Comparison of pathological response of standard chemoradiotherapy versus short course radiotherapy in rectal carcinoma: A pilot study

Introduction

Neoadjuvant chemoradiation (CRT) is standard of care for locally advanced rectal cancer. However short course radiotherapy (SCRT) was developed for the benefit of a shorter treatment duration and early surgical intervention which also helped in reducing the case burden to the hospital. SCRT is routinely practised in European countries, Indian experience with the SCRT is limited and hence a pilot study was conducted to compare the morphological difference and pathological response between SCRT and CRT.

Objectives

A) Evaluate the morphological changes and pathological response between SCRT and CRT. B) Compare the pathologic response with outcome between SCRT and CRT.

Materials and Methods

All rectal cancer patients in clinical stage II and III diagnosed during 2016 to 2020, who underwent SCRT or CRT were selected. Altered histopathologic findings due to therapy such as tumor cell morphology, necrosis and stromal response along with pathological response between the study groups were compared along with the outcome.

Results

Ten (12.6%) patients were subjected to SCRT and 69 (87.4%) patients underwent CRT. Morphological changes such as necrosis was noted in nine (90%) and eight (11.5%) cases in SCRT and CRT group respectively. Pathologic complete response (pCR) was noted in 12 (17.5%) cases of CRT only. Near complete response was seen in one (10%) and 14 (20.5%) cases of SCRT and CRT respectively. Despite lower rates of pCR in SCRT, no difference in survival or outcome was noted between the two study groups.

Conclusion

pCR as expected is less in patients who received SCRT, despite this the outcome during follow up was similar in both the groups. Indian data is very limited and large multi-centre studies should be carried as SCRT offers an advantage of early definitive surgical intervention in addition to shorter duration of hospitalisation when compared with CRT.

Short-Term Outcomes and Cost-Effectiveness between Long-Course Chemoradiation and Short-Course Radiotherapy for Locally Advanced Rectal Cancer

PURPOSE

Long-course chemoradiotherapy (LCRT) has been widely recommended in a majority of rectal cancer patients. Recently, encouraging data on short-course radiotherapy (SCRT) for rectal cancer has emerged. In this study, we aimed to compare these two methods in terms of short-term outcomes and cost analysis under the Korean medical insurance system.

MATERIALS AND METHODS

Sixty-two patients with high-risk rectal cancer, who underwent either SCRT or LCRT followed by total mesorectal excision (TME), were classified into two groups. Twenty-seven patients received 5 Gy×5 with two cycles of XELOX (capecitabine 1000 mg/m² and oxaliplatin 130 mg/m² every 3 weeks) followed by TME (SCRT group). Thirty-five patients received capecitabine-based LCRT followed by TME (LCRT group). Short-term outcomes and cost estimation were assessed between the two groups.

RESULTS

Pathological complete response was achieved in 18.5% and 5.7% of patients in the SCRT and LCRT groups, respectively (p=0.223). The 2-year recurrence-free survival rate did not show significant difference between the two groups (SCRT vs. LCRT: 91.9% vs. 76.2%, p=0.394). The average total cost per patient for SCRT was 18% lower for inpatient treatment (SCRT vs. LCRT: $18787 vs. $22203, p<0.001) and 40% lower for outpatient treatment (SCRT vs. LCRT: $11955 vs. $19641, p<0.001) compared to LCRT. SCRT was shown to be the dominant treatment option with fewer recurrences and fewer complications at a lower cost.

CONCLUSION

SCRT was well-tolerated and achieved favorable short-term outcomes. In addition, SCRT showed significant reduction in the total cost of care and distinguished cost-effectiveness compared to LCRT.

Patient- and physician-reported radiation-induced toxicity of short-course radiotherapy with a prolonged interval to surgery for rectal cancer

AIM

A prolonged interval (>4 weeks) between short-course radiotherapy (25 Gy in five fractions) (SCRT-delay) and total mesorectal excision for rectal cancer has been associated with a decreased postoperative complication rate and offers the possibility of organ preservation in the case of a complete tumour response. This prospective cohort study systematically evaluated patient-reported bowel dysfunction and physician-reported radiation-induced toxicity for 8 weeks following SCRT-delay.

METHOD

Patients who were referred for SCRT-delay for intermediate risk, oligometastatic or locally advanced rectal cancer were included. Repeated measurements were done for patient-reported bowel dysfunction (measured by the low anterior resection syndrome [LARS] questionnaire and categorized as no, minor or major LARS) and physician-reported radiation-induced toxicity (according to Common Terminology Criteria for Adverse Events version 4.0) before start of treatment (baseline), at completion of SCRT and 1, 2, 3, 4, 6 and 8 weeks thereafter.

RESULTS

Fifty-one patients were included; 31 (61%) were men and the median age was 67 years (range 44-91). Patient-reported bowel dysfunction and physician-reported radiation-induced toxicity peaked at weeks 1-2 after completion of SCRT and gradually declined thereafter. Major LARS was reported by 44 patients (92%) at some time during SCRT-delay. Grade 3 radiation-induced toxicity was reported in 17 patients (33%) and concerned predominantly diarrhoea. No Grade 4-5 radiation-induced toxicity occurred.

CONCLUSION

During SCRT-delay, almost every patient experiences temporary mild-moderate radiation-induced toxicity and major LARS, but life-threatening toxicity is rare. SCRT-delay is a safe alternative to SCRT-direct surgery that should be proposed when counselling rectal cancer patients on neoadjuvant strategies.

Neoadjuvant Short-Course Radiotherapy Followed by Consolidation Chemotherapy before Surgery for Treating Locally Advanced Rectal Cancer: A Systematic Review and Meta-Analysis

Neoadjuvant short course radiotherapy (SCRT) followed by consolidation chemotherapy (CCT) is an alternative treatment for locally advanced rectal cancer (LARC). We performed this systematic review and meta-analysis to explore the tumor response and oncological outcomes of this new approach compared to conventional chemoradiotherapy (CRT). An online search of the PubMed, Embase, and Cochrane Library databases was performed. This review included 7507 patients from 14 different cohorts. The pCR rate was higher with SCRT + CCT than that with CRT (RR: 1.60; 95% CI: 1.35−1.91; p < 0.01). SCRT + CCT provided a higher ypN0 response (RR: 1.06; 95% CI: 1.01−1.12; p = 0.02). There were no differences in R0 resection and positive CRM rates; however, more sphincter-preservation surgeries were performed in the SCRT + CCT arm (RR: 1.06; 95% CI: 1.01−1.11; p = 0.02). There was no difference in the OS and DFS between the SCRT + CCT and the CRT arms (OS: HR: 0.85, p = 0.07; DFS: HR: 0.88, p = 0.08). The compliance and toxicity were comparable between the SCRT and CRT groups. In the subgroup analysis, patients who underwent four or more cycles of CCT had better pCR and DFS events. Therefore, SCRT followed by consolidation chemotherapy might be an effective alternative treatment for LARC.