Survival Benefit of Preoperative Versus Postoperative Radiotherapy in Metastatic Rectal Cancer Treated With Definitive Surgical Resection of Primary Tumor: A Population Based, Propensity Score-Matched Study

Rectosigmoid Junction Cancer; The Role of Preoperative and Postoperative Radiation With Novel Nomogram in Predicting Survival in the United States

BACKGROUND

There is controversy and limited data the management of rectosigmoid junction cancer (RSJC), especially the role of radiation. We aim to investigate the role of preoperative and postoperative radiation in RSJC and whether this cancer should be treated as a colon cancer or as a rectal cancer.

METHODS

The data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database and identified from 2000 to 2018.

RESULTS

Of the 50,779 patients, 87% were ≥50 years old, 56.2% were male, 80.8% were White. Regarding tumor characteristics, 76% were Grade II, while 22.7% had distant-stage. 16.4% of patients were treated with multimodal therapy (surgery with chemoradiation), 47.9% surgery alone, 6.5% of patients received preoperative radiation, and 9.9% received postoperative radiation. Regarding prognostic significance of pre-operative and postoperative radiation factors, we evaluated factors, such as age, gender, race, tumor size, histologic variants of adenocarcinoma, and tumor grade. Patients with distant-staged tumors who received preoperative radiation had lower mortality compared to those who received postoperative radiation (95% CI, 0.73 - 0.97, (hazard ratio (HR) = 0.85, p = 0.04). There were no survival differences for localized or regional disease regarding pre and postoperative radiation, or when sub-stratifying for any other significant demographic or tumor characteristics.

CONCLUSION

Surgery with adjuvant chemoradiation had the best prognosis for all demographic and tumor characteristics. Preoperative radiation had a good prognosis only in distant disease. However, further randomized evidence is required to demonstrate the efficacy of pre-and post-operative radiation in rectosigmoid junction cancer.

Effects of PreOperative radiotherapy in a preclinical glioblastoma model: a paradigm-shift approach

PURPOSE

PreOperative radiotherapy (RT) is commonly used in the treatment of brain metastasis and different cancer types but has never been used in primary glioblastoma (GBM). Here, we aim to establish, describe, and validate the use of PreOperative RT for the treatment of GBM in a preclinical model.

METHODS

Rat brains were locally irradiated with 30-Gy, hypofractionated in five doses 2 weeks before or after the resection of intracranial GBM. Kaplan-Meier analysis determined survival. Hematoxylin-eosin staining was performed, and nuclei size and p21 senescence marker were measured in both resected and recurrent rodent tumors. Immunohistochemistry assessed microglia/macrophage markers, and RNAseq analyzed gene expression changes in recurrent tumors. Akoya Multiplex Staining on two human patients from our ongoing Phase I/IIa trial served as proof of principle.

RESULTS

PreOperative RT group median survival was significantly higher than PostOperative RT (p < 0.05). Radiation enlarged cytoplasm and nuclei in PreOperative RT resected tumors (p < 0.001) and induced senescence in PostOperative RT recurrent tumors (p < 0.05). Gene Set Enrichment Analysis (GSEA) suggested a more proliferative profile in PreOperative RT group. PreOperative RT showed lower macrophage/microglia recruitment in recurrent tumors (p < 0.01) compared to PostOperative RT. Akoya Multiplex results indicated TGF-ß accumulation in the cytoplasm of TAMs and CD4 + lymphocyte predominance in PostOperative group.

CONCLUSIONS

This is the first preclinical study showing feasibility and longer overall survival using neoadjuvant radiotherapy before GBM resection in a mammalian model. This suggests strong superiority for new clinical radiation strategies. Further studies and trials are required to confirm our results.

The survival impact of radiotherapy on synchronous metastatic rectal cancer: metastatic site can serve for radiotherapy-decision

Purpose: The metastatic site seems to represent a malignancy with a different biological characteristic. Radiotherapy, as a successful, well-tolerated, cost-effective and time-efficient intervention, is able to provide clear benefits for the treatment of locally advanced rectal cancer and has become an essential component of palliative oncology care. The real-world effect of radiotherapy on the survival outcomes of metastatic rectal cancer (mRC) patients might do exist and was worth exploring. Patients and methods: Data were extracted from the Surveillance, Epidemiology, and End Results (SEER) database in this retrospective analysis. The statistical methods included Pearson's chi-square test, Log-rank test, Cox regression model and propensity score matching (PSM). Results: The multivariable Cox regression displayed that radiotherapy may not be used as a prognostic factor for mRC (p=0.057). However, radiotherapy may be associated with the prognosis if the metastatic site was excluded from the multivariate analysis (p<0.001). Radiotherapy seemed to fail to improve OS before PSM (p<0.001) and after PSM without the metastatic site as a matching factor (p<0.001). Nevertheless, there was no significant survival difference between radiotherapy and non-radiotherapy cohort after PSM with the metastatic site as a matching factor (p=0.057). All of M1a rectal cancer patients appear to obtain survival benefit from radiotherapy without the impact of PSM (p<0.001). Notwithstanding, radiotherapy was associated with improved OS of patients with rectal liver-limited metastasis (p=0.023) and did not appear to provide survival benefit for rectal lung-limited (p=0.386) and other-limited metastasis (p=0.385). Both of M1b mRC with and without liver metastasis did not seem to obtain survival benefit from radiotherapy. Conclusions: Carefully selected data from the SEER database suggested that radiotherapy appears to improve overall survival only in patients with rectal liver-limited metastasis.

