
==== Front
Sao Paulo Med J
Sao Paulo Med J
Sao Paulo Med J
São Paulo Medical Journal
1516-3180
1806-9460
Associação Paulista de Medicina - APM

12563422
10.1590/S1516-31802002000600002
Original Article
Incidental and symptomatic renal tumors: impact on patient survival
Dall'Oglio Marcos Francisco *
Srougi Miguel *
Gonçalves Pierre Damião *
Leite Kátia *
Nesrallah Luciano *
Hering Flávio *
Address for correspondence: Marcos Francisco Dall'Oglio Disciplina de Urologia – Universidade Federal de São Paulo/Escola Paulista de Medicina Rua Manoel da Nóbrega, 853 c/22 São Paulo/SP - Brasil - CEP 04001-084 Tel. (+55 11) 3885-0658 E-mail: marcosdalloglio@uol.com.br
Conflict of interest: None

01 11 2002
2002
120 6 165169
26 4 2001
11 4 2002
24 6 2002
https://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons license.
ABSTRACT

CONTEXT:

Renal cell carcinoma is the third most frequent genitourinary neoplasia, and there is currently an increase in the incidental diagnosis of tumors confined to the kidneys.

OBJECTIVE:

To study the survival of patients with incidental and symptomatic renal tumors who have undergone nephrectomy.

DESIGN:

Retrospective.

SETTING:

Hospital Sírio Libanês and Beneficência Portuguesa de São Paulo.

PARTICIPANTS:

115 patients with diagnosis of renal cell carcinoma, operated on by the same group of surgeons and evaluated by a single pathologist.

MAIN MEASUREMENTS:

Sex, age and diagnosis method, analyzed in two groups, according to the tumor diagnosis: Group 1 with incidental diagnosis and Group 2 with symptomatic tumors. The anatomopathological characteristics and patient survival in both groups were evaluated. A statistical analysis was performed using the Student t, chi-squared, log rank and Kaplan-Meyer tests.

RESULTS:

Among the studied patients, 59(51%) had an incidental diagnosis, with 78% diagnosed by ultrasonography, 20% by computerized tomography scan and 2% during surgeries; 56 patients (49%) were symptomatic. Tumor locations were equally distributed between the two kidneys, and the surgery was conservative for 24% of the incidental and 9% of the symptomatic group. In the incidental group only one patient had tumor progression and there was no death, while in the symptomatic group there were 5 progressions and 10 deaths. The 5-year specific cancer-free survival was 100% in the incidental and 80% in the symptomatic group (p = 0.001) while the disease-free rate was 98% in the incidental and 62% in the symptomatic group (p < 0001).

CONCLUSION:

Incidental renal tumor diagnosis offers better prognosis, providing longer disease- free survival.

RESUMO

CONTEXTO:

O carcinoma de células renais é a terceira neoplasia geniturinária em frequência, havendo atualmente um aumento no diagnóstico incidental de tumores restritos ao rim.

OBJETIVO:

Verificar a sobrevida dos pacientes com tumores de rim incidentais e sintomáticos submetidos a nefrectomia.

TIPO DE ESTUDO:

Retrospectivo.

LOCAL:

Hospital Sírio Libanês e Beneficência Portuguesa de São Paulo.

PARTICIPANTES:

115 pacientes com diagnóstico de carcinoma de células renais e operados por um mesmo grupo de cirurgiões, ava- liados por um único patologista.

VARIÁVEIS ESTUDADAS:

Sexo, idade e método diagnóstico, analisados em dois grupos conforme o diagnóstico do tumor: Grupo 1 com diagnóstico incidental e Grupo 2, com tumores sintomáticos. São também avaliadas as características anatomopatológicas da peça operatória e sobrevida dos pacientes nestes dois grupos. Foi realizada análise estatística através do teste t de Student, qui quadrado, log rank test e Kaplan-Meyer.

