Adjuvant chemotherapy is superior to chemoradiation after D2 surgery for gastric cancer in the per-protocol analysis of the randomized CRITICS trial

BACKGROUND

The Intergroup 0116 and the MAGIC trials changed clinical practice for resectable gastric cancer in the Western world. In these trials, overall survival improved with post-operative chemoradiotherapy (CRT) and perioperative chemotherapy (CT). Intention-to-treat analysis in the CRITICS trial of post-operative CT or post-operative CRT did not show a survival difference. The current study reports on the per-protocol (PP) analysis of the CRITICS trial.

PATIENTS AND METHODS

The CRITICS trial was a randomized, controlled trial in which 788 patients with stage Ib-Iva resectable gastric or esophagogastric adenocarcinoma were included. Before start of preoperative CT, patients from the Netherlands, Sweden and Denmark were randomly assigned to receive post-operative CT or CRT. For the current analysis, only patients who started their allocated post-operative treatment were included. Since it is uncertain that the two treatment arms are balanced in such PP analysis, adjusted proportional hazards regression analysis and inverse probability weighted analysis were used to minimize the risk of selection bias and to estimate and compare overall and event-free survival.

RESULTS

Of the 788 patients, 478 started post-operative treatment according to protocol, 233 (59%) patients in the CT group and 245 (62%) patients in the CRT group. Patient and tumor characteristics between the groups before start of the post-operative treatment were not different. After a median follow-up of 6.7 years since the start of post-operative treatment, the 5-year overall survival was 57.9% (95% confidence interval: 51.4% to 64.3%) in the CT group versus 45.5% (95% confidence interval: 39.2% to 51.8%) in the CRT group (adjusted hazard ratio CRT versus CT: 1.62 (1.24-2.12), P = 0.0004). Inverse probability weighted analysis resulted in similar hazard ratios.

CONCLUSION

After adjustment for all known confounding factors, the PP analysis of patients who started the allocated post-operative treatment in the CRITICS trial showed that the CT group had a significantly better 5-year overall survival than the CRT group (NCT00407186).

Association between hospital volume and quality of gastric cancer surgery in the CRITICS trial

BACKGROUND

Studies investigating the association between hospital volume and quality of gastric cancer surgery are lacking. In the present study, the effect of hospital volume on quality of gastric cancer surgery was evaluated by analysing data from the CRITICS (ChemoRadiotherapy after Induction chemotherapy In Cancer of the Stomach) trial.

METHODS

Patients who underwent gastrectomy with curative intent in the Netherlands were selected from the CRITICS trial database. Annual hospital volume of participating centres was derived from the Netherlands Cancer Registry. Hospital volume was categorized into very low (1-10 gastrectomies per year per institution), low (11-20), medium (21-30) and high (31 or more), and linked to the CRITICS database. Quality of surgery was analysed by surgicopathological compliance (removal of at least 15 lymph nodes), surgical compliance (removal of indicated lymph node stations) and the Maruyama Index. Postoperative morbidity and mortality were also compared between hospital categories.

RESULTS

Between 2007 and 2015, 788 patients were included in the CRITICS study, of whom 494 were analysed. Surgicopathological compliance was higher (86·7 versus 50·4 per cent; P < 0·001), surgical compliance was greater (52·9 versus 19·8 per cent; P < 0·001) and median Maruyama Index was lower (0 versus 6; P = 0·006) in high-volume hospitals compared with very low-volume hospitals. There was no statistically significant difference in postoperative complications or mortality between the hospital volume categories.

CONCLUSION

Surgery performed in high-volume hospitals was associated with better surgical quality than surgery carried out in lower-volume hospitals.

Impact of upfront randomization for postoperative treatment on quality of surgery in the CRITICS gastric cancer trial

BACKGROUND

Preoperative randomization for postoperative treatment might affect quality of surgery. In the CRITICS trial (ChemoRadiotherapy after Induction chemotherapy In Cancer of the Stomach), patients were randomized before treatment to receive chemotherapy prior to a D1 + gastrectomy (removal of lymph node station (LNS) 1-9 + 11), followed by either chemotherapy (CT) or chemoradiotherapy (CRT). In this analysis, the influence of upfront randomization on the quality of surgery was evaluated.

METHODS

Quality of surgery was analyzed in both study arms using surgicopathological compliance (removal of ≥ 15 lymph nodes), surgical compliance (removal of the indicated LNS), and surgical contamination (removal of LNS that should be left in situ). Furthermore, the 'Maruyama Index of Unresected disease' (MI) was evaluated in both study arms, and validated with overall survival.

