AAPA STAGING 2026 ALL

ENDOMETRIUM - invasion

T1a - FIGO IA: limited to endometrium/less than ½ into myometrium

T1b - FIGO IB: ½ or more into myometrium

T2 - FIGO II: invades stromal CT of cervix, no extension beyond uterus

T3a - FIGO IIIA: invades serosa/adnexa (direct/mets)

T3b - FIGO IIIB: invades vagina (direct/mets) / parametrium

T4 - FIGO IVA: invades bladder/bowel mucosa

INVASIVE BREAST - size and extension

T1mi: ≤ 1mm in greatest dimension

T1a: > 1mm, ≤5 mm

T1b: > mm, ≤10 mm

T1c: >10 mm, ≤20 mm

T2: >20 mm, ≤50 mm

T3: >50 mm

T4a: extension to chest wall (not pectoralis muscle)

T4b: ulceration/satellite nodules/edema (peau d’orange)

T4c: T4a + T4b

T4d: inflammatory CA → clinical findings of erythema + edema of ⅓ or more of breast skin

TROPHOBLASTIC TUMORS - extension

T1- FIGO I: confined to uterus

T2 - FIGO II: extension to other genital structures (direct/mets)

M1a - FIGO III: lung mets

M1b - FIGO IV: other distant mets

VAGINA - size and extension

T1a: ≤2 cm

T1b: >2 cm

T2a: ≤2 cm, invading paravaginal tissues, not pelvic wall

T2b: >2 cm, invading paravaginal tissues, not pelvic wall

T3: extension to pelvic sidewall/causing hydronephrosis or nonfunctioning kidney

T4: invades bladder/bowel mucosa/beyond true pelvis

N1 - FIGO III: pelvic/inguinal node mets

M1 - FIGO IVB: distant mets

CERVIX - size and extension

T1a - FIGO IA: microscopic lesion, max DOI ≤5 mm

T1a1 - FIGO IA1: ≤3 mm

T1a2 - FIGO IA2: >3 mm, ≤5 mm

T1b - FIGO IB: visible lesion, DOI >5 mm, tumor size

T1b1 - FIGO IB1: DOI >5mm, ≤2 cm

T1b2 - FIGO IB2: >2 cm, ≤4 cm

T1b3 - FIGO IB3: >4 cm

T2a - FIGO IIA: upper ⅔ vagina without parametrial invasion

T2a1 - FIGO IIA1: ≤4 cm

T2a2 - FIGO IIA2: >4 cm

T2b - FIGO IIB: with parametrial invasion, not up to pelvic wall

T3a - FIGO IIIA: lower ⅓ vagina, no extension to pelvic wall

T3b - FIGO IIIB: extension to pelvic wall/causing hydronephrosis or nonfunctioning kidney

T4 - FIGO IVA: invades bladder/bowel mucosa or spread to adjacent organs

VULVA - size and extension

T1a - FIGO IA: ≤2 cm and ≤1 mm stromal invasion

T1b - FIGO IB: >2 cm or >1 mm stromal invasion

T2 - FIGO II: any size with extension to the lower ⅓ urethra, vagina, or anus

T3 - FIGO III: any size with extension to upper ⅔ urethra, vagina, or bladder/bowel mucosa

T4 - FIGO IVA: tumor fixed to pelvic bone

OVARY, FALLOPIAN TUBE, PERITONEUM - spread

T1a - FIGO IA: limited to 1 intact ovary or fallopian tube

T1b - FIGO IB: limited to both intact ovaries or fallopian tubes

T1c - FIGO IC: limited to 1 or both ovaries or fallopian tubes

T1c1 - FIGO IC1: surgical spill

T1c2 - FIGO IC2: capsule ruptured before surgery or tumor on surface

T1c3 - FIGO IC3: malignant cells in ascites or peritoneal washings

T2a - FIGO IIA: extension/implants on uterus/FT/ovaries

T2b - FIGO IIB: extension/implants on other pelvic tissues

T3a - FIGO IIIA2: microscopic extrapelvic peritoneal involvement with or without mets to retroperitoneal LN

T3b - FIGO IIIB: macroscopic peritoneal mets beyond pelvis ≤2 cm with or without mets to retroperitoneal LN