Tumor Regression Grade as a Prognostic Factor in Metastatic Colon Cancer Following Preoperative Chemotherapy

BACKGROUND

The prognostic value of tumor regression grade (TRG) in patients with locally advanced rectal cancer treated with neoadjuvant chemoradiation therapy has been explored extensively. However, whether TRG is predictive of outcome in colon cancer following preoperative chemotherapy has not been reported.

MATERIALS AND METHODS

A total of 276 colon cancer patients who had undergone preoperative chemotherapy and surgery in Fudan University Shanghai Cancer Center during the period March 2014 through November 2019 were recruited in this study. 113 (40.9%) and 163 (59.1%) patients were diagnosed with locally advanced colon cancer (LACC) and metastatic colon cancer (mCC) before preoperative chemotherapy, respectively. The TRG was divided into TRG0 (complete response), TRG1 (good response), TRG2 (moderate response), and TRG3 (poor response).

RESULTS

Of the 276 patients 4.0% were TRG0, 5.4% were TRG1, 29.3% were TRG2, 61.2% were TRG3. TRG0 and TRG1 or TRG0, TRG1 and TRG2 were combined to simplify analysis due to limited sample size. In entire cohort, the 3-year overall survival for TRG0-1, TRG2, and TRG3 groups were 80.0%, 68.8% and 43.3% (P = .003). In LACC cohort, TRG was not associated with patients' prognosis, which largely resulted from limited outcome events. In mCC cohort, the 3-year overall survival for TRG0-1, TRG2, and TRG3 groups were 74.3%, 62.8% to 28.1% (P<0.001). Multivariate analysis demonstrated that TRG was an independent prognostic factor for overall survival in both entire cohort and mCC cohort (TRG3 vs. TRG0-2).

CONCLUSION

TRG is a prognostic factor in predicting long-term outcomes of mCC patients treated with preoperative chemotherapy.

Neoadjuvant Pelvic Radiotherapy in the Management of Rectal Cancer with Synchronous Liver Metastases: Is It Worth It?

BACKGROUND

The use of neoadjuvant pelvic radiotherapy was a major advance in oncologic care for locally advanced rectal cancer in the twentieth century. The extrapolation of the care of locally advanced rectal cancer to the management of rectal cancer with treatable liver metastases is controversial. The aim of this review is to examine the available data on the role of pelvic radiotherapy and chemoradiation in the setting of treatable metastatic liver disease.

METHODS

A systematic search of MEDLINE was performed to report the landmark randomized controlled trials between 1993 and 2021.

RESULTS

Attaining liver clearance and total mesorectal excision with R0 margin remains the mainstay of cure. There is uncertainty regarding the sequencing of treatment. The literature lacks randomized clinical trials comparing the rectal first, liver first, interval strategy, and simultaneous surgical approaches. A multidisciplinary discussion regarding the utility of radiotherapy is emphasized to achieve the goals of treatment. Short-course radiotherapy has proved comparable disease-control outcomes to long-course chemoradiation with a significantly improved cost-performance. The implementation of short-course radiotherapy in the interval strategy and simultaneous surgical approach is promising. Neoadjuvant pelvic radiotherapy can be omitted in patients with metastatic rectal cancer if adequate margin clearance is achievable.

CONCLUSION

The use of radiotherapy in metastatic rectal cancer is popular but is based on limited data. Treatment should be tailored to the local extent of rectal cancer and priority of liver metastasis management. The optimal treatment strategy in patients with rectal cancer and synchronous liver metastatic disease needs to be studied in randomized trials.

Mutated DNA Damage Repair Pathways Are Prognostic and Chemosensitivity Markers for Resected Colorectal Cancer Liver Metastases

Deficiency of the DNA damage repair (DDR) signaling pathways is potentially responsible for genetic instability and oncogenesis in tumors, including colorectal cancer. However, the correlations of mutated DDR signaling pathways to the prognosis of colorectal cancer liver metastasis (CRLM) after resection and other clinical applications have not been fully investigated. Here, to test the potential correlation of mutated DDR pathways with survival and pre-operative chemotherapy responses, tumor tissues from 146 patients with CRLM were collected for next-generation sequencing with a 620-gene panel, including 68 genes in 7 DDR pathways, and clinical data were collected accordingly. The analyses revealed that 137 of 146 (93.8%) patients had at least one mutation in the DDR pathways. Mutations in BER, FA, HRR and MMR pathways were significantly correlated with worse overall survival than the wild-types (P < 0.05), and co-mutated DDR pathways showed even more significant correlations (P < 0.01). The number of mutated DDR pathways was also proved an independent stratifying factor of overall survival by Cox multivariable analysis with other clinical factors and biomarkers (hazard ratio = 9.14; 95% confidence interval, 1.21–68.9; P = 0.032). Additionally, mutated FA and MMR pathways were positively and negatively correlated with the response of oxaliplatin-based pre-operative chemotherapy (P = 0.0095 and 0.048, respectively). Mutated DDR signaling pathways can predict pre-operative chemotherapy response and post-operative survival in CRLM patients.