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

BACKGROUND: The optimal use and sequencing of short-course radiotherapy (SCRT) in metastatic rectal cancers (mRCs) are not well established. MATERIALS AND METHODS: We retrospectively reviewed the records of mRC patients receiving SCRT followed by palliative chemotherapy between January 1, 2013, and December 31, 2016, in Tata Memorial Hospital. Patients were classified as having “potentially resectable” disease (local and metastatic) or “unresectable” disease at baseline based on prespecified criteria. RESULTS: A total of 105 consecutive patients were available for analysis. The median age of patients was 48 years (range: 16–62 years), and 57.1% were male patients. Signet ring histology was seen in 13.3% of patients. The most common site of metastases was liver limited (29.5%), nonloco-regional nodes (12.4%), and lung limited metastases (9.5%). Chemotherapeutic regimens administered were capecitabine-oxaliplatin (70.5%), modified 5 fluorouracil (5 FU)-leucovorin-irinotecan-oxaliplatin (10.5%), and modified 5 FU-leucovorin-irinotecan (8.6%). Targeted therapy accompanying chemotherapy was administered in 27.6% of patients. About 42.1% of patients with potentially resectable disease and 11.1% with the unresectable disease at baseline underwent curative-intent resection of the primary and address of metastatic sites. With a median follow-up 18.2 months, median overall survival (OS) was 15.7 months (95% confidence interval: 10.42–20.99). Patients classified as potentially resectable had a median OS of 32.62 months while patients initially classified as unresectable had a median OS of 13.04 months (P = 0.016). The presence of signet ring morphology predicted for inferior mOS (P = 0.021). CONCLUSIONS: SCRT followed by systemic therapy in mRC is a feasible, efficacious paradigm for maximizing palliation, and achieving objective responses. The classification of patients based on resectability was predictive of actual resection rates as well as outcomes. Signet ring mRC show inferior outcomes in this cohort of patients.