Clinical predictors of renal mass pathological features

2010 THE AUTHORS; JOURNAL COMPILATION Urological Oncology

2010 BJU INTERNATIONAL

PREDICTING RENAL MASS PATHOLOGY TSIVIAN ET AL.

BJUI

Clinical predictors of renal mass pathological features

BJU INTERNATIONAL

Matvey Tsivian*, Vladimir Mouraviev*, David M. Albala*, Jorge R. Caso*, Cary N. Robertson*, John F. Madden† and Thomas J. Polascik* *Division of Urology, Department of Surgery, and †Department of Pathology, Duke University Medical Center, Durham, NC, USA Accepted for publication 22 April 2010

Study Type – Therapy (case series) Level of Evidence 4 OBJECTIVE • To evaluate the influence of radiographic tumour size and other preoperative variables on the pathological characteristics of the lesion to determine the distribution of pathological features and assess preoperative risk factors for potentially aggressive versus probably indolent renal lesions.

We identified specific preoperative factors associated with renal mass pathological features, and specifically with an increased risk of malignant, potentially aggressive disease. These factors should be considered when evaluating potential candidates for active surveillance and ablative techniques.

RESULTS

CONCLUSIONS

• Malignancy was pathologically confirmed in 628 (81.8%) specimens. • Radiographic size was significantly associated with malignancy (versus benign pathology; OR = 1.13, P = 0.001), high Fuhrman grade (OR = 1.21, P < 0.0001), vascular invasion (OR = 1.19, P < 0.0001) and extracapsular extension (OR = 1.23, P < 0.0001). • Age, symptomatic presentation, solid appearance and radiographic size were independent predictors of potentially aggressive disease, whereas for male gender (OR = 1.43, P = 0.062) a trend toward statistical significance was noted.

• Age, male gender, radiographic size and appearance, as well as symptomatic presentation, are associated with an increased risk of malignant, potentially aggressive disease. • These factors should be considered when evaluating management options for a solitary enhancing renal mass.

locally advanced or metastatic disease [2]. These considerations question the shift towards an earlier stage at presentation and suggest a new epidemiological entity – the small, incidentally detected renal mass – that requires further understanding [2,3]. It is debatable whether the current therapeutic strategy translates into survival benefits so a reassessment of the treatment schemes is warranted [4]. Minimally invasive ablative techniques such as cryosurgery and radiofrequency ablation, as well as noninvasive management with active surveillance, have been proposed as an option

for selected patients [5] but there is no consensus on how the appropriate candidates for these innovative approaches should be selected.

2 0 1 0 B J U I N T E R N A T I O N A L | 1 0 7 , 7 3 5 – 7 4 0 | doi:10.1111/j.1464-410X.2010.09629.x

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PATIENTS AND METHODS • Retrospective review of records for 768 patients who underwent surgery for single, sporadic renal mass between 2000 and 2008 in a tertiary academic institution. • Demographic, radiographic and pathological variables were recorded and analysed with regression analyses for risk factors for potentially aggressive pathological features (malignant pathology, high Fuhrman grade, lymphovascular invasion and extracapsular extension).

INTRODUCTION Currently, most renal masses are detected incidentally when imaging for unrelated problems. As a result of the widespread use of ultrasonography and other cross-sectional imaging modalities, small renal masses are frequently encountered. In spite of the increase in detection of small renal masses, death rates from kidney cancer have decreased by only 0.23–0.25 per 100 000 from 1990 to 2004 [1]. These data may suggest that the increased detection of renal masses is not accompanied by a decreased incidence of

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What’s known on the subject? and What does the study add? Widespread use of abdominal imaging has changed the landscape of kidney lesions with an increase in serendipitously detected small renal masses (SRMs) that represent a new epidemiological entity that requires further understanding and potentially reconsideration of current treatment schemes.

KEYWORDS kidney, tumour, size, renal cell carcinoma, benign, malignant

We evaluated the influence of radiographic tumour size and other preoperative variables on the pathological characteristics of the lesion in patients undergoing surgery for suspected RCC to determine the distribution of pathological features and to assess preoperative risk factors for potentially aggressive versus probably indolent renal lesions.

2010 THE AUTHORS

BJU INTERNATIONAL

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T S I V I A N ET AL.

PATIENTS AND METHODS Following Institutional Review Board approval, the electronic medical records database was searched to identify adult patients who had undergone partial or radical nephrectomy for suspected RCC at the Duke University Medical Center between 2000 and 2008. Patients treated with ablative techniques were excluded. Similarly, we excluded cases with metastatic disease on presentation. We retrieved the following data: patient age, gender and race, personal and family (first-degree relatives) history of cancer, presentation (incidental versus symptomatic), lesion size on imaging expressed as the largest dimension, lesion morphology on imaging (solid versus complex cyst), pathological data regarding histological diagnosis, subtype, Fuhrman grade [6], extracapsular extension and vascular invasion. Incidental presentation was defined as asymptomatic lesions, discovered incidentally upon imaging for unrelated complaints. Fuhrman grade was recorded for all RCC cases. Whenever two nuclear grades were reported, the higher one was used in this analysis. Whenever several radiographic studies were available, the most recent measurement before surgery was used based on contrast-enhanced CT or MRI. We excluded from our analysis patients presenting with multiple lesions, as well as patients with Von Hippel–Lindau syndrome and other known pathologies (e.g. tuberous sclerosis) that may suggest the nature of the renal lesion. We established a cohort of patients undergoing surgery for an enhancing kidney lesion suspected to be RCC. Pathological findings were described according to lesion size and logistic regression models were used to assess potential predictors of malignant pathology, adverse pathological features (high Fuhrman grade, vascular invasion and extracapsular extension) as well as predictors of potentially aggressive versus probably indolent kidney masses. Potentially aggressive disease was defined as at least one of the following characteristics on final pathology: non-RCC malignancy (sarcoma, squamous or transitional cell carcinoma, lymphoma, nephroblastoma), undifferentiated RCC, rare subtypes (medullary and collecting duct carcinoma), sarcomatoid/rhabdoid features,

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TABLE 1 Patient and tumour characteristics N (%) Age (years) Gender: Male Female Race White Black Other Lesion size on imaging (cm) Radiographic appearance Solid Bosniak III Bosniak IV Side Left Right Personal history of malignancy Negative Positive Family history of malignancy Not available Negative Kidney Other than kidney Malignant pathology RCC Other Fuhrman grade (RCC) 1 2 3 4 Not applicable*

Mean (SD) 59.8 (12.0)

Median (IQR) 60.0 (52.0–67.8)

450 (58.6) 318 (41.4) 553 (72.0) 187 (24.3) 28 (3.7) 5.24 (3.67)

4.0 (2.6–7.0)

669 (87.1) 66 (8.6) 33 (4.3) 377 (49.1) 391 (50.9) 604 (78.6) 164 (21.4) 213 (27.7) 305 (39.7) 30 (3.9) 220 (28.6) 628 (81.8) 615 (97.9) 13 (2.1) 116 (18.9) 363 (59.0) 103 (16.7) 32 (5.2) 1 (0.2)

RCC, renal cell carcinoma; IQR, interquartile range. *Fuhrman grade was not available for one specimen of unclassified subtype of RCC.

vascular invasion, extracapsular extension and high (3–4) Fuhrman grade. For regression models, age and radiographic size were treated as parametric variables; all other considered variables were treated categorically. P values