Ultrasensitive detection of BRAF mutations in circulating tumor DNA of non-metastatic melanoma

Background

Implementation of adjuvant therapies in non-metastatic melanoma improved treatment outcomes in some patients; however, adjuvant therapy can be associated with significant cost and risk of toxicity. Therefore, there is an unmet need to better identify patients at high risk of recurrence.

Patients and methods

We carried out an ultrasensitive droplet digital PCR (ddPCR)-based detection of BRAF^V600E-mutated circulating tumor DNA (ctDNA) from blood samples prospectively collected before surgery, 1 hour after surgery, and then serially during follow-up.

Results

In 80 patients (stages ≤III), BRAF^V600E mutations were detected in 47.2% of tissue, in 37.7% of ctDNA samples collected before surgery, and in 25.9% of ctDNA samples collected 1 hour after surgery. Patients with detected ctDNA in blood collected 1 hour after surgery compared to patients without detected ctDNA had higher likelihood of melanoma recurrence (P < 0.001) and shorter median disease-free survival (P = 0.001) and overall survival (P = 0.003).

Conclusions

Ultrasensitive ddPCR can detect ctDNA in pre- and post-surgical blood samples from patients with resectable melanoma. Detection of ctDNA in post-surgical samples is associated with inferior treatment outcomes.

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Ultrasensitive ddPCR can detect ctDNA in pre- and post-surgical samples.

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Detection of ctDNA 1 hour after surgery is associated with inferior treatment outcomes.

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There were no associations between ctDNA detection at other timepoints and clinical outcomes.

P2-15-06: Breast Cancer Liver Metastases – Possibilities and Limits of Surgical Treatment

Background

Breast cancer liver metastases (BCLM) are often considered as a sign of a systemic disease with little hope of therapeutic success. The aim of study was to assess the possibilities and determine the limits of the surgical treatment of BCLM.

Method: 646 patients were operated for malignant and benign lesions of the liver between 1999 and 2010. Liver surgery for BCLM was performed in 21 women of the average age of 48.5 years (33-71). The average time from the primary surgery for breast cancer till BCLM diagnosis was 4.7 years (2 months - 9 years). BCLM were solitary in 17 and in four cases multiple. Patient selection for liver surgery was based on sufficient future remnant liver volume, the absence of systemic non-resectable tumor dissemination and response to chemotherapy. The authors performed six right-sided hepatectomy, four segmentectomies, three left lobectomies, one metastasectomy, six radiofrequency ablations (RFA), one combined procedure -liver resection and RFA. Histological examination revealed ductal carcinoma in fourteen and lobular carcinoma in seven cases. All patients were treated with the curative adjuvant chemotherapy after surgery. The data were statistically evaluated by statistical software Statistica 9.0.

Results: 30 - days mortality rate was 0%. One patient had a complicated hepatectomy with iatrogenic bile duct injury. According to statistical analysis the probability of patients survival twelve, resp. thirty months after surgery was 100, resp. 66.7% and the probability of the tumor relapse anywhere in the body was at the same time intervals 0, resp. 71. 5%.

Conclusion: Liver surgery combined with the adjuvant chemotherapy are a therapeutic methods of choice for highly selected patients with metastases limited to the liver and objective response to neoadjuvant chemotherapy.

The study was supported by the research projects IGA MZ NS 9727 and IGA MZ NS 102 40.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-15-06.