U R O L O G Y – O R I G I N A L P A P E R
Urinary ultrasonography in screening incidental renal cell
carcinoma: is it obligatory?
Ahmet Hakan Haliloglu•Omer Gulpinar•
Eriz Ozden• Yasar Beduk
Received: 30 July 2010 / Accepted: 27 August 2010 / Published online: 17 September 2010 Ó Springer Science+Business Media, B.V. 2010
Abstract
Purpose To analyze the rate of incidental renal carcinoma in patients with no upper urinary tract symptoms (UUTS) or hematuria depending on the sonography reports and medical records of the patients and to determine whether there is a need for routine US screening for RCC.
Materials and methods We reviewed the reports of 18.686 consecutive urinary US examinations per-formed in our department between March 1995 and February 2008. A total of 18.203 urinary US exam-inations formed the study group. Patients with UUTS, patients with presumed diagnosis of or previously diagnosed renal masses, and patients with hematuria were excluded.
Results There were 11,654 male and 6,549 female patients with a mean age of 55 years. Ultrasonogra-phy revealed incidental solid renal masses in 0.44% of the patients. Seven of the 81 patients with incidentally detected renal masses could not be followed up. Thirty-eight of the remaining 74 patients had masses that were proved to be benign with other
imaging techniques. Thirty-six of the 74 patients with preoperative diagnosis of renal tumor underwent surgery, and the histopathological diagnosis was renal cell carcinoma in all patients. One patient expired in the postoperative 18th month due to the progression of the metastatic disease. The rest of the patients with malignant renal tumor are disease free and are still under follow-up.
Conclusion The rate of incidental renal cancer in patients without UUTS is found to be 0.20%. We believe that scanning for incidental renal masses is not obligatory except for the patients with symptoms suggestive of renal carcinoma.
Keywords Renal cell carcinoma Screening Ultrasonography
Introduction
Renal cell carcinoma (RCC) is usually seen in elderly men with associated risk factors including smoking, obesity, hypertension, and genetic predisposition. RCC survival has improved recently due to early diagnosis of the disease with advanced imaging modalities and improvement in surgical techniques, and immunotherapy [1,2].
Ultrasonography (US) is a widely used radiolog-ical examination for the diagnosis of urologradiolog-ical A. H. Haliloglu (&) O. Gulpinar
Department of Urology, Medical Faculty, Ufuk University, Mevlana Bulvari No 86–88, Ankara, Balgat, Turkey
e-mail: ahmethakan75@yahoo.com E. Ozden Y. Beduk
Department of Urology, Medical Faculty, Ankara University, Ankara, Turkey
123
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diseases, and it is a safe, cheap, fast, and noninvasive imaging technique that is easy to perform and that lacks ionizing radiation. The sensitivity and specific-ity of renal ultrasound in detecting renal cancer are reported as 91 and 99%, respectively, [3]. Renal US is also known as the primary imaging modality to evaluate patients with microhematuria in order to exclude urological neoplasms [4]. Therefore, it would be a good choice of method for screening RCC. Nevertheless, when a solid or undetermined mass is detected on US, contrast-enhanced computed tomog-raphy (CT) would be the most appropriate imaging modality for differentiation between benign and malignant lesions [5].
The aim of this study is to asses the rate of incidental renal carcinoma in patients with no upper urinary tract symptoms (UUTS) (fever, low back pain, palpable mass, and gastrointestinal symptoms) or hematuria depending on the sonography reports and medical records of the patients and to determine whether there is a need for routine US screening for RCC.
Materials and methods
We retrospectively reviewed the reports of 18.686 consecutive urinary US examinations performed in our department by the same radiologist between March 1995 and February 2008. Depending on the medical reports, patients with lower urinary tract symptoms (dysuria, pollacuria, nocturia, etc.) and patients who were referred for checkup studies were included in the study. Patients with upper urinary tract symptoms, patients with presumed diagnosis of or previously diagnosed renal masses, and patients with hematuria were excluded. For patients with multiple US examinations, only the initial examina-tion was taken into consideraexamina-tion. A total of 18,203 urinary US examinations formed the study group for scanning incidental renal masses.
Results
Ultrasonography reports and medical reports of 18.203 patients were evaluated. There were 11,654 male (64.03%) and 6,549 female (35.97%) patients with a mean age of 55 years (age range 33–90 years). Ultrasonography revealed incidental solid renal
masses in 81 of the 18.203 patients (0.44%). Seven of the 81 patients with incidentally detected renal masses did not revisit our department after the sonographic examination, and these patients could not be followed up. Thirty-five of the remaining 74 patients were diagnosed as angiomyolipoma by US, and the diagno-sis was confirmed by CT in all patients. These patients are still under follow-up with no significant clinical problems. Three renal masses that could not be classified as cystic or solid by US were proved to be benign with other imaging techniques (CT and/or magnetic resonance imaging (MRI)). Thirty-six of the 74 patients with preoperative diagnosis of renal tumor (mean age 57.6 years, age range 34–75 years) under-went surgery, and all surgically resected tumor spec-imens were examined histopathologically in order to determine the histological grade and TNM stage. The mean tumor diameter was 4.19 cm (2–11 cm), and all of them were solitary tumors. Thirteen of the 36 (36.1%) tumors were located in the right kidney and 23 tumors (63.9%) were located in the left kidney. Nine of the 36 patients (25%) had undergone partial nephrec-tomy, and radical nephrectomy was performed in 27 patients (75%). Two patients who had tumors suitable for partial nephrectomy by size and location had refused this operation and underwent radical nephrec-tomy. The histopathological diagnosis was renal cell carcinoma in all of these 36 patients. According to the Fuhrman grading system, four patients (11.2%) were classified as grade I, 19 patients (52.7%) were grade II, and 13 patients (36.1%) were grade III (Table1). During preoperative evaluation, two pulmonary nod-ules were detected on CT in one of the 36 patients with malignant renal tumor that had a diameter of 11 cm. Immunotherapy was performed after radical nephrec-tomy and the pulmonary nodules regressed by size significantly. Nevertheless, progression occured in the 15th month follow-up and despite immunotherapy the patient continued to deteriorate. He expired in the postoperative 18th month due to the progression of the metastatic disease. The rest of the patients with malignant renal tumor are disease free and are still under follow-up.
