Quantitative evaluation of the intratumoral distribution of platinum in oxaliplatin-treated rectal cancer: In situ visualization of platinum via synchrotron radiation X-ray fluorescence spectrometry.

Oxaliplatin (l-OHP), a platinum-based drug, is a key chemotherapeutic agent for colorectal cancer (CRC), but drug resistance and toxic effects have been major limitations of its use. Synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) is a rapid, nondestructive technique for monitoring the distribution of metals and trace elements in cells or tissue samples. We applied SR-XRF to visualize the distribution of platinum and other elements in 30 rectal cancer specimens resected from patients who received l-OHP-based preoperative chemotherapy and quantified platinum concentration in the tumor epithelium and stroma, respectively, using calibration curves. The platinum concentration in rectal cancer tissue ranged 2.85-11.44 ppm, and the detection limit of platinum was 1.848 ppm. In the tumor epithelium, the platinum concentration was significantly higher in areas of degeneration caused by chemotherapy than in nondegenerated area (p < 0.001). Conversely, in the tumor stroma, the platinum concentration was significantly higher in patients with limited therapeutic responses than in those with strong therapeutic responses (p < 0.001). Furthermore, multivariate analysis illustrated that higher platinum concentration in the tumor stroma was an independent predictive factor of limited histologic response (odds ratio; 19.99, 95% confidence interval; 2.04-196.37, p = 0.013). This is the first study to visualize and quantify the distribution of platinum in human cancer tissues using SR-XRF. These results suggest that SR-XRF analysis may contribute to predicting the therapeutic effect of l-OHP-based chemotherapy by quantifying the distribution of platinum.

Vascular anatomy of the transverse mesocolon and bidirectional laparoscopic D3 lymph node dissection for patients with advanced transverse colon cancer.

Laparoscopic D3 lymph node dissection for transverse colon cancer is technically demanding because of complicated anatomy. Here, we reviewed the vascular structure of the transverse mesocolon, explored the extent of the base of the transverse mesocolon, and evaluated the feasibility and oncological safety of D3 lymph node dissection. We retrospectively reviewed the clinical records of 42 patients with advanced transverse colon cancer who underwent curative surgery and D3 dissection at Kyushu University Hospital between January 2008 and December 2015. We examined the venous and arterial anatomy of the transverse mesocolon of each resection and compared surgical outcomes between patients who underwent laparoscopic D3 (Lap D3) and open D3 (Open D3) dissection. Patients included two with Stage I, 18 with Stage II, 20 with Stage III, and two with Stage IVA. Thirty-six (85.7%) and six (14.3%) patients underwent Lap D3 or Open D3, respectively. The tumor sizes of the Open D3 and Lap D3 groups were 7.8 and 3.7 cm, respectively (P < 0.001). The Lap D3 group had significantly less blood loss (26 mL vs 272 mL, P = 0.002). The other outcomes of the two groups were not significantly different, including 3-year overall survival (87.7% vs 83.3%, P = 0.385). We observed four patterns of the middle colic artery (MCA) arising from the superior mesenteric artery (SMA), and the frequency of occurrence of a single MCA was 64.3%. The right-middle colic vein (MCV) was present in 92.9% of resections and served as a tributary of the gastrocolic trunk, and 90.5% of the left MCVs drained into the superior mesenteric vein (SMV). The root of the transverse mesocolon was broadly attached to the head of the pancreas and to the surfaces of the SMV and SMA. Laparoscopic D3 lymph node dissection may be tolerated by patients with advanced transverse colon cancer.

Laparoscopic excision of neurogenic retrorectal tumors.

Retrorectal tumors (RT) are uncommon and usually managed by open surgical excision. Laparoscopic excision for RT has been reported in only a small number of papers. We aimed to assess the laparoscopic approach for RT and to discuss the factors that made this procedure difficult. We performed laparoscopic excision using a five-trocar technique for neurogenic RT in three patients. Tumors were successfully excised laparoscopically in two patients. However, the third patient required open conversion because the tumor was strongly adhered to the sacrum and could not be mobilized by dissection, resulting in poor visualization of the dissected site. Laparoscopic excision for RT provides excellent intraoperative visualization and good cosmesis in selected patients, but firm adherence to the sacrum may cause difficulty with this procedure.