Time to initiation or duration of S-1 adjuvant chemotherapy; which really impacts on survival in stage II and III gastric cancer?

Abstract

A duration of S-1 AC of ≥6 months, but not time to initiation within 6 weeks, impacts on OS in stage II-III gastric cancer.

Delay in initiation of postoperative adjuvant chemotherapy with S-1 monotherapy and prognosis for gastric cancer patients: analysis of a multi-institutional dataset

“…Thus, it is necessary to eradicate residual microscopic cancer cells during drug administration, which requires a corresponding number of courses, and the duration of administration is important. This logic also applies to postoperative adjuvant chemotherapy for gastric cancer, and the importance of the duration of administration was also demonstrated in the Fujitani et al study [7] and the OPAS-1 trial [8].…”

“…Patients who underwent extended surgery (pancreaticoduodenectomy) or limited surgery without systemic lymphadenectomy were excluded from the study. It is already shown that an administration period of more than 6 months is a significant prognostic factor [7,8], and an administration period of less than 6 months does not allow sufficient benefit from S-1. Thus, we excluded the patients who withdrew from S-1 monotherapy within 6 months for reasons other than recurrence in this study.…”

“…The duration of postoperative chemotherapy with S-1 monotherapy for gastric cancer patients has been recommended as 1 year, based on the ACTS-GC trial results [3]. Recently, a Japanese large-scale retrospective study reported that a duration of more than 6 months correlated with a good prognosis [7]. A prospective randomized controlled trial to confirm non-inferiority of relapse-free survival (RFS) for S-1 administered for 6 months-1 year in pathological stage II gastric cancer patients was conducted [8], but the trial failed.…”

“…Based on the rules of the ACTS-GC trial [3], it is recommended by the Japanese gastric cancer treatment guidelines to start within 6 weeks after surgery, but no persuasive evidence was quoted [2]. There were a few retrospective studies that suggest a correlation between the timing of initiation and prognosis, while some studies reported that delayed initiation was associated with an unfavorable prognosis [9,10], and other studies reported that the timing of initiation was not correlated with prognosis [7]. This correlation remains controversial.…”

Recent updates in perioperative chemotherapy and recurrence pattern of gastric cancer

“…This report also showed poor 3‐year survival rate in patients who were given S‐1 at less than 70% dose intensity. Fujitani et al retrospectively evaluated the duration and time to initiation of S‐1 among 498 patients with pStage II/III gastric cancer . They showed that patients treated for a longer duration (≥6 months) with S‐1 had significantly longer survival compared with those for a shorter duration (<6 months) (74.3% vs 53.0%, respectively, in 5‐year OS; HR: 0.498; 95% CI: 0.355–0.706), while time to initiation was not associated with OS.…”