were circumferential, with four having no procedure-related factor to explain recurrence. Seven of 32 LTPs (22%) were crescentic, with two having no procedure-related factor to explain recurrence. Of the 13 lesions without any obvious procedure-related reason for LTP, six (46%) were <3 cm in size.

CONCLUSION

Although LTP in RF ablation treated CRCLM can often be explained by procedure-related factors or size of the lesion, in this study up to six (5%) of the CRCLM we treated showed LTP without any reasonable cause.

Nomogram for prediction of prognosis in patients with initially unresectable colorectal liver metastases

BACKGROUND

Although recent advances in surgery and chemotherapy have increasingly enabled hepatectomy in patients with initially unresectable colorectal liver metastases (CRLM), not all such patients benefit from surgery. The aim of this study was to develop a nomogram to predict survival after hepatectomy for initially unresectable CRLM.

METHODS

Patients with initially unresectable CRLM treated with chemotherapy followed by hepatectomy between 1990 and 2012 were included in the study. A nomogram to predict survival was developed based on a multivariable Cox model. The predictive performance of the model was assessed according to the C-statistic, Kaplan-Meier curve and calibration plots.

RESULTS

Of a total of 439 patients, liver and globally completed surgery was achieved in 380 (86·6 per cent) and 335 (76·3 per cent) patients respectively. The 5-year overall and disease-free survival rates were 39·9 and 10·0 per cent respectively. Based on the Cox model, the following five factors were selected for the nomogram and assigned specific scores: node-positive primary, 5; more than six metastases at hepatectomy, 7; carbohydrate antigen 19-9 level at hepatectomy above 37 units/ml, 10; disease progression during first-line chemotherapy, 9; and presence of extrahepatic disease, 4. The model achieved relatively good discrimination and calibration, with a C-statistic of 0·66. The overall survival rate for patients with a score greater than 16 was significantly worse than that for patients with a score of 16 or less (5-year survival rate 4 versus 46·3 per cent respectively; P < 0·001).

CONCLUSION

The nomogram facilitates personalized assessment of prognosis for patients with initially unresectable CRLM treated with chemotherapy and with planned resection.