RESULTS

Between 2007 and 2015, 788 patients with gastric cancer were included in the CRITICS study of which 636 patients were operated with curative intent. No difference was observed between the CT and CRT group regarding surgicopathological compliance (74.8% vs 70.9%, P = 0.324), surgical compliance (43.2% vs 39.2%, P = 0.381), and surgical contamination (59.4% vs 59.9%, P = 0.567). Median MI was 1 in both groups (range CT 0-88 and CRT 0-136, P = 0.700). A MI below 5 was associated with better overall survival (CT: P = 0.009 and CRT: P = 0.013).

CONCLUSION

Surgical quality parameters were similar in both study arms in the CRITICS gastric cancer trial, indicating that upfront randomization for postoperative treatment had no impact on the quality of surgery. A Maruyama Index below five was associated with better overall survival.

Adjuvant Chemoradiotherapy for Non-Pretreated Gastric Cancer

BACKGROUND

While the curative approach to gastric cancer includes perioperative regimens in several countries, a substantial proportion of patients may not receive treatment prior to surgery. This study examines the adjuvant provision of chemoradiotherapy (CRT) for non-pretreated patients with cancer of the stomach including the gastric cardia.

METHODS

All surgically treated patients with primary adenocarcinoma of the stomach and gastric cardia diagnosed between January 2004-December 2013 were selected from the Netherlands Cancer Registry. Patients who did not receive neoadjuvant treatment were included. Early gastric cancers (cT1), postoperative deaths within 90 days, patients with metastatic disease (M1), patients who received adjuvant chemotherapy and patients with macroscopic tumor after surgery (R2) were excluded.

RESULTS

Some 3277 patients underwent surgery, and 99 patients (3%) received adjuvant CRT. Treatment was more often administered in patients with a younger age (<65 years) and a high socioeconomic status (SES), in case of non-cardia cancer, positive lymph nodes, and positive resection margins (R1). Median survival time was 28 months (95% CI 17-39), compared to 35 months (95% CI 33-38) in CRT-naïve patients. After adjustment for confounders, a small net benefit for adjuvant CRT was found (hazard ratio, HR: 0.75, 95% CI 0.58-0.96). In subgroup analyses, benefit was most pronounced for patients with seven or more lymph metastases.

CONCLUSIONS

Marginal survival benefit was observed for adjuvant CRT in gastric cancer patients who did not receive neoadjuvant treatment. Treatment could be considered for patients with disease involving nodal invasion and those left with microscopic residual disease after surgery.

The Essentials of Locoregional Control in the Treatment of Gastric Cancer

Gastric cancer is the fourth most frequent cancer in the world. For curative treatment and local control of gastric cancer, surgery is essential. The extent of the lymph node dissection is still under debate. Only one available trial showed significantly increased overall survival, whereas in all other randomised trials no significant difference could be found.

As surgery alone often is not sufficient in the curative treatment in gastric cancer, different (neo)adjuvant treatment strategies have extensively been studied. The recently published MAGIC trial showed downstaging, downsizing and an improved overall survival for patients treated with perioperative chemotherapy, compared to surgery alone (difference 13%, p = 0.009). The INT 0116 trial on the other hand, demonstrated the benefit of postoperative chemoradiotherapy compared to surgery alone for patients with a curative resection of gastric cancer. However, the quality of resections in this trial was poor, illustrating the importance of standardisation by quality control. This could be done by the Maruyama index, which quantifies the likelihood of unresected disease.

In the Netherlands, the CRITICS trial has recently been launched, which will be a quality controlled trial comparing postoperative chemoradiotherapy and chemotherapy on survival and/or locoregional control in patients who receive neoadjuvant chemotherapy followed by a D1+ gastric resection.

Surgical treatment results of intestinal and diffuse type gastric cancer. Implications for a differentiated therapeutic approach?

AIM

To study the outcome of patients who were surgically treated for primary gastric cancer with specific attention to differences in treatment results for intestinal and diffuse type tumours.

METHODS

All patients who underwent a potentially curative gastric resection between 1995 and 2011 in our institute were included. Patient, tumour and treatment characteristics were obtained retrospectively. Binary logistic and Cox regression models were used for multivariate analysis.