T3c - FIGO IIIC: macroscopic peritoneal mets beyond pelvic >2 cm with or without mets to retroperitoneal LN

M1 - FIGO IV: distant mets

UTERINE SARCOMA - size and extension

T1a - FIGO IA: ≤5 cm

T1b - FIGO IB: >5 cm

T2a - FIGO IIA: involves adnexa

T2b - FIGO IIB: involves other pelvic tissues

T3a - FIGO IIIA: infiltrates one site of abdomen

T3b - FIGO IIIB: infiltrates more than one site of abdomen

FIGO IIIC: mets to pelvic/para-aortic lymph nodes

T4 - FIGO IVA - invades bladder or rectum

FIGO IVB: distant mets

MELANOMA - tumor thickness and ulceration

T1a: <0.8 mm thick w/o ulceration

T1b: <0.8 mm thick with ulceration OR 0.8-1.0 mm with or without ulceration

T2a: >1-2 mm thick w/o ulceration

T2b: >1-2 mm thick with ulceration

T3a: >2-4 mm thick w/o ulceration

T3b: >2-4 mm thick with ulceration

T4a: >4 mm without ulceration

T4b: >4 mm with ulceration

SQUAMOUS CELL CARCINOMA - size and extension

T1: ≤2 cm

T2: >2 cm, ≤4 cm

T3: >4 cm OR minor bone erose or perineural invasion or deep invasion

T4a: gross cortical bone / marrow invasion

T4b: skull base invasion / foramen magnum involvement

MERKEL CELL CARCINOMA - size and extension

T1: ≤2 cm

T2: >2 cm, ≤5 cm

T3: >5 cm

T4: invades fascia, muscle, cartilage, or bone

LUNG - size and extension

T1mi: minimally invasive adenoCA

T1a: ≤1 cm

T1b: >1 cm, ≤2 cm

T1c: >2 cm, ≤3 cm

T2: invasion of main bronchus w/o carina involvement, invasion of visceral pleura OR:

T2a: >3 cm, ≤4 cm

T2b: >4 cm, ≤5 cm

T3: >5 cm, ≤7 cm OR invasion of parietal pleura

T4: >7 cm OR invasion of diaphragm, mediastinal organs; separate tumor nodule in ipsilateral lobe different from primary

MESOTHELIOMA - extension

T1: limited to ipsilateral parietal pleura, no involvement of fissure

T2: involving ipsilateral parietal pleura, involvement of fissure, parenchymal or diaphragm invasion

T3: limited to ipsilateral parietal pleura with or without involvement of fissure, invasion of mediastinal fat, pericardial surface, endothoracic fasica, chest wall soft tissue

T4: invasion of ribs, mediastinal organs, chest wall, diaphragm, pericardium, extension to contralateral pleura; malignant pericardial effusion

THYMUS - extension

T1a: no mediastinal pleura involvement

T1b: invasion of mediastinal pleura

T2: invasion of pericardium (partial/full thickness)

T3: invasion into lung, brachiocephalic vein, SVC, phrenic nerve, chest wall, hilar pulmonary vessels

T4: invasion into aorta, arch vessels, intrapericardial PA, myocardium, trachea, esophagus

RETINOBLASTOMA - EXTENSION

T1: w/o local invasion

T2a: focal choroidal invasion and pre- or intralaminar involvement of optic nerve head

T2b: invasion of stroma of iris/trabecular meshwork/Schlemm’s canal

T3a: massive choroidal invasion

T3b: invasion of optic nerve head, not involving margin

T3c: involvement of sclera within inner ⅔s

T3d: full thickness invasion into outer ⅓ of sclera/invasion into or around emissary channels

T4: extraocular tumor, at margin, invasion into meningeal spaces around optic nerve, full thickness invasion into episclera, adjacent fat, muscle, bone, conjunctiva, eyelids

UVEAL MELANOMA - extension to cillary bodies or extraocular extension

EWING SARCOMA and BONE - size

T1: ≤8 cm

T2: >8 cm

T3: discontinuous tumors at primary site

ST SARCOMA OF HEAD AND NECK - size and extension

T1: ≤2 cm

T2: >2 cm, ≤4 cm

T3: >4 cm

T4a: invasion of orbit, skull base, dura, central compartment viscera, facial skeleton, pterygoid muscles

