Home About us Editorial board Search Ahead of print Current issue Archives Submit article Instructions Subscribe Contacts Login 
Home Print this page Email this page
Users Online:: 253

 Table of Contents  
REVIEW ARTICLE
Year : 2017  |  Volume : 20  |  Issue : 4  |  Page : 137-142

Renal cell carcinoma in Nigeria: A systematic review


1 Department of Pathology, Aminu Kano Teaching Hospital/Bayero University, Kano, Nigeria
2 Department of Morbid Anatomy and Forensic Medicine, Usmanu Danfodiyo University, Sokoto/Aminu Kano Teaching Hospital, Kano, Nigeria

Date of Web Publication17-Apr-2018

Correspondence Address:
Dr. Muhammad Sanusi Haruna
Department of Morbid Anatomy and Forensic Medicine, Usmanu Danfodiyo University, Sokoto/Pathology Department, Aminu Kano Teaching Hospital, Kano
Nigeria
Login to access the Email id


DOI: 10.4103/smj.smj_67_16

Rights and Permissions
  Abstract 


Literature on renal cell carcinoma (RCC) in Nigeria is characterized by lacunae in several important areas with resultant incomprehensiveness of data. This requires a review of the literature so as to streamline the data. Using internet search engines, data were extracted from a total of twelve studies reported in peer reviewed journals between 2000 and 2015 from various states of Nigeria including Kano. These were subsequently collated, analyzed, and then compared with those from other parts of the world. There is relatively low incidence rate of 0.3/100,000 population; slight male preponderance and affectation of younger age groups with average age at diagnosis of 45 ± 4 years. Significant smoking history, exposure to industrial dye, family history, and HIV associated immunodeficiency are major risk factors of RCC in Nigeria. A significant number of cases presented with triad of loin pain, hematuria, and loin mass; advanced disease and bulky tumors of up to 3.8 kg and 56 cm. The predominant histological subtypes were clear cell carcinoma 60%–85.7% and papillary carcinoma 23.8%–46.2%. In general, there has been poor overall outcome for RCC bearing patients in the country. RCC in Nigeria is characterized by earlier age at onset and poor outcome, thus necessitating more aggressive case identification at early stages so as to improve prognosis.

Keywords: Clear cell, Nigeria, renal cell carcinoma


How to cite this article:
Atanda AT, Haruna MS. Renal cell carcinoma in Nigeria: A systematic review. Sahel Med J 2017;20:137-42

How to cite this URL:
Atanda AT, Haruna MS. Renal cell carcinoma in Nigeria: A systematic review. Sahel Med J [serial online] 2017 [cited 2018 Aug 19];20:137-42. Available from: http://www.smjonline.org/text.asp?2017/20/4/137/230265




  Introduction Top


Nigeria, with 170 million people,[1] has over 250 ethnic groups and is divided into 36 administrative entities called states and a federal capital territory, Abuja. It is traditionally divided into northern (including north-west, north-east, and north-central) and southern (comprising south-west, south-east, and south-south) Nigeria. Data from a population-based cancer registry in the country put age-standardized rates for cancer in Nigeria at 66.4/100,000 men and 130.6/100,000 women.[2]

Worldwide, cancer of the kidney is ranked 13th among all cancers, 8th in England, and 7th in the United States (US).[3],[4],[5] In Nigeria, it is ranked 20th based on analysis of data from two population-based cancer registries.[6] Globally, renal cell carcinoma (RCC) accounts for about 3% of all adult cancers while in Nigeria, it has accounted for between 0.3% and 2.3%.[6],[7],[8],[9],[10],[11] This is expectedly an underestimation as paucity of records on a national basis has militated against comprehensive data gathering. Cancer epidemiology in the country is also bedeviled by poor patronage of orthodox healthcare facilities because belief in spiritual etiology of diseases is rife. In the same vein, due to high rate of default from follow-up, mortality statistics are characterized by large gaps in data.

