Pathological Prognostic Features and Analysis of Renal Cell Carcinoma

ABSTRACT


Introduction
Renal cell carcinoma (RCC), originating from the epithelium of the renal tubulus, is the most common malignant tumor of the kidney. These tumors are 2-3% of all adult cancers. There were 19,3 million new cancer diagnoses and 10 million cancer deaths worldwide in 2020. Kidney cancer is currently the seventh most common cancer in men and the tenth most common in women. 1,8% of cancer deaths are caused by kidney cancers 1,2 . The incidence of kidney tumors has increased according to the data of the Turkish Ministry of Health. While kidney cancer was the seventh most common cancer in 2002, it was the fifth most common cancer in 2016 in men (5).
RCC is mostly diagnosed between the ages of 65 and 74. Clear cell renal cell carcinoma (CCRCC) is the most common type RCC and papillary renal cell carcinoma (PRCC) is the second most common type RCC 3,5 . Chromophobe renal cell carcinoma (ChRCC) accounts for 4-6% of all RCC and has a better prognosis 5,6 . PRCC is more common in patients over 60 years than CCRCC. ChRCC is not associated with age 7 .
Most RCCs develop sporadically but about 2-4% are familial. It is about twice as common in men than in women. Renal cell carcinoma is very rare in children 5 . According to some studies the etiology of renal cell carcinoma includes smoking, hypertension and high body mass index.
Nuclear grading of RCC is also considered a prognostic factor. The grading for grades 1-3 is based on nucleolar prominence/eosinophilia, while nuclear anaplasia (sarcomatoid differentiation) is required for grade 4 8,9,10 .
Moreover, survival in kidney tumors has a strong correlation with the stage at the time of diagnosis. 5year survival in stage1 tumors is 93%, 72,5% in cases with local lymph node metastases and 12% in metastatic carcinomas cases 3 . There is an inverse correlation between age/tumor size and survival 11 . Metastatic lymph node, tumor necrosis and adipose tissue invasion are associated with poor prognosis 4,12 .

Material-Method
The population of this descriptive, cross-sectional study consists of 179 patients diagnosed with RCC in Sivas Cumhuriyet University Hospital Pathology Department between 2017 and 2022. No sample selection was made and all patients diagnosed with RCC were included in the study.
Primarily, it was classified according to the demographic characteristics (age, sex) of the patients.
Patients diagnosed with renal cell carcinoma were distributed according to the subtypes of the disease (CCRCC, PRCC, ChRCC), and the nuclear grade of the disease was grouped as low (1-2 grade) and high (3-4 grade). Tumor diameters of the patients were examined in 3 groups (1st group with 1-6 cm, 2nd group with 7-13 cm, 3rd group with 14-19 cm).
The types of operations that the patients had undergone were evaluated as radical and partial, on the right and left kidneys of the operation side. In radical nephrectomies cases, the relationship between nuclear grade, tumor diameters, subtypes and vein invasion, microvascular invasion, capsule/ adipose tissue invasion, lymph node metastases, adrenal gland metastates was analyzed as statistically.
SPSS-22 (SPSS INC., Chicago, IL, USA) statistical program was used in the analysis of the data. While count data was give in with numbers and percentages, measurement data was givein with mean, standard deviation, minimum and maximum values. The nominal data were compared with the chi-square test. The findings obtained by statistical analysis are presented with descriptive and analytical tables.
Nuclear grade and tumor diameter were compared with vein invasion, capsule/adipose tissue invasion, microvascular invasion, lymph node metastasis and adrenal gland metastasis. Nuclear grades 1 and 2 were defined as low grade, grades 3 and 4 as high grade. Tumor diameters of 1-6 cm were defined as group 1, 7-13 cm as group 2 and 14-19 cm as group 3. Only surgical margin was evaluated in partial nephrectomies. Surgical margin evaluated in 61 cases was positive in 4 cases and negative in 57 cases (Table  II). There was vein invasion for 5 cases in low grade, for 20 cases in high grade. There is a statistically significant relationship between grade and vein invasion (p=0,005). There was microvascular invasion for 3 cases in low grade, for 17 cases in high grade. There is a statistically significant relationship between grade and micro vascular invasion (p=0,005). There was capsule/adipose tissue invasion for a case in low grade, for 11 cases in high grade. There is a statistically significant relationship between grade and capsule/adipose tissue invasion (p=0,010). 2 cases with high grade had lymph node metastases. There is not a statistically significant relationship between grade and lymph node metastases (p=0,357). Of the 2 cases with adrenal gland metastases, one was low grade and the other was high grade. There is not a statistically significant relationship between grade and adrenal gland metastases (p=0,054) (Table III). There was vein invasion for 8 cases in group 1, for 15 cases in group 2 and for 4 cases in group 3. There is a statistically significant relationship between tumor diameters and vein invasion (p=0,001). There was microvascular invasion for 7 cases in group 1, for 10 cases in group 2 and for 4 cases in group 3. There is a statistically significant relationship between tumor diameters and microvascular invasion (p=0,008). There was capsule/adipose tissue invasion for a case in group 1, for 7 cases in group 2 and for 5 cases in group 3. There is a statistically significant relationship between tumor diameters and capsule/adipose tissue invasion (p=0,00). There was no lymph node metastases in group 1, while there was for a case in group 2 and for 2 cases in group 3. There is a statistically significant relationship between tumor diameters and lymph node metastases (p=0,00). There was no adrenal gland metastases in group 1, while there was for a case in group 2 and for a case in group 3. There is not a statistically significant relationship between tumor diameters and adrenal gland metastases (p=0,053) (Table IV). There is not a statistically significant relationship between subtypes and vein invasion, microvascular invasion, capsule/adipose tissue invasion, lymph node metastases, adrenal gland metastases (Table V).

Discussion
Renal cell carcinomas is 80-85% of all primary malignant tumors of kidney and it is 2-3% of all adult cancers. Renal cell carcinoma is mostly diagnosed between the ages of 65 and 74 1,2 . In this study, the mean age was 58,5±11,9 years (range of 21-90). It is about twice as common in male as in female (-4 . Our data were compatible with the literature (female 38%, male 62%).
PRCC in patients over 60 years of age is more common than CCRCC. ChRCC is not associated with age and has a better prognosis 3,13 . The mean age is 58 in CCRCC cases, 62 in PRCC cases and 55 in ChRCC cases.
The mean age was higher in PRCC cases which was consistent with the literature.
CCRCC is the most common subtype and PRCC is the second most common subtype in RCC. ChRCC accounts for 4-6% of all RCC 4 . Diagnosis of cases were 78,8% CCRCC, 15,1% PRCC and 6,1% ChRCC in this study.
The incidence of renal cell carcinomas has increased in recent years. It is known that the prognosis of RCC depends on nuclear grade, tumor diameters, age and invasions. One study was shown lymphovascular invasion and microvascular invasion are poor prognostic factors in RCC 9,14 .
In RCCs, nuclear grade and tumor diameter are correlated with tumor stage and help in determining the prognosis. In this study, it was found that the increasing in nuclear grade and tumor diameter are associated with poor prognostic factors. There are also studies that have achieved similar results in the literature 11,12 .

Conclusion
In conclusion, there is a statistically significant relationship between nuclear grade and vein invasion, microvascular invasion, capsule/adipose tissue invasion in this study. In addition, there is a statistically significant relationship between tumor diameters and vein invasion, microvascular invasion, capsule/adipose tissue invasion, lymph node metastases.