T4b: invasion of brain parenchyma, prevertebral muscle invasion, CNS involvement by perineural spread, encasement of carotid artery

ST SARCOMA OF TRUNK/EXTREMITY/RETROPERITONEUM - size

T1: ≤5 cm

T2: >5 cm, ≤10 cm

T3: >10 cm, ≤15 cm

T4: >15 cm

ST SARCOMA OF ABDOMEN AND THORACIC - extension

T1: organ confined

T2a: invades serosa or visceral peritoneum

T2b: extends beyond serosa

T3: invades another organ

T4a: multifocal (2 sites)

T4b: multifocal (3-5 sites)

T4c: multifocal (>5 sites)

ORBITAL SARCOMA - size and extension

T1: ≤2 cm

T2: >2 cm w/o invasion of globe or bony walls

T3: any size with invasion of bony walls

T4: any size with invasion of globe

LARYNX - location and extension

T1: limited to 1 subsite of supraglottis with normal VC mobility

T2: invasion of mucosa of >1 adjacent subsite of supraglottis/glottis/region outside the supraglottis without fixation of cords

T3: limited to larynx with fixation/invasion of postcricoid area, preepiglottic space, paraglottic space, inner cortex of thyroid cartilage

T4a: moderately advanced local disease; invasion through outer cortex of thyroid cartilage/tissues beyond larynx

T4b: very advanced local disease, invasion of prevertebral space or mediastinal structures, encasement of carotid artery

LIP/ORAL CAVITY - size and extension

T1: ≤2 cm, DOI ≤5 mm

T2: ≤2 cm with DOI >5 mm OR >2 cm, ≤4 cm with DOI <10 mm

T3: >2 cm, ≤4 cm with DOI >10 mm OR >4 cm with DOI <10 mm

T4a: moderately advanced local disease, >4 cm with DOI >10 mm, invasion of adjacent structures only

T4b: very advanced local disease; invasion of masticator space, pterygoid plates, skull base, encasement of carotid artery

MUCOSAL MELANOMA H&N - extension

T3: limited to mucosa and immediate underlying soft tissue

T4a: moderately advanced disease, invasion of deep soft tissue, cartilage, bone, or overlying skin

T4b: very advanced disease, involvement of brain, dura, skull base, lower cranial nerves, masticator space, carotid artery, prevertebral space, or mediastinal structures

MAXILLARY SINUS - extension

T1: limited to mucosa with no erosion or destruction of bone

T2: causing bone erosion or destruction with extension into hard palate/middle nasal meatus

T3: invasion of bone of posterior maxillary sinus wall, subcutaneous tissues, floor or medial wall of orbit, pterygoid fossa, ethmoid sinuses

T4a: moderately advanced local disease, invasion of anterior orbital contents, skin of cheek, pterygoid plates, infratemporal fossa, cribriform plate, sphenoid or frontal sinuses

T4b: very advanced local disease, invasion of orbital apex, dura, brain, middle cranial fossa, cranial nerves

NASAL CAVITY/ETHMOID SINUS - location and extension

T1: restricted to one subsite with or without bony invasion

T2: invasion of two subsites in a single region or extension to adjacent region within nasoethmoidal complex, with or without bony invasion

T3: invades medial wall or floor of orbit, maxillary sinus, palate, cribriform plate

T4a: moderately advanced local disease, invasion of anterior orbital contents, skin of nose/cheek, min. extension to anterior cranial fossa, pterygoid plates, sphenoid or frontal sinuses

T4b: very advanced local disease, invasion of orbital apex, dura, brain, middle cranial fossa, cranial nerves

NASOPHARYNX - extension

T1: confined to nasopharynx or extension to oropharynx/nasal cavity w/o parapharyngeal extension

T2: extension to parapharyngeal space/adjacent soft tissue involvement

T3: infiltration of bony structures at skull base, cervical vertebrae, pterygoid structures/paranasal sinuses