RESULTADOS:

Dos pacientes estudados, 59 (51%) tinham diagnóstico incidental, sendo 78% diagnosticados pelo exame ultra-sonográfico, 20% por tomografia computa- dorizada e 2% em transoperatório; já 56 pacientes (49%) apresentaram-se sintomáticos. Houve um equilíbrio quanto à lateralidade, sendo a cirurgia conservadora em 24% dos incidentais e 9% dos sintomáticos. No grupo incidental, apenas um paciente teve pro-gressão e nenhum óbito, ao passo que os sintomáticos tiveram 5 progressões e 10 óbitos. A sobrevida câncer-específica em cinco anos foi de 100% para incidentais e 80% para os sintomáticos (p = 0,001) e a sobrevida livre de doença foi de 98% para os incidentais e 62% para os sintomáticos (p < 0,001).

CONCLUSÃO:

O tumor de rim diagnosticado incidentalmente oferece melhor prognóstico, proporcionando maior sobrevida livre de doença.

KEY WORDS:

Carcinoma
Renal
Cell
Diagnosis
Incidental
Survival
PALAVRAS-CHAVE:

Carcinona
Célula
Renal
Diagnóstico
Incidental
Rim
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pmcINTRODUCTION

The incidence of renal cell carcinoma (RCC) and the diagnosis of localized tumors are increasing.1,2 It was predicted that the worldwide mortality due to RCC would reach 100,000 cases in the year 2000.3 The risk of RCC after the age of 40 years is 1.34%, and the risk of death is over 0.5%.4

The most common symptoms are hematuria, low back pain and palpable mass, and these events occur in isolation in 35-59%, 34-41% and 30-45% of the cases, respectively.5-7 The 5-year survival rate for symptomatic tumors is 30-83% while for incidental tumors it is 83-95%8-13 and, according to tumor staging, the rate is 91% for PT1, 74% for PT2, 67% for PT3 and 32% for PT4.14 Metastatic disease is seen in 25-40% of the cases at diagnosis,15,16 with a 5-year survival rate of 13%.17

Twenty years ago, the incidental case rate was less than 5%, but there has been an increase of more than 50% in early diagnosis up to the present day, due to the advent of non-invasive radiological techniques such as ultrasonography and computerized tomography (CT) scans. This has allowed small lesions with favorable prognosis and low incidence of metastasis to be discovered.8,18,19

Nonetheless, there are no indications of methods for predicting the behavior of small tumors discovered incidentally.20 Many authors question the factors that might influence the behavior of such neoplasia, believing that incidental tumors may display biological behavior that differs from that of symptomatic tumors.8,21,22 Would there be a lower degree of malignity and/or slower growth?23

Looking for answers to such questions, this study had the objective of analyzing the survival of patients with incidental and symptomatic RCC.

METHODS

A retrospective non-controlled study was made of 128 patients who underwent renal surgery for RCC between January 1988 and July 1999, with the operation being performed by the same group of surgeons. From this, 115 patients were selected. Their mean age was 59.1 years (range: 9-87) and the median was 60 years, and there were 86 males (74.8%) and 29 females (25.2%).

The complementary diagnostic tests that confirmed the extensive renal lesion were ultrasonography, excretory urography, CT scan, nuclear magnetic resonance and arteriography.

Criteria for inclusion and exclusion

All patients operated on for RCC who had complete files were included. Thirteen patients were excluded, because of insufficient data and pathological material for eight patients, follow-up of previous RCC in four cases, and von Hippel-Lindau disease in one case.

The follow-up was undertaken from the consultation office. When more than three months had elapsed since the preceding consultation, telephone calls was made to inquire about the patient's current status. In this follow-up, consultations took place every three months during the first year, semiannually from the second to the fifth year and yearly thereafter.

Evaluation criteria

The reason that led the patient to the doctor was identified and the patients were divided into two groups, according to the diagnosis of the primary tumor.

Incidental: patients with findings of extensive renal lesion identified in radiological examinations at routine health checkups or because of complaints unrelated to RCC.

