**8. Conclusions**

were 88, 78, and 56%, respectively. They also reported that three-year LC rates were 98, 93, and 79%, respectively. These results indicate that IGABT is an indispensable treatment tool to achieve excellent LC rates. Lindegaard et al. compared the treatment results of MRI-guided IGABT to X-ray-based BT [14]. Both OS and cancer‐specific survival (CSS) rates were signifi-

The mean total HR-CTVs in these reports ranged from 80.3 to 93 Gy in EQD2. All of the total HR-CTV D90s were more than 80 Gy. In our experience with IGABT for 50 cervical cancer patients, the mean total HR-CTV D90 was 77.0 Gy, lower than that at the representative centers. This difference was caused by the CS technique. According to other reports from Japan, although treatment outcomes were excellent, HR-CTV D90s were less than 70 Gy [18, 19]. These results are also lower than our findings. The studies used CT‐based planning, which also accounted for the large difference when combined with CS technique. It is likely that a larger HR‐CTV delineated using CT and a lower WPI dose combined with CS technique resulted in a significantly lower D90. MRI-based planning without CS technique might achieve HR-CTV D90 comparable to that in foreign institutions. More institutions in Japan should perform MRI-based planning because it may become the global standard. Use of CS technique should also be discussed.

In summary, the use of IGABT can help achieve excellent LC even in advanced stage cervical cancer with the help of interstitial needles. Survival results with IGABT showed superiority to those achieved with traditional X‐ray‐based BT. HR‐CTV D90 can be easily affected by imaging modality and variability of EBRT dosing. However, 45 Gy of WPI and MRI-based treatment planning aiming for a total HR-CTV D90 from 80 to 85 Gy should be considered the

Late bladder, gastrointestinal, and vaginal toxicities have been reported by previous studies. In the Retro-EMBRACE study [17], five‐year Grade 3–5 toxicity in the bladder, gastrointestinal tract, and vagina among 610 patients affected 5, 7, and 5%, respectively. Ribeiro et al. also reported Grade 3–4 late rectal, urinary, sigmoid, and vaginal morbidity rates were 5, 6, 2, and 5%, respectively, in their long-term treatment outcome study [16]. They also identified a cor-

at Kobe University Hospital, Grade 3 rectal toxicity occurred in two (4%) patients. No Grade

Acute toxicities are rarely reported in published studies. According to our experience, hematological toxicity is the most frequent, especially in patients treated with concurrent chemoradiotherapy (CCRT). Among the 50 patients treated at Kobe University Hospital, Grade 3 or greater acute hematologic toxicity occurred in 36 (72%) patients. Procedure-related complications should also be reported. In the early period, mild pressure ulcers around the buttocks occurred in five patients. Respiratory suppression occurred in one patient who received intravenous sedation. In addition, interstitial needles may cause severe complications. The most common is bleeding. It is sometimes difficult to manage extravaginal bleeding caused by laceration of the vaginal wall. It is also important to be aware of possible intraabdominal bleeding.

3 or greater late bladder and vaginal toxicities have occurred to date.

> 65 Gy and Grade > 3 late morbidity. Among patients treated

cantly better in the patient group treated with MRI‐guided IGABT.

most appropriate treatment regimen.

100 Radiotherapy

relation between rectal D2cm3

**7. Treatment‐related adverse events**

In this chapter, an overview of our experience of MRI based-IGABT for cervical cancer was described. IGABT using MRI has been widely accepted, especially in European countries, and the combination of 45 Gy in 25 fractions of EBRT without using a CS technique and more than 7 Gy × 4 fractions for HR-CTV is the most standard protocol. Pelvic IMRT has been increasingly performed. The total EQD2 delivered in this protocol is usually more than 85 Gy. Interstitial needles are often implanted for large tumors using a Vienna ring applicator, which is very suitable for combined IC/IS BT because the ring part has the source pathway and can be used as the template of the needles. Tandem and ovoid applicator which had function for the template of the interstitial needles were also reported [7]. Increasing numbers of treatment results have been reported, and the impressive role of IGABT, especially in LC, has been demonstrated when delivering more than 80 Gy as a mean total HR-CTV D90s. Therefore, many representative institutions aimed at least more than 80 Gy [9–13]. Although MRI-based IGABT has been performed since September 2014 at Kobe University, CT-based IGABT still has been performed at most Japanese institutions because of various circumstances, and interstitial needles are less frequently used. CT-based IGABT is well established; however, considerable differences in the delineation of HR‐CTV can occur as compared to MRI‐based BT. In addition, we continue to use a CS technique with EBRT and pelvic IMRT has not been accepted in the definitive RT for cervical cancer. Therefore, although successful outcomes were reported [18, 19], RT for cervical cancer in Japan is still different from that in European countries in both BT and EBRT. In the immediate future, a new treatment protocol (MRI-or CT-based? with or without the CS technique? 3D-CRT or IMRT?), which is closer to the global standard, should be established for the further development of RT treatment of cervical cancer in Japan.
