Page 70 - Read Online

Marquina et al. J Cancer Metastasis Treat 2020;6:6 I http://dx.doi.org/10.20517/2394-4722.2019.39 Page 7 of 8

The Spanish Medical Oncology Society (SEOM) has developed an algorithm which could be useful for
[29]
the management of hyponatremia secondary to SIADH in cancer patients based on the prior algorithm
[30]
developed in Spain for hyponatremia patients .
According to the SEOM algorithm, management will depend on the two scenarios mentioned above: the
patient is a candidate vs. a non-candidate for chemotherapy.

When the patient is a candidate for chemotherapy [Figure 1]
(1) Mild hyponatremia (130-135 mmol/L): proceed with chemotherapy. Re-evaluate during the next
cycle. Note that there are discrepancies in this point, as Tolvaptan would prevent the exacerbation of
[19]
hyponatremia and the development of severe hyponatremia following the first cycle of chemotherapy ;
(2) Moderate hyponatremia (120-130 mmol/L): consider Tolvaptan if chemotherapy requires pre-hydration,
hyponatremia is progressively worsening, or hyponatremia is symptomatic. As mentioned above for mild
hyponatremia, Tolvaptan could prevent worsening hyponatremia;
(3) Severe hyponatremia (< 120 mmol/L): use the same as treatment as for severe hyponatremia. Once 24-
48 h have elapsed following therapy with hypertonic saline solution, Tolvaptan could be started.

When SIADH-induced hyponatremia is caused by the anti-cancer treatment itself (for example, vincristine) , a
[8]
modification of cancer therapy should be considered. When a change in medication is not feasible, SIADH
in these cases should be treated with Tolvaptan.

When the patient is not a candidate for chemotherapy [Figure 2]
As mentioned above, supportive treatment and treatment of hyponatremia should be prioritized according
to the severity of the symptoms, rather than the level of hyponatremia per se:
(1) Mild hyponatremia (130-135 mmol/L): focus on supportive care management;
(2) Very symptomatic moderate/severe hyponatremia (< 130 mmol/L): consider Tolvaptan. If < 120 mmol/L,
treat the acute phase with hypertonic sodium solution and, once stabilized, consider Tolvaptan;
(3) Mild symptomatic moderate/severe hyponatremia (< 130 mmol/L): focus on supportive care
management.

DECLARATIONS
Authors’ contributions
Wrote and reviewed the manuscript: Marquina G, Gomez-Hoyos E, Runkle I

Availability of data and materials
Not applicable.

Financial support and sponsorship
None.

Conflicts of interest
All authors declared that there are no conflicts of interest.

Ethical approval and consent to participate
Not applicable.

Consent for publication
Not applicable.