Classification of ovarian carcinoma

The TNM classification is not very well adapted to ovarian carcinoma due to the major role of surgery in obtaining an acurate classification. The FIGO (Fédération Internationale de Gynécologie et Obstétrique) classification is preferred.

The following table compares the two classification systems: a complete laparotomy and systematic histological samplings are mandatory for complete classification. Any incomplete surgery makes classification difficult, and for this reason (for instance when the lesion is apparently limited to one ovary but when no systematic samplings have been made), a new laparotomy is mandatory in order to confirm the localised characteristics of a tumour, thus avoiding unnecessary systematic chemotherapy.

TNM	FIGO	Description
Tx		Primary tumour cannot be assessed
T0		No evidence of primary ovarian tumour
T1 T1a T1b T1c	Stage I Ia Ib Ic	Tumour limited to ovary(ies) Tumour limited to 1 ovary; capsule intact, no tumour on ovarian surface. No malignant cells in ascites or peritoneal washings. Tumour limited to both ovaries; capsules intact, no tumour on ovarian surface. No malignant cells in ascites or peritoneal washings. Tumour limited to 1 or both ovaries with any of the following: capsule ruptured, tumour on ovarian surface, malignant cells in ascites or peritoneal washings.
T2 T2a T2b T2c	St II IIa IIb IIc	Tumour limited to pelvis Extension and/or implants on the uterus and/or fallopian tubes. No malignant cells in ascites or peritoneal washings. Extension to and/or implants on other pelvic tissues. No malignant cells in ascites or peritoneal washings. Pelvic extension and/or implants (stage IIA or stage IIB) with malignant cells in ascites or peritoneal washings.
T3 T3a T3b T3c or N1	St III IIIa IIIb IIIc-p et IIIc-g	Tumour limited to the abdominal cavity Microscopic peritoneal metastasis beyond pelvis (no macroscopic tumour). Macroscopic peritoneal metastasis beyond pelvis <=2 cm at largest diameter Peritoneal metastasis beyond pelvis >2 cm at largest diameter and/or Regional lymph node metastasis.
M1	St IV	Remote metastases Tumour involving 1 or both ovaries with distant metastasis. If pleural effusion is present, positive cytological test results must exist to designate a stage IV case. Parenchymal liver metastasis is equivalent to stage IV.

Therapeutic results

Here are the results of FIGO registries concerning 11,600 patients treated between 1982 and 1986. Therefore, we cannot evaluate possible recent progress (such as better use of platinum or paclitaxel). (Annual report on the results of treatment in gynecological cancer. Twenty-first volume. Statements of results obtained in patients treated in 1982 to 1986, inclusive 3 and 5-year survival up to 1990. Int J Gynaecol Obstet. 1991 Sep;36 Suppl:1-315)

Please note the important figure of stage III NP which represents cases for which details on tumour mass size during laparotomy were not recorded. The following table shows the importance of complete and quality surgery since the size of residual disease is inversely correlated to survival.

For French speaking readers, the website of Lorraine oncology network, Oncolor is a very interesting website which describes tumour classification as well decision trees.

Another interesting website for pathology is Webpath from the University de Florida.

Ch 6	Example of Cancer Classification
Classification des cancers	Ovarian carcinoma
Classification des cancers	Ovarian carcinoma

% of patients	FIGO stage	5 year Survival
27%	St I	79%
13%	St II	57%
20%	St III NP	22%
3%	St III a	49%
5%	St III b	33%
17%	St III c	19%
15%	St IV	8%

Tumour residues	Stage 3a	Stage 3b	Stage 3c
Complete surgery	83%	60%	47%
Residues <= 2cm	50%	38%	30%
Residues > 2cm	20%	25%	15%