Wat complications will occur if i hav a cancer in the goiter and if it hav to be removed?

Goiter is the enlargement of the thyroid gland in front of your neck and can be due to:
Iodine deficiency
Autoimmune thyroiditis: Hashimoto or postpartum thyroiditis
Excess iodine (Wolff-Chaikoff effect) or lithium ingestion, which decrease release of thyroid hormone
Goitrogens
Stimulation of TSH receptors by TSH from pituitary tumors, pituitary thyroid hormone resistance, gonadotropins, and/or thyroid-stimulating immunoglobulins
Inborn errors of metabolism causing defects in biosynthesis of thyroid hormones
Exposure to radiation
Deposition diseases
Thyroid hormone resistance
Subacute thyroiditis (de Quervain thyroiditis)
Silent thyroiditis
Riedel thyroiditis
Infectious agents
Acute suppurative: bacterial
Chronic: mycobacteria, fungal, and parasitic
Granulomatous disease
Thyroid malignancy
The incidence of malignancy within a multinodular goiter is usually significantly less than 5%. If the nodule is cold on thyroid scanning, then it may be slightly higher than this.
The complication or prognosis of thyroid cancer depends on the type of cancer (follicular, papillary, anaplastic, medullary, etc.), size, extent (confined in the gland or invading surround tissue), lymph node involvement and distant metastasis (spread outside the area). The surgeon should remove the cancer. The Pathologist will examine the specimen and give a report with useful information for prognosis and plan for further treatment if necessary.

The most noticable problem will be your voice. Medically you'll need to take medication to replace the benefits of a healthy goiter.