Assessing the Early Progression and Survival of Follicular Lymphoma Patients Compared to the General Population from the GALLIUM Trial

Follicular lymphoma (FL) is a slow-growing type of non-Hodgkin lymphoma, a blood cancer that affects white blood cells called B lymphocytes. It is characterized by the abnormal growth of these B cells, which can form lumps or swellings in lymph nodes or other organs. FL is the second commonest lymphoma with favourable survival (>15 years) due to effective treatment. It is considered incurable with monoclonal antibody and chemotherapy treatment as patients typically have sustained remissions for years but most relapse with long follow up. There are three common chemotherapy options (bendamustine, CHOP (cyclophosphamide, doxorubicin, vincristine, prednisolone) and CVP (cyclophosphamide, vincristine, prednisolone)) with controversy regarding the optimal selection as they have different safety profiles and survival has been similar in prior trials. For patients achieving remission (absence of disease at the end of treatment), a focus is when they can expect the disease or treatment to no longer reduce their expected survival.

Considering the average age of diagnosis is 60, relative survival, the survival of a patient compared to the expected survival of an age-matched member of the general population, is an important issue. As front-line treatment improves, the expectation is that relative survival will improve; however, it may not ever be the same as the general population due to disease recurrence or the uncommon event of therapy-related mortality (i.e., death from infection or second cancer or another condition caused by chemotherapy).

The GALLIUM trial was a large (1202 patients) randomised trial in FL that demonstrated that obinutuzumab with chemotherapy was superior to rituximab with chemotherapy. There was an increased risk of infections and second cancers with bendamustine compared to CHOP/CVP; however, chemotherapy allocation was not randomised. The GALLIUM trial represents the largest randomised evidence with patient-level data to assess relative survival in patients treated with CHOP, CVP or bendamustine. The long-term follow of 8 years enables an assessment of the impact of FL and its treatment on survival relative to the general population.

We aim to compare the survival of patients to the general population, to compare the survival of patients receiving each chemotherapy to the general population, and determine if there is a timepoint after treatment where survival is similar to the general population. For patients in remission at defined timepoints (e.g., 1, 2, 3, 4 or 5 years after treatment), their survival will be compared to the general population using expected survival data from life tables. This information will be important for doctors at the time chemotherapy selection, for patient counselling and for helping to determine follow up and surveillance imaging strategies for patients in remission.