Following from the foregoing, different tertiary centers in Nigeria where cancer treatment is given, have concentrated mainly on highlighting different aspects of RCC demonstrable locally in their centers, without a clear picture emerging. This systematic review therefore seeks to synthesize data from our own center in Aminu Kano Teaching Hospital, Kano, with all studies on RCC from other centers in the country and then compare this with those from other parts of the world. This will serve to give a clearer picture of RCC in the country.


  Methods Top


Study selection

All studies on RCC in peer-reviewed journals from different parts of Nigeria between years 2000 and 2015 were included in the review. Pediatric nephroblastomas were excluded. Only the most recent of multiple studies from the same center was selected if the studies were on the same theme.

Data sources

All studies were found by searching through electronic databases including Pubmed, Google, Google scholar, Saudi Journal of Kidney Diseases and Transplantation and African Journals Online. Search words employed were “RCC” followed by adding the individual names of all the 36 states in Nigeria and Abuja, the capital.


  Results Top


Twelve studies met the search criteria, and from these, relevant data were extracted. There were five studies from the northern and seven studies from the southern parts of the country and one from Kano [Table 1].
Table 1: Characteristics of renal cell carcinoma highlighted in studies from different regions of Nigeria

Click here to view



  Frequency Top


Synthesizing data from the 12 centers and Kano,[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19] approximately 45 cases of RCC, are diagnosed per year (Σn/year; [Table 1]) in Nigeria. However, this may be an underestimation because of hitherto-mentioned cancer registration lapses. Worldwide, in 2013, about 338,000 new cases of kidney cancer were diagnosed.[20]


  Incidence Top


Using standard census population, the incidence rate for RCC in the country is about 0.3 per 100,000 populations. This is low compared to worldwide rates that have ranged from as low as 6.1/100,000 in Brazil, Latin America to as high as 22.5/100,000 in parts of Europe.[3] In Africa, it has ranged from 2.6/100,000 in southern Africa to as high as 3.3/100,000 populations in northern Africa.[3] The global age-standardized incidence rate is 4 per 100,000 people per year.[3] Karim-Kos et al.[21] have proposed that these racial disparities in incidence may be attributable to differences in frequency of diagnostic imaging, access to health care, genetic background, and prevalence of lifestyle or environmental risk factors.


  Gender Top


Males are slightly more affected in our population, evidenced by overall male:female ratio of 1.1 although this supports the general trend observed in most studies worldwide of a male preponderance, our ratio is quite low compared to ratio of 1.75 among an Arab population; 2.1 in North America; 2.1 among Australians; 2.2 among Brazilians of Latin America; 2.3 among Italians in Europe; and as high as 3.4 among Japanese in the Asian continent.[3],[21],[22] Our ratio is also low compared to the trend across Africa with ratios of 1.4 in northern Africa and 1.9 in southern Africa.[3]


  Age Top


The age range from the studies in the country is between 8 and 89 years with an average age of 45 ± 4 years (peak age in the fifth decade).[8],[9],[10],[11],[12],[13],[14],[15],[16],[17],[18],[19] This is about two decades less than the pattern described for western countries where the peak age incidence is in the seventh decade.[22],[23],[24] Earlier age at onset was also documented in an analysis of data from a population-based cancer registry in Morocco, North Africa, Ghana in West Africa, Kenya in East Africa, and in India.[25],[26],[27],[28] Reasons for this observed age-related variations are unclear but changing lifestyle and higher exposure to hazardous work environment among younger Africans may underlie this.


  Risk Factors Top


Even though most putative risk factors for the development of RCC have been associated with conflicting data, several have shown sufficient evidence to warrant mention. Chow et al.[29] have classified these into those with established association such as cigarette smoking, obesity, and hypertension and those with suspected association including diabetes mellitus, high parity, physical inactivity, alcohol consumption, and exposure to trichloroethylene.