T4: intracranial extension, involvement of cranial nerves, hypopharynx, orbit, parotid, or extensive soft tissue infiltration beyond lateral surface of lateral pterygoid muscle

p16+ (HPV+) OROPHARYNX - size and extension

T1: ≤2 cm

T2: >2 cm, ≤4 cm

T3: >4 cm or extension to lingual surface of epiglottis

T4: moderately advanced local disease, invasion of larynx, extrinsic muscle of tongue, medial pterygoid, hard palate, mandible

p16- (HPV-) OROPHARYNX - size and extension

T1: ≤2 cm

T2: >2 cm, ≤4 cm

T3: >4 cm or extension to lingual surface of epiglottis

T4a: moderately advanced local disease, invasion of larynx, extrinsic muscle of tongue, medial pterygoid, hard palate, mandible

T4b: very advanced local disease, invasion of lateral pterygoid muscle, pterygoid plates, lateral nasopharynx, or skull base, encasement of carotid

HYPOPHARYNX - size and extension

T1: limited to one subsite of hypopharynx/ ≤2 cm

T2: invasion of more than one subsite of hypopharynx or adjacent site, >2 cm, ≤4 cm without fixation of hemilarynx

T3: >4 cm or fixation of hemilarynx or extension to esophageal mucosa

T4a: moderately advanced disease, invasion of thyroid/cricoid cartilage, hyoid bone, thyroid, esophageal muscles, central compartment soft tissue

T4b: very advanced local disease, invasion of prevertebral fascia, mediastinal structures, encasement of carotid artery

SALIVARY GLANDS - size and extension

T1: ≤2 cm without extraparenchymal extension

T2: >2 cm, ≤4 cm, without extraparenchymal extension

T3: >4 cm /extraparenchymal extension

T4a: moderately advanced disease, invasion of skin, mandible, ear canal, facial nerve

T4b: very advanced disease, invasion of skull base/pterygoid plates or encasement of carotid artery

BLADDER - invasion

T1: invasion of lamina propria

T2a: invasion of superficial muscularis propria

T2b: invasion of deep muscularis propria

T3a: invasion of perivesical soft tissue microscopically

T3b: invasion of perivesical soft tissue macroscopically

T4a: invades directly into prostatic stroma, seminal vesicles, uterus, vagina

T4b: invades pelvic or abdominal wall

URETHRA - invasion

T1: invasion of subepithelial connective tissue

T2: invasion into corpus spongiosum, periurethral muscle

T3: invasion into corpus cavernosum, anterior vagina

T4: invasion of adjacent organs

PROSTATIC URETHRA - invasion

T1: invasion of urethral subepithelial connective tissue underlying urothelium

T2: invasion of prostatic stroma surrounding ducts either by direct 9extension from urothelial surface or by invasion from prostatic ducts

T3: invasion of periprostatic fat

T4: invasion of adjacent organs

URETER/RENAL PELVIS - invasion

T1: invasion of subepithelial connective tissue

T2: invasion muscularis

T3: renal pelvis - invasion into peripelvic fat or renal parenchyma; ureter - invasion into periureteric fat

T4: invasion of adjacent organs, or through kidney into perinephric fat

TESTIS - size and extension

T1a: ≤3 cm

T1b: >3 cm

T2: limited to testis with lymphovascular invasion OR invasion of hilar soft tissue or epididymis or penetration of visceral mesothelial layer covering external surface of tunica albuginea with or without lymphovascular invasion

T3: invasion of spermatic cord soft tissue with or without lymphovascular invasion

T4: invasion of scrotum with or without lymphovascular invasion

PROSTATE - extension

T1a: incidental histologic finding in ≤5% tissue resected

T1b: incidental histologic finding in >5% tissue resected

T1c: identified by needle biopsy found in one or both sides, not palpable

T2a: involves ≤ ½ of one side

T2b: involves > ½ of one side but not both

T2c: involves both sides

T3a: extraprostatic extension (unilateral/both)

T3b: invasion of seminal vesicles

T4: fixed or invades external sphincter, rectum, bladder, levator muscles, pelvic wall

PENIS - invasion

T1: invasion depending on site:

