Placenta

• All gestational trophoblastic neoplasms (GTN) are covered by this staging system
• These topics are not covered: nongestational trophoblastic tumors (e.g., ovarian choriocarcinoma), benign trophoblastic tumors (e.g., placental site nodule, complete and partial hydatidiform moles)

• Not applicable

Notes:

• N classification is not used in the staging of gestational trophoblastic neoplasm, as nodal involvement is rare and portends an extremely poor prognosis
• Any lymph node metastasis should be classified as metastatic (M1b) disease

• pM0: no distant metastasis
• pM1: distant metastasis
  • pM1a: lung metastasis
  • pM1b: all other distant metastasis

Notes:

• Any lymph node metastasis should be classified as metastatic (M1b) disease
• Lung is the most common site of metastasis and is not considered an adverse prognostic factor

Prognostic factor	Risk score
	0	1	2	4
Age	< 40	≥ 40	-	-
Antecedent pregnancy	Mole	Abortion	Term	-
Interval months from index pregnancy	< 4	4 - 6	7 - 12	> 12
Pretreatment hCG (IU/mL)	< 103	103 - < 104	104 - < 105	≥ 105
Largest tumor size, including uterus (cm)	< 3	3 - 5	> 5	-
Site of metastases	Lung	Spleen, kidney	GI tract	Brain, liver
Number of metastases	-	1 - 4	5 - 8	> 8
Previous failed chemotherapy	-	-	Single drug	2 or more drugs

Note:

• Lung is the most common site of metastasis and is not considered an adverse prognostic factor

TNM classification		FIGO stage	Stage with risk score
T1	M0	I	I: risk score
T2	M0	II	II: risk score
Any T	M1a	III	III: risk score
Any T	M1b	IV	IV: risk score

Contributed by Elizabeth Kertowidjojo, M.D., Ph.D., M.P.H.

Contributed by Elizabeth Kertowidjojo, M.D., Ph.D., M.P.H.

Which of the following is the pTNM stage (per the AJCC 8th edition) of the gestational trophoblastic neoplasm in the image above? The tumor involves the uterus and bilateral ovaries with metastases to the lung.

1. pT1 M0, FIGO stage I
2. pT1 M1a, FIGO stage III
3. pT2 M0, FIGO stage II
4. pT2 M1a, FIGO stage III
5. pT2 M1b, FIGO stage IV

D. pT2 M1a, FIGO stage III. The figure shows a trophoblastic tumor with geographic necrosis, consistent with an epithelioid trophoblastic tumor. Any tumor with M1a, regardless of the pT status, is staged as FIGO stage III. Answers A and B are incorrect because metastasis to other genital structures is present, which makes this case a pT2 tumor. Answer C is incorrect because this case shows metastasis to the lung, classifying it as a M1a tumor. Answer E is incorrect because the tumor shown would be classified as stage III not IV as it does not extend to other sites outside of the reproductive organs or lungs.

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Reference: Staging-gestational trophoblastic neoplasms

A 32 year old woman was diagnosed with a placental site trophoblastic tumor. She had a missed abortion 2 years prior to diagnosis. Her serum hCG before surgery was 550 mIU/mL. Imaging did not identify any metastatic foci. The patient underwent a total hysterectomy and bilateral salpingo-oophorectomy. The tumor was found to measure 6.5 cm in greatest dimension with focal extension into the right ovary. What is her FIGO stage and prognostic score?

1. FIGO stage I; risk score 4
2. FIGO stage I; risk score 5
3. FIGO stage II; risk score 4
4. FIGO stage II; risk score 7
5. FIGO stage III; risk score 7

D. FIGO stage II; risk score 7. Involvement of the ovary and the lack of metastasis makes this a pT2 M0 tumor, which corresponds to FIGO stage II. The patient is < 40 years old (score 0) with an antecedent abortion (score 1) which occurred 2 years prior (score 4). Her pretreatment hCG is below 1,000 IU/mL (score 0) and her largest tumor size is 6.5 cm (score 2). She has no metastatic disease or involvement beyond the reproductive organs (score 0 + 0) and no prior treatment (score 0). Taken together, her prognostic score is 0 + 1 + 4 + 0 + 2 + 0 + 0 + 0 = 7.

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Reference: Staging-gestational trophoblastic neoplasms