Testicular Cancer as a Model for Understanding the Impact of Evolving Treatment Strategies on the Long-Term Health of Cancer Survivors

An exploration of testicular cancer survivors' experience of ejaculatory dysfunction following retroperitoneal lymph node dissection-a sub-study of the PREPARE clinical trial

PURPOSE

Ejaculatory dysfunction secondary to retrograde ejaculation or anejaculation is a complication of retroperitoneal lymph node dissection (RPLND) for survivors of testicular cancer. We explored survivors' experiences of ejaculatory dysfunction following RPLND.

METHODS

In a sub-study of a single-arm phase 2 clinical trial (ACTRN12622000537752/12622000542796), participants reporting ejaculatory dysfunction ≥ 6 months following RPLND were invited to complete semi-structured interviews. Purposive sampling was used. Interviews continued until thematic saturation occurred, and codebook thematic analysis of interviews was performed.

RESULTS

Of 58 individuals recruited to the trial, 33 (57%) reported ejaculatory dysfunction. Of these, 32 (97%) agreed to interview and 15 participated. Participants interviewed had median age 34 years (range 24-66), 12 (80%) in a long-term relationship with median time from surgery 36 months (range 11-112). Three overarching themes were identified. The first reflected the value of RPLND despite ejaculatory dysfunction. The second illuminated the impact(s) of ejaculatory dysfunction closely mapped to life stage, with flow-on impacts to fertility, sex, psychological wellbeing and communication. The third reflected information needs. Fertility was a substantial source of concern for some participants. Ejaculatory dysfunction had no effect on sex for some, whilst for others, sex was less pleasurable. Some reported benefits. Few reported ejaculatory dysfunction challenged masculinity, confidence, or self-esteem.

CONCLUSIONS

Future research should examine interventions to reduce distress related to fertility, challenged masculinity and body image.

IMPLICATIONS FOR CANCER SURVIVORS

Whilst most participants considered ejaculatory dysfunction to have little impact on their sexual function and relationships, some reported significant difficulties varying by life stage and relationship status.

Bias correction for estimates from linear excess relative risk models in small case-control studies

Epidemiologic studies conducted to quantify the impact of radiation dose d on an outcome typically model the hazard ratio (HR) for association using a linear term, HR ( d ) = 1 + β d , via a linear excess relative risk (ERR) model, based on biological considerations. To study associations of risk of a second cancer with radiation treatment for a first cancer, several nested case-control designs to estimate β have been proposed that use refined doses received by different locations in the organ of interest. Here we first evaluated the small sample bias in maximum likelihood estimates of β for the linear ERR model using location-specific radiation doses in simulations. As we found substantial upward bias for studies of realistic sample sizes (more than 50% relative bias for studies with 75 cases), we also proposed and investigated several approaches to correct this bias. We studied first and second order jackknife bias corrections and we derived a modified set of score functions under retrospective case-control sampling, from which we directly obtained bias-corrected estimates. In simulations based on doses from a study of stomach cancer among testicular cancer survivors and synthetically generated data, neither the first nor second order jackknife bias correction performed well. Estimates based on the modified score equations corrected the bias much better, albeit not completely, and were numerically much more stable.