Long-term follow-up of advanced gastric cancer patients who achieved a pathologic complete response with neoadjuvant chemotherapy.

133 Background: Adjuvant chemotherapy (AC) after D2 gastrectomy has become a standard treatment for stage 2/3 gastric cancer in Japan and Korea; however, the results remain unsatisfactory due to insufficient risk reduction in patients with stage 3 disease and low compliance. Although the administration of neoadjuvant chemotherapy (NAC) is a promising approach associated with a high rate of compliance and a downstage effect, the long-term survival benefits of this modality are unclear. Moreover, the impact of the pathological response on survival has not been evaluated. Based on the hypothesis that the pathological response grade is associated with survival, we conducted a search for reports of a pathological complete response (pCR) obtained with NAC. Methods: A total of 27 gastric cancer patients who achieved a pCR following NAC therapy were identified using PubMed and the Japanese medical search engine “Ichu-shi,” with the search words “gastric cancer,” “NAC,” and “pCR.” A questionnaire regarding the patients’ prognoses was posted in 23 institutions in Japan in July 2013. Results: Answers regarding 22 patients were obtained from 20 institutions. The subjects included 13 males and nine females. The mean age was 67.5 years. Tumors with stage 3/4 (95.4%: 21/22) and a diffuse-type histology (61.9%: 13/21) were dominant. S1/CDDP was the most frequently selected NAC regimen. A total of 77.2% (17/22) of the patients required combined resection of adjacent organs, and all patients underwent R0 resection and D2 lymphadenectomy. At present, 86.3% (19/22) of the patients are alive without recurrence; none of the ten patients who received postoperative AC demonstrated any recurrence, while three of twelve patients who did not receive postoperative AC developed recurrence, and two patients died of the disease after surgery (at 71 months and nine months, respectively). The overall and recurrence-free survival rates at three/five years were 95.5%/85.1% and 90.9%/75.1%, respectively. Conclusions: Patients with gastric cancer who achieve a pCR with NAC are rare; however, their prognoses are excellent. It is therefore important to develop a NAC regimen focusing on a high pCR rate.