Facilitated completion of 1-year adjuvant S-1 monotherapy for pathological stage II or III gastric cancer by medical oncologists

Preoperative low skeletal muscle volume can result in insufficient administration of S-1 adjuvant chemotherapy in older patients with stage II/III gastric cancer

BACKGROUND AND PURPOSE

Older patients are more likely to encounter difficulties receiving chemotherapy, but the factors involved in the continuation of chemotherapy in these patients remain unclear. We investigated the importance of muscle mass as a factor involved in delivering a sufficient dose of postoperative S-1 adjuvant chemotherapy (ACT) to older patients with gastric cancer.

METHODS

The subjects of this study were 79 patients aged ≥ 65 years with stage II/III gastric adenocarcinoma, who underwent curative gastrectomy and received S-1 ACT.

RESULTS

The overall median relative dose intensity (RDI) was 75.0% (18.8-93.5%). Patients were divided into two groups for receiver operating characteristic analysis according to the cutoff value. Significantly more patients in the high skeletal muscle index (SMI) group achieved > 62% RDI of S-1 ACT (p = 0.03). Conversely, more patients in the low SMI group suffered from S-1-induced nausea (p = 0.03) and discontinued chemotherapy because of adverse events (p = 0.02). Multivariate analysis identified low SMI as an independent factor for insufficient S-1 dose delivery (p = 0.03, hazard ratio = 2.87).

CONCLUSION

Preoperative SMI is an indicator of the low-dose intensity of S-1 ACT in older patients following curative gastrectomy.

Completion of adjuvant S-1 chemotherapy after surgical resection for biliary tract cancer: A single center experience

BACKGROUNDS

A recent randomized control trial (JCOG1202; ASCOT trial) demonstrated the efficacy of adjuvant S-1 chemotherapy (ASC) for biliary tract cancer (BTC) after surgical resection; however, the significance of the completion of ASC in the real-world setting remains unknown.

METHODS

Data of consecutive patients who underwent surgical resection for biliary tract cancer (BTC) from 2011 to 2021 were retrospectively reviewed. Of these, patients who underwent ASC were enrolled in this study. Patients were divided into two groups according to whether ASC was completed: the completion group and the non-completion group. Clinicopathological features and survival outcomes were assessed.

RESULTS

Of the 223 patients with BTC who underwent surgical resection, 75 patients who underwent ASC were included for analysis. Among them, 48 (64.0 %) completed the intended ASC course, while 27 cases (36.0 %) discontinued the treatment. The most common reason for the discontinuation was adverse event (n = 16, 59.3 %), followed by disease recurrence (n = 9, 33.3 %). Patients in the completion group showed significantly better overall survival (OS) (p < 0.001) and recurrence-free survival (RFS) (p < 0.001) compared to the non-completion group. Further, after excluding the patients in the non-completion group who discontinued ASC due to disease recurrence, the significance of ASC completion was retained for both OS and RFS.

CONCLUSION

The completion of ASC was associated with improved prognosis in patients with BTC after surgical resection. The achievement of ASC should be the goal after surgical resection, while further study may be warranted regarding the resistance of ASC.

Real-World Therapeutic Outcomes of S-1 Adjuvant Chemotherapy for pStage II/III Gastric Cancer in the Elderly

BACKGROUND

The predictive factors for discontinuation of S-1 administration and prognostic factors in elderly patients with pStage II/III gastric cancer receiving S-1 adjuvant chemotherapy remain unclear.

METHODS

Between January 2004 and December 2016, 80 elderly gastric cancer patients (≥70 years) undergoing curative D2 gastrectomy were enrolled in this study. Predictive factors for completion of S-1 administration over 1 year, adverse events due to S-1 administration, and prognostic factors for overall survival (OS) and relapse-free survival (RFS) were evaluated.

RESULTS

Twenty-eight patients (35%) completed 8 courses of S-1. The median relative dose intensity was 82.1% (IQR 31.1-100%). The incidence rates of hematological and nonhematological adverse events were acceptable. Distal gastrectomy was an independent predictive factor for completion of S-1 administration (odds ratio [OR] 0.364; 95% confidence interval [CI] 0.141-0.939; p = 0.037). Higher postoperative neutrophil count/lymphocyte count (N/L) ratio and more advanced stage adversely influenced OS. Multivariate analysis revealed that a higher postoperative N/L ratio and more advanced stage adversely affected RFS.

