Can vocal cord nodules turn cancerous?

No: Often the word "nodule" is used to describe various types of growths on the vocal folds. Classic bilateral screamer's or singer's noduels do not turn cancerous. If you have a unilateral "nodule" and are a smoker and alcohol user, i would be more concerned and would recommend further evaluation.

Unlikely: Most nodules are benign but like any growth rarely they can be malignant. Some nodules may be premalignant and over time - especially in smokers - they can become cancerous.

Not if it's a nodule: By definition, vocal cord nodules are benign (not cancerous). If the lumps on the vocal cords are not nodules, that's a different story.