Stereotactic body radiation therapy via helical tomotherapy to replace brachytherapy for brachytherapy-unsuitable cervical cancer patients – a preliminary result

Abstract

AimTo review the experience and to evaluate the results of stereotactic body radiation therapy (SBRT) via helical tomotherapy (HT), for the treatment of brachytherapy-unsuitable cervical cancer.MethodsBetween September 1, 2008 to January 31, 2012, nine cervical cancer patients unsuitable for brachytherapy were enrolled. All of the patients received definitive whole pelvic radiotherapy with or without chemotherapy, followed by SBRT via HT.ResultsThe actuarial locoregional control rate at 3 years was 78%. The mean biological equivalent dose in 2-Gy fractions of the tumor, rectum, bladder, and intestines was 76.0 ± 7.3, 73.8 ± 13.2, 70.5 ± 10.0, and 43.1 ± 7.1, respectively. Only two had residual tumors after treatment, and the others were tumor-free. Two patients experienced grade 3 acute toxicity: one had diarrhea; and another experienced thrombocytopenia. There were no grade 3 or 4 subacute toxicities. Three patients suffered from manageable rectal bleeding in months 11, 14, and 25, respectively. One stage I VA patient experienced fistula formation in month 3.ConclusionSBRT via HT provides the possibility for treatment of locally advanced cervical cancer in patients who are unsuitable for brachytherapy. Long-term follow up and enrollment of more such patients to receive SBRT via the HT technique are warranted.

Tumor Boost Using External Beam Radiation in Cervical Cancer Patients Unable to Receive Intracavitary Brachytherapy

“…Except for 1 study reporting a 5-year local tumor control rate of 21.9%, 13 most of the studies showed that approximately 60% to 100% of patients achieved local tumor control after curative whole pelvic radiotherapy and EBRT-B. 3,8,9,12,15 Likewise, we noted in our study that the 5-year local tumor control rate was 70.0%, and the rate of late grade 3 or higher toxicity was 2.6% after curative radiotherapy using FIGURE 1. A, Comparison of EQD2 10 total between patients treated with 3D-CRT versus IMRT.…”

External beam techniques to boost cervical cancer when brachytherapy is not an option—theories and applications

“…On the other hand, SBRT was the technique of choice in all the four recent studies that delivered 16-30 Gy in 2-6 Gy per fraction to the cervical target volume not amenable for BT. The preliminary results of three studies were promising (LC rates ranging from 78-100% and negligible late toxicity) although the median follow up duration was relatively short (6-36 months) (16,69,71). The study by Kubicek et al was the exception with a paradoxically high late rectal toxicity (25% grade 3 or higher) in spite of using MR imaging to define the CTV, 0.5 cm CTV to PTV expansion, Cyberknife (CK) (Accuray Incorporated, Sunnyvale, CA, USA) to track cervical implanted gold fiducial for increased SBRT precision.…”

“…The CK platform tracking cervical tumor with implanted markers was similarly adopted in Haas et al with advanced cervical disease and/or prolonged overall treatment time (median 79 days). After delivering 50-54 Gy to the pelvis, Helical Tomotherapy (HT) (TomoTherapy Inc., Madison, WI, USA) was employed to obtain a megavoltage CT image before each fraction; thus ensuring precise and consistent radiotherapy delivery and potentially avoiding late severe toxicity (71). High-tech radiotherapy delivery in this setting was not limited to photon beam.…”

Patient's specific integration of OAR doses (D2 cc) from EBRT and 3D image‐guided brachytherapy for cervical cancer

“…For patients unable to undergo BT, stereotactic‐body radiotherapy (SBRT) techniques have been explored with different fractionation schemes such as 20 Gy in five fractions (23 Gy 10 in EQD2),37, 38 14 Gy in two fractions (20 Gy 10 in EQD2),38, 39 25 Gy in five fractions (31 Gy 10 in EQD2),40 5 Gy in three fractions (31 Gy 10 in EQD2),41 or 6 Gy in five fractions (40 Gy 10 in EQD2) 42. 3D conformal radiotherapy (3D‐CRT) or IMRT techniques38, 39, 41, 43 along with CyberKnife (Accuracy Inc., Sunnyvale, CA, USA)37, 40, 42 have also been tested. However, the majority of clinical SBRT results37, 38, 40, 42 are still in the early stage with only small number of patients (<20 patients) and short‐term follow‐up (<26 months).…”