Early stage colorectal cancer is treated with surgery, while more advanced stages receive surgery plus chemotherapy or radiation and chemotherapy. Metastatic or recurrent disease is treated with chemotherapy, targeted therapy, and sometimes radiation or surgery. Radiation is commonly used to treat rectal cancer before or after surgery to reduce the risk of local recurrence. It can safely expand the surgical resection area and increase the chance of sphincter preservation. Radiation techniques use imaging like CT and PET scans to precisely target the radiation dose to areas at risk while minimizing side effects. Radiation can also effectively palliate symptoms from recurrent or metastatic colorectal cancer.
4. Treatment of colorectal
cancer
• Early stages are treated with surgery
• More advanced stages have surgery followed
by chemotherapy (colon) or radiation and
chemotherapy prior to surgery (rectum)
• Metastatic or recurrent disease treated with
chemotherapy or targeted therapy and
possibly radiation, some patients benefit from
surgical resection or RF ablation
10. Radiation can safely cover the sites
where rectal cancer is most likely
to recur
3D reconstruction of sites of relapse in patients with rectal cancer
15. Imaging rectal cancer radiation fields
Portal image (x-ray
image showing the
area of radiation (light
blue)
Computer generated
radiation target (dark blue)
16. Sites of Relapse in Red
Based on the location of
the most common sites for
a relapse after surgery the
radiation field in green
should be large enough to
cover these areas
18. Radiation Fields
• Include the tumor and tumor bed with
a 2 to 5cm margin
• Include the presacral nodes and internal iliac nodes
• Include the external iliac nodes if T4 involving
anterior structures
• Top: Usually L5-S1 or 1.5cm above sacral
promontory and the bottom 4 to 5cm below edge of
tumor
• Posterior 1cm behind the sacrum and anterior the
post wall of the vagina or a large portion of the
prostate
34. PET Scan will also show if
the cancer has spread
elsewhere in the body such
as the lymph nodes or liver
This case show areas of
liver metastases so the
patient would be classified
as having stage IV rectal
cancer and would need
chemotherapy
36. Benefit of Combining chemoradiation
with surgery for rectal cancer
• Will lower the risk of a local
recurrence in the pelvic region and
improve survival
• If given prior to surgery may help the
surgeon avoid a permanent
colostomy
• If given before surgery may be less
complications than if given after
surgery
37. Improved Outcome after Surgery by
Adding Chemoradiation
Gastrointestinal Tumor Study Group
N Engl J Med 1985; 312:1465-1472
38. German Trial of PreOp or PostOp
Chemoradiation for Rectal Cancer
NEJM 2004;351:1731
Outcome PreOp PostOp
Survival 76% 74%
Local Relapse 6% 13%
Complication 27% 40%
41. Appearance of
advanced rectal cancer
at colonoscopy before
chemoradiation
Appearance after
PreOp Chemoradiation for
Locally Advanced Rectal Cancer
42. PreOp Chemoradiation for Locally Advanced
Rectal Cancer and Sphincter Preservation
Shrink the size or bulk
of the tumor A to B to
make surgery easier
Shrink the
location away
from the sphincter
making surgery
possible
43. Benefits of preOp chemoradiation for
Rectal Cancer in Avoiding a
Permanent Colostomy
In series where patients were expected
to require a colostomy, after preOp
therapy the number who were able to
avoid a permanent colostomy (sphincter
preservation) in such reports ranges
from 39 to 94 percent, averaging 67
percent
44. Typical Course of Preoperative radiation
• Daily radiation (Monday through Friday) 5 days a week for 28
treatments (so 5 and half weeks
• Treatments generally take about 10 minutes
• Radiation is combined with daily chemotherapy (usually continuous
IV infusion of 5FU)
• Side effects typically show up after the second week and fade away
starting a week or two after completion
• Surgery is generally scheduled 3 to 6 weeks after completing the
radiation
• Further chemotherapy is often given after surgery
45. Side Effects of Pelvic Radiation
Radiation fields
Radiation may hit the small
bowel causing some
cramps, diarrhea and fatigue
Fatigue, diarrhea, loss of appetite and rectal
irritation are very common during the combined
chemoradiation period
46. Side Effects of Pelvic Radiation
Radiation fields
Radiation may hit the
bladder and rectum causing
urinary burning or frequency
and rectal irritation
In pre-menopausal women, radiation is likely to effect
ovarian function and should not be used if the woman is
pregnant
51. Combine a CT scan and linear accelerator to ultimate in
targeting (IGRT) and ultimate in delivery (dynamic, helical
IMRT) ability to daily adjust the beam (ART or adaptive
radiotherapy)
Image Guided (IGRT) and Intensity
Modulated Radiation Therapy (IMRT
52. Using image guided IMRT can better target the
cancer and limit the dose to normal structures
53. Clinical outcomes using stereotactic body
radiotherapy for abdominopelvic tumors.
Department of Radiation Oncology, Mayo
Clinic
Tumor responses of the 48 target were
complete response in 18 lesions (36%), partial
response in 12 lesions (24%), stable disease
in 12 lesions (24%), and progressive disease
in 6 lesions (12%).
So 60% response
Am J Clin Oncol. 2012 Dec;35(6):537-42.
58. A phase I/II dose-escalation trial of
Cyberknife radiation for control of primary
or metastatic liver disease
Early toxicity has been mild with 3 patients (13%) experiencing grade 2 or
greater toxicity. In the 21 patients with >3 month follow-up, 3 (14%) have
experienced a late toxicity. There have been 6 local recurrences. The lesion
local recurrence rate is 17% and the patient local recurrence rate is 25%.
Mean time to recurrence was 8.4 months.
Conclusion: Cyberknife radiation can be delivered safely in doses up to 30
Gy in a single fraction. Accrual of long-term local control and toxicity data is
ongoing.
61. Radiosurgery for Brain Metastases
from colorectal Cancer
152 patients with 616 tumors for metastatic brain
tumors from colorectal cancer
The primary tumors were located in the colon in 88
patients and the rectum in 64.
The local tumor growth control rate, based on MR
imaging, was 91.2%
Cause of death was systemic in 90% and brain 10%
J Neurosurg. 2011 Mar;114(3):782-9