Abstract
Objectives
Management of liver metastasis (LM) from a non-colorectal, non-neuroendocrine primary carcinoma remains controversial. Few data exist on the management of hepatic metastasis from primary renal cell carcinoma (RCC). This study sought to determine the safety and efficacy of surgery for RCC LM.
Methods
A total of 43 patients who underwent surgery for RCC hepatic metastasis between 1994 and 2011 were identified in a multi-institution hepatobiliary database. Clinicopathologic, operative and outcome data were collected and analysed.
Results
Mean patient age was 62.4 years and most patients (67.4%) were male. The mean tumour size of the primary RCC was 6.9 cm and most tumours (72.1%) were designated as clear cell carcinoma. Nine patients (20.9%) presented with synchronous LM. Among the patients with metachronous disease, the median time from diagnosis of the primary RCC to treatment of LM was 17.2 months (range: 2.1–189.3 months). The mean size of the RCC LM was 4.0 cm and most patients (55.8%) had a solitary metastasis. Most patients (86.0%) underwent a minor resection (up to three segments). Final pathology showed margin status to be negative (R0) in 95.3% of patients. Postoperative morbidity was 23.3% and there was one perioperative death. A total of 69.8% of patients received perioperative chemotherapy. Overall 3-year survival was 62.1%. Three-year recurrence-free survival was 27.3% and the median length of recurrence-free survival was 15.5 months.
Conclusions
Resection of RCC hepatic metastasis is safe and is associated with low morbidity and near-zero mortality. Although recurrence occurs in up to 50% of patients, resection can be associated with long-term survival in a well-selected subset of patients.
Keywords: renal cell carcinoma, liver metastasis, hepatectomy, metastasectomy, outcomes, surgery
Introduction
An estimated 58 000 Americans were diagnosed with renal cell carcinoma (RCC) during 2010 and 13 000 died of this disease.1 Although many patients with RCC present with early-stage disease, a subset of patients will develop metastatic disease. In general, metastatic disease from RCC has been associated with a poor prognosis, with 5-year survival ranging from 5% to 15%.1–6 Among patients with metastatic disease, resection represents the only hope for cure, but indications for surgery of metastatic RCC remain poorly defined. Patients with oligometastatic disease that is restricted to one organ may be candidates for surgical therapy and may derive a survival benefit.1
Most data on resection of metastatic RCC come from series examining the role of surgery in RCC metastatic to the lung because the lung is the most common site of RCC metastasis.5 Although it is less common, the liver is another frequent site of metastatic disease. Unfortunately, the development of hepatic metastasis is generally considered a poor prognostic factor and is often associated with more widespread disease. A subset of patients, however, will have metastatic RCC confined to the liver and surgical therapy may be warranted. Most data on the surgical management of RCC hepatic metastasis are largely anecdotal or derived from limited case reports.6,7 Although larger series that focus on non-colorectal, non-neuroendocrine metastasis have been published, patients with RCC metastasis represented only a small subgroup in these samples and were not the focus of these studies.8
The objective of this study was to assess the efficacy of surgical therapy for hepatic metastasis of RCC in a large cohort of patients treated at three major hepatobiliary centres. Specifically, the study sought to define the benefit of surgery in a well-selected group of patients with RCC liver metastasis (LM) and to determine which factors were associated with prognosis. To evaluate the relative survival benefit in patients operated for RCC LM, the study utilized a matched-pair analysis to compare outcomes in patients undergoing surgery for RCC LM with outcomes in patients operated for colorectal carcinoma (CRC) LM.
Materials and methods
Using an international, multi-institution database, 43 patients with histologically proven RCC LM who underwent surgical resection with curative intent between January 1994 and January 2011 at one of three institutions (Johns Hopkins University School of Medicine, Baltimore, MD, USA; Ospedale San Raffaele, Milan, Italy; Royal Prince Alfred Hospital, Sydney, NSW, Australia) were identified. The institutional review board of each institution approved this study. Only patients with histologically confirmed RCC who were treated for RCC at a study centre were included.
