Volumetric dose correlation with clinical control and toxicity in patients of carcinoma cervix undergoing HDR Intra cavitary Brachytherapy

Dr. (Col) Nilotpal Chakravarty; Dr. (Major) Gaurav Trivedi; Dr. Manoj Semwal

Volume : IX, Issue : IV, April - 2019

Volumetric dose correlation with clinical control and toxicity in patients of carcinoma cervix undergoing HDR Intra cavitary Brachytherapy

Dr. Col Nilotpal Chakravarty, Dr. Major Gaurav Trivedi, Dr. Manoj Semwal

Abstract :

Conclusions: Our analysis indicated that the ICRU bladder point dose was substantially lower than bladder D2cc & ICRU rectum point dose was higher than the rectum D2cc. No significant acute toxicities were observed, and late toxicities only rectum. The threshold EQD2 dose for rectal toxicity estimated with the curve coordinates was 89.15Gy for Rectum ICRU point (sensitivity 75%, specificity 77.8%). The rectal toxicity threshold dose V2cc EQD2 was 72.18Gy (sensitivity 75% & specificity of 59.3%). D2cc bladder was well within the tolerance limit for all patients. The bladder toxicities were not observed, probably because the bladder doses were overestimated & rectum toxicities were common, probably because the rectal doses were underestimated. With vaginal stricture (13%) common in the study, there is a definite need to evaluate the dose to vagina as a separate OAR as recommended by the ICRU 89. With 3% incidence of faecal incontinence, the rectal sphincter dosimetric evaluation is important for its prevention. This study also conclude that point–dose estimates to be viewed with caution, looking beyond simple reference doses to assess the position qualitatively and packing ICRT placements using diagnostic imaging studies, whenever possible, to improve understanding of the relationship between intra cavitary applications and the underlying anatomy