Glans - invasion of lamina propria

Foreskin - invasion of dermis, lamina propria, dartos fascia

Shaft -invades connective tissue between epidermis and corpora

T1a: without lymphovascular/perineural invasion/ not high grade

T1b: with lymphovascular/perineural invasion/high grade

T2: invasion into corpus spongiosum with or without urethral invasion

T3: invasion into corpora cavernosum with or without urethral invasion

T4: invasion into adjacent structures

KIDNEY - size and extension

T1a: ≤4 cm

T1b: >4 cm, ≤7 cm

T2a: >7 cm, ≤10 cm

T2b: >10 cm

T3a: extension to renal vein or pelvicalyceal system, or invasion of perirenal/sinus fat but not beyong Gerota’s fascia

T3b: extension to vena cava below diaphragm

T3c: extension to vena cava above diaphragm or invasion of vena cava wall

T4: invasion beyond Gerota’s fascia

STOMACH - invasion

T1a: invasion of lamina propria or muscularis mucosa

T1b: invasion of submucosa

T2: invasion of muscularis propria

T3: penetrates subserosal CT without invasion of visceral peritoneum or adjacent structures

T4a: invasion of serosa

T4b: invasion of adjacent structures/organs

SMALL INTESTINE - invasion

T1a: invasion of lamina propria

T1b: invasion of submucosa

T2: invasion of muscularis propria

T3: invasion into subserosa or nonperitonealized perimuscular tissue without serosal penetration

T4: invasion into the visceral peritoneum or invasion of other organs or structures

PERIHILAR BILE DUCTS - invasion

T1: confined to bile duct with extension up to muscle layer or fibrous tissue

T2a: invasion beyond bile duct wall to surrounding adipose tissue

T2b: invasion of adjacent hepatic parenchyma

T3: invasion of unilateral branches of portal vein or hepatic artery

T4: invasion of main portal vein or branches bilaterally, or common hepatic artery

EXOCRINE PANCREAS - size and extension

T1a: ≤0.5 cm

T1b: >0.5 cm, ≤1 cm

T1c: >1 cm, ≤2 cm

T2: >2 cm, ≤4 cm

T3: >4 cm

T4: involvement of celiac axis, superior mesenteric artery or common hepatic artery

INTRAHEPATIC BILE DUCTS - size and extension

T1a: ≤5 cm without vascular invasion

T1b: >5 cm without vascular invasion

T2: intrahepatic vascular invasion or multiple tumors, with or without vascular invasion

T3: invasion into visceral peritoneum

T4: invasion of local extrahepatic structures by direct invasion

DISTAL EXTRAHEPATIC BILE DUCTS - depth and invasion

T1: invasion of wall with depth ≤5 mm

T2: invasion of wall with depth >5 mm, ≤12 mm

T3: invasion of wall with depth >12 mm

T4: involvement of celiac axis, superior mesenteric artery or common hepatic artery

HEPATOCELLULAR CARCINOMA - size and focality

T1a: single tumor ≤2 cm

T1b: single tumor >2 cm without vascular invasion

T2: single tumor >2 cm with vascular invasion, multiple tumors ≤5 cm

T3: multiple tumors, at least one >5 cm

T4: one or more tumors of any size invading major branch of portal vein or hepatic vein, or tumors with direct invasion of adjacent organs or visceral peritoneum

GIST - size

T1: ≤2 cm

T2: >2 cm, ≤5 cm

T3: >5 cm, ≤10 cm

T4: >10 cm

GALLBLADDER - invasion

T1a: invasion of lamina propria

T1b: invasion of muscular layer

T2a: invasion of perimuscular CT on peritoneal side without involvement of serosa

T2b: invasion of perimuscular CT on hepatic side, no liver extension

T3: perforation of serosa or invasion of liver or adjacent organs/structures

T4: invasion of main portal vein, hepatic artery, or invades two or more extrahepatic organs or structures

ESOPHAGUS - invasion

T1a: invasion of lamina propria, muscularis mucosa

T1b: invasion of submucosa

T2: invasion of muscularis propria

T3: invasion of adventitia

T4a: resectable tumor invading pleura, pericardium, azygos vein, diaphragm or peritoneum

