Computed Tomography-Based Interstitial Brachytherapy for Recurrent Cervical Carcinoma in the Vaginal Apex.

AIMS: To determine the factors influencing the outcomes of patients with recurrences post-hysterectomy for cervical cancers treated with external beam radiotherapy (EBRT) and interstitial brachytherapy. MATERIALS AND METHODS: This prospective study accrued 90 patients between October 2008 and May 2014. All patients had had a prior hysterectomy and were diagnosed with recurrent vaginal apex cancers with squamous cell carcinomas. All underwent EBRT of 50 Gy (2 Gy/fraction) using tomotherapy-based image-guided intensity-modulated radiotherapy with concurrent chemotherapy of weekly cisplatin (40 mg/m2) followed by high dose rate interstitial brachytherapy boost of 20 Gy (4 Gy/fraction twice a day). Local relapse, disease-free and overall survival were determined. RESULTS: At a median follow-up of 74 months (4-123 months), 10/90 (11%) patients had local failure as the first site of relapse and 12/90 (13.3%) had first distant relapse. Only one patient had synchronous local and distant relapse. The 7-year local relapse-free, disease-free and overall survival were 87.6, 68.3 and 68.3%, respectively. Grade 2 and 3 rectal toxicity were seen in 5.6 and 3.1% of patients, respectively. Among these, two (2.2%) patients underwent temporary diversion colostomy due to vaginal sigmoid and rectovaginal fistula. Grade 2 and 3 bladder toxicity were seen in 5.6 and 1.1% of patients, respectively. In summary, the lateral disease extent (P = 0.048) and the presence of nodal disease at diagnosis (P = 0.08) had a statistically significant or borderline impact on local relapse without any impact on disease-free survival. Tumour size in itself did not affect overall survival. CONCLUSION: With the integration of EBRT and interstitial brachytherapy, most vaginal apex recurrences can be salvaged. An excellent local control and survival is achievable using intensity-modulated radiotherapy with image guidance and concurrent chemotherapy followed by high dose rate interstitial brachytherapy.

Set-Up Errors, Organ Motion, Tumour Regression and its Implications on Internal Target Volume-Planning Target Volume During Cervical Cancer Radiotherapy: Results From a Prospective Study.

AIMS: Uterocervical motions and organ filling during cervical cancer conformal radiotherapy is complex. This prospective, observational study investigated set-up margins (clinical target vo, ume [CTV] to planning target volume [PTV]) for pelvic nodal CTV and internal margin (CTV to internal target volume [ITV]) expansions for uterocervical movements during cervical cancer radiotherapy. MATERIALS AND METHODS: During cervical cancer radiotherapy, a daily kilovoltage, cone-beam computed tomography (CBCT) scan was acquired. Bony anatomy-based rigid co-registration and matching to vessels/pelvic nodal region was carried out to document shifts, errors (systematic and random) and to calculate CTV to PTV margins. Subsequently, soft-tissue matching was carried out at the mid-cervical region and uterine fundus to record shifts, errors and to calculate CTV to ITV margins. RESULTS: In 67 patients, 1380 CBCT scans were analysed. The mean (±standard deviation) couch shifts for CTV pelvic nodal region in all directions were within 4.5-5.3 mm, systematic and random errors 3.0-3.6 mm and set-up margins of within 10 mm (except anterior margin 10.3 mm). For the mid-cervical region, mean shifts were 4.5-5.5 mm, systematic and random errors 2-4 mm amounting to <10 mm internal margins (CTV-ITV for cervix) and for uterine fundus mean (±standard deviation) shifts were larger in the superior direction (12.1 mm) but 4.0-7.5 mm in other directions, systematic and random errors 2-7 mm amounting to anisotropic margins in various directions (10 mm in anterior-posterior and lateral directions, 12-20 mm in superior-inferior directions) (CTV-ITV for uterine fundus). CONCLUSION: Our study suggests anisotropic CTV to ITV and CTV to PTV margins for cervical cancer radiotherapy.