Treatment►
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Anal cancer treatment involves a variety of
therapies including surgery, radiation, chemotherapy, or a combination of
these.
Surgery
Historically, all but the smallest anal
cancers were treated with a radical surgery called abdominoperineal resection
leading to a permanent end colostomy. About 70% of patients survived more than
5 years in limited studies of this approach. This is no longer the primary anal
cancer treatment of choice. Chemotherapy and radiation are now favored.
A limited resection of small stage I
cancers can be curative for these small cancers of the anal margin or perianal
skin when the anal sphincter is not involved. Radical resection today is
reserved for some cases of residual or recurrent cancer in the anal canal after
non-operative treatment. Other nonsurgical approaches (involving chemotherapy
with a radiation boost or radioactive seed applications) may be used to avoid
colostomy in those circumstances.
Radiation theapy
Radiation therapy alone for localized anal
cancer may confer a greater than a 70% likelihood of 5 year survival. The high
doses of radiation used (over 60 Gy [Gy is a unit of energy absorbed from
ionizing radiation or 1 joule/Kg of matter]) can lead to significant tissue
damage and scarring sometimes necessitating colostomy surgery for control and
repair. This approach is not favored today.
Combination chemotherapy and radiation therapy
Today the optimal primary therapy for stage
I, II, IIIA, and IIIB anal cancers that are too large for potentially curative
local resection is the combination of lower doses of radiation therapy (45 to
60 Gy) combined with two older chemotherapy medicines, 5-FU and Mitomycin C.
The combination treatment results in 5-year colostomy free survival of over 75%
of stage I, 65% of stage II, and 40% to 50% of stage 3 anal cancer cases. Anal
cancers that are located in an area where they cannot be resected may benefit from
combination therapy.
Salvage chemotherapy with an alternative
regimen of the medicines 5-FU and cisplatin combined with a radiation boost can
be used for residual or recurrent local disease to avoid radical surgery.
Radioactive seed implants can be used to establish local control for residual
or recurrent disease to avoid radical surgery.
Stage IV anal cancer or metastasis treatment
Today there is no standard chemotherapy
with curative potential for metastatic disease. Local symptom control, referred
to as palliative care, is extremely important.
Rare patients with stage IV disease have
truly localized metastatic disease for which surgery to remove the metastasis
could theoretically be curative. This option should be considered in those
unusual cases. The disease is rare enough that there are no studies
specifically supporting or refuting this approach.
Patients with stage IV disease are
excellent candidates for clinical research trials if they are well enough and
give truly informed consent. A clinical trial is a research study investigating
new approaches to treatment which may benefit the patient and help develop
treatments for those patients who develop this disease in the future.
Thus for most patients with stage IV
disease the treatment options include:
Palliative surgery
Palliative radiation therapy
Palliative combined chemotherapy and
radiation
Clinical trials