Studies across Nigeria have only paid minimal attention to evaluating risk factors in published literature. However, Tijjani and Badmus in separate studies from southwestern Nigeria documented significant smoking history in 7.8% and 16.7% of cases, respectively.[17],[18] The former also identified exposure to industrial dyes in 4.7% and family history in 1.6% of their cases. Immunodeficiency from HIV infection was also reported in 9.5% of patients in Enugu, southeastern Nigeria.[15]

The almost even gender-related pattern of RCC overall in studies from Nigeria would suggest that risk factors associated with the disease uniformly apply to both genders in the country. Hypertension, an established risk factor, has almost equal prevalence among males (6.2%–48.9%) and females (10%–47.3%) in our setting.[30] Similarly, comparable with other countries, diabetes mellitus, with a prevalence of 5.27% (142nd of 193 countries) as at 2014,[31] is relatively a low risk factor in Nigeria. Obesity among males in Nigeria is 5.9% (133rd worldwide) and 16.3% among females (133rd of 189 countries worldwide).[32]

Cigarette smoking, on the other hand, may account for some of the earlier age of onset among our patients. The Global Adult Tobacco Survey for 2012 showed that about 4% of adult Nigerians smoked tobacco products at an average of 8 cigarettes per day.[33] In northeastern Nigeria, where the prevalence was highest, rate of smoking peaked at age range 30–39 years, with 71% having started smoking between 13 and 15 years of age.[34]

In addition to smoking, authors of an Indian study,[28] where a significant number of their cases were also found to be younger than those in Europe and the US, have suggested poor nutrition as a risk factor to explain this. This may aptly explain the situation in our country based on reported adolescent underweight ranging from 18.7% to 22.4%.[35]


  Clinical Presentation Top


Among our patients, hematuria was found in 9–87% (mean 36%), loin pain in 14–94% (mean 50%), weight loss in 82–100% (mean 84%), and loin mass in 13–100% (mean 97%).[7],[9],[14],[15],[16],[17] This pattern is similar to that described in developed countries over four decades ago, when clinical practice then more closely reflects what is obtainable in present day developing countries like ours. However, diagnosis of RCC has historically relied on the demonstration of a triad of symptoms including loin mass, hematuria, and loin pain. In this respect, 8–46% of our cases presented with this triad in contrast to 10–15% reported in developed countries.[36] The high number of symptomatic cases in the country reflects late presentation and advanced disease.


  Stage Top


Results show that 80%–96% of our patients presented in advanced stages T3/T4. This contrasts with 37% in Brazil and 15% documented from an European cancer registry.[37],[38] Conversely, unlike findings in developed countries where over 50% of cases are incidental tumors,[39] in Nigeria, these have been documented in only about 1.6%–11.8% of tumors recorded.[13],[17] This is similar to the pattern described in the study from Sudan, another African country, where only 10% of their cases were incidentally discovered.[40] This may reflect illness behavior in economically challenged countries where nonorthodox care is first sought and then hospital care when all else fails. Inadequacy of ultrasonography and computed tomography scans as well as inadequacy of trained radiologists may also be a contributory factor. Average time from observation of first symptoms/signs to diagnosis could not be ascertained in every case; however, data from centers in the country which documented this information have shown that this ranged between 1 and 208 weeks (mean 45.8 weeks).[17],[18] The advanced stage at presentation may also suggest that the tumors are more clinically aggressive in our patients.


  Tumor Size Top


Various centers in the country have documented very bulky tumors with weights ranging between 0.48 and 3.8 kg and tumor widths averaging 18.7 ± 3.2 cm (15–56 cm).[9],[10],[11],[17],[18] A study from Ghana, another West African country, also recorded tumor sizes with mean diameter of 16.8 ± 4.0 cm.[26] In contrast, a large population-based study from Europe and a study from the US showed that tumors ≤7 cm accounted for 58.3% and 89.7% of cases diagnosed, respectively.[41] Such bulky tumors as recorded among our patients support tardiness in presentation for treatment and may also suggest the tumors are aggressive. This is buttressed by the observation by Igor et al.[42] that only 1% of all tumors <1 cm and 9.2% of all tumors <2 cm were high-grade malignancies. Similarly, most tumors encountered in western countries are <0.5 kg.[43]


  Predominant Subtype Top


Clear cell carcinoma (CCC) was the most common histological subtype with frequency ranging from 60% to 85.7%.[9],[11],[12],[13],[16],[18] The predominance of CCC has also been reported from other regions of the world with frequencies of up to 85%.[40],[44],[45] This group of tumors are derived from cells of the proximal tubules and majorly show 3p deletion. Similar to observations from most studies globally, the acinar subvariant was more commonly reported in Nigeria with sarcomatoid subvariant of it accounting for 2.2% in one of our studies.[17]