RESULTS

A consecutive series of 132 patients was included. Median follow-up was 53 months. There were no significant differences between patients with intestinal (N = 62) versus diffuse type (N = 70) gastric cancer with regard to the proportion of patients who underwent (neo)adjuvant treatment. Postoperative mortality was 2%. Pathological T- and N-stage were significantly more advanced for patients with diffuse type tumours. There was a significant difference in the percentage of microscopically irradical resections (2% versus 24%, p < 0.001) and median overall survival (129 versus 17 months, p < 0.001) between patients with intestinal type tumours and those with diffuse type tumours. On multivariate analysis, diffuse type histology was the only factor significantly associated with an R1 resection. In a multivariate Cox regression model, diffuse type histology was a significant adverse prognostic factor for overall survival.

CONCLUSIONS

Striking differences were found between patients with diffuse type tumours and those with intestinal type tumours. These differences call for a differentiated approach in the potentially curative treatment of these two tumour types.

Postoperative chemoradiotherapy in gastric cancer--a phase I-II study of radiotherapy with dose escalation of weekly cisplatin and daily capecitabine chemotherapy

BACKGROUND

Postoperative chemoradiotherapy with concurrent 5-fluorouracil improves gastric cancer outcome. We previously demonstrated that chemoradiotherapy with a more intensified--and therefore potentially more effective--schedule with daily cisplatin and oral capecitabine is feasible. Because such an intensive schedule requires an extensive logistic infrastructure which is not available in every hospital, we additionally investigated the tolerability of this combined regimen with weekly instead of daily cisplatin in a dose-escalation study.

PATIENTS AND METHODS

After R0 or R1 resection, treatment initiated with capecitabine 1000 mg/m(2) b.i.d. for 2 weeks and 1-week rest. Subsequently, patients received capecitabine (575-650 mg/m(2) orally b.i.d., 5 days/week) and cisplatin (20-25 mg/m(2) i.v., once weekly) according to a predefined dose-escalation schedule concurrent with radiation. Radiotherapy was given to a fixed total dose of 45 Gy in 25 fractions.

RESULTS

Thirty-one patients were eligible and started treatment. During chemoradiotherapy, seven patients developed 10 items of grade III and one episode of grade IV (mainly hematological) toxicity (National Cancer Institute-Common Toxicity Criteria version 3.0). The maximum tolerable dose was determined to be for cisplatin 20 mg/m(2) i.v. weekly and for capecitabine 575 mg/m(2) b.i.d. orally.

CONCLUSIONS

This phase I-II study demonstrated that postoperative chemoradiotherapy with weekly cisplatin and daily capecitabine is feasible in gastric cancer at the defined dose level. This schedule is currently being tested as the experimental arm in a phase III multicenter study (CRITICS: chemoradiotherapy after induction chemotherapy in cancer of the stomach; Clinicaltrials.gov NCT 00407186).

Postoperative chemoradiotherapy in gastric cancer -- a Phase I/II dose-finding study of radiotherapy with dose escalation of cisplatin and capecitabine chemotherapy

We hypothesised that gastric cancer outcome could be improved with more effective and intensified postoperative chemoradiotherapy. This phase I/II study was performed to determine the maximal tolerated dose (MTD) and toxicity profile of postoperative radiotherapy with concurrent daily cisplatin and capecitabine. Patients were treated with capecitabine 1000 mg m⁻² twice a day (b.i.d.) for 2 weeks. Subsequently, patients received capecitabine (250–650 mg m⁻² orally b.i.d., 5 days week⁻¹) and cisplatin (3–6 mg m⁻² i.v., 5 days week⁻¹) according to an alternating dose-escalation schedule. Radiotherapy was given to a total dose of 45 Gy in 25 fractions. Thirty-one patients completed treatment. During chemoradiotherapy, eight patients developed nine items of grade III and one episode of grade IV (mainly haematological) toxicity. The MTD was determined to be cisplatin 5 mg m⁻² i.v. and capecitabine 650 mg m⁻² b.i.d. orally. This phase I/II study demonstrated that chemoradiotherapy with daily cisplatin and capecitabine is feasible in postoperative gastric cancer at the defined dose level and is currently being tested in a phase III multicenter study.

[New insights in the adjuvant treatment of gastric cancer]

The current standard treatment of patients with gastric cancer is partial or total stomach resection and dissection of the draining lymph nodes. This approach, however, results in a rather low survival rate, partly because the diagnosis is often established in an advanced stage. Various strategies, including adjuvant radiotherapy, chemotherapy or more extensive surgical procedures, have resulted mainly in increased morbidity without improving survival. In a recent randomised trial, concurrent postoperative radiotherapy and chemotherapy prolonged survival and reduced the chance of a local recurrence at an acceptable toxicity. Although several aspects of combined radiochemotherapy require further study, this new treatment concept appears to be a promising addition to the therapeutic arsenal for gastric cancer.