Data collection
Standard demographic and clinicopathologic data were collected, including sex, age and primary tumour characteristics. Specifically, data were collected on primary tumour location and size, as well as histologic subtype. Data on treatment-related variables, such as type of surgery (complete or partial nephrectomy) and adjuvant therapy, were also obtained. Similar data were collected on the number, size and location of metastatic hepatic lesions, as well as time to RCC LM (i.e. synchronous vs. metachronous). Data on the utilization of perioperative chemotherapy were obtained. Operative information included type of liver-directed therapy (i.e. resection, ablation) and extent of resection. Hepatectomy was classified as minor (less than three segments) or major (three or more segments). Margin status was ascertained based on final pathologic assessment. Data on operative morbidity and mortality were recorded. The date of last follow-up and vital status were collected for all patients.
Statistical analysis and matching cohort
Summary statistics were obtained using established methods and presented as percentages, means or median values. Data were analysed using Student's t-test and Wilcoxon rank sum test for continuous variables, and the chi-squared test or Fisher's exact test for discrete variables, where appropriate. Overall survival was examined using the Kaplan–Meier method and compared using the log-rank test. In order to compare subgroups of patients who underwent surgery for hepatic metastasis of, respectively, RCC and CRC, a 1 : 3 matched controlled analysis was performed. Specifically, patients were matched for age, date of surgery, disease-free interval between primary and metastatic disease, and the size and number of LM lesions, as well as for the presence of any extrahepatic disease. Statistical analyses were performed using stata Version 11.2 for Macintosh (StataCorp LP, College Station, TX, USA).
Results
Patient, tumour and primary surgery characteristics
Characteristics of the 172 patients included in the current study are detailed in Table 1. Of the 172 patients, 43 patients had RCC metastatic to the liver and 129 had CRC hepatic metastasis and served as the control cohort. Among the patients with RCC hepatic metastasis, mean patient age was 62.4 years and most patients (67.4%) were male. There was a relatively equal distribution of primary tumour location (right kidney, 46.5%; left kidney, 53.5%); the majority (83.8%) of patients had lymph node metastasis associated with the primary tumour. The mean size of the RCC primary tumour was 6.9 cm (range: 3.0–13.0 cm) and most tumours were pathologic T3 lesions (T1, 34.9%; T2, 14.0%; T3, 46.5%; T4, 4.6%). The most prevalent histology of the primary kidney cancer showed clear cell carcinoma (72.1%), followed by chromophobe carcinoma (18.6%).
Table 1.
Clinicopathologic characteristics of patients with renal cell carcinoma (RCC) liver metastasis (LM) and matched controls with colorectal carcinoma (CRC) LM
| RCC LM group (n= 43) | CRC LM group (n= 129) | |
|---|---|---|
| Age, years, mean (standard deviation) | 62.4 (10.8) | 61.5 (12.5) |
| Male sex, n (%) | 29 (67.4) | 84 (65.1) |
| Primary tumour | ||
| Size, cm, median (range) | 6.9 (3–13) | – |
| Right side, n (%) | 20 (46.5) | – |
| Histology, n (%) | ||
| Clear cell | 31 (72.1) | – |
| Chromophobe | 8 (18.6) | – |
| Papillary | 4 (9.3) | – |
| Grade, n (%) | ||
| Low (Fuhrman 1–2) | 11 (25.6) | – |
| High (Fuhrman 3–4) | 32 (74.4) | – |
| Caval tumour thrombus, n (%) | ||
| No | 34 (79.1) | – |
| Below the insertion of the hepatic veins | 4 (9.3) | – |
| Within the intrahepatic vena cava | 5 (11.6) | – |
| Intra-atrial tumour thrombus extension | 0 | – |
| Staging on presentation | ||
| T-stage, n (%) | ||
| T1 | 15 (34.9) | – |
| T2 | 6 (14.0) | – |
| T3 | 20 (46.5) | – |
| T4 | 2 (4.6) | – |
| N-stage, n (%) | 43 (100) | – |
| N0 | 7 (16.3) | – |
| N1 | 30 (69.8) | – |
| N2 | 6 (13.9) | – |
| Hepatic metastasis | ||
| Size of the largest lesion, cm, median (range) | 4.0 (2.0–15.0) | 3.4 (0.5–11.0) |
| Number of hepatic metastases, n (%) | ||
| Solitary | 24 (55.8) | 72 (55.8) |
| 2–5 | 19 (44.2) | 57 (44.2) |
| Bilobar distribution, n (%) | 6 (14.0) | – |
| Liver-directed therapy | ||
| Disease-free interval >12 months, n (%) | 21 (48.8) | 68 (52.7) |
| Type of liver resection, n (%) | ||
