Tumour budding refers to lone tumour cells or small clusters of tumour cells at the advancing front of a tumour.
Definition in rectal carcinoma - based on international consensus:
- Tumour bud = 1-4 cell(s) -- at the tumour front.
- Low grade: 0-4 tumour buds.
- Intermediate grade: 5-9 tumour buds.
- High grade: >=10 tumour buds.
- Assessed in a field area of 0.785 mm2.
- Microscopes with a 22 mm eye pieces typically have a 0.2376 mm*mm field area with the 40x objective; thus, three fields is 0.7128 mm*mm.
- Tumour budding was previously assessed in a field of 0.385 mm2.
- "Tumour buds suspended in pools of mucin should not be counted" as per the consensus.
- Poorly differentiated adenocarcinoma.
Tumour budding in CRC - intermed. mag. (WC)
There are <5 tumour buds/0.785 mm*mm; this tumour has low grade tumour budding.
There are 5-9 tumour buds/0.785 mm*mm; this tumour has intermediate grade tumour budding.
There are >=10 tumour buds/0.785 mm*mm; this tumour has high grade tumour budding.
The tumour is NEGATIVE for significant tumour budding (<5 buds/0.785 mm*mm).
- High risk features in colorectal adenomatous polyps.
- In-transit metastasis.
- Tumour deposits.
- Worst pattern of invasion.
- Spread through air spaces.
- Ueno, H.; Murphy, J.; Jass, JR.; Mochizuki, H.; Talbot, IC. (Feb 2002). "Tumour 'budding' as an index to estimate the potential of aggressiveness in rectal cancer.". Histopathology 40 (2): 127-32. PMID 11952856.
- Mitrovic, B.; Schaeffer, DF.; Riddell, RH.; Kirsch, R. (Oct 2012). "Tumor budding in colorectal carcinoma: time to take notice.". Mod Pathol 25 (10): 1315-25. doi:10.1038/modpathol.2012.94. PMID 22790014.
- Gujam, FJ.; McMillan, DC.; Mohammed, ZM.; Edwards, J.; Going, JJ. (Sep 2015). "The relationship between tumour budding, the tumour microenvironment and survival in patients with invasive ductal breast cancer.". Br J Cancer 113 (7): 1066-74. doi:10.1038/bjc.2015.287. PMID 26263482.
- Lugli, A.; Kirsch, R.; Ajioka, Y.; Bosman, F.; Cathomas, G.; Dawson, H.; El Zimaity, H.; Fléjou, JF. et al. (Sep 2017). "Recommendations for reporting tumor budding in colorectal cancer based on the International Tumor Budding Consensus Conference (ITBCC) 2016.". Mod Pathol 30 (9): 1299-1311. doi:10.1038/modpathol.2017.46. PMID 28548122.