Clinical T1a Renal Cell Carcinoma, Not Always a Harmless Disease—A National Register Study

Predictive factors for recurrence and outcomes in T1a renal cell carcinoma: Analysis of the INMARC (International Marker Consortium for Renal Cancer) database

OBJECTIVE

Stage migration in renal cell carcinoma (RCC) has led to an increasing proportion of diagnosed small renal masses. Emerging knowledge regarding heterogeneity of RCC histologies and consequent impact on prognosis led us to further explore outcomes and predictive factors in surgically-treated T1a RCC.

METHODS

The INMARC database was queried for T1aN0M0 RCC. Patients were stratified into groups based on recurrence. Primary outcome was overall survival (OS). Multivariable analyses (MVA) were performed for factors associated with recurrence, cancer-specific (CSM), and all-cause mortality (ACM). Kaplan-Meier analyses (KMA) assessed survival by histology and grade. Subset analysis for time to recurrence was conducted for grade and histologic groups and compared with recent AUA follow-up guidelines [low-risk (AUA-LR), intermediate-risk (AUA-IR), high-risk (AUA-HR), and very-high risk (AUA-VHR) groups].

RESULTS

We analyzed 1,878 patients (median follow-up 35.2 months); 101 (5.4%) developed recurrence. MVA for recurrence demonstrated increasing age (P = 0.026), male sex (P = 0.043), diabetes (P = 0.007), high/unclassified grade (P < 0.001-0.007), and variant histology (P = 0.017) as independent risk factors for increased risk, while papillary (P = 0.016) and chromophobe (P = 0.049) were associated with decreased risk. MVA identified high/unclassified grade (P = 0.003-0.004) and pT3a upstaging (P = 0.043) as predictive factors for worsened risk of CSM while papillary (P = 0.034) was associated with improved risk. MVA for ACM demonstrated increasing age (P < 0.001), non-white (P < 0.001), high-grade (P = 0.022), variant histology (P = 0.049), recurrence (P = 0.004), and eGFR<45 at last follow-up (P < 0.001) to be independent risk factors. KMA comparing clear cell, chromophobe, papillary, and variant RCC revealed significant differences for 5-year CSS (P = 0.018) and RFS (P < 0.001), but not OS (P = 0.34). Median time to recurrence was 23.8 months for low-grade (AUA-LR), 17.3 months for high-grade (AUA-IR), 18 months for pT3a upstaging (AUA-HR), and 12 months for variant histology (AUA-VHR; P < 0.001).

CONCLUSION

We noted differential outcomes in T1a RCC based on histology and grade for recurrence and CSM, while renal functional decline in addition to pathological factors and recurrence were predictive for ACM. Our findings support recently promulgated AUA follow-up guidelines for low-grade and variant histology pT1a RCC, but call for consolidation of follow-up protocols for high-grade pT1a and pT3a upstaged patients, with intensification of frequency of imaging follow-up in pT1a high-grade RCC.

Clear cell likelihood score may improve diagnosis and management of renal masses

The detection of solid renal masses has increased over time due to incidental findings during imaging studies conducted for unrelated medical conditions. Approximately 20% of lesions measuring less than 4 cm are benign and 80% are malignant. Clear cell renal cell carcinoma (ccRCC) is the most frequent among renal carcinomas, responsible for 65-80% of cases. The increased detection of renal masses facilitates early diagnosis and treatment. However, it also leads to more invasive interventions, which result in higher morbidity and costs. Currently, only histological analysis can offer an accurate diagnosis. Surgical nephron loss significantly elevates morbidity and mortality rates. Active surveillance represents a conservative management approach for patients diagnosed with a solid renal mass that is endorsed by both American Urological Association and the European Society for Medical Oncology. However, active surveillance is used in a minority of patients and varies across institutions. The lack of clinical studies using a standardized approach to incidentally detected small renal masses precludes the widespread use of active surveillance. Hence, there is an urgent need for better patient selection, distinguishing those who require surgery from those suitable for active surveillance. The clear cell likelihood score (ccLS) represents a novel MRI tool for assessing the probability of a renal mass being a ccRCC. In this study, we present a comprehensive review of renal masses and their evaluation using the ccLS to facilitate shared decision between urologists and patients.

Ablative or Surgical Treatment for Small Renal Masses (T1a): A Single-Center Comparison of Perioperative Morbidity and Complications

The purpose of this study is to evaluate the treatment safety of thermal ablation compared to surgical treatment of T1a tumors (small renal masses) at a high-volume center. We conducted an observational single-center study based on data collected form the National Swedish Kidney Cancer Register (NSKCR) between 2015 and 2021. In total, 444 treatments of T1a tumors were included. Patients underwent surgery (partial or total nephrectomy) or ablative treatment-radiofrequency ablation (RFA) or microwave ablation (MWA). Patient characteristics were retrieved from patient records, and tumor complexity was estimated from pre-interventional CT scans. The odds ratio (OR) of suffering from a severe surgical complication following ablative treatment was estimated using a logistic regression model adjusted for age, BMI, ASA physical status classification, smoking status and RENAL nephrometry score. The frequency of severe surgical complications was 6.3% (16/256 treatments) after surgical intervention and 2.1% (4/188 treatments) following ablative treatment. Our primary hypothesis that ablative treatment is associated with a lower risk of severe surgical complications is supported by the results (OR 0.39; 0.19-0.79; p = 0.013). When adjusting for age, smoking status, ASA score, BMI score and RENAL nephrometry score, we see an even greater difference between the two groups (OR 0.34; 0.17-0.68; p = 0.002). Our study was limited by the differences in patient and tumor characteristics between the two compared groups and the study design. If oncological outcomes are found to be comparable, ablative treatment should be considered as a first-line treatment for all small renal masses.

