Percutaneous renal tumor ablation

Contrast-Enhanced Transrectal Ultrasound in Focal Therapy for Prostate Cancer

PURPOSE OF REVIEW

Contrast-enhanced transrectal ultrasound (CeTRUS) is an emerging imaging technique in prostate cancer (PCa) diagnosis and treatment. We review the utility and implications of CeTRUS in PCa focal therapy (FT).

RECENT FINDINGS

CeTRUS utilizes intravenous injection of ultrasound-enhancing agents followed by high-resolution ultrasound to evaluate tissue microvasculature and differentiate between benign tissue and PCa, with the latter demonstrating increased enhancement. The potential utility of CeTRUS in FT for PCa extends to pre-, intra- and post-operative settings. CeTRUS may detect PCa, facilitate targeted biopsy and aid surgical planning prior to FT. During FT, the treated area can be visualized as a well-demarcated non-enhancing zone and continuous real-time assessment allows immediate re-treatment if necessary. Following FT, the changes on CeTRUS are immediate and consistent, thus facilitating repeat imaging for comparison during follow-up. Areas suspicious for recurrence may be detected and target-biopsied. Enhancement can be quantified using time-intensity curves allowing objective assessment and comparison. Based on encouraging early outcomes, CeTRUS may become an alternative imaging modality in prostate cancer FT. Further study with larger cohorts and longer follow-up are needed.

MRI features of renal cell carcinoma that predict favorable clinicopathologic outcomes

OBJECTIVE

The purpose of this article is to determine whether MRI features of renal cell carcinoma (RCC), such as enhancing solid component and T1 signal intensity, are associated with clinicopathologic outcomes.

MATERIALS AND METHODS

This retrospective study included 241 RCCs in 230 patients who underwent preoperative MRI, had pathologic analysis results available, and were monitored for at least 3 months. A radiologist assessed tumor features on MRI, including unenhanced T1 signal relative to renal cortex and the percentage of solid enhancing components. The electronic medical record or follow-up images were reviewed to assess for the development of local recurrence or metastases. Statistical analysis was performed to correlate imaging features at MRI with pathologic and clinical outcome.

RESULTS

The following tumor features were observed: predominantly cystic morphologic features (defined as solid component≤25%, n=33), solid component greater than 25% (n=208), T1 hypointensity (n=97), and T1 intermediate intensity or hyperintensity (n=144). Local recurrence or metastases were observed in 14 patients. Compared with T1-intermediate or -hyperintense lesions, T1-hypointense RCCs were more likely to be low stage (90.7% vs 74.3%; p=0.001) and low grade (78.9% vs 41.8%; p<0.001) and had a lower rate of recurrence or metastases (3.3% vs 8%; p=0.167). Compared with lesions with greater than 25% solid enhancement, predominantly cystic RCCs were more likely to be lower stage (93.9% vs 78.8%; p=0.053) and lower grade (94.7 vs 56.5%; p<0.001) and to have no incidence of recurrence or metastasis (0% vs 6.9%; p=0.227). RCCs that were both cystic and T1 hypointense (n=14) were lower stage (100% vs 79.6%; p=0.047) and lower grade (92.9% vs 58.1%; p=0.01) and had no recurrence or metastases on follow-up.

CONCLUSION

Cystic and T1-hypointense RCC show less-aggressive pathologic features and favorable clinical behavior.

Incidence of multiple sporadic renal cell carcinomas in patients referred for renal radiofrequency ablation: implications for imaging follow-up

OBJECTIVE

The objective of our study was to report the incidence of multiple sporadic primary renal cell carcinomas (RCCs) in patients referred for radiofrequency ablation (RFA).

