S-1-Induced, Prolonged Complete Regression of Lung Metastasis from Gastric Cancer Refractory to 5'-DFUR: a Case Report with Pharmacokinetic Study

Ten cases of resected solitary pulmonary metastases arising from gastric cancer

BACKGROUND

Because carcinomatous lymphangitis and carcinomatous pleuritis are the usual forms of metastasis associated with gastric cancer, resection of solitary pulmonary metastases arising from gastric cancer is rarely performed. To clarify the characteristics of pulmonary metastases from gastric cancer, we investigated patients who underwent resection of metastatic solitary lung tumors arising from gastric cancer.

METHODS

Between October 2003 and October 2012, 10 patients underwent pulmonary metastasectomy for metastatic gastric cancer at our institution. We retrospectively evaluated features of the primary gastric cancer and the clinicopathological features of the pulmonary metastases in these cases.

RESULTS

70% of the patients had stage II disease. Lymphatic invasion was observed in all cases of primary gastric cancer. The method of pulmonary resection was partial resection in 5 cases, segmentectomy in 1, and lobectomy in 4. On histopathological examination, immunohistochemical staining was negative for thyroid transcription factor-1 and napsin A in all cases. Patients who underwent resection of pulmonary metastases arising from gastric cancer had a good prognosis: the 4-year survival rate was 75%.

CONCLUSIONS

Carefully chosen patients have a good opportunity to obtain benefits from resection of pulmonary metastases arising from gastric cancer.

Phase I/II study of a 3-week cycle of irinotecan and S-1 in patients with advanced colorectal cancer

The combination of an oral fluoropyrimidine derivative, S-1, and irinotecan is expected to be a promising regimen for advanced colorectal cancer. This study was performed to determine the maximum tolerated dose (MTD) and recommended dose (RD) of irinotecan combined with S-1 in a 3-week cycle regimen and to observe the safety and efficacy for patients with previously untreated advanced colorectal cancer. Eighty milligrams per m(2) of S-1 was given orally for 14 consecutive days and escalated doses of irinotecan were administered on days 1 and 8 every 3 weeks in the phase I trial. Forty patients were treated at the RD during the phase II trial. Forty-three patients were enrolled between February 2005 and March 2007. The dose-limiting toxicity was diarrhea and abdominal pain. The MTD of irinotecan was 100 mg/m(2) and the RD was determined to be 80 mg/m(2) of irinotecan combined with 80 mg/m(2) of S-1. The phase II trial showed that 22 of 40 patients achieved a complete or partial response and eight had stable disease. The overall response rate was 55.0%. The median progression-free survival time and median survival time were 6.7 and 21 months, respectively. There were no treatment-related deaths. The main toxicities were leukopenia, neutropenia, anorexia and diarrhea. This study suggests the combination of irinotecan and S-1 repeated every 3 weeks is tolerable and effective for patients with previously untreated advanced colorectal cancer.

Advanced gastric cancer showing long-term complete remission in response to S-1 monotherapy: two case reports

We herein report two cases showing long-term complete remission (CR) in response to S-1 monotherapy. Case 1 was a 65-year-old male diagnosed with an advanced poorly differentiated adenocarcinoma of the stomach with paraaortic lymph node metastases, which disappeared after S-1 monotherapy. Subsequently a total gastrectomy was performed, and histological CR was evident. His progress is presently uneventful without recurrence 50 months after surgery. Case 2 was a 59-year-old female who underwent a total gastrectomy with a jejunal pouch. The resected tumor was a medullary type poorly differentiated adenocarcinoma infiltrating the serosa and involving the regional lymph nodes. One year after surgery, endoscopy revealed a recurrent tumor in the jejunal pouch. After the administration of S-1, this recurrent tumor completely disappeared, and she has since maintained CR for 39 months. These cases suggest that a subgroup of patients with advanced gastric cancer may attain CR with S-1 monotherapy.

Potassium oxonate, an enzyme inhibitor compounded in S-1, reduces the suppression of antitumor immunity induced by 5-fluorouracil

S-1 is an oral formulation combining tegafur (FT), 5-chloro-2,4-dihydroxypyridine (CDHP), and potassium oxonate (Oxo) in a molar ratio of 1:0.4:1. We examined whether Oxo reduces the immunosuppression induced by 5-fluorouracil (5-FU) in the rat. The body weight of rats treated with S-1 (FT + CDHP + Oxo) for seven consecutive days was significantly higher than that of rats treated with a combination of FT plus CDHP (FT + CDHP) for a similar period. The number of peripheral leukocytes was significantly higher in the S-1-treated rats (S-1 group) than that in the FT + CDHP-treated rats (FT + CDHP group). There was no apparent difference between the two treated groups in phenotypic changes of CD3-, CD45-, CD4-, or CD8-positive cells from the spleen or mesenteric lymph nodes. However, the natural killer activities of both spleen cells and mesenteric lymph node cells were significantly higher in the S-1 group than in the FT + CDHP group. Interleukin (IL)-2 production by spleen cells stimulated with concanavalin A was significantly lower in the FT + CDHP group than in the S-1 group. Although IL-2 production by mesenteric lymph node cells in the S-1 group was lower than that in untreated rats, it was higher than that in the FT + CDHP group. These findings suggest that Oxo in S-1 may reduce the suppression of antitumor immunity induced by 5-FU.