Comparative study of neoadjuvant chemoradiotherapy in carcinoma rectum using 3DCRT versus bonemarrow sparing IMRT

Abstract

BACKGROUND:-   Neoadjuvant chemoradiation  is standard of care for the treatment of locally    advanced rectal cancer.The experiences in the treatment of rectal cancers with IMRT and 3DCRT remain sparse with conflicting results.We undertook a study at our institute where we compared IMRT and 3DCRT in the neoadjuvant  treatment of locally advanced rectal cancer.

OBJECTIVES:-   To compare the two modalities 3DCRT and IMRT in neoadjuvant setting  concurrent with capecitabine in terms of pathological tumor response  and toxicities.

STUDY DESIGN:-  An prospective comparative observational study.

PARTICIPANTS:-  50 patients ,Stage II-III, age equal to or more than 15,good performance  status.

METHODS:-   All patients were biopsy proven adenocarcinoma of  rectum.Patientswere  divided into two arms. First arm received  3DCRT  and second arm received IMRT.Both groups received 45Gy in 25# over a period of 5 weeks concurrent with capecitabine.RTOG toxicity scale was used to grade toxicities.Surgery was done  within 6-8 weeks of completion of chemoradiation.Pathological response assessment was done using Mandards Tumor Regression Grade.

RESULTS: -   A total of 50 patients were analyzed.Male: Female ratio was 1.5:1.Mean age   in 3DCRT group  was  43.8 years and IMRT was 40.7 years. Clinical characteristics were similar across RT groups. The outcome of the study showed that preoperative concurrent chemoradiotherapy using IMRT resulted in improved PR rates  as compared to 3DCRT (P<0.041). There was a reduction in acute skin toxicity with the use of IMRT  (p=0.032).There was also a reduction in acute lower GI toxicities use of IMRT as compared to 3DCRT concurrent with capecitabine(p=0.047).Late toxicity was not not observed in any patient in both the arms.

CONCLUSION:- Neoadjuvant  radiotherapy with  IMRT for locally advanced rectal cancer leads  to reduced acute toxicities and improved pathological response compared to 3DCRT.

IMPLICATIONS:- IMRT should be considered standard treatment for locally advanced rectal  carcinoma as it improves the conformity and spares the normal tissues but long term follow up is needed to draw definitive conclusion.