Risk of Scrotal Hydroceles After Nephrectomy For Kidney Cancer

\*Laparoscopic total nephrectomy\*

Inclusion criteria

Male individuals who underwent laparoscopic complete/total nephrectomy between April 1, 2002, and March 31, 2024, with a most responsible diagnosis of malignant kidney, renal pelvis, or ureter cancer at the time of nephrectomy. The index date is defined as the date of the first laparoscopic total nephrectomy during the study period.

Exclusion criteria

* Individuals with data record errors (e.g., missing or invalid age, sex, or date of birth), who are less than 0 years of age or greater than 105 years of age, with a death record on or before their cohort entry, or have a date of last contact \<4 months after cohort entry (to restrict to permanent residents of the province).
* Prior partial nephrectomy at any time in the lookback.
* Prior total nephrectomy before the start of accrual.
* Individuals who underwent conversion from laparoscopic to open nephrectomy during the same surgical episode.
* Individuals with no recorded primary care visit in the year prior to the index date.
* History of scrotal or male genital conditions or procedures prior to the index date, including hydrocele, hydrocelectomy, scrotal ultrasound, scrotal or testicular malignancy, or other scrotal/genital procedures.

\*Laparoscopic partial nephrectomy\*

Inclusion criteria

Male individuals who underwent laparoscopic partial nephrectomy between April 1, 2002, and March 31, 2024, with a most responsible diagnosis of malignant kidney, renal pelvis, or ureter cancer at the time of nephrectomy. The index date is defined as the date of the first laparoscopic partial nephrectomy during the study period.

Exclusion criteria

* Individuals with data record errors (e.g., missing or invalid age, sex, or date of birth), who are less than 0 years of age or greater than 105 years of age, with a death record on or before their cohort entry, or have a date of last contact \<4 months after cohort entry (to restrict to permanent residents of the province).
* Prior total nephrectomy at any time in the lookback.
* Any nephrectomy before the start of accrual.
* Individuals who underwent conversion from laparoscopic to open nephrectomy during the same surgical episode.
* Individuals with no recorded primary care visit in the year prior to the index date.
* History of scrotal or male genital conditions or procedures prior to the index date, including hydrocele, hydrocelectomy, scrotal ultrasound, scrotal or testicular malignancy, or other scrotal/genital procedures.

\*Open total nephrectomy\*

Inclusion criteria

Male individuals who underwent open complete/total nephrectomy between April 1, 2002, and March 31, 2024, with a most responsible diagnosis of malignant kidney, renal pelvis, or ureter cancer at the time of nephrectomy. The index date is defined as the date of the first open total nephrectomy during the study period.

Exclusion criteria

* Individuals with data record errors (e.g., missing or invalid age, sex, or date of birth), who are less than 0 years of age or greater than 105 years of age, with a death record on or before their cohort entry, or have a date of last contact \<4 months after cohort entry (to restrict to permanent residents of the province).
* Prior partial nephrectomy at any time in the lookback.
* Prior total nephrectomy before the start of accrual.
* Individuals who underwent conversion from laparoscopic to open nephrectomy during the same surgical episode.
* Individuals with no recorded primary care visit in the year prior to the index date.
* History of scrotal or male genital conditions or procedures prior to the index date, including hydrocele, hydrocelectomy, scrotal ultrasound, scrotal or testicular malignancy, or other scrotal/genital procedures.

\*Open partial nephrectomy\*

Inclusion criteria

Male individuals who underwent open partial nephrectomy between April 1, 2002, and March 31, 2024, with a most responsible diagnosis of malignant kidney, renal pelvis, or ureter cancer at the time of nephrectomy. The index date is defined as the date of the first open partial nephrectomy during the study period.

Exclusion criteria

* Individuals with data record errors (e.g., missing or invalid age, sex, or date of birth), who are less than 0 years of age or greater than 105 years of age, with a death record on or before their cohort entry, or have a date of last contact \<4 months after cohort entry (to restrict to permanent residents of the province).
* Prior total nephrectomy at any time in the lookback.
* Any nephrectomy before the start of accrual.
* Individuals who underwent conversion from laparoscopic to open nephrectomy during the same surgical episode.
* Individuals with no recorded primary care visit in the year prior to the index date.
* History of scrotal or male genital conditions or procedures prior to the index date, including hydrocele, hydrocelectomy, scrotal ultrasound, scrotal or testicular malignancy, or other scrotal/genital procedures.

\*Non-Nephrectomy Control Cohort\*

Inclusion criteria

The control cohort will consist of male individuals identified in RPDB. Index dates will be randomly assigned by bootstrapping dates from the appropriate nephrectomy group, such that each control is assigned an actual nephrectomy index date randomly sampled with replacement from that group. Controls will be carefully screened to ensure that none are included in the nephrectomy cohort being compared.

Exclusion criteria

* Individuals with data record errors (e.g., missing or invalid age, sex, or date of birth), who are less than 0 years of age or greater than 105 years of age, with a death record on or before their cohort entry, or have a date of last contact \<4 months after cohort entry (to restrict to permanent residents of the province).
* Any nephrectomy (partial or total).
* Individuals with no recorded primary care visit in the year prior to the index date.
* History of scrotal or male genital conditions or procedures prior to the index date, including hydrocele, hydrocelectomy, scrotal ultrasound, scrotal or testicular malignancy, or other scrotal/genital procedures.