CONCLUSION

To complete adjuvant S-1 administration to elderly patients with pStage II/III gastric cancer, total gastrectomy should be avoided if possible. A new regimen for elderly gastric cancer patients with higher postoperative N/L ratios and more advanced stage should be established.

The efficacy and toxicity of adjuvant S-1 schedule with 2-week administration followed by 1-week rest in gastric cancer patients

Background

This study aimed to investigate the clinical outcome of adjuvant S-1 with 2-week administration followed by a 1-week rest for locally advanced gastric cancer (GC) patients.

Methods

The current study was a single retrospective cohort study that focused on the efficacy and toxicity of adjuvant S-1 with a 3-week schedule. A total of 60 patients who underwent total or subtotal gastrectomy plus D2 lymph node dissection and adjuvant S-1 treatment were identified. S-1 treatment began within 4 weeks after the operation; it was administered orally for 2 weeks, followed by a 1-week rest. The dose of S-1 was adjusted depending on adverse events (AEs), with at least 80 mg administered daily. The completion of 1-year S-1 was defined as S-1 continuation for 1 year with over 70% of the planned dose. Patients were followed up with for 5 years postoperatively and underwent hematologic tests and assessments of clinical symptoms every 3-6 weeks for 1 year after surgery. Computed tomography of the abdomen and panendoscopy were performed every 6 months during the first 2 years and at 1-year intervals thereafter until year 5 after surgery.

Results

The completion rate of 1-year adjuvant S-1 was 71.7%, and the 3-year disease-free survival and overall survival rates were 70.2% and 79.5%, respectively. Seventeen patients did not complete S-1 for 1 year, including 11 patients with tumor recurrence and 6 patients who developed intolerance. Most AEs of S-1 were grade 1-2, and the most frequent AEs (>20%) included anemia, fatigue, pigmentation, nausea, and diarrhea. The most common grade 3-4 AE was fatigue, which was observed in 6.7% of patients. Most patients tolerated the side effects.

Conclusions

The results of our study confirm that the efficacy and safety of schedule modification of adjuvant S-1 treatment in patients with GC who underwent gastrectomy with D2 lymph node dissection are equal to those in a previous phase 3 study.

A prospective feasibility study of one-year administration of adjuvant S-1 therapy for resected biliary tract cancer in a multi-institutional trial (Tokyo Study Group for Biliary Cancer: TOSBIC01)

Background

Although surgery is the definitive curative treatment for biliary tract cancer (BTC), outcomes after surgery alone have not been satisfactory. Adjuvant therapy with S-1 may improve survival in patients with BTC. This study examined the safety and efficacy of 1 year adjuvant S-1 therapy for BTC in a multi-institutional trial.

Methods

The inclusion criteria were as follows: histologically proven BTC, Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1, R0 or R1 surgery performed, cancer classified as Stage IB to III. Within 10 weeks post-surgery, a 42-day cycle of treatment with S-1 (80 mg/m²/day orally twice daily on days 1–28 of each cycle) was initiated and continued up to 1 year post surgery. The primary endpoint was adjuvant therapy completion rate. The secondary endpoints were toxicities, disease-free survival (DFS), and overall survival (OS).

Results

Forty-six patients met the inclusion criteria of whom 19 had extrahepatic cholangiocarcinoma, 10 had gallbladder carcinoma, 9 had ampullary carcinoma, and 8 had intrahepatic cholangiocarcinoma. Overall, 25 patients completed adjuvant chemotherapy, with a 54.3% completion rate while the completion rate without recurrence during the 1 year administration was 62.5%. Seven patients (15%) experienced adverse events (grade 3/4). The median number of courses administered was 7.5. Thirteen patients needed dose reduction or temporary therapy withdrawal. OS and DFS rates at 1/2 years were 91.2/80.0% and 84.3/77.2%, respectively. Among patients who were administered more than 3 courses of S-1, only one patient discontinued because of adverse events.

Conclusions

One-year administration of adjuvant S-1 therapy for resected BTC was feasible and may be a promising treatment for those with resected BTC. Now, a randomized trial to determine the optimal duration of S-1 is ongoing.

Trial registration

UMIN-CTR, UMIN000009029. Registered 5 October 2012-Retrospectively registered, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000009347