Second in frequency to the CCC is the chromophilic (papillary) carcinoma. This ranged in frequency between 23.8% and 46.2%.[9],[12],[17] This is higher than the 10%–15% quoted in western literature.[46],[47] This higher rate of papillary tumors highlights the need to more comprehensively investigate risk factors that may locally underlie this. Other histological patterns are relatively uncommon with collecting duct, sarcomatoid, and chromophobe subtypes accounting for 8.9%, 2.2%, and 2.2%, respectively, in one of our local studies.[17] Xp11.2-related carcinoma was scarcely reported probably due to lack of facilities for its definitive diagnosis, but based on morphological appearance after sampling, two cases were reported in Kano.


  Outcome Top


Even though data from most centers in Nigeria on outcome of patients with RCC are incomplete, available data demonstrate very poor outcome. Loss to follow-up was the most common clinical outcome, and this was recorded in 45.5%–67% of cases (Jos, Ibadan, Zaria, Lagos.[9],[13],[16],[17] This high frequency may be a reflection of number of factors which include: long distance patients have to travel to the referral centers in the country; high cost of chemo and adjuvant therapy; inability to afford cost of cancer management; and illness behavior skewed in favor of patronage of alternative medicine practitioners and spiritual center.

High mortality rate has also been reported and has ranged from 40.9 to over 90%.[9],[13],[17] Two centers [9],[16] in the country report 1–5-year survival rates of 13.6% and 56% for patients managed with or without resection, chemotherapy, radiotherapy, and adjuvant therapy. Only 7.8% of patients in one of the centers [17] were able to afford adjuvant therapy including interferon. In addition to this, perioperative mortality, where documented, ranged between 6.3 and 7.8%, and these mostly resulted from hemorrhage and sepsis.[17],[18] This rate of perioperative deaths is higher than 2.8% documented in western countries.[48] This probably highlights our inability to implement more modern treatment options such as nephron-sparing and laparoscopic surgery because of inadequate infrastructural support. In contrast to the foregoing, 1 and 5 year survival rates in Europe have reached 72% and 55%, respectively, while in the US, SEERs statistics puts survival at 73.2%.[4],[49]

In spite of the dismal mortality figures highlighted from the foregoing, common denominators for those who had the best outcome from all the centers in the country were early stage tumors and ability to afford therapy.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
  References Top

1.
Censuses – National Population Commission. Available from: http://www.population.gov.ng/index.php/censuses. [Last accessed on 2016 Jan 14].  Back to cited text no. 1
    
2.
Jedy-Agba E, Curado MP, Ogunbiyi O, Oga E, Fabowale T, Igbinoba F, et al. Cancer incidence in Nigeria: A report from population-based cancer registries. Cancer Epidemiol 2012;36:e271-8.  Back to cited text no. 2
    
3.
Ferlay J, Shin HR, Bray F, Forman D, Mathers C, Parkin DM. Estimates of worldwide burden of cancer in 2008: GLOBOCAN 2008. Int J Cancer 2010;127:2893-917.  Back to cited text no. 3
    
4.
Cancer Research UK. Kidney Cancer Incidence Statistics. Available from: http://www.cancerresearchuk.org/content/kidney-cancer-incidence-statistics. [Last Acccessed on 2015 Dec 14].  Back to cited text no. 4
    
5.
Jemal A, Murray T, Ward E, Samuels A, Tiwari RC, Ghafoor A, et al. Cancer statistics, 2005. CA Cancer J Clin 2005;55:10-30.  Back to cited text no. 5
    
6.
Awodele O, Adeyomoye AA, Awodele DF, Fayankinnu VB, Dolapo DC. Cancer distribution pattern in south-western Nigeria. Tanzan J Health Res 2011;13:125-31.  Back to cited text no. 6
    