| <3 segments | 36 (85.7) | 77 (59.7) |
| ≥3 segments | 6 (14.3) | 52 (40.3) |
| Ablation, n (%) | 7 (16.3) | 10 (7.8) |
| Margin status, n (%) | ||
| R0 | 41 (95.3) | 125 (96.9) |
| R1 | 2 (4.7) | 4 (3.1) |
| Chemotherapy, n (%) | ||
| Adjuvant | 25 (58.1) | – |
| Neoadjuvant | 5 (11.6) | – |
| Cytotoxic | 21 (48.8) | – |
| Immunotherapy | 4 (9.3) | – |
| Both | 5 (11.6) | – |
| Extrahepatic metastases, n (%) | 14 (32.6) | 38 (29.5) |
Although nine (20.9%) patients presented with synchronous RCC LM, the overwhelming majority (n= 34, 79.1%) developed metachronous disease after a median disease-free interval of 17.2 months (range: 2.1–189.3 months). The majority of patients (n= 24, 55.8%) had a solitary hepatic metastasis. The median size of the largest lesion was 4.0 cm (range: 2.0–15.0 cm). A subset of patients had extrahepatic disease in conjunction with liver disease (n= 14, 32.6%). Patients with RCC LM and those with CRC LM were comparable regarding the clinicopathologic factors on which they were matched (Table 1).
Of the 43 patients with RCC LM who underwent surgery, 30 (69.8%) patients received chemotherapy. Adjuvant chemotherapy was administered to 25 (58.1%) patients and five patients received neoadjuvant chemotherapy. Chemotherapy consisted of immunotherapy (n= 4), cytotoxic therapy (n= 21), or a combination of both (n= 5).
Details of liver-directed surgery and postoperative course
All patients with synchronous LM (n= 9) underwent an extended procedure in which hepatic resection was carried out at the same time as resection of the primary renal tumour; no patient underwent staged liver-directed surgery. Overall, among the 43 patients with RCC LM, surgery consisted of resection only (n= 36, 83.7%), ablation only (n= 1, 2.3%) or combined resection and ablation (n= 6, 14.0%). Among patients who underwent resection, the extent of resection was minor in most patients (n= 36, 85.7%). On final pathologic analysis of the liver specimen, the overwhelming majority of patients (n= 41, 95.3%) had a negative hepatic margin (R0); only two patients (4.7%) were noted to have microscopic disease at the margin (R1) and no patient had residual macroscopic disease (R2).
There was one postoperative death within 30 days of surgery, giving a mortality rate of 2.3%. Ten patients experienced a postoperative complication, giving a morbidity rate of 23.3%. Most complications (n= 7) were related to wound infection, bleeding and respiratory insufficiency.
Recurrence and overall survival
Following liver-directed surgery, 18 (41.9%) patients suffered recurrence after a median disease-free interval of 15.5 months (range: 3.1–76.4 months) (Fig. 1). Among the 18 patients with recurrence, the pattern of recurrence was intrahepatic only in 13 (30.2%) patients, extrahepatic only in three (7.0%) patients, and both intra- and extrahepatic in two (4.7%) patients.
Figure 1.
Following liver-directed surgery, 41.9% of patients operated for renal cell carcinoma (RCC) liver metastasis (LM) suffered recurrence. Median disease-free survival was 15.5 months in patients undergoing resection of RCC LM and 26.9 months in patients operated for colorectal carcinoma LM (P= 0.142)
A matched analysis was performed to assess the impact of liver-directed therapy for RCC hepatic metastasis compared with the more traditional indication of CRC LM. Specifically, patients who underwent surgery for LM of, respectively, RCC and CRC were matched 1 : 3 for age, date of surgery, disease-free interval between primary and metastatic disease, and size and number of LM lesions, as well as for the presence of any extrahepatic disease. Following liver-directed surgery, median disease-free survival was found to be slightly worse in patients who underwent resection of RCC LM (15.5 months) than in patients who underwent surgery for CRC LM (26.9 months), but the difference was not statistically significant (P= 0.142). Overall median survival in patients who underwent surgery for RCC LM was not reached (range: 2.0–109.1 months), whereas that in patients who underwent resection of CRC LM was 62.9 months (range: 0.6–136.7 months) (P= 0.582) (Table 2). One- and 3-year survival rates in patients who underwent liver-directed surgery for RCC LM (94.2% and 62.1%, respectively) were comparable with those in patients operated for CRC LM (89.4% and 69.2%, respectively) (P= 0.582) (Table 2, Fig. 2).
