Serum calcitonin nadirs to undetectable levels within 1 month of curative surgery in medullary thyroid cancer

Abstract

Objective: Because serum calcitonin (CT) is a reliable marker of the presence, volume, and extent of disease in medullary thyroid cancer (MTC), both the ATA and NCCN guidelines use the 2-3 month post-operative CT value as the primary response to therapy variable that determines the type and intensity of follow up evaluations. We hypothesized that the calcitonin would nadir to undetectable levels within 1 month of a curative surgical procedure. Subjects and methods: This retrospective review identified 105 patients with hereditary and sporadic MTC who had at least two serial basal CT measurements done in the first three months after primary surgery. Results: When evaluated one year after initial surgery, 42 patients (42/105, 40%) achieved an undetectable basal calcitonin level without additional therapies and 56 patients (56/84, 67%) demonstrated a CEA within the normal reference range. In patients destined to have an undetectable CT as the best response to initial therapy, the calcitonin was undetectable by 1 month after surgery in 97% (41/42 patients). Similarly, in patients destined to have a normalize their CEA, the CEA was within the reference range by 1 month post-operatively in 63% and by 6 months in 98%. By 6 months after curative initial surgery, 100% of patients had achieved a nadir undetectable calcitonin, 98% had reached the CEA nadir, and 97% had achieved normalization of both the calcitonin and CEA. Conclusion: The 1 month CT value is a reliable marker of response to therapy that allows earlier risk stratification than the currently recommended 2-3 month CT measurement.

Unilateral Surgery for Medullary Thyroid Carcinoma: Seeking for Clinical Practice Guidelines

“…In 105 Brazilian MTC patients, Ctn was undetectable after the first operation: the nadir of postoperative bCtn was 63% at 1 month and 98% at 6 months ( 26 – 30 ).…”

Carcinoembryonic antigen should be concurrently checked with calcitonin to identify distant metastases in medullary thyroid cancer

“…While the calcitonin level decreased, it did not completely normalize. This likely reflects residual disease burden after surgical resection within our studied populations [21][22][23]. Given the similar change seen with CEA, this may be a basis of considering whether a similar phenomenon of 'biochemical cure' could be observed with CEA normalization.…”

Combination of ultrasound and serological tests for detecting occult lateral lymph node metastases in medullary thyroid cancer

“…26 Postoperative CEA reached the nadir in approximately 63% of cured patients in 1 month and 98% patients by 6 months postoperatively. 26 The American Thyroid Association (ATA) guideline currently recommends a serum test for calcitonin and CEA 3 months postoperatively (grade C); if results are in the normal range, followups can be carried out every 6 months for 1 year and then annually. If abnormal values are detected, especially a postoperative calcitonin above 150 pg/mL, imaging and physical examination should be additionally carried out to examine potential metastases.…”

“…Regarding the normalization of postoperative serum CEA and calcitonin, there is no consensus as to how long it takes for the markers to reach a nadir. Some studies suggest that 3 months may be a reasonable duration for calcitonin, 24,25 while other studies suggested that calcitonin should reach an undetectable nadir within 1 month postoperatively if the surgical procedure is curative 26 . Postoperative CEA reached the nadir in approximately 63% of cured patients in 1 month and 98% patients by 6 months postoperatively 26 .…”

“…Some studies suggest that 3 months may be a reasonable duration for calcitonin, 24,25 while other studies suggested that calcitonin should reach an undetectable nadir within 1 month postoperatively if the surgical procedure is curative 26 . Postoperative CEA reached the nadir in approximately 63% of cured patients in 1 month and 98% patients by 6 months postoperatively 26 . The American Thyroid Association (ATA) guideline currently recommends a serum test for calcitonin and CEA 3 months postoperatively (grade C); if results are in the normal range, follow‐ups can be carried out every 6 months for 1 year and then annually.…”