7.
Jemal A, Siegel R, Xu J, Ward E. Cancer statistics, 2010. CA Cancer J Clin 2010;60:277-300.  Back to cited text no. 7
    
8.
Seleye-Fubara D, Etebu EN, Jebbin NJ. A ten-year pathological study of renal tumours in Port Harcourt, Nigeria. Ann Afr Med 2006;5:64-7.  Back to cited text no. 8
    
9.
Akpayak IC, Shuaibu SI, Ofoha CG, Dakum NK, Ramyil VM. Presentation and management of renal cell carcinoma: A 7-year review. J Dent Med Sci 2015;14:16-9.  Back to cited text no. 9
    
10.
Madziga AG, Ali N, Nggada HA. Renal cancer in Maiduguri: An 8-year review of clinico-pathological pattern. Sahel Med J 2009;12:1-5.  Back to cited text no. 10
  [Full text]  
11.
Olu-Eddo AN, Ekanem VJ. Histopathlogical appraisal of adult renal tumours- A 20yrs retrospective study. Inter J Pathol 2008;6:(2) Available from http://www.jpathology.com/Issues/I J P % 2 0 2 0 0 8 - 2 / 1 5 _ -Brief%20Communication.htm. [Last accessed 2015 Dec 15].  Back to cited text no. 11
    
12.
Isah RT, Sahabi SM, Adamu SN, Muhammad AT, Mungadi IA. Histopathological pattern of renal tumours seen in Usmanu Danfodiyo University Teaching Hospital, Sokoto, Nigeria. Afr J Cell Pathol 2013;1:9-13.  Back to cited text no. 12
    
13.
Muhammed A, Ahmad B, Yusuf MH, Almustapha LA, Abdullahi S, Tijjani LA. Pathologic characteristics and management of renal cell carcinoma in Zaria, Nigeria. Sub Saharan Afr J Med 2015;2:1-4.  Back to cited text no. 13
    
14.
Dauda MA, Misauno MA, Ojo EO, Nnadozie UU. Pattern of urological malignancies seen at Federal Medical Centre Gombe North Eastern Nigeria. Niger J Med 2012;21:237-40.  Back to cited text no. 14
    
15.
Aghaji AE, Odoemene CA. Renal cell carcinoma in Enugu, Nigeria. West Afr J Med 2000;19:254-8.  Back to cited text no. 15
    
16.
Takure AO, Shittu OB, Adebayo SA, Okolo CA, Sotunmbi PT. Renal cell carcinoma in Ibadan: A 5-year clinicopathologic review. Afr J Med Med Sci 2013;42:239-43.  Back to cited text no. 16
    
17.
Tijani KH, Anunobi CC, Ezenwaa EV, Lawal A, Habeebu MY, Jeje EA, et al. Adult renal cell carcinoma in Lagos: Experience and challenges at the Lagos University Teaching Hospital. Afr J Urol 2012;18:20-3.  Back to cited text no. 17
    
18.
Badmus TA, Salako AA, Arogundade FA, Sanusi AA, Adesunkanmi AR, Oyebamiji EO, et al. Malignant renal tumors in adults: A ten-year review in a Nigerian hospital. Saudi J Kidney Dis Transpl 2008;19:120-6.  Back to cited text no. 18
[PUBMED]  [Full text]  
19.
Mbaeri TU, Orakwe JC, Nwofor AM, Oranusi CK, Ulebe AO. Malignant renal tumours in adults in Nnamdi Azikiwe University Teaching Hospital, Nnewi, Nigeria. Niger J Med 2012;21:300-3.  Back to cited text no. 19
    
20.
Ferlay J, Soerjomataram I, Ervik M, Dikshit R, Eser S, Mathers C, et al. GLOBOCAN 2012 Ver. 1.1, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 11. Lyon, France: International Agency for Research on Cancer; 2014. Available from: http://www.globocan.iarc.fr. [Last accessed on 2016 Jan 16].  Back to cited text no. 20
    
21.
Karim-Kos HE, De Vries E, Soerjomataram I, Lemmens V, Siesling S, Coebergh JW. Recent trends of cancer in Europe: A combined approach of incidence, survival and mortality for 17 cancer sites since the 1990s. Eur J Cancer. 2008;44:1345-89.  Back to cited text no. 21
    