Symptomatic: patients with symptoms related to RCC.

The patients were followed up for periods ranging from 2 to 138 months, with a median of 26 months for incidental cases and 33 months for symptomatic cases.

Statistical analyses

Statistical analyses were performed via the Student t and chi-squared tests. The specific cancer-free survival and disease-free rates were calculated using the Kaplan-Meyer curves and the log rank test was used to compare differences in the survival of the groups. The statistical significance level utilized was p < 0.05.

RESULTS

In the incidental group there were 59 patients (51%) and in the symptomatic group, 56 (49%). The lesions of the incidental group were identified by ultrasonography in 46 patients (78%), by CT scan in 12 (20%) and one case was identified during the operation (2%).

The male to female ratios were, respectively, 45:14 in the incidental and 41:15 in the symptomatic group. The mean ages of males and females were, respectively, 62.7/ 57.2 in the incidental and 57.2/55.0 in the symptomatic group (non-significant).

In the incidental group, 45 radical (76%) and 14 conservative (24%) surgeries were performed, while in the symptomatic group 51 radical (91%) and 5 conservative (9%) nephrectomies were performed.

The dominant cell type was clear cells in 59% (68), chromophile cells in 23% (26), chromophobe in 10%, and sarcomatous in 8%.

When the tumor size was related to the type of clinical presentation, it was noticed that lesions of between 0.5 and 4 cm were present in 30 (51%) of the incidental and 11 (20%) of the symptomatic cases; between 4.1 and 7 cm in 21 (36%) and 22 (39%); between 7.1 and 10 cm in 5 (8%) and 14 (25%); and tumors greater than 10 cm in 3 (5%) and 9 (16%), respectively (p = 0.001). The mean tumor size was 4.6 ± 2.3 cm (range 0.5 to 13) in the incidental and 7.3 ± 3.6 cm (range 1.5 to 19.5) in the symptomatic group (p = 0.001).

With regard to the pathological staging, among the incidental cases there were 47 patients in stage PT1, 5 in stage PT2 and 7 in stage PT3. Among the symptomatic cases there were 27 patients in stage PT1, 11 in stage PT2, 10 in stage PT3 and 8 in stage PT4 (p < 0.001).

The reasons for consultations sought with different specialties are seen in Figure 1, and subsequently the urological consultations were separated out (Figure 2). The main complaints in the symptomatic group are seen in Figure 3. Complaints were balanced with regard to which of the kidneys was involved and the presentation.

Figure 1 Reasons for consultations sought by patients with incidental diagnosis.

Figure 2 Reasons for urological consultations sought by patients with incidental diagnosis.

Figure 3 Reasons for consultations sought by patients in the symptomatic group.

By the end of the study, only one patient in the incidental group showed progression of the disease and there was no death, while in the symptomatic group there were five progressions and 10 deaths. Only four patients were lost during the follow-up period of 2 to 138 months (Table).

Table. Survival situation at the end of the study, according to the presentation.

Situation at the end of the study	Incidental group	Symptomatic group	Total	
Alive, without evidence of disease	54	36	90	
Alive, with disease (progression of disease)	1	5	6	
Death due to the kidney cancer	0	10	10	
Death due to other causes (unrelated to the disease)	4	1	5	
Lost from the follow-up	0	4	4	
Total	59	56	115	

The specific cancer-free survival (p = 0.001) and disease-free survival (p < 0.001) are shown in Graphics 1 and 2 respectively.

Graph 1 Specific cancer-free survival curve according to presentation.
Log rank test: c21gl = 10.16; p = 0.001; Incidental group = () dotted line; Symptomatic group = (——) full line

Graph 2 Disease-free survival curve according to presentation.
Log rank test: c21gl = 12.48; p < 0.001; Incidental group = () dotted line; Symptomatic group = (——) full line

DISCUSSION

This study shows that incidental tumors have a better prognosis and provided longer disease-free survival then the symptomatic tumors did during the period analyzed. Although this study was retrospective, 96.6% of the patients were followed up and thus the results can be considered reliable.

