Dr Spur's mystery case : connecting the dots in IEI : infections and tumours

I am seeing a 25-year-old female patient who has a history of frequent respiratory infections since adolescence. She had an uneventful childhood, but started getting infections of increasing frequency and severity during her adolescence, to the point where she required several antibiotic prescriptions per year, and hospital admission at least twice a year for pneumonia. She had chronic productive cough between pneumonia episodes, with features of early bronchiectasis. We diagnosed common variable immunodeficiency (CVID) and prescribed a prophylactic antibiotic. The patient is not using corticosteroids, immunosuppressant medications or anticonvulsants. She receives 75 mcg of L-thyroxine daily for hypothyroidism. While she reports no family members with frequent or atypical infections, there is a history of thyroid disease, inflammatory bowel disease (IBD), leukaemia and gastric cancer affecting several relatives. I saw her again this week, and she reports only minor upper respiratory infections over the past six months. There are no signs of anaemia, jaundice, oedema, clubbing or lymphadenopathy. However, I palpated an enlarged spleen and sonographic investigation confirmed splenomegaly with an estimated spleen size of 18 cm × 15 cm. I ordered a thoracoabdominopelvic CT scan which excluded hepatobiliary disease and lymphadenopathy. A sonar-guided splenic biopsy revealed diffuse large B-cell lymphoma (DLBCL). It appears to me that several immune system processes are simultaneously compromised in different members of this family including infection immunity, immunological tolerance and anti-tumour immunity. Is this new cancer diagnosis linked to the patient's known CVID diagnosis? If so, how should we adjust our follow-up care plan for this patient in future? Your guidance is appreciated.