Table 2.
Disease-free and overall survival in patients with renal cell carcinoma (RCC) liver metastasis (LM) and matched controls with colorectal carcinoma LM
| RCC LM group (n= 43) | CRC LM group (n= 129) | P-value | |
|---|---|---|---|
| Disease-free survival, n (%) | |||
| 1-year | 79.5 (56.9–91.1) | 82.8 (73.1–88.9) | |
| 3-year | 27.3 (7.5–52.1) | 33.3 (22.3–44.6) | |
| Time to recurrence, months, median (range) | 15.5 (3.1–76.4) | 26.9 (3.4–32.8) | 0.142 |
| Overall survival, n (%) | |||
| 1-year | 94.2 (81.9–99.6) | 89.4 (87.3–97.0) | |
| 3-year | 62.1 (36.8–83.2) | 69.2 (58.0–77.9) | |
| Survival, months, median (range) | NR (2.0–109.1) | 62.9 (0.6–136.7) | 0.582 |
NR, not reached.
Figure 2.
Overall median survival in patients who underwent liver-directed surgery for renal cell carcinoma liver metastasis (LM) was comparable with that in patients operated for colorectal carcinoma LM (P= 0.582)
On univariate analyses, disease-free interval and presence of extrahepatic disease were associated with overall survival (Table 3). Median survival after surgery for RCC LM in patients who had a disease-free interval of ≤12 months between the time of LM and primary tumour diagnosis was 21.5 months and was thus worse than that in patients who had a disease-free interval of >12 months (not reached) (P= 0.021). Similarly, median survival in patients with extrahepatic disease before or at liver surgery was worse than in patients without extrahepatic disease (median survival: 21.9 months vs. not reached; P= 0.033) (Fig. 3).
Table 3.
Univariate analysis of prognostic factors for disease-free and overall survival
| Median survival, months | P-value | Median time to recurrence, months | P-value | |
|---|---|---|---|---|
| Disease-free interval | ||||
| ≤12 months | 21.5 | 14.8 | ||
| >12 months | NR | 0.022 | 14.1 | 0.762 |
| Number of lesions | ||||
| One | 39.9 | 19.9 | ||
| Multiple lesions | NR | 0.761 | 14.1 | 0.711 |
| Extrahepatic disease | ||||
| No | NR | 14.8 | ||
| Yes | 21.9 | 0.024 | 14.1 | 0.663 |
| Size of the largest lesion | ||||
| ≤5 cm | NR | 15.5 | ||
| >5 cm | 21.9 | 0.433 | 8.9 | 0.384 |
| Grade | ||||
| Low (Fuhrman 1–2) | 21.4 | 15.4 | ||
| High (Fuhrman 3–4) | 46.5 | 0.913 | 19.9 | 0.052 |
NR, not reached.
Figure 3.
In patients with renal cell carcinoma liver metastasis, median survival was worse in those with extrahepatic disease than in those without extrahepatic disease (median survival: 21.9 months vs. not reached; P= 0.033)
Discussion
The management of patients with non-neuroendocrine, non-colorectal LM has been a topic of increasing interest.8–10 Data from these studies have largely focused on patients with metastasis from breast cancer, sarcomas, melanomas and a variety of non-colorectal gastrointestinal primary tumours. Patients with RCC LM have not been a focus of these reports and data on this topic remain scarce. As such, information on whether surgery plays a role in outcomes in patients with RCC LM remains controversial. Surgery for RCC LM is a particular subject of debate as RCC LM has been thought to indicate a particularly poor prognosis compared with RCC lung metastasis.5,6,11 The current study is important because it examines outcomes in a relatively large cohort of patients managed with surgery for RCC LM. Although these patients were obviously highly selected, the data suggest that liver-directed surgery in a subset of patients with RCC LM can be associated with long-term survival. Data from the current study show that surgery is safe, is associated with low rates of morbidity and mortality and with 5-year survival of ≍60%. In fact, overall survival in patients operated for RCC LM was similar to that in a matched cohort of patients who underwent surgery for CRC LM. Taken together, these data suggest that a surgical approach to hepatic metastasis from RCC is justified in a select subset of patients.
