Renal Cell Recurrence for T1 Tumors After Laparoscopic Partial Nephrectomy

Abstract

Objectives:

There is lack of consensus in the Urology community regarding surveillance after laparoscopic partial nephrectomy (LPN), particularly for patients with stage I tumors. The purpose of this article is to characterize the rate of recurrence after partial nephrectomy in a low risk cohort.

Methods:

Data were collected on all laparoscopic partial nephrectomies performed at a single institution from January 2006 through May 2011. Patients without at least 1 year of follow-up information were excluded from examination. Patients were stratified based on the pathologic tumor stage at the time of partial nephrectomy. Patients with stage I (a and b) tumors were then examined for recurrence.

Results:

A total of 639 patients underwent LPN during the time period. Of this, 360 patients had stage T1 renal cell carcinoma (RCC) (302 with pT1a and 58 with pT1b) and met research criteria. There were 8 recurrences (2.2%) within this cohort (Table 1). All of the tumors were of clear cell histology and none had Furhman grade 1 histology. Only one of these patients had a positive margin at the time of partial nephrectomy and all patients had negative biopsy of the tumor resection bed. A majority of the recurrences occurred locally in the ipsilateral kidney or retroperitoneum. Most of the recurrences occurred within 1–2 years postoperatively.

Conclusions:

Introduction

Renal cell carcinoma (RCC) is among the 10 most common malignancies and accounts for 2%–3% of adult malignant neoplasms.¹ In recent years, a greater proportion of patients presenting at lower clinical stages is hypothesized to be the result of increased use of multiparametric imaging that leads to incidental discovery.^2,3 With this, along with data regarding the equivalent oncologic outcomes and probable long-term overall health benefits, there is increased use of nephron sparing surgery (NSS).^4,5 Generally, surveillance regimens have been created based on the tumor stage with stage I tumors surveyed less than their more advanced counterparts. There is no consensus, however, regarding how to survey T1 tumors. Important in this determination, is characterizing the risk of recurrence for this cohort. The purpose of this article is to characterize the risk of recurrence for a modern cohort of patients with pathologic T1 RCC after laparoscopic partial nephrectomy (LPN).

Materials and Methods

Data were collected on all laparoscopic partial nephrectomies performed at a single institution by a single surgeon (L.R.K.) from January 2006 through May 2011. After obtaining IRB approval, these cases were retrospectively reviewed using the electronic medical record. Demographic and clinical data were collected. Patients without at least 1 year of follow-up information or with incomplete records were excluded from examination. Patients with familial syndromes were also excluded. A total of 639 consecutive cases were identified and patient information was compiled into a de-identified database. Patients were then stratified based on the American Joint Commission on Cancer (AJCC) pathologic tumor stage at the time of partial nephrectomy. Benign renal neoplasms were excluded. Patients with stage I (a and b) RCCs (n=360) were identified.

Clinical staging was performed on all patients with no evidence of distant disease before surgery. LPN was performed by a single surgeon. Intraoperative ultrasound was used to aide in intracorporeal identification of tumor boundaries. Both hilar clamping and off-clamp techniques were used at the discretion of the surgeon. Postcold scissor extirpation, biopsies were taken of the resection bed and sent to the frozen section. Patients were generally followed using multimodal renal imaging to minimize radiation risk by alternating between ultrasound and computed tomography/magnetic resonance imaging (CT/MRI) every 6 months for the first 2–3 years and then annually thereafter.

Results

After exclusions, a total of 639 patients underwent LPN during the 5.5-year time period. Of this, 360 patients had stage T1 RCC corresponding to 302 patients with pT1a pathology and 58 patients with pT1b pathology. The mean follow-up was 34±17 months. The overall positive margin rate was 3.5%. There were eight recurrences within this cohort (Table 1), equating to a recurrence rate of 2.2%. Recurrence for pT1a tumors was 1.7% and is 5.2% for pT1b tumors. These recurrences were then examined.

Table 1.

Clinical Information for Patients with Renal Cell Carcinoma Recurrence

T stage	Age	Gender	Surgical laterality	BMI	ASA	Furhman grade	Largest tumor size (cm)	Margin	Surgical bed	Time to recurrence (months)	Location of recurrence
T1a	72	F	R and L	26.62	2	2	3.5	Negative	Negative	53	Right retroperitoneum
T1a	68	M	L	55.07	3	4	4	Negative	Negative	20	Contralateral adrenal
T1a	64	M	L	26.12	2	2	3.8	Negative	Negative	17	Ipsilateral kidney
T1a	63	M	R	27.19	3	2	3	Negative	Negative	24	Ipsilateral kidney
T1a	61	M	L	37.28	3	3	4	Positive	Negative	15	Ipsilateral kidney
T1b	41	F	R	27.97	3	2	5	Negative	Negative	18	Ipsilateral kidney
T1b	61	M	R	27.80	3	2	5	Negative	Negative	26	Liver, lung, brain
T1b	55	M	L	28.86	2	3	7	Negative	Negative	14	Lung

ASA=American Society of Anesthesiologists Score.