T4b: invasion of aorta, vertebral body, or airway

COLON/RECTUM - invasion

T1: invasion of submucosa

T2: invasion of muscularis propria

T3: invasion into pericolorectal tissues

T4a: invasion through visceral peritoneum

T4b: invasion or adherence to adjacent organs or structures

APPENDIX - invasion

Tis: LAMN

T1: invasion of submucosa

T2: invasion of muscularis propria

T3: invasion of subserosa or mesoappendix

T4a: invasion of serosa

T4b: invasion or adherence to adjacent organs or structures

ANUS - size and extension

T1: ≤2 cm

T2: >2 cm, ≤5 cm

T3: >5 cm

T4: invasion of adjacent organs

AMPULLA OF VATER - invasion

T1a: limited to ampulla of Vater or sphincter of Oddi

T1b: invasion beyond sphincter or into duodenal submucosa

T2: invasion into muscularis propria of duodenum

T3a: invasion of pancreas (≤0.5 cm)

T3b: invasion >0.5 cm into pancreas, or extension into peripancreatic tissue or periduodenal tissue or duodenal serosa without involvement of celiac axis or SMA

T4: invasion of celiac axis, SMA, or common hepatic artery

THYROID - size and extension

T1a: ≤1 cm

T1b: >1 cm, ≤2 cm

T2: >2 cm, ≤4 cm

T3a: >4 cm

T3b: gross extrathyroidal extension invading only strap muscles, any size

T4a: gross extrathryoidal extension invading subcutaneous soft tissues, larynx, trachea, esophagus, or recurrent laryngeal nerve, any size

T4b: gross extrathryoidal extension invading prevertebral fascia or encasing carotid artery, or mediastinal vessels

MEDULLARY THYROID CA - size and extension

T1a: ≤1 cm

T1b: >1 cm, ≤2 cm

T2: >2 cm, ≤4 cm

T3a: >4 cm limited to thyroid

T3b: gross extrathyroidal extension invading only strap muscles, any size

T4a: moderately advanced disease, gross extrathyroidal extension into nearby tissues of neck

T4b: very advanced disease, extension toward the spine or into nearby large blood vessels

STOMACH NET - size and invasion

T1: invasion of mucosa/submucosa and ≤1 cm

T2: invasion of muscularis propria into subserosal tissue without penetration of overlying serosa

T3: invasion through muscularis propria into subserosal tissue without penetrating serosa

T4: invasion of serosa or other adjacent organs or structures

ENDOCRINE PANCREAS - size and invasion

T1: ≤2 cm

T2: >2 cm, ≤4 cm

T3: >4 cm or invasion of duodenum, ampulla of vater, or CBD

T4: invasion of adjacent organs, or wall of large vessels

JEJUNUM/ILEUM NET - size and invasion

T1: invasion of mucosa/submucosa and ≤1 cm

T2: invasion of muscularis propria or >1 cm

T3: invasion through muscularis propria into subserosal tissue without penetrating serosa

T4: invasion of serosa or other adjacent organs or structures

DUODENAL/AMPULLA NET - size and extension

T1: duodenal - invasion of mucosa and submucosa, ≤1 cm; ampulla - ≤1 cm confined within sphincter

T2: duodenal - invasion of muscularis propria, >1 cml ampulla - invasion through sphincter into duodenal submucosa or muscularis propria, >1 cm

T3: invasion of pancrea or peripancreatic soft tissue

T4: invasion of seros or other organs

COLON NET - size and invasion

T1a: ≤1 cm

T1b: >1, ≤2 cm

T2: >2 cm, invasion of muscularis propria

T3: invasion of subserosal tissue without involvement of serosa

T4: invasion of serosa or adjacent organs/structures

APPENDIX NET - size and invasoon

T1: ≤2 cm

T2: >2 cm, ≤4 cm

T3: >4 cm or with subserosal invasion or mesoappendix

T4: invasion of peritoneum or adjacent organs/structures

ADRENAL GLAND - size and invasion

T1: ≤5 cm, no extra-adrenal invasion

T1: >5 cm, extra-adrenal invasion

T3: any size with local invasion but not invading adjacent organs

T4: any size with invasion of adjacent organs (kidney, diaphragm, pancreas, spleen, liver) or renal vein/vena cava