22.
Alabbadi B, Alasmar A, Alqarallah A, Saaydah N. Renal Cell Carcinoma Clinical Presentation and Histopathological Findings: A Retrospective Analysis of a Jordanian Population at King Hussein Medical Center. JRoyalMed Services. 2015; 22(1): 18-23/DOI: 10.12816/0009781.  Back to cited text no. 22
    
23.
Chow WH, Devesa SS. Contemporary epidemiology of renal cell cancer. Cancer J. 2008;14:288-301.  Back to cited text no. 23
    
24.
Cohen HT, McGovern FJ. Renal-Cell Carcinoma. N Engl J Med 2005; 353:2477. doi: 10.1056/NEJMra043172.  Back to cited text no. 24
    
25.
Cancer Profile in Aswan, Egypt: Methodology and Results Chart Book 2008. Available from: http://www.mcit.gov.eg/Upcont/Documents/Final%20Chart%20Book20105611283.pdf. [Last accessed 2016 Jan 17].  Back to cited text no. 25
    
26.
Kyei MY1, Klufio GO, Mensah JE, Gyasi RK, Gepi-Attee S, Ampadu K. Nephrectomy in adults: Experience at the Korle Bu Teaching Hospital, Accra, Ghana. Saudi J Kidney Dis Transpl. 2015;26(3):638-42. doi: 10.4103/1319-2442.157438.  Back to cited text no. 26
    
27.
Oliech JS. Clinical presentation and management of renal cell carcinoma. East Afr Med J. 1998;75(10):594-7.  Back to cited text no. 27
    
28.
Agnihotri S, Kumar J, Jain M, Kapoor R, Mandhani A. Renal cell carcinoma in India demonstrates early age of onset and a late stage of presentation. The Indian Journal of Medical Research. 2014;140(5): 624-9.  Back to cited text no. 28
    
29.
Chow WH, Dong LM, Devesa SS. Epidemiology and risk factors for kidney cancer. Nat Rev Urol. 2010; 7(5): 245–57. doi: 10.1038/nrurol. 2010.46.  Back to cited text no. 29
    
30.
Akinlua JT, Meakin R, Umar AM, Freemantle N (2015). Current Prevalence Pattern of Hypertension in Nigeria: A Systematic Review. PLoS ONE 10 (10): e0140021. doi: 10.1371/journal.pone. 0140021.  Back to cited text no. 30
    
31.
Diabetes prevalence (% of population ages 20 to 79)-Country Ranking. Source: International Diabetes Federation, Diabetes Atlas. Available from: http://www.indexmundi.com/facts/indicators/SH.STA.DIAB.ZS/rankings. [Last accessed on 2016 Jan 22].  Back to cited text no. 31
    
32.
World Bank Gender Statistics, October 2015: Adult obesity prevalence ranking. Available from: http://knoema.com/atlas/ranks/Adult-obesity-prevalence-female?baseRegion=NG. [Last accessed on 2016 Jan 22].  Back to cited text no. 32
    
33.
Global Adult Tobacco Survey: Country Report 2012. Available from: Global.tobaccofreekids.org/files/pdfs/en/GATS_Nigeria_Report_2012.pdf. [Last accessed on 2016 Jan 18].  Back to cited text no. 33
    
34.
Desalu OO, Olokoba A, Danburam A, Salawu F, Issa B. Epidemiology Of Tobacco Smoking Among Adults Population In North-East Nigeria. The Internet Journal of Epidemiology. 2008; Volume 6 Number 1.  Back to cited text no. 34
    
35.
Olumakaiye MF. Prevalence of Underweight: A Matter of Concern among Adolescents in Osun State, Nigeria. Pak J Nutr. 2008; 7(3): 503-8.  Back to cited text no. 35
    
36.
McPhee SJ, Papadakis MA. Current Medical Diagnosis and Treatment 2009. McGraw-Hill Professional. (2008) ISBN: 0071591249.  Back to cited text no. 36
    
