From the Guidelines
The nodule found on the CT scan three years after a partial nephrectomy for low-grade chromophobe renal cell carcinoma (RCC) is likely a post-surgical change rather than a recurrence, and thus, continued surveillance with imaging every 6-12 months is recommended rather than immediate intervention. This recommendation is based on the fact that the nodule was retrospectively visible one month post-operatively, suggesting it represents post-surgical scarring or granulation tissue rather than a new growth 1. The lack of enhancement and stability over time are reassuring features, as chromophobe RCC typically has a favorable prognosis, especially when initially diagnosed as T1a (tumor ≤4 cm limited to the kidney), with recurrence rates under 5% 1.
Key Considerations
- Post-surgical changes can mimic recurrence on imaging, which is why comparing to immediate post-operative scans is crucial for accurate assessment 1.
- CT of the abdomen is the most commonly used method for surveillance after surgical excision of RCC, and it is a sensitive method for the detection of recurrences in the resection bed and in other more common sites of metastases in the abdomen 1.
- For patients in whom contrast is contraindicated (e.g., previous anaphylactic reaction), CT of the abdomen without IV contrast may be considered appropriate 1.
Recommendations
- Continued surveillance with imaging every 6-12 months is recommended for small, non-enhancing lesions that have remained stable since the immediate post-operative period.
- If there are concerns about the nature of the nodule, a multidisciplinary discussion involving urology, radiology, and oncology would be beneficial to determine if biopsy or more frequent imaging is warranted.
- The use of dual-energy CT and material decomposition techniques can generate adequate virtual noncontrast images and iodine-only image data sets, which can assist in the evaluation of contrast enhancement of the treated lesions 1.
From the Research
Significance of a Newly Detected Nodule on CT Scan
- The detection of a newly detected nodule on a computed tomography (CT) scan three years after a partial nephrectomy for a low-grade chromophobe renal cell carcinoma (RCC) staged as T1A is a significant finding that requires careful evaluation 2, 3.
- The nodule's characteristics, such as size, shape, and attenuation, should be assessed using CT scans to determine its potential malignancy 4, 5.
- Studies have shown that malignant nodules can manifest growth slowly on follow-up CT, and stability at 3-month follow-up should not instill high confidence in benignancy 2.
- The Fleischner Society recommends measuring pulmonary nodules at CT to assess their size and changes over time, which can help determine the likelihood of malignancy 3.
Implications for Renal Cell Carcinoma
- Renal cell carcinoma (RCC) is a type of cancer that can be treated with partial nephrectomy, and the detection of a new nodule on CT scan may indicate a potential recurrence or metastasis 5, 6.
- Presurgical sunitinib has been shown to reduce tumor size and facilitate partial nephrectomy in patients with RCC, but its effectiveness in reducing the size of the newly detected nodule is uncertain 5, 6.
- Further evaluation and follow-up are necessary to determine the significance of the newly detected nodule and to develop an appropriate treatment plan 2, 3.