Night sweats, unexplained fevers and sudden weight loss belong to a generalized set of symptoms known as B symptoms. However, night sweats can occur whether a person has lymphoma or not.
Combined with other symptoms, a clinical exam and some scans, night sweats can indicate Hodgkin's lymphoma.
Oprah's own Dr. Oz discusses night sweats in the context of menopause. He mentions lymphoma at about the 3:30 mark, but for the most part this is a practical video for women approaching perimenopause.
Meanwhile, WebMD examines eight causes of night sweats, noting that the disease most commonly associated with night sweats isn't lymphoma, but tuberculosis.
The American Academy of Family Physicians (AAFP) points out that night sweats can be caused by a wide variety of conditions and situations, including:
Although it is well-established that night sweats are a common symptom of Hodgkin's lymphoma, the reason for this remains unclear. However, it is important to keep in mind that another of the B symptoms associated with Hodgkin's is persistent fevers. It has been postulated that the fevers one experiences with Hodgkin's may be causing the night sweats, similar to when you have the flu and your fever breaks overnight. What happens? You wake up with sheets soaked from sweating.
The AAFP writes:
High fluctuating fevers accompanied by drenching night sweats (Pel-Ebstein fevers) may persist for several weeks with Hodgkin's disease. Night sweats may be the only presenting complaint for some patients. One study of patients with Hodgkin's disease who had sweating as their only symptom found a correlation with unperceived elevations in body temperature, or minor febrile pulses.
Also keep in mind that in this context, minor sweating at night does not constitute night sweats. In order to be considered in the context of Hodgkin's, night sweats have to be of such a drenching nature that you wake up at least one time during the night and have to change your bed sheets because they are drenched in sweat.