Wim Koops

BACKGROUND AND OBJECTIVES: In patients with colorectal cancer, it is important to diagnose peritoneal carcinomatosis as well as to detect location and size of peritoneal tumor dissemination in view of treatment planning. The aim of this study was to investigate the detection accuracy of computed tomography (CT). METHODS: Preoperative CT-scans from 25 consecutive patients with peritoneal carcinomatosis from colorectal or appendiceal origin were independently blindly reviewed by 2 radiologists. The presence and diameter of tumor deposits were noted in seven abdominopelvic areas. Intraoperative findings were regarded as the gold standard. Agreement was assessed using the Kappa index and the chi-square test. RESULTS: The presence of peritoneal carcinomatosis was detected in 60 and 76% of those patients by each of the radiologist. Detection of individual peritoneal implants was poor (kappa = 0.11/0.23) and varied from 9.1%/24.3% for tumor size <1 cm to 59.3%/66.7% for tumor size >5 cm. Overall sensitivity, specificity, accuracy, positive (PPV) and negative predictive value (NPV) for tumor involvement per area were 24.5%/37.3%, 94.5%/90.4%, 53.0%/60.0%, 86.2%/84.4%, and 47.3%/50.8%, respectively. Accuracy of tumor detection varied widely per anatomic site. Statistically significant interobserver differences were noted, specifically for tumor size of 1-5 cm (P = 0.007) and localization on mesentery and small bowel (kappa = 0.30, P = 0.04). CONCLUSIONS: In colorectal cancer, CT detection of peritoneal carcinomatosis is moderate and of individual peritoneal tumor deposits poor. Interobserver differences are statistically significant. Therefore, preoperative CT seems not to be a reliable tool for detection of presence, size, and location of peritoneal tumor implants in view of treatment planning in patients with colorectal cancer.

BACKGROUND: The incidence of pelvic and aortic lymph node involvement in endometrial carcinoma depends on both tumor differentiation grade and myometrial invasion depth. It was evaluated whether magnetic resonance imaging (MRI) provides a preoperative technique to assess the depth of myometrial invasion. METHODS: The study includes 34 patients with an endometrial carcinoma. MRI (T5 Gyroscan, Philips) was made a few days before operation. Myometrial invasion was divided in four categories. Cervical invasion was classified as absent, superficial or deep. For comparison an in vitro MRI of the uterus was made directly after the operation. Histo-pathological examination of the uterus was used as a golden standard of the depth of myometrial invasion. RESULTS: The estimation by MRI of the myometrial invasion depth was correct in 25 out of 31 patients. In three patients estimation was not possible, because of bad image quality. In four patients the MRI underestimated the cervical invasion. CONCLUSIONS: Preoperative MRI in patients with an endometrial carcinoma can be used to estimate myometrial and cervical invasion. Therefore, in combination with the histological grading of the tumor, a preoperative MRI can be used to select patients at high risk of nodal involvement.

Accurate tumor excision is crucial in the locoregional treatment of cancer, and for this purpose, surgeons often rely on guide wires or radioactive markers for guidance toward the lesion. Further improvement may be obtained by adding optical guidance to currently used methods, in the form of intra-operative fluorescence imaging. To achieve such a multimodal approach, we have generated markers that can be used in a pre-, intra-, and post-operative setting, based on a cocktail of a dual-emissive inorganic dye, lipids, and pertechnetate. Phantom experiments demonstrate that these seeds can be placed accurately around a surrogate tumor using ultrasound. Three-dimensional bracketing provides delineation of the entire lesion. Combined with the multimodal nature, this provides the opportunity to predetermine the resection margins by validating the placement accuracy using multiple imaging modalities (namely, x ray, MRI, SPECT/CT, and ultrasound). The dual-emissive fluorescent properties of the dye provide the unique opportunity to intra-operatively estimate the depth of the seed in the tissue via multispectral imaging: emission green λmax=520 nm≤5 mm penetration versus emission red λmax=660 nm≤12 mm penetration. By using particles with different colors, the original geographic orientation of the excised tissue can be determined.