**9. Conclusion**

Magnetic resonance imaging plays a key role in planning rectal cancer treatment, as it not only accurately depicts the local extent of the cancer and its anatomical positional relationship to the key structures, but can also generate relevant information for prognoses and thus can directly influence the choice of the optimal therapeutic procedure for each individual patient.

To exploit the full potential of MRI, the following must also be reported in addition to the T-stage, including the respective T3 sub-classifications:


Endosonography (EUS) is a very important complementary method, especially for determining tumor stage T1 versus T2. A CT thorax/abdomen is routinely used to assess the M status. A PET-CT does not play a significant role in local primary diagnosis and restaging. In this context, the expertise of the radiologist plays an important role, especially in more difficult restaging. We expressly encourage everyone to include 3D volumetry in the standard protocol, because this new technique is already playing an increasingly important role in precise, preoperative surgery planning.

Due to the multitude of therapeutic options available for the treatment of rectal cancer today, it has become an international standard to discuss each patient's findings pre-therapeutically in a tumor board comprising a multidisciplinary team (MDTmeetings). This procedure ensures that all therapeutic options are considered for the benefit of the patient, according to need.

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*Imaging and Diagnosis for Planning the Surgical Procedure*

*DOI: http://dx.doi.org/10.5772/intechopen.93873*

**Appendix**

**Appendix**

*Colorectal Cancer*

**Table 2.**

regression stages).

*MRI based tumor regression grading.*

**9. Conclusion**

of MRI.

surgery planning.

Good tumor regression rate in the pathological examination correlates with a tumor volume reduction of more than 70% after nCRT [21, 22] and a higher disease-free survival [21]. Moreover, a volume reduction of more than 75% is significantly associated with pCR [21, 23]. mrTRG can be used to effectively assess the response of rectal carcinomas to CRT. This classification is easy, effective and practice-oriented. According to our experience, a good agreement in histology can be achieved even with minimal training. Again, the focus should be on facilitating the identification of good responders (see **Table 2** for tumor

mrTRG-3 Moderate response >50% fibrosis or mucin lakes; detectable tumor signal. mrTRG-4 Poor response Predominance of tumor signal over fibrosis and mucin lakes.

Magnetic resonance imaging plays a key role in planning rectal cancer treatment, as it not only accurately depicts the local extent of the cancer and its anatomical positional relationship to the key structures, but can also generate relevant information for prognoses and thus can directly influence the choice of the optimal

To exploit the full potential of MRI, the following must also be reported in addi-

• the lymph node status, under consideration of the methodological limitations

Endosonography (EUS) is a very important complementary method, especially for determining tumor stage T1 versus T2. A CT thorax/abdomen is routinely used to assess the M status. A PET-CT does not play a significant role in local primary diagnosis and restaging. In this context, the expertise of the radiologist plays an important role, especially in more difficult restaging. We expressly encourage everyone to include 3D volumetry in the standard protocol, because this new technique is already playing an increasingly important role in precise, preoperative

Due to the multitude of therapeutic options available for the treatment of rectal

cancer today, it has become an international standard to discuss each patient's findings pre-therapeutically in a tumor board comprising a multidisciplinary team (MDTmeetings). This procedure ensures that all therapeutic options are considered

therapeutic procedure for each individual patient.

**Grade Response MRI Finding**

mrTRG-1 Complete response No tumor signal, nor evidence of relapse. mrTRG-2 Good response Dense fibrosis, no detectable tumor signal.

mrTRG-5 No response No change in tumor signal after therapy.

for the benefit of the patient, according to need.

tion to the T-stage, including the respective T3 sub-classifications:

• the distance to the circumferential resection margin (CRM),

• presence of extramural vascular infiltration (EMVI), and

**98**


*Colorectal Cancer*
