Systemic chemotherapy and short-course radiation in metastatic rectal cancers: A feasible paradigm in unresectable and potentially resectable cancers

TAS-102 Plus Bevacizumab as an Effective and Well Tolerated Regimen in Chemotherapy-Refractory Advanced Colorectal Cancers – A Single Institution Retrospective Analysis

Objective There are limited data on the utility of TAS-102 plus bevacizumab in patients with chemotherapy-refractory metastatic colorectal cancer (mCRC) treated in India.

Methods Patients diagnosed with chemotherapy-refractory mCRC, defined as having received at least prior oxaliplatin and irinotecan–based chemotherapy between January 2017 and January 2022, and who began treatment with a combination of TAS-102 and bevacizumab were retrospectively analyzed for demographic variables, survivals, and prognostic parameters. The primary endpoint of the study was estimation of the median overall survival (OS) by the Kaplan–Meier method.

Results The data of 143 patients satisfied the prespecified inclusion criteria and were included for analysis. There was a predominance of left-sided CRCs (78%) and patients having greater than two sites of distant metastases (87%), with 41% of patients with at least two lines of prior therapy. With a median follow-up of 11.6 months, the median OS of the entire cohort was 10.9 months, while the median progression-free survival was 4.4 months. The combination was well tolerated, with the most common grade 3/4 side effects being neutropenia (25%), anemia (6%), and thrombocytopenia (4%). Dose modifications in TAS-102 were required in 20% of patients, though this did not entail permanent cessation of TAS-102 in any patient. The presence of a resected primary was prognostic for improved OS (p < 0.001), while signet ring histology predicted inferior OS (p < 0.001).

Conclusion The combination of TAS-102 and bevacizumab is an efficacious and safe therapeutic option in patients with mCRC who have received at least two lines of prior systemic therapy. There were no requirements for cessation of the combination in the current study, underlying the well-tolerated nature of the combination.

Optimal neoadjuvant strategy for signet ring cell carcinoma of the rectum-Is TNT the solution?

INTRODUCTION

The results of total neoadjuvant therapy (TNT) for locally advanced rectal cancers (LARC) cannot be extrapolated to signet-ring cell cancers (SRCC) that have an extremely aggressive biology.

METHODS

A retrospective study comparing long course chemoradiation (CTRT) against short course radiation (SCRT) and 12 weeks of chemotherapy for high-risk LARC. Primary endpoints were treatment failure and disease-free survival (DFS) RESULTS: CTRT was given to 74 (59.7%) and SCRT/Chemotherapy to 50 patients (40.3%). Additional chemotherapy was required in 54.1% and 28%, respectively. Except for nodal staging, no other MRI parameter down-staged. Treatment failures were seen in 33.9% and 25.8% had progression. The peritoneum was the commonest site of progression (59.4%). Of the patients that were surgically explored, 63.7% had R0 resections and pathological complete response was seen in 9.7%. At a median follow-up of 35 months, 56.5% had DFS events with a 3-year DFS of 39.5%. Recurrences were noted in 45.1% after curative resections and the 3-year OS/DFS of these patients were 67.2%/56.4%. On multivariate regression, the type of preoperative therapy did not influence treatment failures or DFS.

CONCLUSIONS

SRCC is a very aggressive disease and none of the treatment strategies could show superiority over the other with very high peritoneal progression rates and relapses.

Outcomes of Definitive Treatment of Signet Ring Cell Carcinoma of the Rectum: Is Minimal Invasive Surgery Detrimental in Signet Ring Rectal Cancers?

The outcome of surgery for signet ring adenocarcinoma of rectum is suboptimal with high predilection for locoregional and peritoneal metastases. Lack of intercellular adhesion due to focal loss of epithelial cell adhesion molecule (EpCAM) may account for this. In such patients, whether minimal invasive surgery carries a high risk of dissemination by pneumoperitoneum and tumor implantation remains uncertain. The aim of this study was to compare the outcomes of patients undergoing minimally invasive surgery (MIS) versus open surgery in patients with signet ring cell adenocarcinoma of rectum. A retrospective study was conducted at a tertiary care center over 3 years on 39 patients undergoing open surgery and 40 patients undergoing MIS diagnosed with signet ring cell carcinoma (SRCC) identified from our surgical database. Patient characteristics in terms of demographics, clinicoradiological staging, neoadjuvant therapy, and type of surgery with morbidity were compared in the two groups. Data on patients undergoing adjuvant therapy and 3 years disease-free survival (DFS) and overall survival (OS) were analyzed. Recurrence patterns in both groups were separately identified as locoregional, peritoneal, or systemic. The number of patients undergoing surgery in the two arms was 40 (MIS) and 39 (open). In the MIS arm, mean DFS was 29 months whereas in the open arm, it was 25.8 months. The mean OS was 33.65 months for the MIS arm and that for the open arm was 36.34 months. This retrospective study reveals no significant difference in outcomes of surgery for signet ring cell rectal cancers with either MIS or open approach.