Neoadjuvant Pembrolizumab in Localized Microsatellite Instability High/Deficient Mismatch Repair Solid Tumors

PURPOSE

Pembrolizumab significantly improves clinical outcomes in advanced/metastatic microsatellite instability high (MSI-H)/deficient mismatch repair (dMMR) solid tumors but is not well studied in the neoadjuvant space.

METHODS

This is a phase II open-label, single-center trial of localized unresectable or high-risk resectable MSI-H/dMMR tumors. Treatment is pembrolizumab 200 mg once every 3 weeks for 6 months followed by surgical resection with an option to continue therapy for 1 year followed by observation. To continue on study, patients are required to have radiographic or clinical benefit. The coprimary end points are safety and pathologic complete response. Key secondary end points are response rate and organ-sparing at one year for patients who declined surgery. Exploratory analyses include interrogation of the tumor immune microenvironment using imaging mass cytometry.

RESULTS

A total of 35 patients were enrolled, including 27 patients with colorectal cancer and eight patients with noncolorectal cancer. Among 33 evaluable patients, best overall response rate was 82%. Among 17 (49%) patients who underwent surgery, the pathologic complete response rate was 65%. Ten patients elected to receive one year of pembrolizumab followed by surveillance without surgical resection (median follow-up of 23 weeks [range, 0-54 weeks]). An additional eight did not undergo surgical resection and received less than 1 year of pembrolizumab. During the study course of the trial and subsequent follow-up, progression events were seen in six patients (four of whom underwent salvage surgery). There were no new safety signals. Spatial immune profiling with imaging mass cytometry noted a significantly closer proximity between granulocytic cells and cytotoxic T cells in patients with progressive events compared with those without progression.

CONCLUSION

Neoadjuvant pembrolizumab in dMMR/MSI-H cancers is safe and resulted in high rates of pathologic, radiographic, and endoscopic response, which has implications for organ-sparing strategies.

Is neoadjuvant therapy an alternative strategy to immediate surgery in locally perforated colon cancer?

BACKGROUND

Perforations are a rare but serious complication of colorectal cancer. The current standard of treatment is emergent surgery followed by adjuvant chemotherapy. The concern with this approach is not only the uncertainty of achieving a R0 resection but also potential injury to adjacent vessels, nerves and ureters due to inflamed tissue planes. A subset of this patient population with a contained perforation who are clinically stable may have superior oncological outcomes with local sepsis control, neoadjuvant therapy followed by radical resection. The aim of this study is to report on the pre-operative safety profile for neoadjuvant therapy in the setting of an abscess from colon cancer perforation and the short-term oncological surgical quality outcomes.

METHODS

In this retrospective observational study, all consecutive perforated colon cancer receiving neoadjuvant therapy from Jan 2010 to Dec 2019 were included.

RESULTS

There were 21 patients that met the inclusion criteria. The most common symptom at presentation was abdominal pain (71.4%) and most common site of perforation was sigmoid colon (61.9%). Local sepsis control was achieved with a combination of radiological or surgical drainage, diverting ostomy and/or intravenous antibiotics. Thirteen patients had long-course chemoradiation and eight patients had neoadjuvant chemotherapy. Of these, 13 (61.9%) had tumour regression, with one patient having a pathological complete response. All patients achieved a R0 resection.

CONCLUSIONS

In a small subset of patients with colon cancer perforation, this study has demonstrated the potential safe usage of neoadjuvant therapy first before radical surgery to achieve a clear resection margin.

Quality and Location of the Surgical Episode Mediate a Large Proportion of Socioeconomic-Based Survival Disparities in Patients with Resected Stage I-III Colon Cancer

INTRODUCTION

Lower socioeconomic status (SES) is associated with shorter overall survival (OS) in patients with locoregional colon cancer. We aimed to estimate: (1) the proportion of SES-based OS disparities mediated by disparities in the quality and location of surgical treatment in patients with resected stage I-III colon cancer and (2) the relative importance of components of surgical quality.

PATIENTS AND METHODS

We examined patients ages 18-80 years with resected stage I-III colon adenocarcinoma using the 2010-2016 National Cancer Database. SES was defined at the zip code level. Inverse odds weighting mediation analysis was used to estimate the proportion mediated (PM) for nine treatment quality-related and facility-related factors and composite PMs in models including all nine mediators. Models compared high SES patients with each lower SES stratum.

RESULTS

Among 171,009 patients, 5-year OS increased from 70.4% in low SES patients to 78.1% in high SES. When high SES patients were compared with low, lower-middle, and upper-middle SES patients, PM ranges among lower SES strata were: minimally invasive surgery 16.0-16.6%, lymph nodes examined 7.7-9.6%, positive margins 3.8-6.5%, length of stay 16.7-28.1%, readmissions insignificant to 3.7%, treatment at > 1 CoC facility 2.7-3.1%, facility type insignificant to 7.3%, facility volume 2.9-8.2%, and adjusted facility 90-day mortality rates 33.2-42.8%. Composite PMs were 76.9% (95% CI 61.3%, 92.4%) for low SES, 68.7% (95% CI 56.4%, 81.1%) for lower-middle SES, and 60.9% (95% CI 43.1%, 78.6%) for upper-middle SES.

CONCLUSIONS

These data suggest that improving the quality of the surgical episode for disadvantaged patients undergoing resection for locoregional colon cancer could decrease SES-based survival disparities by over half.

Robotic rectal cancer surgery: comparative study of the impact of obesity on early outcomes

The aim of this study was to compare the outcomes of robotic total mesorectal excision (TME) in obese versus non-obese patients. A total of 533 patients, of whom 161 were obese (30·2 per cent) underwent robotic proctectomy during the study interval. Patient obesity was not associated with adverse short-term clinical outcomes after robotic rectal cancer surgery. Indicated in the obese perhaps?

Patients' Perspectives of Surgical Safety: Do They Feel Safe?

BACKGROUND

Increased focus on reducing patient harm has led to surgical safety initiatives, including time-out, surgical safety checklists, and debriefings. The perception of the lay public of the surgical safety process is largely unknown.

METHODS

A 20-question survey focused on perceptions of surgical safety practice was distributed to a random sample of patients following elective operations requiring hospitalization. Responses were measured by a 7-point Likert scale. Qualitative feedback was obtained through nonphysician-moderated sessions. Participation was voluntary and anonymous.

RESULTS

Surveys were distributed to 345 patients of whom 102 (29.5%) responded. Overall, patients felt safe as evidenced by scores for the questions "I felt safe the day of my surgery" (6.53 ± 0.72) and "Mistakes rarely happen during surgery" (5.39 ± 1.51). Patients undergoing their first surgery and patients with higher income levels were associated with a significant decrease in specific safety perceptions. Qualitative feedback sessions identified the physician-patient relationship as the most important factor positively influencing patient safety perceptions.

CONCLUSION

Current surgical safety practice is perceived positively by our patients; however, patients still identify physician-patient interactions, relationships, and trust as the most positive factors influencing their perception of the safety environment.