Three-dimensional conformal brachytherapy boost in locally recurrent or residual cervical carcinoma: does it impact clinical outcome?
OBJECTIVE
To analyze the influence of computed tomography (CT)-guided 3D conformal interstitial brachytherapy (3D-IBT) boost for better coverage of target volumes and study the diametric impact to organ at risk in patients with post-surgery recurrent and residual cervical cancer.


METHODS
Fourteen consecutive patients with recurrent or residual cervical cancer who were treated with interstitial brachytherapy as a boost were included in the study. All patients received 50.4 Gy external radiation (EBRT) to whole pelvis with conformal technique to reduce the dose to bowel. The clinical target volume (CTV) and organs at risk were contoured on CT scan with gold seeds being a surrogate marker of initial tumor extent implanted before commencing treatment. The median dose of prescription was 10.5-12Gy in 3 fractions. Dose volume histogram was calculated to evaluate the dose that covers 100% and 90% of the target volume and dose to the bladder, rectum and bowel (2 mL, 1 mL volume).


RESULTS
The median follow-up was 12 months (range 6-18). The doses to CTV (D90, D100) ranged from 1141 to 2014 cGy, and 585 to 969 cGy, respectively. The mean cumulative 2-mL rectal, bladder and bowel doses were 66.70, 73.15 and 61.01Gy, respectively. Rectal toxicity of grade 2 or more had a strong correlation with the dose delivered (Spearman's correlation, 0.950). The local control rate at one year was 92% with failure seen in one patient only.


CONCLUSIONS
Conformal EBRT supplemented with 3D-IBT seems to be a practical and appropriate approach to give the most optimal therapeutic benefit with the least side-effects in postoperative recurrent and residual cervical cancer patients.
Departments of Radiation Oncology Medical Physics Urology-Gynecology Surgical Oncology, Rajiv Gandhi Cancer Institute and Research Centre, Delhi, India.
Vivek
V
Bansal
Gaurav
G
Kumar
Ritu
R
Bhutani
Gurusamy
G
Venkadamanickam
Surender Kumar
SK
Sharma
Ashok Kumar
AK
Sigamani
Rupinder
R
Shekhon
Sudhir Kumar
SK
Rawal
D000328:Adult; D001918:Brachytherapy / Q000379:methods*; D002277:Carcinoma / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D018365:Neoplasm, Residual; D011859:Radiography; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012007:Rectum / Q000000981:diagnostic imaging / Q000528:radiation effects; D016896:Treatment Outcome; D001743:Urinary Bladder / Q000000981:diagnostic imaging / Q000528:radiation effects; D002583:Uterine Cervical Neoplasms / Q000000981:diagnostic imaging / Q000532:radiotherapy*