Interventional strategies in the treatment of gynecologic cancers

Biopsy of peritoneal carcinomatosis in suspected ovarian cancer

Surgical cytoreduction followed by chemotherapy is the mainstay of therapy for patients with ovarian cancer. Often patients will have debulking surgery prior to tissue diagnosis, ovarian cancer may be presumed based on elevated CA-125 and imaging findings. In patients with unresectable disease at the time of presentation or in those with medical comorbidities that preclude surgery, induction or neoadjuvant chemotherapy is typically administered first. Unfortunately, the diagnosis of ovarian cancer is not always clear and a tissue diagnosis is warranted prior to these treatments. Additionally, some medical therapies rely on pathologic or molecular analysis.

Advanced ovarian cancer can sometimes be indistinguishable from peritoneal and adnexal metastases from other primary tumors, and up to 20% of women undergoing surgical debulking for suspected ovarian cancer are found to have metastatic disease from a nongynecologic source. ^, Moreover, in women with a history of a primary cancer known to demonstrate peritoneal spread, such as breast or gastrointestinal tract malignancies, new ovarian or peritoneal lesions do not always represent spread of disease. At least two series have demonstrated a diagnosis of a different primary Müllerian cancer (ovarian or primary peritoneal) on resection. ^, There also can be considerable overlap with the imaging appearance of benign complex ovarian masses. In these situations, a site-specific diagnosis is imperative to avoid unnecessary surgery or inappropriate chemotherapy.

Image-guided biopsy (IGB) of omental, peritoneal and pelvic masses is a safe and effective alternative to surgical biopsy via exploratory laparotomy or laparoscopy. ^, In the largest published study to date of IGB in 149 women with peritoneal carcinomatosis, a site-specific diagnosis was made in 93% of patients. Smaller series in women with peritoneal carcinomatosis and suspected ovarian cancer also had favorable results, with reported accuracy rates of 92% and 87%.

Both ultrasound and CT-guided techniques have been described, modality selection depends largely on the patient and his or her disease burden as well as operator comfort. ^, For patients with bulky disease likely to be visualized sonographically, ultrasound may be the appropriate choice as it is typically faster, allows for real-time visualization of vasculature, and spares the patient and physician from ionizing radiation. However, isolating peritoneal or omental masses from the adjacent bowel under ultrasound guidance can be challenging for a less experienced operator. CT may be a better choice in these cases or with smaller, more inaccessible lesions. Often CT and ultrasound are used in conjunction, as the portability of ultrasound allows operators to image the target lesions using both modalities in the same room and choose the most appropriate modality at the time of the procedure ( Figures 18-1 and 18-2 ).

All patients should undergo a diagnostic CT of the abdomen and pelvis with intravenous and oral contrast shortly prior to the procedure to identify disease burden and distinguish peritoneal disease from adjacent bowel or liver. Ultrasound-guided biopsies require no patient preparation, though one may request a full bladder for a better acoustic window. Multiple authors have described CT-guided techniques that employ oral contrast prior to the procedure to opacify and help identify bowel from adjacent disease. ^{, ,} With both techniques, the procedure can be combined with a diagnostic or therapeutic drainage of ascites. Although trace fluid may improve sonographic visualization, removal of large-volume ascitic fluid prior to biopsy can help minimize the risk of hemorrhage.

The safety of larger-gauge (18 gauge and below) core biopsy needles for use in peritoneal or omental disease is well documented, these are preferred to the finer gauge (20-gauge and higher) self-aspirating needles because the increased specimen size allows for assessment of the tissue architecture and further analysis with immunohistochemistry if necessary. ^, Coaxial systems, commonly available as a 17/18-gauge or 19/20-gauge introducer/biopsy needle combinations, are preferred as they allow the operator to take several specimens through a single needle track. This is also advantageous for small, difficult-to-reach lesions as the introducer needle can help anchor the target lesion, facilitating multiple passes.

Both CT- and ultrasound-guided biopsies are quick, taking roughly 15–20 minutes and can safely be performed in an outpatient setting. Other than local pain and bruising at the puncture site, there have been few reported complications, the most serious being a rectus sheath hematoma that was managed conservatively and focal abdominal wall cellulitis. Though there is a theoretical risk of tracking tumor into the abdominal wall, as this has been reported in a laparoscopy scar, there have been no reported cases following IGB or during percutaneous interventional treatments. IGB is fast, safe, accurate and an important tool in the diagnosis and management of women with suspected ovarian cancer.