Investigations
1st investigations to order
anoscopy
Test
The most effective way to visualise the tumour and the area to biopsy.
Result
anal mass seen
biopsy of tumour
Test
Confirms the diagnosis. An excisional biopsy can be performed on small superficial lesions. In other cases, an incisional biopsy is recommended.
Result
cancerous cells seen on pathological examination
pelvis MRI scan
Test
High resolution T2-weighted MRI or CT of the pelvis should be performed to assess the primary tumour and pelvic lymph nodes, and to evaluate whether the tumour involves other organs.[4][8] US guidelines advise using either CT with contrast or MRI with contrast to evaluate the pelvis.[8] European guidelines recommend using MRI pelvis for assessment of the primary tumour and CT pelvis with contrast to screen for metastatic disease.[4]
Result
anatomical extent of primary tumour, lymphadenopathy, involvement of other pelvic organs
pelvis CT scan
Test
CT or high resolution T2-weighted MRI of the pelvis should be performed to assess the primary tumour and pelvic lymph nodes, and to evaluate whether the tumour involves other organs.[4][8] US guidelines advise using either CT with contrast or MRI with contrast to evaluate the pelvis.[8] European guidelines recommend using MRI pelvis for assessment of the primary tumour and CT pelvis with contrast to screen for metastatic disease.[4]
CT-based simulation is conducted for radiotherapy planning. (18F)-fluoro-2-deoxy-D-glucose (FDG)-PET/CT, FDG-PET/MRI, and MRI pelvis results may also influence planning, in particular dose or field changes.[8][33]
Result
anatomical extent of primary tumour, lymphadenopathy, involvement of other pelvic organs
abdominal and chest CT scan
Test
Abdominal and chest CT scans are done routinely to evaluate for distant metastases.[4][8]
Twelve percent of patients have distant metastases at the time of diagnosis.[17] The para-aortic nodes and the liver are the most common sites of metastatic spread. Lungs, bones, skin, and peritoneum are less frequently affected.[4]
Result
metastatic lesions may be visualised
Investigations to consider
PET scan
Test
FDG-PET/CT and FDG-PET/MRI scans are included in the standard staging of anal cancer and should be considered, in addition to standard diagnostic imaging with CT or MRI.[8]
PET/CT has a sensitivity of 99% for the detection of primary disease and a sensitivity of 93% for the detection of inguinal lymph node involvement.[33][34] In one meta-analysis, PET/CT led to a change in nodal staging in 28% of patients.[34]
CT-based simulation is conducted for radiotherapy planning. FDG-PET/CT, FDG-PET/MRI, and MRI pelvis results may also influence planning, in particular dose or field changes.[8][33]
Result
primary tumour seen; metastatic lesions may be able to be visualised; upstaging or downstaging of patient
inguinal node needle biopsy
Test
Performed as part of the initial work-up if the patient has enlarged inguinal lymph nodes.[4]
Result
cancerous cells seen on pathological examination
serum HIV enzyme-linked immunosorbent assay (ELISA)
Test
HIV testing is recommended for patients with anal cancer whose HIV status is unknown.
Result
may be positive
cervical cancer screening
Test
Female patients with anal cancer should be offered screening for synchronous cervical epithelial neoplasia, vulvar intraepithelial neoplasia, and vaginal intraepithelial neoplasia, which are also associated with human papillomavirus infection.[4]
Result
may show cervical intraepithelial neoplasia or invasive cervical cancer
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