Introduction:

Small testicular masses are increasingly detected in parallel with widespread utilization of current imaging techniques such as scrotal ultrasound. The natural history of incidentally discovered small testicular masses has not been consistently demonstrated in the literature, with examples of variable histology and clinical behavior noted in small cases series. As such, current management practices remain controversial, particularly when considering active surveillance versus the need for treatment. Active surveillance is predicated on the assumption that size correlates with histology and behavior. We hypothesize that small tumors behave less aggressively, lending to management with surveillance or partial orchiectomy. In the current study, we utilize a national database to assess the behavior of small testis tumors and practice patterns in the management of small testis masses.

Methods:

Using the National Cancer Database testis cancer data set (2004-2017), we identified patients with incident diagnosis of a testicular mass <1 cm. Using descriptive statistics, we compared the distributions of patient demographics and clinical characteristics of small (<1 cm) versus large (>1 cm) tumors based on size criteria most frequently encountered in the literature. Pearson’s chi-square test was used to assess differences in the frequency of underlying tumor histology across size categories. Multivariable logistic regression was used to determine the predictive value of tumor size for high-risk pathologic features such as lymphovascular invasion. Post estimation marginal probabilities were computed from the multivariable model including patient and tumor characteristics. Finally, multivariable logistic regression was utilized to determine whether care setting (i.e. academic cancer centers compared to community centers) differed in their management of small masses.  

Results:

Compared to tumors >1 cm, small testicular masses demonstrated a higher incidence of intratubular germ cell neoplasia (ITGCN), embryonal carcinoma, mixed germ cell tumor, and Leydig cell histology (p<0.01, Figure 1). In turn, these cases demonstrated lower incidence of pure teratoma, seminoma, and yolk sac tumor. High-risk features, such as lymphovascular invasion, were less common in small masses compared to larger masses (incidence 10.2% vs 23.6%, p<0.01; Figure 2). However, post-operative tumor marker and pathologic upstaging was seen in cases of small masses at the same rate as larger masses. 

Partial orchiectomy was infrequently used as a management strategy overall, accounting for fewer than 1% of cases. However, patients with small testis masses were more likely to receive partial orchiectomy, compared to masses >1 cm in size (p<0.01). Hospital setting was not predictive of treatment modality in either group.

Conclusion:

Our study had two specific aims. First, we sought to evaluate the validity of a size hypothesis, which presumes that smaller masses have lower malignant potential when compared to larger masses. In this regard, our data is mixed. Small masses harbor ITGCN at greater rates than larger masses and have a lower incidence of lymphovascular invasion. However, small masses also harbor aggressive pathologic variants such as embryonal carcinoma. Furthermore, while we selected for patient cases with negative tumor markers at the time of initial diagnosis, the rate of nodal and marker-based upstaging was the same in both size groups. Secondly, we sought to compare management strategies between academic and community hospitals. We show that management strategy is not predicted by care setting, and that partial orchiectomy was infrequently used overall. We conclude that further data is required to determine the optimal safe management of these patients. 

Funding: N/A