Discussion
Screening tests to detect malignancies in the early stages have always been a subject of interest.
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Detection of clinically occult small tumors may increase the life expectancy and the quality of survival. It has been shown that the relationship between tumor size and malignancy is important, and
the more size of the tumor increases, the more risk of malignant potential occurs.
In their retrospective study, Schlomer et al. found that there is a significant difference between the size of incidental and symptomatic renal tumors. The mean size of incidental renal tumors was 3.7 cm, and the mean size of symptomatic tumors was 6.2 cm [6]. In addition to this statement, it has also been suggested that survival rates are higher in renal cancer patients with small tumors than patients with tumors over 7 cm. This is consistent with the increased incidence of high-grade malignancy reported in symptomatic and large renal tumors. The improvement and widespread use of imaging techniques have increased the early diagnosis of renal cancer as well as many other malignancies. Therefore, one can expect better survival rates and higher quality of life [7,8]. On the contrary, there are also reports suggesting that the baseline size of the renal tumor does not predict tumor’s malignant potential and growth rate; hence there is no additional surgical morbidity due to a delay in treatment [9].
In the evaluation of patients with lower back pain or hematuria, intravenous urography, cystoscopy, and/or US can be used to investigate the etiology and when present renal tumors can be detected [4,
10]. Many benign or malignant incidental renal masses can also be detected on US, CT, or MRI studies performed for indications rather than UUTS [11]. It is well known that simple renal cysts are frequently seen over 50 years of age, and they can easily be defined by US. Nevertheless, complex cystic or solid renal masses should be further evaluated by CT or MRI in all patients regardless of symptoms [12]. Angiomyolipoma, oncocytoma, and focal infarction are among incidental benign renal lesions that can be detected by US [11].
On the other hand, there would also be patients with renal cancer and no obvious symptoms. There-fore, the question, is there a need for renal cancer screening, arises.
In well-selected cases besides the opportunity of offering curative treatment options, the high costs of intense hospital care for the advanced disease can be avoided with the early detection of a malignant tumor. Nevertheless, the patient population and the method of screening should be selected appropriately with respect to the cost-effectivity of the process [13]. For renal cancer screening, the appropriate patient population is defined as elderly men with a high Table 1 Number Patient age Tumor size (cm)/location Type of surgery Fuhrman grade 1 34 4/right PN 2 2 45 3/left RN 2 3 53 5/left RN 2 4 54 3/left PN 2 5 55 4/right RN 1 6 57 2/left PN 3 7 58 4/left RN 3 8 49 6/left RN 2 9 44 6/right RN 2 10 43 7/right RN 2 11 42 11/left RN 2 12 68 3/right RN 2 13 71 2/left PN 2 14 73 3/right RN 2 15 45 3/right RN 1 16 54 2/right PN 1 17 55 3/left RN 3 18 59 2/left PN 3 19 53 3/right PN 3 20 65 5/left RN 3 21 64 6/left RN 3 22 69 5/left RN 3 23 63 4/left RN 3 24 57 5/right RN 2 25 59 4/left RN 3 26 39 6/right RN 2 27 41 5/left RN 3 28 72 5/left RN 1 29 73 3/left RN 2 30 62 2/right PN 3 31 64 3/left RN 2 32 67 3/right PN 2 33 69 4/left RN 2 34 58 5/left RN 2 35 75 5/left RN 2 36 68 5/left RN 3 PN Partial nephrectomy RN Radical nephrectomy
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prevalence of risk factors for RCC, the most impor-tant being history of smoking [1]. Therefore, renal cancer screening gains importance in countries in which tobacco use is common. The rate of incidental renal cancer detected on US in patients without UUTS was found approximately 0.20% (36 of 18.196 patients) in this study. This rate is in correlation with the literature [1]. The rate of incidental renal cancer would even be lower if the study population was more homogenous. More than 50% of our patients were men, and the mean age of our study population was 55 years. We should also mention the common habit of smoking in our country which unfortunately usually begins before the age of 20. Nevertheless, as a limitation of this study, we could not obtain the smoking rate in our study group because of the retrospective nature of the study.
The choice of treatment for solid renal masses is radical or partial nephrectomy, and preoperative imaging is of significant importance for planning the surgical approach. Imaging studies can usually be useful to differentiate malignant lesions from benign ones and are important to adequately assess the tumor size, localization, and organ confinement. What a surgeon needs to know before planning the strategy of treatment includes lymph node and/or visceral metas-tases, and the presence/extent of renal vein and inferior vena cava thrombus [5,12]. Therefore, abdominal CT is a very important preoperative imaging modality and should be performed after renal US.
In conclusion; the rate of incidental renal cancer in patients without UUTS is found 0.20% in this study. We believe that this rate, which is in correlation with the literature, is not high enough to suggest renal US scanning for incidental renal masses. Nevertheless, if abdominal US is considered to be necessary for any indication in a man over 40 years of age and with a history of smoking, kidneys should also be included in the study. This may improve a man’s life expectancy and quality of life.
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