All of the tumors were of clear cell histology and none had Furhman grade 1 histology. Only one of these patients had a positive margin at the time of partial nephrectomy and all patients had negative biopsy of the tumor resection bed. A majority of the recurrences occurred locally in the ipsilateral kidney or retroperitoneum. This corresponds to a local recurrence rate of 1.4% and a distant metastatic rate of 0.83%. Most of the recurrences occurred within 1–2 years postoperatively.

Discussion

Partial nephrectomy has become an accepted standard approach to small renal masses with laparoscopy offering a minimally invasive approach. Multiple studies have shown equivalent oncologic outcomes for partial nephrectomy relative to its radical nephrectomy counterpart. There does appear to be, however, a survival advantage for partial nephrectomy secondary to decreased cardiovascular long-term risk. Whereas recurrence rates are low for pT1 tumors, recurrences both local and distant do occur.

There are no consensus guidelines for how to follow patients to identify recurrence after partial nephrectomy for pT1 tumors. National Comprehensive Cancer Network (NCCN) guidelines for renal masses recommend follow-up for RCC stage I-III every 6 months for 2 years and then annually for 5 years.⁶ In this, the only imaging recommendation is at 2–6 months and then as indicated. Modality used for chest and abdominal +/− pelvic imaging is not elucidated. The European Association of Urology recommends renal ultrasound at 6 months and CT at 1 year postoperatively for low risk patients after partial nephrectomy.⁷

Review of the literature shows high variability in the characterization and rates of recurrence after partial nephrectomy for T1 tumors. Belldegrun et al. found an overall recurrence rate of 1.4% among patients with pT1 RCC after open NSS, including 1 local recurrence and 1 distant recurrence after a mean follow-up of 57 months.⁸ Antonelli et al. retrospectively reviewed partial and radical open nephrectomies and showed a local recurrence rate of 0.56% overall after a median follow-up of 47 months.⁹ This corresponded to a local recurrence rate of 0.5% in pT1a tumors and 1.0% rate in pT1b tumors. There was no explicit determination of distant recurrence rates. Marszalek et al. examined outcomes between laparoscopic and open partial nephrectomies in pT1 tumors.¹⁰ After an average of 43 months of follow-up in 200 patients, there was a local recurrence of 2.4% and a distant recurrence rate of 4.5%. The overall positive margin rate was 4% in this cohort. Ha et al. examined late recurrences (>5 years) in patients with clinical T1 RCC who had previously undergone open radical or partial nephrectomy and had a 5-year interval without any evidence of disease.¹¹ They found a recurrence rate of 3.3% in these patients beyond 5 years. Last, Lane et al. produced a recent large series of both laparoscopic and open partial nephrectomies, for clinical T1 tumors showed a local recurrence rate of 3.2% with long-term (average 7.2 years of follow-up).¹² With an overall positive margin rate of 1% and 0.3% for laparoscopic and open partials, respectively, none of the patients who experienced local recurrence had positive surgical margins. Distant metastatic disease occurred in 4.9% of patients. None of these articles specifically address recurrence in a LPN cohort.

Our data show a comparable recurrence rate to the aforementioned series, but within a specific LPN subset of pT1 tumors. As with other series, there were both local and distant recurrences. There was a single patient with a positive margin who had local recurrence, but the significance of a positive margin remains unclear. There is high variability in the time to recurrence (14–53 months in our series). As demonstrated here and with other series (open, laparoscopic, partial nephrectomy, and radical nephrectomy), it is important to continue surveillance on even these low risk patients given the propensity to recur even greater than 5 years postextirpation.

An inherent limitation of this article is its retrospective nature. Given the low incidence of recurrence, the study is underpowered to draw conclusions regarding statistically significant risks for recurrence. As such, it is observational. This is, however, a very large cohort of small renal masses of all who underwent partial nephrectomy by a single surgeon.

Conclusions

Approximately 2% of patients who underwent LPN for RCC with resultant low risk, stage I tumor pathology developed metastasis. There were no recurrences in nonclear cell pathologies and no recurrences with Furhman grade 1 or tumors smaller than 3 cm. Further long-term research should be conducted to aide in the understanding of disease recurrence and thus assist in the creation of surveillance outcomes for these increasingly common pT1 RCCs.

Footnotes

Disclosure Statement

No competing financial interests exist.

Abbreviations Used

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