Several authors have reported high percentages of incidental tumors identified via ultrasonography, with rates of 38%-97%.24-28 In this study, 78% of the diagnoses were made by ultrasound and 20% by CT scan. These data show that the ultrasonography examination has an important role in the early detection of such tumors, considering that it is used for evaluating cardiac, hepatic, gallbladder, pancreas and gynecological diseases as well as in routine health check-ups. Currently, two- thirds of incidental tumors are found by other physicians, in non-urological situations.25,29 The finding of a 50% incidental diagnosis rate in this study is probably due to the fact that the research was performed in a specialized clinic. In the present study, tumor location was equally distributed between the two kidneys, but some series have shown greater numbers of incidental cases in the right kid- ney.24,26,27

Currently, large centers defend the use of some type of screening.9 The screening of high risk populations, especially for those undergoing dialysis or with von Hippel-Lindau disease, and for those over 50 years of age, is advised.30,31 On the other hand, some other groups reject this approach in the belief that the cost/benefit relationship of such screening is not well de-fined.24,25,32 However, rapid routine examination of the kidneys during ultrasonography of other organs is also defended.25,33

Hematuria was the main complaint in the symptomatic cases, in 47% of the cases in this study, and only one patient showed the classical triad (hematuria, back pain and palpable mass) that in the past was seen in 10% of cases5 and is now only rarely seen.30

In the last few years there has been an increase in the detection of incidental tumors,18 directly related to the use of imaging exams, especially ultrasonography and CT scans.18,34,35 The "internist's tumor"36 can thus be renamed the "radiologist's tumor",30 because of the identification of RCC at its early stages, thereby increasing the apparent disease prevalence.37 These tumors are frequently small and found in routine examinations and evaluations of other diseases,38,39,40 with greater incidence among younger males and females with a useful working life.25 Considering that RCC occurs in the proportion of 3:1 for men to women, in the fifth and sixth decades of life, most of these patients might be diagnosed by their own urologist. The practical implication of this study is that incidental diagnosis of renal carcinoma will dramatically change the prognosis for patients with RCC, offering a real possibility of cure for most patients.

In a study by Nakano et al.,23 incidental diagnosis was more prevalent among the elderly, which can be related to the lower degree of malignity and slower growth of RCC. In the present series, there was no statistical difference regarding age at diagnosis, for either group.

In the incidental group, conservative surgery was performed in 24% of the cases, while this was done in 9% of the symptomatic cases. Such surgery was performed in tumors smaller than 4 cm, in accordance with advice in the literature,41,42 with no recurrence. Obviously, the difference in the use of conservative surgery between the groups is justified by the smaller size of incidental tumors, which forms an indication for preservation of the renal unit.

The 5-year survival rate found in different studies for asymptomatic and symptomatic patients is, respectively, 83-95% and 30-83%.8-13 In the present series, by the end of the study period, in the incidental group there was only one case of progression, while among the 56 patients in the symptomatic group, 5 showed progression and 10 died. The probability of disease-free survival after 5 and 9 years was respectively, 98% and 98% for the incidental group and 62% and 53% for the symptomatic group (p < 0.001).

It has been shown that 80% of RCC metastases occur by the third year of follow-up.43 With this in mind and with the objective of more clearly showing the survival in time units, a cutoff was established for patients with a follow-up equal to or longer than 30 months. This confirmed the better survival curves for the incidental group (p < 0.001).

CONCLUSION

RCC that is found incidentally offers a better prognosis for patients because it provides for longer disease-free survival.

Marcos Francisco Dall'Oglio, MD, PhD in Urology. Attending doctor in the Departamento de Urologia, Universidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil.

Miguel Srougi, MD. Professor of Urology at the Univer-sidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil.

Pierre Damião Gonçalves, MD, PhD in Urology. Univer-sidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil.

