Borussia Dortmund striker Sebastien Haller says second operation to remove a testicular tumour 'went well' - and thanks medical staff for their 'daily help' - as former West Ham man continues cancer treatment

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Borussia Dortmund striker Sebastien Haller said a second operation to remove a testicular tumour was a success.

'A new step ticked off. Operation number two went well! A big thank you to the medical team for their daily help,' the 28-year-old wrote on Twitter on Thursday.

The 28-year-old has been undergoing chemotherapy after being diagnosed with testicular cancer in July.

Borussia Dortmund strike Sebastien Haller underwent surgery to remove a testicular tumour

Haller tweeted that a second op to remove a testicular tumour 'went well' on Thursday

Haller spent 18 months with West Ham after joining in 2019 for a then club-record £45million from Eintracht Frankfurt.

He moved to Ajax in January last year and signed for Dortmund this summer.

Haller has scored four goals in 15 appearances for Ivory Coast.

Haller had been training with former club Ajax as part of his recovery as he was rehabilitating in Holland. 

Haller also thanked medical staff for their' daily care' as he continues his cancer treatment

He signed for Dortmund over the summer but was diagnosed during their pre-season tour

After feeling unwell during Dortmund's pre-season tour of Switzerland, he underwent tests which revealed a malignant tumour. 

Haller is yet to make his debut for the Bundesliga giants and has previously opened up about the treatment he has undergone.

Speaking to UEFA last month, he revealed he has spent 'five days at a time at the hospital, where I am hooked up 24/7' and cannot get out of bed while the treatment is injected. He then has a two-week rest period.

'That's one phase, and I have to do that four times. Four phases of chemotherapy lasting roughly three weeks each,' he added.

'After that, depending on how my cancer is progressing and how it is spreading, I may be forced to undergo surgery.

Haller has remained positive during a course of chemotherapy to fight the cancer  

Haller watches Dortmund's Champions League game with Copenhagen from the stands

'A lot of people are asking me when I will be back, but there's a lot to take into account so it's hard to give them a straight answer.

Haller had previously spoken in August about how his family reacted to the news, with the former West Ham striker admitting his mother had struggled to come to terms with his diagnosis.

'My wife was in shock, but she could deal with it. But.. my mum.. it wasn't the same, because mothers are mothers,' Haller said in an interview with ESPN.

'I called my brothers and sisters to make sure they will be there for her, so that she wouldn't feel alone. This is what I have done.'

The striker starred at Ajax last season, netting 34 goals in all competitions for the Dutch side