Prediction of clinically significant recurrence after partial nephrectomy. Data from the Cancer Registry of Norway with more than five years of follow-up

OBJECTIVE

To determine recurrence incidence after partial nephrectomy (PN) for renal cell carcinoma and identify predictors for local recurrence (LR) and metastasis.

MATERIAL AND METHODS

We retrospectively evaluated a cohort of 524 patients from the Cancer Registry of Norway, who underwent PN between January 2014 and December 2015 and were followed-up for >6 years. Patient demographics and pathological characteristics were correlated with recurrence and progression-free survival using Kaplan-Meier and Cox regression analyses.

RESULTS

Median patient age was 64 years, and the median tumour size was 2.6 cm. A positive surgical margin (PSM) was observed in 11% of the cases, while the LR and metastasis rates were 3.4% and 3.2%, respectively. PSM (hazard ratio [HR], 55.4; 95% confidence interval [CI], 12.55-244.6), tumour number (HR, 45.4; 95% CI, 6.5-316.1) and stage (HR, 33.5; 95% CI, 5.4-205.3) were independent predictors for LR. Undetermined margin status was also a risk factor for LR. Tumour stage (HR, 41.05; 95% CI, 8.52-197.76), tumour necrosis (HR, 1.3; 95% CI, 0.4-4.31) and age (HR, 1.07; 95% CI, 1.01-1.14) were predictors for metastasis.

CONCLUSIONS

Both local and distant recurrences after PN were rare, and the pT stage was a common predictor. PSM or indeterminate surgical margin and tumour number were LR predictors, while age at surgery and the presence of tumour necrosis predicted metastasis.

Predictive characteristics for disease recurrence and overall survival in non-metastatic clinical T1 renal cell carcinoma - results from the National Swedish Kidney Cancer Register

OBJECTIVE

Patients with clinical T1 renal cell carcinoma (cT1RCC) have risks for recurrence and reduced overall survival despite being in the best prognostic group. This study aimed to evaluate the association of different treatments on disease recurrence and overall survival using clinical and pathological characteristics in a nation-wide cT1RCC cohort.

MATERIALS AND METHODS

A total of 4,965 patients, registered in the National Swedish Kidney Cancer Register (NSKCR) between 2005 and 2014, with ≥ 5-years follow-up were identified: 3,040 males and 1,925 females, mean age 65 years. Times to recurrence and overall survival were analyzed with Kaplan-Meier curves, log-rank test, and Cox regression models.

RESULTS

Age, TNM-stage, tumor size, RCC-type, and performed treatment were all associated with disease recurrence. Patients selected for ablative treatments had increased risk for recurrent disease: hazard ratio (HR) = 3.79 [95% confidence interval (CI) = 2.69-5.32]. In multivariate analyses, age, gender, tumor size, RCC-type, N-stage, recurrence and performed treatment were all independently associated with overall survival. Patients with chRCC had a 41% better overall survival (HR = 0.59, 95% CI = 0.44-0.78; p < 0.001) than ccRCC. Patients treated with partial nephrectomy (PN) had an 18% better overall survival (HR = 0.83, 95% CI = 0.71-0.95, p < 0.001) than patients treated with radical nephrectomy.

CONCLUSIONS

Age, gender, T-stage, tumor size, RCC type and treatment modality are all associated with risk of recurrence. Furthermore, age, male gender, tumor size, N-stage and recurrence are associated with reduced overall survival. Patients with chRCC, compared with ccRCC and pRCC patients, and PN compared with RN treated patients, had an advantageous overall survival, indicating a possible survival advantage of nephron sparing treatment.

Ultrasound-Guided Percutaneous Thermal Ablation of Renal Cancers-In Search for the Ideal Tumour

Over the recent years, the progress in imaging techniques has led to an increased detection of kidney tumours, including small renal masses. While surgery is still the standard of care, there is a growing interest in minimally invasive methods. Ultrasound (US)-guided percutaneous ablation is particularly attractive because it is a safe and relatively simple procedure. In this study, we investigated the success of percutaneous radiofrequency ablation (RFA) in relation to kidney tumour diameter and location. Between August 2016 and September 2021, 253 patients with 259 renal tumours underwent US-guided RFA as a primary treatment in our institution. A total of 67 patients were excluded from this study. Abdominal computed tomography (CT) and tumour biopsy were performed before the procedure. Patients were followed with contrast-enhanced CT, the average follow-up time was 28 months. The studied group was composed of 186 patients with 191 renal tumours-only biopsy-confirmed renal cancers were included. During the follow-up, 46 cases of residual disease and 4 cases of local progression were found. There was a significant correlation between tumour size and the ablation success rate. The success rate was 73.5% and 87.6% for lesions ≤25 mm, 94.6% for lesions ≤25 mm and exophytic, 79.1% for lesions 26-30 mm and 84.4% for lesions 26-30 mm and exophytic, respectively. Four Clavien-Dindo grade ≥2 complications were observed. US-guided percutaneous RFA of T1a renal cancers is safe and well-tolerated. Its effectiveness depends on tumour size, with best results for exophytic lesions smaller than 3 cm. Most of the recurrent or residual tumours can be successfully re-treated with US-guided percutaneous RFA.