Kátia Leite, MD, PhD in Pathology. Universidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil.

Luciano Nesrallah, MD, PhD in Urology. Attending doctor in the Departamento de Urologia, Universidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil.

Flávio Hering, MD, PhD in Urology. Attending doctor in the Departamento de Urologia, Universidade Federal de São Paulo/Escola Paulista de Medicina, São Paulo, Brazil.

Sources of funding: None

Hospital Sírio Libanês and Hospital Beneficência Portuguesa de São Paulo, São Paulo, Brazil
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REFERENCES

1 Vogelzang NJ Stadler WM Kidney cancer Lancet 1998 352 1691 1696 9853456
2 Chow WH Devesa SS Warren JL Fraumeni JF Rising incidence of renal cell cancer in the United States JAMA 1999 281 1628 1631 10235157
3 Pisani P Parkin DM Ferlay J Estimates of the worldwide mortality from eighteen major cancers in 1985. Implications for prevention and projections of future burden Int J Cancer 1993 55 891 903 8253525
4 Ries LAG Kosary CK Hankey BF Miller BA Edwards BK SEER Cancer Statistics Review, 1973-1994, National Cancer Institute NIH Publication No. 97-2789 Bethesda National Institute of Health 1997
5 Skinner DG Colvin RB Vermillion CD Pfister RC Leadbetter WF Diagnosis and management of renal cell carcinoma. A clinical and pathologic study of 309 cases Cancer 1971 28 1165 1177 5125665
6 Chisholm GD Roy RR The systemic effects of malignant renal tumors Br J Urol 1971 43 687 700 5159572
7 Patel NP Lavengood RW Renal cell carcinoma: natural history and results of treatment J Urol 1978 119 722 726 660755
8 Sweeney JP Thornhill JA Grainger R McDermott TE Butler MR Incidentally detected renal cell carcinoma: pathological features, survival trends and implications for treatment Br J Urol 1996 78 351 353 8881940
9 Tsui KH Shvarts O Smith RB Figlin R deKernion JB Belldegrun A Renal cell carcinoma: prognostic significance of incidentally detected tumors J Urol 2000 163 426 430 10647646
10 Rodriguez-Rubio FI Díez-Caballero F Martín-Marquina A Abad JI Berian JM Incidentally detected renal cell carcinoma Br J Urol 1996 78 29 32 8795396
11 Tosaka A Ohya K Yamada K Incidence and properties of renal masses and asymptomatic renal cell carcinoma detected by abdominal ultrasonography J Urol 1990 144 1097 1099 2231878
12 Licht MR Novick AC Goormastic M Nephron-sparing surgery in incidental versus suspected renal cell carcinoma J Urol 1994 152 39 42 8201682
13 Thompson IM Peek M Improvement in survival of patients with renal cell carcinoma – the role of the serendipitously detected tumor J Urol 1988 140 487 490 3411657
14 Pantuck AJ Zisman A Belldegrun AS The changing natural history of renal cell carcinoma J Urol 2001 166 1611 1623 11586189
15 Ritchie AWS Chisholm GD The natural history of renal carcinoma Semin Oncol 1983 10 390 400 6665566
16 Kovacs G The value of molecular genetic analysis in the diagnosis and prognosis of renal cell tumours World J Urol 1994 12 64 68 8087142
17 deKernion JB Ramming KP Smith RB The natural history of metastatic renal cell carcinoma: a computer analysis J Urol 1978 120 148 152 78992
18 Smith SJ Bosniak MA Megibow AJ Hulnick DH Horii SC Raghavendra BN Renal cell carcinoma: earlier discovery and increased detection Radiology 1989 170 699 703 2644658
19 Wolf JS Evaluation and management of solid and cystic renal masses J Urol 1998 159 1120 1133 9507815
