Monday, July 12, 2010

Cholangiocarcinoma treated with CyberKnife

Cholangiocarcinoma treated with CyberKnife

Introduction: Cholangiocarcinoma is a relatively rare disease, however has poor prognosis. Liver resection or transplantation is only curative treatment (1). Unfortunately, majority of the patients present with locally advanced, unresectable disease with extensive tumor spread (2). The treatment is not yet standardized. They are treated with either chemotherapy or radiotherapy or in combination (2-6). CyberKnife is recent advancement in radiation therapy delivery system which has high accuracy and flexibility in targeting the tumor through image-guided stereotactic body radiotherapy (SBRT) system (7).

Case history: Forty eight year old gentleman from Uttar Pradesh, India was diagnosed with inoperable cholangiocarcinoma eight months back. He was treated with chemotherapy for four months. However, post-chemotherapy imaging evaluation did not show any significant response. He was diagnosed as chemo-resistant inoperable cholangiocarcinoma. His liver function was maintained and general condition was good. As he was suffering from inoperable, chemotherapy resistant cholangiocarcinoma, he was referred for radiation therapy and was evaluated for robotic radiosurgery (CyberKnife) treatment. After appropriate evaluation, imaging (PET scan), fiducial placement and planning he was treated with CyberKnife. He received 30 Gy in 5 fractions in one week. Dose to the target was adequate and to adjacent normal structures were within normal limits. He completed treatment without any severe toxicity and is on regular follow up.

Discussion: In early operable choloangiocarcinoma, 3-year overall survival rate after curative surgery is only 40-60% (1-2). Advanced unresectable cholangiocarcinoma patients have poorer prognosis as well as severe complications due to biliary stasis (3,4). They are mainly treated with supportive or palliative care. Main aims of treatment in these patients are to preserve quality of life and improve survival rate. Palliative therapy options in these patients are chemotherapy, radiotherapy, photodynamic therapy and biliary drainage procedures (5). Median survival with palliative chemotherapy and external beam radiation therapy are 5 to 9 and 9 to 12 months respectively (2-6). Inoperable, advanced cholangiocarcinomas remain localized and distant metastasis is not common (1). Hence, these tumours may be treated with localized treatment options with maximum effect. However, cholangiocarcinomas are relatively resistant to both radiation and chemotherapy. Hence, high dose radiation therapy is required to have desired loco-regional control (7). CyberKnife radiosurgery is a SBRT using real time respiratory-motion tracking system, and is known to exert minimal normal tissue injury. High dose of radiation treatment in few fractions are possible with CyberKnife which increases tumour control probability without increasing toxicity (7). High dose radiation therapy with proton beam therapy also has shown promising loco-regional control without additional severe toxicity (2). We suggest that CyberKnife might be a safe and useful treatment option in advanced, unresectible cholangiocarcinoma.

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