Immune checkpoint inhibitors for POLE or POLD1 proofreading-deficient metastatic colorectal cancer.

BACKGROUND: POLE and POLD1 proofreading deficiency (POLE/D1pd) define a rare subtype of ultramutated metastatic colorectal cancer (mCRC; over 100 mut/Mb). Disease-specific data about the activity and efficacy of immune checkpoint inhibitors (ICIs) in POLE/D1pd mCRC are lacking and it is unknown whether outcomes may be different from mismatch repair-deficient (dMMR)/microsatellite instability-high (MSI-H) mCRCs treated with ICIs. PATIENTS AND METHODS: In this global study, we collected 27 patients with mCRC harboring POLE/D1 mutations leading to proofreading deficiency and treated with anti-programmed cell death-ligand 1 alone +/- anti-cytotoxic T-lymphocyte antigen-4 agents. We collected clinicopathological and genomic characteristics, response, and survival outcomes after ICIs of POLE/D1pd mCRC and compared them with a cohort of 610 dMMR/MSI-H mCRC patients treated with ICIs. Further genomic analyses were carried out in an independent cohort of 7241 CRCs to define POLE and POLD1pd molecular profiles and mutational signatures. RESULTS: POLE/D1pd was associated with younger age, male sex, fewer RAS/BRAF driver mutations, and predominance of right-sided colon cancers. Patients with POLE/D1pd mCRC showed a significantly higher overall response rate (ORR) compared to dMMR/MSI-H mCRC (89% versus 54%; P = 0.01). After a median follow-up of 24.9 months (interquartile range: 11.3-43.0 months), patients with POLE/D1pd showed a significantly superior progression-free survival (PFS) compared to dMMR/MSI-H mCRC [hazard ratio (HR) = 0.24, 95% confidence interval (CI) 0.08-0.74, P = 0.01] and superior overall survival (OS) (HR = 0.38, 95% CI 0.12-1.18, P = 0.09). In multivariable analyses including the type of DNA repair defect, POLE/D1pd was associated with significantly improved PFS (HR = 0.17, 95% CI 0.04-0.69, P = 0.013) and OS (HR = 0.24, 95% CI 0.06-0.98, P = 0.047). Molecular profiling showed that POLE/D1pd tumors have higher tumor mutational burden (TMB). Responses were observed in both subtypes and were associated with the intensity of POLE/D1pd signature. CONCLUSIONS: Patients with POLE/D1pd mCRC showed more favorable outcomes compared to dMMR/MSI-H mCRC to treatment with ICIs in terms of tumor response and survival.

Prognosis after neoadjuvant chemoradiation or chemotherapy for locally advanced gastro-oesophageal junctional adenocarcinoma.

BACKGROUND: Trials typically group cancers of the gastro-oesophageal junction (GOJ) with oesophageal or gastric cancer when studying neoadjuvant chemoradiation and perioperative chemotherapy, so the results may not be fully applicable to GOJ cancer. Because optimal neoadjuvant treatment for GOJ cancer remains controversial, outcomes with neoadjuvant chemoradiation versus chemotherapy for locally advanced GOJ adenocarcinoma were compared retrospectively. METHODS: Data were collected from all patients who underwent neoadjuvant treatment followed by surgery for adenocarcinoma located at the GOJ at a single high-volume institution between 2002 and 2017. Postoperative major complications and mortality were compared between groups using Fisher's exact test. Overall survival (OS) and disease-free survival (DFS) were assessed by log rank test and multivariable Cox regression analyses. Cumulative incidence functions were used to estimate recurrence, and groups were compared using Gray's test. RESULTS: Of 775 patients, 650 had neoadjuvant chemoradiation and 125 had chemotherapy. These groups were comparable in terms of clinical tumour and lymph node categories, although the chemoradiation group had greater proportions of white men, complete pathological response to chemotherapy, and smaller proportions of diffuse cancer, poor differentiation, and neurovascular invasion. Postoperative major complications (20.0 versus 17.6 per cent) and 30-day mortality (1.7 versus 1.6 per cent) were not significantly different between the chemoradiation and chemotherapy groups. After adjustment, type of therapy (chemoradiation versus chemotherapy) was not significantly associated with OS (hazard ratio (HR) 1.26, 95 per cent c.i. 0.96 to 1.67) or DFS (HR 1.27, 0.98 to 1.64). Type of recurrence (local, regional, or distant) did not differ after neoadjuvant chemoradiation versus chemotherapy. CONCLUSION: In patients undergoing surgical resection for locally advanced adenocarcinoma of the GOJ, OS and DFS did not differ significantly between patients who had neoadjuvant chemoradiation compared with chemotherapy.

Treating advanced cancer of the gastro-oesophageal junction (GOJ) poses a challenge given its location in the distal oesophagus and proximal stomach, and whether it should be treated as oesophageal or gastric cancer. Given the indistinct location, it is unclear whether GOJ cancer should be treated with neoadjuvant chemoradiation, which is the treatment of choice for advanced oesophageal cancers, or perioperative chemotherapy, which is the treatment of choice for advanced gastric cancers. Few studies have addressed treatment options specifically for GOJ cancers. This study investigated whether there was a difference in survival between patients with GOJ cancer who were treated with chemoradiation versus chemotherapy.

Small-cell carcinoma of the esophagus and gastroesophageal junction: review of the Memorial Sloan-Kettering experience.

BACKGROUND: Esophageal small-cell carcinoma (SCC) is rare, highly malignant and the optimal treatment approach has not been defined. PATIENTS AND METHODS: We report the largest single-institution retrospective review of patients with esophageal and gastroesophageal (GE) junction SCC. RESULTS: Twenty-five patients were identified, with complete records available for 22. Eighty-two percent were male, 82% had pure SCC histology and 86% of tumors were in the lower esophagus or GE junction. On the basis of the Veterans' Administration Lung Study Group criteria, 14 patients (64%) presented with limited disease (LD). Median survival was 19.8 months (range, 1.5 months to 11.2+ years); for LD patients, 22.3 months (range, 6 months to 11.2+ years); for extensive disease (ED) patients, 8.5 months (range, 1.5 months to 2.2 years, P = 0.02). With a median follow-up of 38 months, six patients (27%) are alive, one with ED and five with LD. Two LD patients are alive and free of disease for >5 years. Four of the five LD patients who are long-term survivors received induction chemotherapy followed by chemoradiotherapy without surgery. CONCLUSIONS: Our data indicate that patients with LD esophageal SCC treated with induction chemotherapy followed by consolidative chemoradiation can achieve long-term survival. The contribution of surgery remains unclear.