The evolution of tubal sterilization

Tubal ligation and risk of ovarian cancer subtypes: a pooled analysis of case-control studies

BACKGROUND

Tubal ligation is a protective factor for ovarian cancer, but it is unknown whether this protection extends to all invasive histological subtypes or borderline tumors. We undertook an international collaborative study to examine the association between tubal ligation and ovarian cancer subtypes.

METHODS

We pooled primary data from 13 population-based case-control studies, including 10,157 patients with ovarian cancer (7942 invasive; 2215 borderline) and 13,904 control women. Invasive cases were analysed by histological type, grade and stage, and borderline cases were analysed by histological type. Pooled odds ratios were estimated using conditional logistic regression to match on site, race/ethnicity and age categories, and to adjust for age, oral contraceptive use duration and number of full-term births.

RESULTS

Tubal ligation was associated with significantly reduced risks of invasive serous (OR, 0.81; 95% CI, 0.74-0.89; P < 0.001), endometrioid (OR, 0.48; 95% CI, 0.40-0.59; P < 0.001), clear cell (OR, 0.52; 95% CI, 0.40-0.67; P < 0.001) and mucinous (OR, 0.68; 95% CI, 0.52-0.89; P = 0.005) cancers. The magnitude of risk reduction was significantly greater for invasive endometrioid (P < 0.0001) and clear cell (P = 0.0018) than for serous cancer. No significant associations were found with borderline serous or mucinous tumours.

CONCLUSIONS

We found that the protective effects of tubal ligation on ovarian cancer risk were subtype-specific. These findings provide insights into distinct aetiologies of ovarian cancer subtypes and mechanisms underlying the protective effects of tubal ligation.

Surgical competence of obstetrics and gynecology residents performing microsurgical tubal anastamoses

OBJECTIVE

To assess tubal patency rates after microsurgical tubal anastamosis in a residency program.

STUDY DESIGN

Retrospective cohort analysis. Primary outcome measurement was tubal patency rates.

RESULTS

Twenty-seven of the forty-nine patients (55.1%) had bilateral tubal patency and twenty-one of the forty-nine (42.9%) had only one tube open after surgery. No statistical difference in tubal patency rate was noted between the REI staff (85.7%) and the resident (71.4%) (p=0.09). No statistical difference was noted when comparing the patency rate of the residents' first procedure (68.6%) to subsequent procedures (72.8%) (p=0.99).

CONCLUSIONS

These data suggest that with appropriate guidance, residents without prior experience are able to perform microsurgical procedures under direct supervision. Residents completed the procedure with patency rates similar to the REI staff. Additionally, tubal patency rates were not significant different in comparing the residents' first or subsequent procedures.

Tubal sterilization in relation to breast cancer risk

Tubal sterilization methods may damage surrounding tissue, potentially disrupting the ovarian blood supply and hormonal functioning, and may decrease breast cancer risk. We examined this hypothesis, within the Nurses' Health Study, among 77,511 women, aged 30-55 years and free of cancer at the start of follow-up in 1976. We documented 4,176 cases of invasive breast cancer from 1976 to 2000. Cox proportional hazards models, adjusting for multiple breast cancer risk factors, provided rate ratios (RR) and 95% confidence intervals (CI). Overall, tubal sterilization was not associated with breast cancer risk (RR=0.95, 95% CI=0.88-1.03). However, tubal sterilizations performed from 1970 to 1974 were inversely associated with risk (RR=0.84, 95% CI=0.73-0.97), while procedures performed in other years were not associated with risk. Among women with procedures performed in 1970-1974, those who were >or=35 years old at the time of sterilization were at the lowest risk (RR=0.81, 95% CI=0.66-0.98), while younger women had a suggested decreased risk (RR=0.87, 95% CI=0.72-1.06). Overall, tubal sterilization was not associated with breast cancer risk. However, a modest inverse association was observed at a time when the potentially destructive unipolar electrocautery method was commonly used, providing some support for an association between lower lifetime exposure to hormones and a decreased risk of breast cancer.

The Endosquid, a new device for laparoscopic Pomeroy tubal ligation

The Pomeroy method is a most widely practiced and most familiar form of tubal ligation. It traditionally requires laparotomy or multiple-puncture laparoscopic suturing, which is not a realistic option for the average endoscopist. We designed a 5-mm device, the Endosquid, to reproduce Pomeroy tubal ligation laparoscopically using a single 5-mm accessory puncture site. It is able to ligate, transect, and remove a loop of isthmic tube. We tested the Endosquid in a porcine model by ligating 25 bicornuate uterine horns and aortas. Ligation times averaged less than 5 minutes for each application. Gross and histologic evaluation of ligation specimens performed at necropsy confirmed correct placement. Blood loss was negligible and there were no operative complications.

Microsurgical reversal of sterilization: a six-year study

A prospective study of 113 personal consecutive microsurgical reversals of female sterilization during the 6-year period from 1979 to 1984 was carried out to determine factors affecting the pregnancy rate. The sterilizations were performed by laparoscopic unipolar coagulation in 54% of the patients, by the Pomeroy technique in 28%, by fimbriectomy in 8%, by the Irving operation in 5%, and by clips or rings in 4%. In the group with no minimum follow-up period, 50% had intrauterine pregnancies and 5% had ectopic gestations. Eighty-nine patients had at least 12 months of follow-up after reversal surgery. This group is studied in detail. Factors affecting the pregnancy rate were length of tube, type of sterilization performed, anastomotic site, and availability of both tubes for reconstruction. Age, parity, and interval from sterilization to reversal surgery did not affect the pregnancy rate. Fifty percent of the intrauterine pregnancies were conceived within 6 months of reversal surgery.