MATERIALS AND METHODS

A retrospective search identified 162 patients (104 men and 58 women; mean age, 74 years) without a history of von Hippel-Lindau disease with a total of 175 tumors treated with RFA for biopsy-proven primary renal malignancies at our institution from 1998 to 2009. Three groups of patients with multiple RCCs were identified: patients with a history of nephrectomy for RCC who had been referred for RFA of a new renal tumor, patients who presented with multiple renal tumors at the time of referral for RFA, and patients who were shown to have developed a new renal tumor on follow-up imaging after RFA.

RESULTS

Twenty-eight patients (17%) had multiple biopsy-proven RCCs. Eighteen patients (11%) had undergone prior nephrectomy for surgically proven RCC. The mean interval between prior nephrectomy and RFA referral was 122 months (range, 12-456 months). Seven patients (4%) without a history of nephrectomy presented with two biopsy-proven RCCs at RFA referral. Three patients (2%) who had not undergone nephrectomy and had a solitary RCC at the time of RFA had developed a new biopsy-proven RCC separate from the original treatment site on follow-up imaging after RFA. The mean time to diagnosis from the initial RFA treatment was 52 months (range, 25-89 months).

CONCLUSION

Imaging surveillance of patients referred for renal RFA may be important not only to assess treatment success but also to detect new RCCs.

Application of contrast-enhanced ultrasonography after radiofrequency ablation for renal cell carcinoma: is it sufficient for assessment of therapeutic response?

PURPOSE

To assess the efficacy of contrast-enhanced ultrasonography (CEUS) with Sonovue in the evaluation of therapeutic response to radiofrequency ablation (RFA) of renal cell carcinoma (RCC).

MATERIALS AND METHODS

In a recent 3 years, 63 patients (mean age, 60 years; range 26-81 years) with 64 RCCs were treated by RFA. The lesions had a diameter between 1.8 and 9.8 cm (average diameter, 3.1 cm). The indications for RFA treatment included chronic renal insufficiency (n = 10), presence of solitary kidney (n =3), bilateral renal carcinoma (BRCC) (n =2), advanced age (n =12), significant medical comorbidity (n =29) or refusal of conventional therapy (n =7). Tumors were treated by laparoscopy-assisted (n =41), open surgical (n =18) or percutaneous US guidance (n =4). Follow-up CEUS and contrast-enhanced CT were performed 1 month after treatment to assess the necrotic area. Technical success was defined as elimination of areas that enhanced at imaging within the entire tumor.

RESULTS

On the 1-month CEUS and CT imaging after RFA, 62 of 64 tumors (96.9%) were successfully ablated with one session, and residual tumors were found in two RCCs. One of the two tumors was subjected to additional RFA treatment. We could not obtain a complete ablation in the other tumor of a patient with solitary kidney. The diagnostic concordance between the CEUS and 1-month follow-up CT was 100%. Sixty-one patients survived in the follow-up phase which ranged from 2 to 34 months. One patient with solitary kidney died of systemic disease progression and one patient was lost to follow-up. Of the 61 tumors without residual on both CT and CEUS after RFA, four had suspicious findings of recurrence on follow-up CEUS, and two of them were confirmed by subsequent CT examination. With CT as the reference imaging procedure in the assessment of renal tumor ablation, the sensitivity, specificity, positive predictive value, and negative predictive value of CEUS for detecting recurrence during follow-up were 100%, 96.6%, 50%, and 100%.

CONCLUSION

Despite its limitation of false-positive value, CEUS is potentially effective in assessing the therapeutic response to RFA of RCC.

The ongoing history of thermal therapy for cancer

Through 5,000 years of practice, physicians, surgeons, clergy, or lay people have used thermal therapy to treat mass lesions now known as cancer. The methods have changed dramatically over this time span and certainly the techniques have improved the efficacy and safety. Hyperthermia used in combination with chemotherapy or ionizing radiation continues to improve outcomes. The authors briefly describe the historical role of hyperthermia in cancer care as well as modern expectations based on technological advancements. In particular, the article focuses on the role of hyperthermia for cancers that do not have other, more effective treatments.