From the Guidelines
Lanreotide may slow the growth of another undetected primary cancer, but only if that cancer expresses somatostatin receptors, as evidenced by the CLARINET study 1. Lanreotide is a somatostatin analog that works by binding to somatostatin receptors on tumor cells, inhibiting hormone secretion and potentially slowing tumor growth. While it's effective for neuroendocrine tumors (NETs) like pancreatic NETs that typically express these receptors, most other cancer types do not. Common cancers such as breast, lung, colon, or prostate cancer generally lack sufficient somatostatin receptor expression for lanreotide to be effective. If the undetected primary cancer happens to be another NET or a rare tumor with somatostatin receptor expression, lanreotide might provide some growth inhibition, as seen in the PROMID study 1. However, for most other cancer types, lanreotide would likely have little to no effect on tumor growth. This is why lanreotide is specifically approved for NETs and not used as a broad-spectrum anticancer agent. Comprehensive imaging and possibly additional biopsies would be necessary to identify and properly treat any second primary cancer. Some key points to consider include:
- The effectiveness of lanreotide in slowing tumor growth is dependent on the presence of somatostatin receptors on the tumor cells 1.
- The CLARINET study demonstrated the efficacy of lanreotide in improving progression-free survival in patients with locally advanced or metastatic nonfunctioning pancreatic or intestinal NETs 1.
- The PROMID study showed that octreotide LAR, another somatostatin analog, can improve time to tumor progression in patients with midgut NETs 1. It is essential to note that lanreotide's effect on tumor growth is highly specific to the type of cancer and its receptor expression, and its use should be guided by the presence of somatostatin receptors on the tumor cells.
From the FDA Drug Label
SOMATULINE DEPOT is a somatostatin analog indicated for: the treatment of adult patients with unresectable, well- or moderately-differentiated, locally advanced or metastatic gastroenteropancreatic neuroendocrine tumors (GEP-NETs) to improve progression-free survival. (1.2)
The FDA drug label does not answer the question.
From the Research
Lanreotide's Effect on Neuroendocrine Tumors
- Lanreotide, a somatostatin analogue, has been shown to exert antiproliferative effects and inhibit tumor growth via the somatostatin receptor 2 (SSTR2) 2.
- Studies such as the PROMID and CLARINET trials have demonstrated a statistically significant prolongation of time to progression/progression-free survival (TTP/PFS) upon SSA treatment, compared to placebo 2.
Lanreotide's Potential Effect on Undetected Primary Cancers
- There is no direct evidence to suggest that lanreotide would slow the growth of an undetected primary cancer elsewhere in the body.
- However, somatostatin analogues have been shown to be effective in managing hormone-related symptoms and controlling tumor growth in patients with well-differentiated neuroendocrine tumors (NETs) 3, 4.
- The efficacy of lanreotide in treating NETs is thought to be due to its ability to bind to somatostatin receptors, which are often expressed on the surface of NET cells 5.
Considerations for Metastatic Cancer of Unknown Primary
- In cases where the primary tumor is unknown, the term "primary metastatic cancer" (PMC) has been proposed to denote a distinct cancer entity 6.
- The treatment of PMC often involves a tissue-agnostic approach, targeting actionable genomic alterations rather than attempting to identify the primary tumor site 6.
- However, there is currently no evidence to suggest that lanreotide would be effective in treating PMC or slowing the growth of an undetected primary cancer.