20 Ritchie AW deKernion JB Incidental renal neoplasms: incidence in Los Angeles County, treatment and prognosis Prog Clin Biol Res 1988 269 347 357 3393554
21 Steinbach F Stückle M Griesinger A Multifocal renal cell tumors: a retrospective analysis of 56 patients treated with radical nephrectomy J Urol 1994 152 1393 1396 7933167
22 Mukamel E Konichezky M Engelstein D Servadio C Incidental small renal tumors accompanying clinically overt renal cell carcinoma J Urol 1988 140 22 24 3379689
23 Nakano E Iwasaki A Seguchi T Incidentally diagnosed renal cell carcinoma Eur Urol 1992 21 294 298 1459151
24 Vallancien G Torres LO Gurfinkel E Veillon B Brisset JM Incidental detection of renal tumours by abdominal ultrasonography Eur Urol 1990 18 94 96 2226591
25 Aso Y Homma Y A survey on incidental renal cell carcinoma in Japan J Urol 1992 147 340 343 1732589
26 Bretheau D Lechevallier E Eghazarian C Grisoni V Coulange C Prognostic significance of incidental renal cell carcinoma Eur Urol 1995 27 319 323 7656910
27 Rousseau T Peyret C Zerbib M Thiounn N Flam T Debre B Circumstances of the detection of kidney cancer. Current part of accidental discoveries J Urol 1994 100 4 189 195
28 Bielsa O Arango O Carrasco N Incidental diagnosis of renal carcinoma. Impact on prognosis and survival Actas Urol Esp 1996 20 601 604 8975544
29 Tsukamoto T Kumamoto Y Yamazaki K Clinical analysis of incidentally found renal cell carcinomas Eur Urol 1991 19 109 113 2022212
30 Jayson M Sanders H Increased incidence of serendipitously discovered renal cell carcinoma Urology 1998 51 203 205 9495698
31 Ebert T Owusu G Strotmann P Heydthausen M Gerharz CD Ackermann R Do we need screening for renal cell carcinoma (RCC)? J Urol Suppl 1999 161 169 169 abstract 651
32 Dinney CP Awad SA Gajewski JB Analysis of imaging modalities, staging systems, and prognostic indicators for renal cell carcinoma Urology 1992 39 122 129 1736503
33 Rodriguez R Fishman EK Marshall FF Differential diagnosis and evaluation of the incidentally discovered renal mass Semin Urol Oncol 1995 13 4 246 253 8595547
34 Konnak JW Grossman HB Renal cell carcinoma as an incidental finding J Urol 1985 134 1094 1096 4057398
35 Ueda T Mihara Y Incidental detection of renal carcinoma during radiological imaging Br J Urol 1987 59 513 515 3319006
36 Motzer RJ Bander NH Nanus DM Renal-cell carcinoma N Engl J Med 1996 335 865 875 8778606
37 Ritchie AW Kemp IW Chisholm GD Is the incidence of renal carcinoma increasing? Br J Urol 1984 56 571 573 6534467
38 Curry NS Schabel SI Betsill WL Small renal neoplasms: diagnostic imaging, pathologic features, and clinical course Radiology 1986 158 113 117 3940366
39 Bosniak MA The small (less than or equal to 3.0 cm) renal parenchymal tumor: detection, diagnosis, and controversies Radiology 1991 179 307 317 2014269
40 Amendola MA Bree RL Pollack HM Small renal cell carcinomas: resolving a diagnostic dilemma Radiology 1988 166 637 641 3277239
41 Lee CT Katz J Shi W Thaler HT Reuter VE Russo P: Surgical management of renal tumors 4 cm or less in a contemporary cohort J Urol 2000 163 730 736 10687966
42 Hafez KS Fergany AF Novick AC Nephron-sparing surgery for localized renal cell carcinoma: impact of tumor size on patient survival, tumor recurrence and TNM staging J Urol 1999 162 1930 1933 10569540
43 Ljungberg B Alamdari FI Rasmuson T Roos G Follow-up guidelines for nonmetastatic renal cell carcinoma based on the occurrence of metastases after radical nephrectomy BJU Int 1999 84 405 411 10468753