Recently, Ruys and colleagues published their experience in the surgical treatment of RCC LM.6 Their study reported on patients retrieved from the local databases of the Netherlands Task Force for Liver Surgery. The study included 33 patients who underwent either resection (n= 29) or local ablation (n= 4) of RCC LM at one of 14 centres. Although the current study is comparable with that by Ruys et al.,6 the present series involved a larger number of patients (n= 43) from dramatically fewer centres (n= 3). Nonetheless, these data underscore the relative rarity and highly selected nature of patients with RCC LM who are offered and eventually undergo surgical therapy. In the current series, the overwhelming majority of patients (79.1%) had metachronous disease and most patients (55.8%) had a solitary hepatic metastasis that measured <5 cm. Surgery was therefore offered only to a very select subset of patients who had a low burden of disease that often presented in a metachronous fashion. Although the current study did not allow for the estimation of the overall utilization of surgery in patients presenting with RCC LM, others have estimated that fewer than 5% of patients with RCC LM are candidates for surgical resection.6
It may be that the very stringent patient selection criteria applied in the present study had some influence on the finding that overall survival following surgery for RCC LM in this series was very good. In fact, the present study reports a 5-year overall survival following liver-directed surgery for RCC LM of ≍60%. This is somewhat superior to 5-year survival rates of 40–45% reported in several other series.6–8,12 The reasons for this are probably multifactorial, but may relate, in part, to the population-based nature of previous data.6 In particular, the study by Ruys et al. represented a population-based experience from the Netherlands and included patients from a large number of centres without standardization of selection criteria or operative approach.6 Previous studies have noted that population-based data are often associated with worse short- and long-term outcomes compared with institution-level data.13–15 The current study not only used institution-level data, but also compared outcomes in patients with RCC LM with those in an internal control group by performing a 1 : 3 matched analysis of outcomes in RCC LM patients matched with CRC LM patients on a number of clinicopathologic factors. On matched analysis, overall survival in patients with RCC LM was comparable with that in patients with CRC LM (Fig. 2). In sum, the findings on survival presented in the current study and in previous studies suggest it is possible to identify a subset of RCC LM patients in whom outcomes of hepatic resection will be similar to those reported in CRC LM patients.6–8,12
Two factors were associated with overall survival: disease-free interval, and presence of extrahepatic disease (Fig. 3). Specifically, metachronous disease with a disease-free interval of ≥12 months was strongly associated with increased survival. Patients with a disease-free interval of ≥12 months had a median survival that was not reached, whereas median survival in patients with a disease-free interval of <12 months was only 21.5 months. Ruys et al. reported that patients with synchronous disease had significantly worse survival compared with patients who presented with metachronous LM.6 Staehler et al. similarly noted that patients with metachronous disease had a median survival of 155 months, whereas patients with synchronous disease had a median survival of 29 months.16 The presence of extrahepatic disease was also associated with long-term outcome. Extrahepatic disease has been considered a relative contraindication for liver resection in CRC LM and the presence of extrahepatic disease has been shown to adversely impact survival following resection of CRC LM.17 Among RCC LM patients, extrahepatic disease also adversely affected outcome as these patients achieved a median survival of only 21.9 months following liver resection. In RCC patients with LM, the present data strongly suggest that patients with a long disease-free interval and those with no extrahepatic disease derive the most benefit from surgical therapy.
The present study has several limitations. Although the study combined data from three major hepatobiliary centres, the overall sample size was still somewhat small. As such, statistical analyses were limited and causal inferences should be considered in this light. Given that the study was retrospective in nature, like many studies of surgical outcomes, it is undoubtedly affected by selection bias in how patients were chosen for surgical therapy. For example, the use of preoperative chemotherapy may be an important selection tool, but only five patients received neoadjuvant therapy and thus this factor could not be more fully examined. The aim of the current study, however, was to define whether surgical resection was feasible and beneficial in a select subset of patients with RCC LM.
In conclusion, the present study demonstrates that surgical therapy for metastatic RCC to the liver is beneficial and results in good long-term survival in a subset of patients. Patients undergoing surgery for RCC LM achieved outcomes similar to those found in a matched group of CRC LM patients. The low number of patients with RCC LM who underwent surgical resection, and the low burden of disease among these patients, underscore the very selective nature of the current cohort. However, the present data do suggest that surgical therapy should be considered in select patients with RCC LM as a subset of patients can derive long-term benefit.
Conflicts of interest
None declared.
References
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