37.
OrnellasAO, AndradeIDM, OrnellasIP, WisnesckyA, DeSantosSchwindtAB. Prognostic factors in renal cell carcinoma: Analysis of 227 patients treated at the Brazilian National Cancer Institute. Int. BrazJUrol. 2012; 38(2): 185-94  Back to cited text no. 37
    
38.
Guðmundssona E, Hellborgb H, Lundstamc S, EriksondS, Ljungberge B. Metastatic potential in renal cell carcinomas≤7cm: Swedish Kidney Cancer Quality Register data. European Urology. 2011; 60(5): 975-82  Back to cited text no. 38
    
39.
Jayson M, Sanders H. Increased incidence of serendipitously discovered renal cell carcinoma. Urology. 1998; 51: 203.  Back to cited text no. 39
    
40.
Mohammed Y, Mansour MO, Mohammed Elemam Mohammed Ahmed S. Pattern and Presentation of Renal Cell Carcinoma in Ingezira Hospital for Renal Diseases and Surgery. Global J Med Res. 2013; 7: 13(2).  Back to cited text no. 40
    
41.
Hafez KS, Fergany AF, NovickAC. Nephron sparing surgery for localized renal cell carcinoma: Impact of tumor size on patient survival, tumor recurrence and TNM staging. J Urol. 1999; 162(6): 1930-3.  Back to cited text no. 41
    
42.
Frank I, Blute ML, Cheville JC, Lohse CM, Weaver AL, ZinckeH. Solid renal tumors: An analysis of pathological features related to tumor size. J Urology. 2003; 170(6): 2217-20  Back to cited text no. 42
    
43.
Yaycioglu O, Rutman MP, Balasubramaniam M, Peters KM, Gonzalez JA. Clinical and pathologic tumor size in renal cell carcinoma; Difference, correlation and analysis of the influencing factors. Urology 2002;60(1):33-8.  Back to cited text no. 43
    
44.
Ezenwa EV, Tan YH. Ethnic variation of the histological subtypes of renal cell carcinoma in Singapore. Afr J Urol. 2014; 20(4): 184–8. doi: 10.1016/j.afju. 2014.08.006.  Back to cited text no. 44
    
45.
Presti JC Jr, Rao PH, Chen Q, et al. Histopathological, cytogenetic, and molecular characterization of renal cortical tumors. Cancer Res. 1991;51: 1544-52.  Back to cited text no. 45
    
46.
Campbell SC, Novick AC, Bukowski RM. Renal tumors. In: Wein AJ, Kavoussi LR, Novick AC, Partin AW, Peters CA, editors. Campbell–Walsh urology. 9th ed. Philadelphia: Saunders Elsevier; 2007. p. 1567–637.  Back to cited text no. 46
    
47.
Verhoest G, Veillard D, Guille F, De La Taille A, Salomon L, Abbou C, et al. Relationship between age at diagnosis and clinicopathologic features of renal cell carcinoma. European Urology. 2007;51: 1298–305.  Back to cited text no. 47
    
48.
Thoroddsen A, Gudbjartsson T, Jonsson E, Gislason T, Einarsson GV. Operative mortality after nephrectomy for renal cell carcinoma. Scandinavian JUrolNephrol 2003;37(6): 507–11.  Back to cited text no. 48
    
49.
SEER Stat Fact Sheets: Kidney and Renal Pelvis Cancer. Available from: http://www.seer.cancer.gov/statfacts/html/kidrp.html. [Last accessed on 2016 Jan 20].  Back to cited text no. 49
    



 
 
    Tables

  [Table 1]



 

Top
 
 
  Search
 
Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
Access Statistics
Email Alert *
Add to My List *
* Registration required (free)

 
  In this article
   Abstract
  Introduction
  Methods
  Results
  Frequency
  Incidence
  Gender
  Age
  Risk Factors
   Clinical Present...
  Stage
  Tumor Size
  Predominant Subtype
  Outcome
   References
   Article Tables

 Article Access Statistics
    Viewed333    
    Printed29    
    Emailed0    
    PDF Downloaded74    
    Comments [Add]    

Recommend this journal


[TAG2]
[TAG3]
[TAG4]